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1
Wang, Ting. "Degradation and stabilisation of diisocyanate cured polybutadiene." Thesis, Aston University, 1992. http://publications.aston.ac.uk/9792/.
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Hydroxyl terminated polybutadiene (HTPB) has been used as a rocket propellant binder which is required to be stored for at least twenty years. It is found that the excellent stress-strain characteristics of this propellant can be totally lost, during this long storage, due to the deterioration of the polybutadiene chains. As a result, the propellant can not stand the service loads, which may lead to a catastrophe. The study of the HTPB binder degradation, below 80°C, has been carried out by investigating the environmental factors and the changes which occur along the macromolecular chains. Results have shown that oxygen is the main factor which causes the crosslinking and chain scission reactions. The former is the predominant reaction and proceeds rapidly under oxygen sufficient environment. The unsaturation of polymer chain, which provides the desired physical properties to the binder, was lost with the increase in crosslink density. At the same time hydroperoxides were found to form and decompose along the polymer chains. Therefore, the deterioration of the binder results from the oxidation of polymer chains. Since the oxidation reaction occurred at higher rate than oxygen diffusion rate and oxygen diffusion rate is inversely proportional to the crosslink density, the binder, below the surface layer in a thick section container, could be naturally protected under an oxygen deficient condition for a long time. Investigation of the effectiveness of antioxidants in HTPB binder has shown that the efficiency of an antioxidant depends on its ability to scavenge radicals. Generally, aromatic amines are the most effective binder antioxidants. But when a peroxide decomposer is combined with an aromatic amine at the appropriate ratio, a synergistic effect is obtained, which gives the lowest binder gel increase rate.
2
Giraud, Stéphane Bourbigot Serge Tighzert Lan. "Microencapsulation d'un diisocyanate et d'un phosphate d'ammonium." [S.l.] : [s.n.], 2002. http://www.univ-lille1.fr/bustl-grisemine/pdf/extheses/50376-2002-311-312.pdf.
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3
Mhike, Morgen. "Characterization of Methylene Diphenyl Diisocyanate Protein Conjugates." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1844.
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Diisocyanates (dNCO) such as methylene diphenyl diisocyanate (MDI) are used primarily as cross-linking agents in the production of polyurethane products such as paints, elastomers, coatings and adhesives, and are the most frequently reported cause of chemically induced immunologic sensitization and occupational asthma (OA). Immune mediated hypersensitivity reactions to dNCOs include allergic rhinitis, asthma, hypersensitivity pneumonitis and allergic contact dermatitis.
There is currently no simple diagnosis for the identification of dNCO asthma due to the variability of symptoms and uncertainty regarding the underlying mechanisms. Immunological sensitization due to dNCO exposure is traditionally thought to require initial conjugation of the dNCO to endogenous proteins to generate neoantigens, which trigger production of dNCO specific T lymphocytes and ultimately dNCO specific IgE. Testing for dNCO-specific IgE, for diagnosis of dNCO asthma is however, only specific (96-98%) but not sensitive (18-27%). The low prevalence of detectable dNCO specific IgE has been attributed to both assay limitations and a potential IgE-independent dNCO asthma mechanism(s). The identity of the conjugated proteins responsible for the sensitization also remains unknown. It is also not clear whether dNCOs bind to extracellular, cell membrane, or intracellular proteins as a way of triggering non-IgE asthma. Standardization and optimization of immunoassays used to screen for dNCO specific antibodies in sera is important if its utility as a dNCO asthma diagnostic tool is to be achieved. This will potentially improve sensitivity and allow comparison of results across studies. Current studies on assays of dNCO-specific IgE and IgG lack or have limited characterization of the conjugates used.
Diisocyanates bound to hemoglobin (Hb), human serum albumin (HSA), and THP-1 proteins were quantified by HPLC with fluorescence detection. Proteomic tandem mass spectrometry (MS) was used to delineate TDI and MDI specific amino acid binding sites on Hb as well as identification of proteins from MDI exposed THP-1 cells. The trinitrobenzene sulfonic acid assay (TNBS) and SDS gel electrophoresis were used to evaluate extent of intra and intermolecular cross-linking in dNCO-HSA conjugates. Binding of monoclonal antibodies (mAbs) to dNCO bound proteins in enzyme-linked immunosorbent assay (ELISA) was used to evaluate antigenicity of dNCO-protein conjugates.
The amount of dNCO binding to HSA and Hb increased with the concentration of the dNCO used for conjugation. All the dNCOs reacted with HSA more than with Hb. Eight binding sites were observed with both MDI and TDI on Hb. The N-terminal valines of both the alpha and beta subunits on Hb, lysine 40 of the alpha subunit and lysine 61 of the beta subunit were common binding sites for both TDI and MDI. Lysine 7 of the alpha subunit and lysines 8, 65 and 66 of the beta subunit were unique to MDI. On the other hand, lysines 11, and 16 of the alpha subunit and lysines 17 and 144 of the beta subunit were unique to TDI. Protein bound MDI was detected in a dose-dependent manner in membrane and cytoplasm fractions of MDI exposed THP-1 cells. MDI was also detected in 11 of the 13 cytoplasmic protein bands. The extent of MDI intracellular protein binding was not affected by cytochalasin D, a chemical that binds actin filaments and inhibits active uptake into cells. The extent of cross-linking shown using the TNBS assay was found to increase with amount of dNCO used. Clear bands from both intra and intermolecular cross-linking were observed on all dNCO-Hb/HSA SDS gels. Using ELISA, both TDI-Hb and TDI-HSA conjugates were reactive to monoclonal antibodies produced against TDI conjugated HSA indicating that dNCO-Hb is also antigenic.
The best characterization of dNCO-protein conjugates is achieved by the quantitative determination of conjugated dNCO per mole of protein as well as determining the extent of dNCO cross-linking. Although HSA is more reactive to dNCOs than other serum proteins such as Hb, contribution from other serum proteins to development of OA should not be overlooked as dNCO-Hb was found to be reactive to dNCO specific mAbs. dNCO-conjugated proteins identified in the soluble fraction of MDI exposed THP-1 cells were all of intracellular origin suggesting that MDI can cross the cell membrane and react with intracellular proteins. The entry of MDI into live cells is a passive process, as the extent of intracellular binding was not affected by cytochalasin D. The present study support the potential involvement of dNCO-haptenated membrane and intracellular proteins in development of non-IgE dNCO asthma.
4
Tardio, Sabrina. "The interaction of methylene diphenyl diisocyanate and related compounds with metallic surfaces." Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/811968/.
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Methylene diphenyl diisocyanate (MDI) is the most widely employed diisocyanate for the production of polyurethanes (PUs). This family of polymers is used for many applications including adhesives and coatings where an important characteristic is good adhesion. Considering how widely PUs are employed, the importance of MDI production in the world becomes evident. The phosgenation step, in the MDI production process, ultimately leads to fouling of the climbing �lm evaporators (CFEs) employed, resulting in the loss of their thermal e�- ciency. This work is concerned with the interactions between MDI (and related compounds) with metal substrates such as steels, which are employed in the CFEs as well as substrates for adhesion. For this study, surface analysis techniques, in particular X-ray photoelectron spectroscopy (XPS) and time of ight secondary ion mass spectrometry (ToF-SIMS), have been employed. Both substrates (316L and duplex steels) and adsorbates (MDI, polymeric MDI, methylene diphenyl amine and amine hydrochloride) have been characterised. The interaction between phenyl ring � electrons (present in MDI and related compounds) and metal have been studied by observing the XPS �-�� shake-up satellite at high spectral resolution. The interface between MDI and related compounds was then investigated. After the investigation of the model samples, plant facsimile samples were produced and analysed. Finally, actual plant samples were characterised. Proof was found of interaction between the phenyl ring � electrons and the silicon substrate, as well as the formation of covalent bonds at the interface between MDI and steel as a result of the reaction between isocyanate and metal oxides and hydroxides, present on the surface of the steel. The facsimile samples showed the same types of interactions observed in the model samples and it was also found that the corrosion of the metal strongly influences the adhesion and fouling mechanisms. The samples from the plant showed similarities with the model and facsimile samples, proving that they provide a good basis for understanding the real world scenario.
5
Rungvichaniwat, Adisai. "The structure-property relationships of water-dispersed polyurethanes based on tetramethyl xylene diisocyanate." Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/27146.
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Novel water-dispersed polyurethanes based on tetramethyl xylene diisocyanate (TMXDI), polycaprolactone or polytetramethylene glycols and alipbatic diamine chain extenders were synthesised. 2,2-bis(hydroxymethyl) propionic acid (DMPA) and triethylamine (TEA) were used respectively as potential carboxylic anionic emulsifying centres and neutralising agent in the resulting aqueous phase to form pendent quaternary ammonium salts. These were necessary to provide high hydrophilicity to the polyurethanes sufficient to make the polyurethanes easily dispersed in water without the assistance of organic solvent.
6
Descheres, Isabelle. "Cinétique et thermodynamique de polycondensation d'un polybutadiène hydroxytéléchélique radicalaire avec un diisocyanate aliphatique." Lyon 1, 1985. http://www.theses.fr/1985LYO19037.
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Microstructure du polybutadiene hydroxytelechelique arco r45m; cinematique et thermodynamique de la condensation, en solution et en masse de pbht r45m avec les isocyanates de propyle et de phenyle, en l'absence et en presence d'un catalyseur, le dilaurate de dibutyl etain; cinetique et thermodynamique de la polycondensation du r45m avec le diisocyanate d'hexamethylene en solution et en masse, avec ou sans catalyseur; tentative d'etablissement de quelques relations microstructure-prpprietes physico-mecaniques des polyurethannes en fonction des taux de conversion, de la nature du diisocyanate (aliphatique ou aromatique) et du mode de synthese (presence ou absence de catalyseur)
7
Vock, Esther Hilda. "The genotoxic potential of methylenediphenyl-4,4'-diisocyanate and methylene-4,4'-dianiline in the rat /." [S.l.] : [s.n.], 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11171.
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8
Kothari, Jehan. "Synthesis and Thermal Analysis of Hexamethylene Diisocyanate/Polyurea Formaldehyde Core/Shell Self-Healing Microcapsules." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504803190656406.
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9
Ruwona, Tinashe Blessing. "Production, Characterization and Possible Applications of Monoclonal Antibodies Generated against Toluene Diisocyanate-conjugated Proteins." PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/30.
Full textAbstract:
Diisocyanates are very reactive low molecular weight chemicals that are widely used in the manufacture of polyurethane products. Diisocyanate exposure is one of the most commonly reported causes of occupational asthma. Although diisocyanates have been identified as causative agents of respiratory diseases, the specific mechanisms by which these diseases occur remain largely unknown. Tandem mass spectrometry was used to unambiguously identify the binding site of isocyanates within four model peptides (Leu-enkephalin (Leu-enk, YGGFL), Angiotensin I (DRVYIHPFHL), Substance P-amide (RPKPQQFFGLM-NH2), and Fibronectin-adhesion promoting peptide (FAPP, WQPPRARI)). In each case, isocyanates were observed to react to the N-terminus of the peptide. No evidence of side chain/isocyanate adduct formation exclusive of the N-terminus was observed. However, significant intra-molecular diisocyanate crosslinking between the N-terminal amine and a side chain amine group was observed for arginine, when located within two residues of the N-terminus. Addition of multiple isocyanates to the peptide occurs via polymerization at the N-terminus, rather than addition of multiple isocyanate molecules to varied residues within the peptide. Toluene diisocyanate (TDI)-specific monoclonal antibodies (mAbs) with potential use in immunoassays for exposure and biomarker assessments were produced. A total of 59 unique mAbs were produced (29 IgG1, 14 IgG2a, 4 IgG2b, 2 IgG3 and 10 IgM) against 2,4 and 2,6 TDI bound protein. The reactivities of these mAbs were characterized by a solid phase indirect enzyme-linked immunosorbent assay (ELISA), Dot ELISA and Western immunoblot against various monoisocyanate, diisocyanate and dithioisocyanate protein conjugates. A subset of the mAbs were specific for 2,4 or 2,6 TDI-conjugated proteins only while others reacted to multiple dNCO conjugates including methylene diphenyl diisocyanate- and hexamethelene diisocyanate- human serum albumin . Western blot analyses demonstrated that some TDI conjugates form inter- and intra-molecular links resulting in multimers and a change in the electrophoretic mobility of the conjugate. In general, 2,4/2,6 TDI reactive mAbs displayed (1) stronger recognition of monoisocyanate haptenated proteins when the isocyanate was in the ortho position relative to the tolyl group, and were able to discriminate between (2) isocyanate and isothiocyanate conjugates (i.e. between the urea and thiourea linkage); and (3) between aromatic and aliphatic diisocyanates. The mAbs produced were not carrier protein specific with estimated affinity constants toward toluene diisocyanate conjugated human serum albumin ranging from 2.21 x 107 to 1.07 x 1010 M-1 for IgG mAbs. Studies using TDI vapor exposed lung and epithelial cell lines suggest potential utility of these mAbs for both research and biomonitoring of isocyanate exposure.
10
Haupt, Robert A. "Structural Determination of Copolymers from the Cross-catalyzed Reactions of Phenol-formaldehyde and Polymeric Methylenediphenyl Diisocyanate." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/22025.
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This work reports the elucidation of the structure of a copolymer generated by the cross- catalyzed reactions of PF and pMDI prepolymers. The electronic behavior of phenolic monomers as perturbed by alkali metal hydroxides in an aqueous environment was studied with 1H and 13C NMR. Changes in electronic structure and thus reactivity were related to solvated ionic radius, solvent dielectric constant, and their effect on ion generated electric field strength. NMR chemical shifts were used to predict order of reactivity for phenolic model compounds with phenyl isocyanate with good success. As predicted, 2-HMP hydroxymethyl groups were more reactive than 4-HMP in forming urethane bonds under neutral conditions and 2-HMP hydroxymethyl groups were more reactive than 4-HMP in forming urethane bonds under alkaline conditions.<br />The structure of the reaction products of phenol, benzyl alcohol, 2-HMP, and 4-HMP with phenyl isocyanate were studied using 1H and 13C NMR under neutral organic and aqueous alkaline conditions. Reactions in THF-d8 under neutral conditions, without catalyst, were relatively slow, resulting in residual monomer and the precipitation of 1,3-diphenyl urea from the carbamic acid reaction. The reactions of phenol, 2-HMP, and 4-HMP in the presence of TEA catalyst favored the formation of phenyl urethanes (PU). Reactions with benzyl alcohol, 2-HMP, and 4-HMP in the presence of DBTL catalyst favored the formation of benzyl urethanes (BU). Reactions of 2-HMP and 4-HMP led to formation of benzylphenyldiurethane (BPDU). DBTL catalysts favored formation of BDPU strictly by a benzyl urethane pathway, while TEA favored its formation mostly via phenyl urethane, although some BU was also present. Under aqueous alkaline conditions, 2-HMP was more reactive than 4-HMP, exhibiting an enhanced reactivity that was attributed to intramolecular hydrogen bonding and a resulting resonance stabilization of the phenolic aromatic ring. <br />ATR-FTIR spectroscopic studies generated real time structural information for model compound reactions of the cross-catalyzed system, differentiating among reaction peaks generated by the carbamic acid reaction, PU and BU formation. ATR-FTIR also permitted monitoring of propylene carbonate hydrolysis and accelerated alkaline PF resole condensation. ATR-FTIR data also showed that the overall reaction stoichiometry between the PF and pMDI components drove copolymer formation. Benzyl urethane formation predominated under balanced stoichiometric conditions in the presence of ammonium hydroxide, while phenyl urethane formation was favored in its absence. Accelerated phenolic methylene bridge formation became more important when the PF component was in excess in the presence of sufficient accelerator. A high percentage of free isocyanate was present in solid copolymer formed at ambient temperature. The combination of ammonium hydroxide and tin (II) chloride synergistically enhanced the reactivity of the materials, reducing the residual isocyanate.<br />From 13C CP/MAS NMR of the copolymer, the presence of ammonium hydroxide and tin (II) chloride and the higher PF concentration resulted in substantial urethane formation. Ammonium hydroxide favored formation of benzyl urethane from the 2-hydroxymethyl groups, while phenyl urethane formed in its absence. The low alkalinity PF resole with ammonium hydroxide favored benzyl urethane formation. Comparison of these results with the 13C NMR model compound reactions with phenyl isocyanate under alkaline conditions confirmed high and low alkalinity should favor phenyl and benzyl urethane formation respectively. These cross catalyzed systems are tunable by formulation for type of co-polymer linkages, reactivity, and cost.<br /><br>Ph. D.
11
Sivaraman, Karthik R. "Hexamethylene Diisocyanate Homopolymer and Monomer Exposure Assessment and Characterization at an Automobile Manufacturer in the United States." Thesis, University of South Florida, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10144696.
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<p> A variety of paint products are used for their aesthetic and anti-corrosive properties. Isocyanates are consistently found in automobile paint products, particularly in clear coat polyurethane products. Clear coat is typically sprayed via pressurized air by means of an auto-spray robot. In clear coat repair situations, manual, air-powered spray guns are used, and manual spray Operators administer the clear coat material. The isocyanates are a primary anti-corrosive agent in polyurethane products. The Occupational Safety and Health Administration (OSHA) has not established a Permissible Exposure Limit (PEL). The National Institute for Occupational Safety and Health (NIOSH) and American Conference of Governmental Industrial Hygienists (ACGIH) have set Recommended Exposure Limit (REL) and Threshold Limit Value (TLV), respectively. NIOSH recommends a 0.005 parts per million (ppm), 10-hour Time Weighted Average (TWA), and a ceiling exposure of 0.020 ppm in a 10 minute period. Similarly, ACGIH recommends a 0.005 ppm, 8 hour TWA. </p><p> Automobile manufacturers use clear coats in a variety of ways. Some may use clear coats with blocked isocyanates, or isocyanates that are completely reacted, and others may use clear coat products that allow isocyanates to be liberated during an application, baking, and curing process. The research objective of this study was to characterize exposure, focusing on a single manufacturer’s use of isocyanate-containing clear coats in their Paint Department. A newly evaluated medium (ISO 17734) using di-n-butylamine as a derivative agent, in a denuder tube, was selected instead of NIOSH methods 5521, 5522, and 5525. The ISO evaluated medium was selected to reduce secondary hazard exposure to toluene in impingers. Second, a medium developed by SKC, Inc., called ISO-CHEK®, was not selected because of the short collection time, sensitivity of the medium after collection, and storage and shipping requirements for analysis. </p><p> Sampling took place over two days, one day for manual spray operations with 2 personal samples from Operators, and 4 area samples collected, and the second day for auto-sprayer Inspectors with 4 personal samples collected. The samples were then analyzed for hexamethylene diisocyanates (HDI) monomer and homopolymer species. The 0.005 ppm, 10 hour TWA; the 0.020 ppm ceiling limit (10 minutes); and the 0.005 ppm 8-hour TWA TLV were not exceeded on either day of sampling. Neither the area nor the personal samples exceeded the 10 hour TWA, ceiling limit, or TLV. In fact, the results had to be recalculated in to parts per billion (ppb). The average exposure for manual spray Operators was 0.052 ppb for the homopolymer, and 0.024 ppb for the monomer species. For auto-spray Inspectors, the average was 0.053 ppb for the homopolymer component and 0.021 ppb for the monomer species. Though the average isocyanate concentration was similar for both Operators and Inspectors, the averages are still below REL and TLV recommendations. These data provided preliminary information regarding the exposure to isocyanates from clear coat use, and also provide context for future evaluation of isocyanate use at this automobile manufacturer. The low concentration of isocyanates could indicate working ventilation systems, liberation of isocyanate species to non-hazardous forms, or low volatilization of isocyanates from the clear coat.</p>
12
Sivaraman, Karthik Reguram. "Hexamethylene Diisocyanate Homopolymer and Monomer Exposure Assessment and Characterization at an Automobile Manufacturer in the United States." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6392.
Full textAbstract:
A variety of paint products are used for their aesthetic and anti-corrosive properties. Isocyanates are consistently found in automobile paint products, particularly in clear coat polyurethane products. Clear coat is typically sprayed via pressurized air by means of an auto-spray robot. In clear coat repair situations, manual, air-powered spray guns are used, and manual spray Operators administer the clear coat material. The isocyanates are a primary anti-corrosive agent in polyurethane products. The Occupational Safety and Health Administration (OSHA) has not established a Permissible Exposure Limit (PEL). The National Institute for Occupational Safety and Health (NIOSH) and American Conference of Governmental Industrial Hygienists (ACGIH) have set Recommended Exposure Limit (REL) and Threshold Limit Value (TLV), respectively. NIOSH recommends a 0.005 parts per million (ppm), 10-hour Time Weighted Average (TWA), and a ceiling exposure of 0.020 ppm in a 10 minute period. Similarly, ACGIH recommends a 0.005 ppm, 8 hour TWA.
Automobile manufacturers use clear coats in a variety of ways. Some may use clear coats with blocked isocyanates, or isocyanates that are completely reacted, and others may use clear coat products that allow isocyanates to be liberated during an application, baking, and curing process. The research objective of this study was to characterize exposure, focusing on a single manufacturer’s use of isocyanate-containing clear coats in their Paint Department. A newly evaluated medium (ISO 17734) using di-n-butylamine as a derivative agent, in a denuder tube, was selected instead of NIOSH methods 5521, 5522, and 5525. The ISO evaluated medium was selected to reduce secondary hazard exposure to toluene in impingers. Second, a medium developed by SKC, Inc., called ISO-CHEK®, was not selected because of the short collection time, sensitivity of the medium after collection, and storage and shipping requirements for analysis.
Sampling took place over two days, one day for manual spray operations with 2 personal samples from Operators, and 4 area samples collected, and the second day for auto-sprayer Inspectors with 4 personal samples collected. The samples were then analyzed for hexamethylene diisocyanates (HDI) monomer and homopolymer species. The 0.005 ppm, 10 hour TWA; the 0.020 ppm ceiling limit (10 minutes); and the 0.005 ppm 8-hour TWA TLV were not exceeded on either day of sampling. Neither the area nor the personal samples exceeded the 10 hour TWA, ceiling limit, or TLV. In fact, the results had to be recalculated in to parts per billion (ppb). The average exposure for manual spray Operators was 0.052 ppb for the homopolymer, and 0.024 ppb for the monomer species. For auto-spray Inspectors, the average was 0.053 ppb for the homopolymer component and 0.021 ppb for the monomer species. Though the average isocyanate concentration was similar for both Operators and Inspectors, the averages are still below REL and TLV recommendations. These data provided preliminary information regarding the exposure to isocyanates from clear coat use, and also provide context for future evaluation of isocyanate use at this automobile manufacturer. The low concentration of isocyanates could indicate working ventilation systems, liberation of isocyanate species to non-hazardous forms, or low volatilization of isocyanates from the clear coat.
13
Guney, Aysun. "Composition-property Relationship Of Pcl Based Polyurethanes." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614253/index.pdf.
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The desirable properties of polyurethanes (PUs) such as mechanical flexibility
associated with chemical versatility make these polymers attractive in the
development of biomedical devices. In this study, various segmented
polyurethanes were synthesized through polymerization reactions between
polycaprolactone (PCL) diol or triol and excess hexamethylene diisocyanate
(HDI) with varying NCO/OH ratios and the effect of composition on the
properties of the resultant polyurethane films were examined. Initially, isocyanate
terminated prepolymers were synthesized through one-shot polymerization, and
then these prepolymers were cured by introducing crosslinkages into the structure
and thus PUs were obtained. In order to enhance biocompatibility and
hydrophilicity of the resulting polymers, heparin was added into the prepolymer before the curing process. The influence of excess HDI as a crosslinker on the
degree of H-bond formation between hard-hard segments or hard-soft segments
was examined by using Fourier transform infrared-Attenuated total reflectance
spectroscopy (FTIR-ATR). Also the effects of HDI content on the chemical,
physical and mechanical properties of the polyurethanes were examined with
differential scanning calorimetry (DSC), X-Ray diffraction spectroscopy (XRD),
dynamic mechanical analyzer (DMA), mechanical tester and goniometer. FTIR-
ATR, DSC and DMA analyses showed that use of triol resulted in better network
formation and homogenous distribution of hard segments within soft segment
matrix. Incorporation of heparin into the polymer matrix produced more
hydrophilic films (water contact angle reduced from 80 to 60). Polyurethanes
from PCL and HDI in the absence of any solvent, initiator, catalyst or chain
extender were successfully synthesized and this kind of synthesis enhanced
biocompatibility and increased the potential of polymers for use in biomedical
applications.
14
Bucksch, Lars. "Sprühpolymerisation Herstellung von thermoplastischen Polyurethanpulvern durch Sprüh-Polyaddition." Berlin Wiss.-und-Technik-Verl, 2008. http://d-nb.info/992894336/04.
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Giraud, Stéphane. "Microencapsulation d'un diisocyanate et d'un phosphate d'ammonium : application : élaboration d'un systè́me polyuréthane monocomposant à propriété retardatrice de flamme pour l'enduction textile." Lille 1, 2002. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2002/50376-2002-311-312.pdf.
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Les enduits textiles polyuréthane (PU), présents dans de nombreux secteurs industriels, ont deux inconvénients. D'une part, leur mise en oeuvre est rendue délicate par la présence de fonctions isocyanates toxiques et très réactives. D'autre part, les procédés d'ignifugation utilisés pour les enduits PU ne sont pas totalement satisfaisants. Notamment les sels de phosphate d'ammonium, qui sont des additifs "retard au feu" (FR) non toxiques développant avec les PU un système intumescent, ont le défaut de migrer à travers les matrices polymère et d'ètre solubles dans l'eau. Nous avons développé deux solutions innovantes, basées sur le concept de la microencapsulation. La dispersion dans un polyol de microcapsules renfermant un diisocyanate liquide peut aboutir à une formulation PU monocomposant d'utilisation simple et sans danger. Les contraintes thermomécaniques des machines d'enduction permettent de libérer le diisocyanate au dernier moment<br>L'incorporation dans une formulation PU de phosphate d'ammonium encapsulé avec une membrane imperméable peut donner un caractère FR permanent à l'enduit. Cette étude est consacrée à la mise au point de procédés de microencapsulation, principalement selon la technique par polymérisation interfaciale, pour l'isophorone diisocyanate (IPDI) et pour le diammonuim hydrogénophosphate (DAHP). Différents paramètres expérimentaux ont étés maitrisés afin de donner aux deux types de microcapsules les caractéristiques déterminantes pou leur application : contrôle de leur taille, de leurs propriétés thermomécaniques et de la perméabilité de leur membrane. Après l'étude de la réactivité d'un mélánge microcapsules d'IPDI - polyol, nous sommes parvenus à synthétiser un PU solide avec une température de réaction peu élevée (80°C). Les microcapsules de DAHP donnent aux enduits PU appliqués sur tissu coton un réel effet retardateur de flamme, même si le char développé avec les microcapsules résiste un peu moins bien à la chaleur que celui avec le DAHP pur
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Fent, Kenneth W. Nylander-French Leena A. "Quantitative monitoring and statistical modeling of dermal and inhalation exposure to monomeric and polymeric 1,6-hexamethylene diisocyanate during automotive spray-painting." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1490.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.<br>Title from electronic title page (viewed Sep. 16, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Environmental Sciences and Engineering." Discipline: Environmental Sciences and Engineering; Department/School: Public Health.
17
Cui, Zhiying. "Denim Fiberboard Fabricated from MUF and pMDI Hybrid Resin System." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505281/.
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In this study, a series of denim fiberboards are fabricated using two different resins, malamine urea formaldehyde (MUF) and polymeric methylene diphenyl diisocyanate (pMDI). Two experimental design factors (1) adhesive content and (2) MUF-pMDI weight ratio, were studied. All the denim fiberboard samples were fabricated following the same resin blending, cold-press and hot-press procedures. The physical and mechanical tests were conducted on the fiberboard following the procedures described in ASTM D1037 to obtain such as modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), thickness swell (TS), and water absorption (WA). The results indicated that the MOE was significantly affected by both factors. IB was affected significantly by weight ratio of different glue types, with 17 wt% more MDI resin portion in the core layer of the denim boards, the IB for total adhesive content 15% fiberboard was enhanced by 306%, while for total adhesive content 25% fiberboard, enhanced by 205%. TS and WA, with higher adhesive content used in denim boards' fabrication, and more pMDI portion in the core layer of the boards, the boards' TS and WA was reduced by up to 64.2% and 78.8%, respectively.
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Zysk, Jaroslaw Grzegorz. "Composites thermoplastiques du LLDPE ou LLDPE/PP et Switch Grass : effets du polybutadiène diisocyanate et du peroxyde dicumyle sur les propriétés finales /." Trois-Rivières : Université du Québec à Trois-Rivières, 2004. http://www.uqtr.ca/biblio/notice/resume/24102831R.pdf.
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Zysk, Jaroslaw Grzegorz. "Composites thermoplastiques du LLDPE ou LLDPE/PP et Switch Grass : effets du polybutadiène diisocyanate et du peroxyde dicumyle sur les propriétés finales." Thèse, Université du Québec à Trois-Rivières, 2004. http://depot-e.uqtr.ca/1261/1/000123407.pdf.
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Durrieu, Vanessa. "Synthèse et caractérisation de dispersions aqueuses de polyuréthane." Phd thesis, Grenoble INPG, 2002. http://tel.archives-ouvertes.fr/tel-00010512.
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Ce travail de thèse a porté sur la synthèse et la caractérisation de dispersions aqueuses de polyuréthane. Les matières premières envisagées pour la synthèse ont tout d'abord été caractérisées et un procédé de fabrication adapté a été mis en place. Des dispersions de polyuréthane commerciales et leurs polymères ont aussi été caractérisés, afin d'établir une référence en terme de propriétés physico-chimiques (taille de particules, viscosité, température de transition vitreuse, énergie de surface). Les dispersions aqueuses de polyuréthane ont ensuite été synthétisées. Différents paramètres ont été analysés, tels que la nature du diisocyanate, le rapport NCO/OH, la nature du (ou des) diol(s) et leurs poids moléculaire, la proportion d'agent émulsifiant et son degré de neutralisation. Toutes ces dispersions ainsi que leurs polymères ont enfin été caractérisés afin de mettre en évidence des relations structures-propriétés.
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Edou, Engonga Prosper. "Greffage de chaînes hydrocarbonées et perfluorées sur le bois et étude des propriétés conférées aux nouveaux matériaux." Nancy 1, 2001. http://www.theses.fr/2001NAN10023.
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Les études menées au cours de ces travaux de recherche portent sur la mise au point de nouvelles méthodes de modification chimique du matériau bois basées sur l'utilisation de produits fortement hydrophobes tels que des composés à chaînes grasses ou perfluorées dans le but d'augmenter sa stabilité dimensionnelle ainsi que sa résistance aux microorganismes. La première partie concerne la modification chimique du bois à l'aide d'anhydrides impliquant soit des anhydrides symétriques perfluorés, soit des anhydrides mixtes obtenus à partir d'acides gras et d'anhydride trifluoroacétique. Après avoir vérifié la faisabilité de la réaction sur de la sciure, la transposition des différents traitements au cas d'éprouvettes de hêtre a permis de mettre en évidence dans le cas des spécimens traités une augmentation de la stabilité dimensionnelle, une augmentation du caractère hydrophobe de la surface ainsi qu'une augmentation de la résistance à Coriolus versicolor, particulièrement dans le cas de l'utilisation d'acides gras. La deuxième partie concerne le greffage d'alcools hydrophobes (alcools gras ou perfluorés) sur le bois en utilisant un diisocyanate comme maillon d'ancrage. Plusieurs stratégies ont été envisagées utilisant soit des mélanges alcool/diisocyanate, soit des monoadduits alcool-diisocyanate ou encore des adduits bloqués alcool-diisocyanate-oxime de butanone. Dans tous les cas les traitements conduisent à une hydrophobation de la surface, à une augmentation de la stabilité dimensionnelle et à une augmentation de la résistance aux microorganismes. Des études par microscopie électronique à transmission ont permis de localiser le greffage qui se situe principalement à la surface de la paroi secondaire et dans le lumen constituant une barrière hydrophobe à l'humidité et aux microorganismes.
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Pholosi, Agnes. "Synthesis, characterization and application of a novel biosorbent-magnetic nanomaterial cross-linked with cyclodextrin using epichlorohydrin and hexamethylene diisocyanate as adsorbents for heavy metals and organics." Thesis, Vaal University of Technology, 2019. http://hdl.handle.net/10352/412.
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D. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology<br>In the present era of water resources scarcity, efficient treatment of wastewater is a major prerequisite especially for growing economy. Numerous approaches have been studied for the development of cheaper and more effective adsorbents for removal of both organic and inorganic pollutants from wastewater. The present study seeks to harness the potential of biosorption and nanotechnology by producing more efficient, selective, mechanically stable and effective adsorbents for removal of organic and inorganic pollutants. The biosorbent-magnetic nanomaterial was synthesized by coating magnetite nanoparticles with sodium hydroxide treated pine cone by co-precipitation method. Magnetite coated pine bio-composite was then modified by cross-linking with hexamethylene diisocyanate and epichlorohydrin to the molecular recognition compound “cyclodextrin”. These novel biosorbent-magnetic nanoparticle materials were explored in overcoming the drawbacks of the biosorbent alone and selectively remove inorganic and organic pollutants from complex matrices.
The synthesized materials were characterized by several analytical techniques including, Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM–EDX), Transmission Electron Microscopy (TEM), Brunauer, Emmett and Teller Isotherm (BET) surface area analysis, X-ray Photoelectron Spectroscopy (XPS), Vibrating Sample Magnetometer (VSM) and pH at point of zero charge (pHpzc). Sodium hydroxide treated pine cone and magnetite coated pine cone were applied for both chromium(VI) and arsenic(III) adsorption while the magnetite coated pine cone, magnetite coated pine cone crosslinked to cyclodextrin using both epichlorohydrin and hexamethylene diisocyanate were applied for 4-nitrophenol removal from aqueous solution. Batch adsorption studies were performed to optimize operating parameters such as solution pH, adsorbent dose, contact time, temperature and initial concentration. Pseudo first, pseudo second, intraparticle diffusion, pore and film diffusion kinetic models were determined to investigate the mechanism of adsorption process. Coefficient of correlation, r2, and variable error, methods were also applied in the determination of the best fit of the kinetic method.
Structural characterization of magnetite coated pine cone and the magnetite coated pine crosslinked to cyclodextrin using 1,6-hexamethylene diisocyanate and epichlorohydrin were confirmed by characterization techniques applied. The adsorption of Cr(VI), As(III) and 4-nitrophenol was found to be dependent on the solution pH, adsorbent dose, initial concentration, temperature and ionic strength. Kinetic modelling revealed that the adsorption of Cr(VI), As(III) and 4-nitrophenol is controlled by pseudo second order kinetic model suggesting surface adsorption and intraparticle diffusion model. Intraparticle, pore and film diffusion models gave further insight into the controlling diffusion mechanism involved in the adsorption process for all pollutants investigated. Equilibrium studies indicated that the adsorption of all pollutants followed Langmuir isotherm indicating that adsorption sites are homogeneous in nature. The obtained thermodynamic parameters demonstrated that the adsorption of Cr(VI), As(III) and 4-nitrophenol were spontaneous, favourable and endothermic in nature. Anionic effect positively affected Cr(VI) and As(III) removal but had a negative effect on the 4-nitrophenol adsorption. Adsorption of 4-nitrophenol onto the nanocomposite adsorbents was attributed to multiple adsorbent-adsorbate interactions such as hydrogen bonding, hydrophobic attraction and guest host interaction. Magnetite coated pine better removed Cr(VI) and As(III) from aqueous solution than NaOH treated pine cone biomaterial while the magnetite coated pine crosslinked to cyclodextrin using 1,6-hexamethylene diisocyanate exhibited better adsorption performance for 4-nitrophenol removal than the nanocomposite crosslinked using epichlorohydrin and the magnetite coated pine cone.
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Maisonneuve, Lise. "Vegetable oils as a platform for the design of sustainable and non-isocyanate thermoplastic polyurethanes." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR15218/document.
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Cette thèse porte sur la synthèse de polyuréthanes thermoplastiques plus durables à partir de dérivés des huiles végétales. La première voie étudiée est basée sur la réaction, largement utilisée, entre un diol et un diisocyanate. Aussi, pour s’affranchir de l’utilisation des diisocyanates toxiques, une approche via la polyaddition entre un bis carbonate cyclique et une diamine a également été étudiée. Pour ce faire des précurseurs bi-fonctionnels : diols, bis carbonates cycliques à 5 et 6 chainons et diamines ont été préparés à partir de dérivés de l’huile de tournesol (oléate de méthyle) et de l’huile de ricin (undécénoate de méthyle et acide sébacique). Les propriétés thermo-mécaniques des polyuréthanes et poly(hydroxyuréthane)s thermoplastiques obtenus ont pu être ajustées par le choix adapté de la structure chimique des précurseurs (gras) utilisés. Les travaux réalisés démontrent un effet de la taille du cycle du carbonate sur la réactivité. En effet, les (bis) carbonates cycliques à 6 chainons se sont avérés plus réactifs que leurs homologues à 5 chainons. De plus, la synthèse de diamines via un intermédiaire dinitrile semble très prometteuse pour le « design » d’une plateforme de diamines issues d’acides gras et de poly(hydroxyuréthane)s entièrement bio-sourcés<br>This thesis aims to synthesize more sustainable thermoplastic polyurethanes from vegetable oil derivatives. The first route that has been investigated is based on the well-known reaction between a diol and a diisocyanate. Then to avoid the use of diisocyanates, the route via the polyaddition of a bis cyclic carbonate and a diamine have been studied as well. For this purpose, bifunctional precursors such as diols, bis 5- and 6-membered cyclic carbonates and diamines have been prepared from sunflower oil derivative (methyl oleate) and castor oil derivatives (methyl undecenoate and sebacic acid) The thermo-mechanical properties of the PUs have been modulated by designing and selecting the chemical structure of the (fatty acid-based) monomers. The performed model reaction kinetics revealed the higher reactivity of the 6-membered cyclic carbonates compare to the 5-membered ones. Finally, the developed route to fatty acid-based diamines via dinitriles synthesis in mild conditions was really efficient and this route is really promising to develop a fatty acid based-diamines platform and fully bio-based poly(hydroxyurethane)s
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Bellot, Muriel. "Expression et régulation des cytochromes P450 et des glutathion S-transférases pulmonaires sous l'effet des polluants." Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13008.
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Les cytochromes P450 (CYP) et les glutathion S-transférases (GST) sont des enzymes dont le rôle principal est la détoxication de l'organisme. Cependant, leur activité peut conduire à la formation de métabolites ayant à des effets pharmacologiques, toxicologiques ou inflammatoires. Dans le poumon, les connaissances sur l'expression des CYP et des GST restent limitées. Au cours de nos travaux, nous avons caractérisé le profil d'expression pulmonaire de ces enzymes chez deux espèces de rongeurs, le rat et la souris, et étudié leur régulation éventuelle par des polluants ou des médicaments. Nous avons montré, chez le rat, une diminution de l'expression du CYP 2B1 sous l'effet du diisocyanate de toluène (TDI) et une augmentation de l'expression du CYP 3A1 après exposition à l'ypérite, deux polluants atmosphériques responsables d'atteintes respiratoires. Chez la souris, nous avons mis en évidence une induction du Cyp 1a1 dans un modèle d'asthme au TDI et caractérisé l'expression pulmonaire des Cyp 3a après exposition à un glucocorticoi͏̈de, la dexaméthasone. Les CYP étudiés au cours de ces travaux sont impliqués dans la bioactivation des xénobiotiques (CYP 1A1), le métabolisme de substances endogènes (CYP 2B1) ou l'action des médicaments (CYP 3A). Une modification de leur expression et/ou leur activité sous l'effet des polluants ou des médicaments est donc susceptible d'avoir des conséquences sur la capacité de détoxication du poumon et sur le traitement des atteintes respiratoires d'origine toxique.
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Komorowska, Marta. "Luftprovtagning samt analys av mono- och diisocyanater." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-85247.
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When exposed to them, isocyanates can induce serious injuries in the respiratory tract and irritation on the skin and in the eyes. They are therefore interesting from the point of view of occupational health. The purpose of this thesis was to collect isocyanates in air with impinger-filter samplers and solvent free samplers. Furthermore the isocyanates were to be analyzed with liquid chromatography-mass spectrometry. The solvent free sampler consists of a polypropylene tube and filter holder fitted with glass fiber filters impregnated with derivatization reagent, coupled with a pump. The impinger-filter sampler was made out of an impinger flask, containing a derivatization solution, coupled in series with a filter holder and a pump. Di-n-butylamine was used as derivatization reagent in both samplers to stabilize the reactive isocyanates and to enable mass spectrometric detection. The solvent free sampler is highly advantageous because of its user friendliness during field measurements, as opposed to the impinger-filter method. An exposure chamber, equipped with two interior fans to ensure good circulation, was used to generate an atmosphere containing isocyanates. Analyzing the isocyanate-DBA derivates with LC-MS/MS worked very well and the method made it possible to detect isocyanate levels below 1 ng/mL. During quantification of isocyanates a standard curve with concentrations from 1 to 1000 ng/mL was used. Detection of isocyanate levels as low as one fifth of the limit value of some isocyanates was found to be possible, which would indicate that the methods are sensitive. Even though the solvent free sampler worked, the impinger-filter sampler was found to be more effective in collecting isocyanates. The coefficient of variation calculated from concentrations of isocyanates from the solvent free sampler varied between 0-35 %. The reason for this might be due to the fact that an optimized extraction method had not been tried out within the time limit of this project. Questions, identified during this thesis work, need to be answered before being able to obtain reliable results from field measurements with the solvent free sampler.
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Cardoso, Oldemar Ribeiro. "Prepara??o de resinas de poliuretana ? base de ?leo de mamona e dietanolamina." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17592.
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Previous issue date: 2007-10-30<br>Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico<br>The aim of this work was the preparation of polyols from reactions between castor oil and dietanolamine to increase the hydroxyl content and the network degree in the products to application in electronic devices. The polyols and the mixtures obtained were characterized by nuclear magnetic ressonance. Castor oil (CO) is a natural triglyceride - based polyol possessing hydroxyl groups, which allow several
reactions that produce many different products. Among them are the polyurethanes (PU), which have been considered an ideal product for the covering of electricelectronic circuits, due to their excellent electrical, shock-absorbing, solvents
resistance and hydrolytic stability properties. About 90% of the fatty acids present in the castor oil are ricinoleic acid (12-hydroxyoleic acid), while the remaining 10% correspond to non-hydroxylated fatty acids, mainly linoleic and oleic acids. The chemical analysis of castor oil indicates a hydroxyl number of 2.7. In this work, a polyol was obtained by the reaction of the CO with diethanolamine (DEA), in order to
elevate the hydroxyl value from 160 to 230 or to 280 mgKOH/g, and characterized by nuclear magnetic resonance (NMR) 1H and 13C (Mercury 200). The polyadition of the
resulting polyol with isophorone diisocianate (IPDI) was carried out at 60?C, and the reaction kinetics was followed by rheological measurements in a Haake RS150 rheometer. The electrical properties were determined in a HP LCR Meter 4262A, at 1.0 Hz and 10.0 KHz. The chemical analysis showed that the polyols obtained presented hydroxyl number from 230 to 280 mgKOH/g. The polyadition reaction with IPDI produced polyurethane resins with the following properties: hardness in the range from 45 shore A to 65 shore D (ASTM D2240); a dielectric constant of 3.0, at 25?C (ASTM D150). Those results indicate that the obtained resins present compatible properties to the similar products of fossil origin, which are used nowadays for covering electric-electronic circuits. Therefore, the PUs from castor oil can be considered as alternative materials of renewable source, free from the highly
harmful petroleum - derived solvents<br>O presente trabalho teve como objetivo a obten??o de poli?is a partir das rea??es do ?leo de mamona (OM) com dietanolamina (DEA), visando elevar o ?ndice de hidroxila e consequentemente o grau de reticula??o dos produtos finais, cuja aplica??o se destinou ao encapsulamento de circuitos eletroeletr?nicos. A caracteriza??o desses poli?is e respectivas misturas foram feitas utilizando-se a t?cnica da resson?ncia magn?tica nuclear (NMR). O OM (triglicer?deo do ?cido ricinoleico) ? um poliol vegetal natural por apresentar grupo funcional hidroxila que permite v?rias rea??es e produ??o de diferentes produtos. Entre eles est?o as
poliuretanas (PU) que t?m sido consideradas como produtos ideais para encapsulamento de componentes de circuitos eletro-eletr?nicos, devido as suas excelentes propriedades com rela??o ? resist?ncia mec?nica e qu?mica. As poliuretanas derivadas do ?leo de mamona podem ser consideradas materiais alternativos de fonte renov?vel e, para as produzidas neste trabalho, n?o foram empregados nenhum tipo de solvente. Cerca de 90% dos ?cidos graxos que
comp?em o ?leo de mamona s?o ?cido ricinoleico (?cido 12-hidroxioleico), enquanto os outros 10% s?o ?cidos graxos n?o hidroxilados (?cidos linoleico e oleico). As an?lises qu?micas do ?leo de mamona indicam uma funcionalidade m?dia de 2,7, em
rela??o aos grupos hidroxila. A poliadi??o entre o poliol resultante e o isocianato de isoforona (IPDI) teve sua cin?tica aco mpanhada com o aux?lio do re?metro Haake RS 150 ? temperatura de 60 ?C. As propriedades el?tricas foram determinadas em uma ponte HP LCR Meter 4262 A a 1,0 Hz e 10,0 KHz. As an?lises qu?micas mostraram que os poli?is obtidos apresentaram ?ndice de hidroxila entre 230 e 280
mgKOH/g. A rea??o de poliadi??o com IPDI produziu resinas de poliuretana com as seguintes propriedades: dureza entre 45 e 65 shore D (ASTM D2240); constante diel?trica de 3,0 a 25 ?C (ASTM D150). Os resultados, de um modo geral, indicaram que as resinas, cujo extensor de cadeia foi a DEA, apresentaram propriedades compat?veis e em muitos casos superiores, quando comparadas ?s dos produtos atualmente dispon?veis no mercado, sintetizados ? base de trietanolamina (TEA)
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Foster, Loren Lee. "Characterization of the Airborne Particulates Generated by a Spray Polyurethane Foam Insulation Kit." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5420.
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Spray Polyurethane Foam insulation (SPF) kits are currently being marketed and sold to do-it-yourselfers to meet various insulating needs. Like commercial SPF systems, the primary health concern with SPF kits is user overexposure to the isocyanates during product application. The potential health risk associated with SPF applications is driven by several factors including (but not limited to): the toxicity of isocyanates; the potentially high exposure intensity; the quantity of isocyanates used in the process; the enclosed nature of the environment in which the product could be applied; the potentially high exposure duration/frequency; and the limited availability of control measures to reduce agent intensity (e.g., personal protective equipment, dilution ventilation). To better understand the potential hazards associated with the use of SPF kits, the current study was designed to provide an initial characterization of user exposure to airborne particulate during the application process. Specifically, the study would aim to answer the following:
* What is the particle size distribution of the aerosol a SPF kit user is exposed to during application?
* What is the airborne particle mass concentration a SPF kit user is exposed to during application?
To answer these questions, a single commercially available SPF kit was selected for use and a mock residential environment was constructed to support repeated applications of SPF. Size-selective and total dust air sampling were conducted during the applications to determine the particle size distribution and mass concentration of aerosols generated by the selected kit. The particle size distributions developed from the size selective sampling results showed the presence of airborne particulate capable of penetration to the gas exchange regions of the respiratory tract. The average mass median diameter and geometric standard deviation of the particle size distributions were 4.6 µm and 2.7 respectively. The total dust sampling results showed mean airborne concentrations of 10.40 mg/m3. Based on the sampling results the study, personal air monitoring is needed to assess the degree of user exposure to methylene diphenyl diisocyanate (MDI) and to provide information for the selection of exposure control methods.
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Keskin, Selda. "Synthesis And Characterization Of Copolymers Of Diisocyanates And Dialcohol." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609995/index.pdf.
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This study was aimed to synthesize low molecular weight hydroxyl terminated polyurethane acrylate polymers that can be used in biomedical applications. Acrylate end capping via inter-esterification reaction was successfully achieved with the methacryloyl chloride addition to the hydroxyl ends of the polyurethane at low temperatures. Isocyanate terminated polyurethane acrylates were also synthesized for the sake of comparison. TDI, HDI and MDI were used as diisocyanates for urethane synthesis and they were end capped with MMA and HEMA. Nature of the monomers used had an effect on thermal, morphological, and rheological properties that were interpreted in terms of the level of hydrogen bonding and degree of phase separation. Synthesized polymers were characterized by NMR, FTIR-ATR, DSC, TGA, GPC, Mass Spectroscopy, SEM and rheometry.
In the literature, polyurethane acrylate polymers have been synthesized from the isocyanate terminated polyurethanes in which the urethane chains were ended with isocyanate groups. However, the toxicity of the isocyanate groups limited their biomedical applications especially in prosthetic dentistry as a soft lining material. Therefore, it is inevitable to explore the cytotoxicity of polyurethane acrylate polymers. For this purpose, silver nanoparticles that have an average particle size of 40 nm, were incorporated to the synthesized polymers. This addition, which intends to improve the degree of cytotoxicity, was successful to a certain extent.
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Sousa, Kenia Garrido Marques de. "Estudo Viscosimétrico de Soluções de Pré-Polímeros Uretânicos à Base de Poli(Glicol Propilênico) e Diisocianato de Isoforona." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=104.
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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro<br>Neste estudo, o comportamento em solução diluída de pré-polímeros uretânicos à base de poli(glicol propilênico) (PPG) e diisocianato de isoforona (IPDI) foi avaliado por medidas viscosimétricas a 30 C em dois tipos de solventes, com diferentes polaridades: isopropanol e tolueno. Os pré-polímeros foram sintetizados em massa, ou seja, na ausência de qualquer solvente, e nas formulações foram variadas as razões entre o número de equivalentes-grama de grupamentos isocianato e hidroxila [NCO/OH] e a massa molar do PPG. Os pré-polímeros foram caracterizados por espectrometria na região do infravermelho. No tratamento matemático dos dados viscosimétricos, foram empregadas cinco diferentes equações para determinar os valores de viscosidade intrínseca: Huggins; Kraemer e Schulz-Blaschke, por extrapolação gráfica; e Solomon-Ciuta; Deb-Chanterjee e; novamente, Schulz-Blaschke, para determinações por um único ponto. Os valores de viscosidade intrínseca obtidos pelos dois métodos (extrapolação gráfica e por um único ponto) foram comparados a fim de se verificar a validade da determinação por um único ponto para os sistemas analisados, bem como determinar qual equação seria a mais adequada para esse tipo de cálculo. Foram calculadas as constantes viscosimétricas de Huggins, Kraemer e Schulz-Blaschke, e foi feita uma análise da qualidade do solvente.<br>In this study the behavior of urethanes prepolymers based on poly(propylene glycol) (PPG) and isophorone diisocyanate (IPDI), in diluted solutions, were studied by viscosimetric measurements, at 30 C, in two types of solvents with different polarities: isopropyl alcohol and toluene. The prepolymers were synthesized in bulk, i.e, in the absence of solvent. In the formulations were varied the ratio between the equivalent-grams number of isocyanate functional groups and hydroxyl group [NCO/OH] and PPG molecular mass. The prepolymers were characterized by infrared spectrometry (FTIR). Five different equations were used to determine intrinsic viscosities values: Huggins; Kraemer and Schulz-Blaschke, by graphic extrapolation; and Solomon-Ciuta; Deb-Chanterjee and; again, Schulz-Blaschke, by a single point determination. The intrinsic viscosities values obtained by two methods (graphic extrapolations and through a single point determination) were compared in order to verify the validity of the single point determination for the systems studied, as well as the more accurate equation for this type of calculation. Viscometric constants from Huggins; Kraemer and Schulz-Blaschke equations were also determined to verify solvent quality.
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Silva, José Eduardo Estevam da. "Técnicas termoanalíticas aplicadas ao processo produtivo de painéis MDF : análises de fibras de madeira de eucalipto e resinas sintéticas termofixas /." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153553.
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Previous issue date: 2018-01-26<br>O processo de fabricação de painéis MDF é muito dinâmico e a todo instante surgem novidades tecnológicas buscando não somente otimizar custos de processo, mas incrementar novas características ou melhorar a resistência mecânica e usinabilidade. As fibras de madeira de eucalipto e as resinas termofixas como a uréia-formaldeído desempenham papel importantíssimo no contexto industrial. Um grande número de pesquisas e estudos se direciona a aperfeiçoar os processos de fabricação por meio do aprimoramento da matéria-prima. Muitos materiais foram desenvolvidos e adicionados tanto as fibras como as resinas sendo muito comum a busca por melhorias na resistência mecânica nas chapas MDF. A resina MDI (metileno difenil diisocianato), por exemplo, possui muitas vantagens conhecidas como a isenção de emissão de formol e a alta resistência a água, porém, outras características relacionadas à interação química com a madeira são pouco estudadas. Nesse contexto tecnológico, o presente trabalho se dedicou ao uso das técnicas termoanalíticas TG/DTG-DTA e DSC para investigar e compreender melhor a interação química entre as fibras de madeira de eucalipto e as resinas sintéticas termofixas e por fim, sugerir melhorias ao processo produtivo buscando assim, reduzir custos de fabricação. Além das técnicas termogravimétricas, a espectroscopia vibracional de absorção na região infravermelho médio com transformada de Fourier também foi usada para auxiliar na proposta reacional de polimerização e principalmente na identificação da estrutura química dos produtos gerados. Investigou-se também o processo de polimerização térmica do monômero MDI bem como sua degradação térmica seguindo as recomendações do ICTAC. As curvas TG/DTG-DTA mostraram que a polimerização foi incompleta em todas as resinas indicando a necessidade de ajustes no processo. A proposta reacional para as resinas UF e MDI está de acordo com os dados das curvas TG e espectros de MIR. A partir da polimerização da resina MDI sugeriu-se a formação de carbodiimidas como produto final. Ao final da pesquisa, algumas melhorias foram propostas como o aumento da temperatura da prensa e a diminuição da concentração de resina visto que na situação atual, a polimerização é incompleta e deixa resíduos nas chapas MDF. Comprovou-se também que as chapas fora de especificação podem ser usadas como biomassa combustível nas caldeiras em substituição ao cavaco de eucalipto, pois liberam mais calor quando estão em combustão.<br>The process of manufacturing MDF panels is very dynamic and at every moment technological innovations are emerging, seeking not only to optimize process costs, but to increase new characteristics or improve mechanical strength and machinability. Eucalyptus wood fibers and thermoset resins such as urea-formaldehyde play a very important role in the industrial context. A great number of researches and studies are directed at perfecting the manufacturing processes through the improvement of the raw material. Many materials have been developed and added to both fibers and resins, and the search for improvements in mechanical strength in MDF sheets is very common. MDI resin (methylene diphenyl diisocyanate), for example, has many advantages known as formaldehyde emission exemption and high water resistance, but other characteristics related to the chemical interaction with wood are little studied. In this technological context, the present work was dedicated to the use of TG / DTG-DTA and DSC thermoanalytical techniques to investigate and better understand the chemical interaction between eucalyptus wood fibers and thermosetting synthetic resins and, finally, to suggest improvements to the production process thus seeking to reduce manufacturing costs. In addition to the thermogravimetric techniques, the vibrational absorption spectroscopy in the medium infrared region with Fourier transform was also used to aid in the polymerization reaction proposal and mainly in the identification of the chemical structure of the generated products. The thermal polymerization process of the MDI monomer as well as its thermal degradation following the recommendations of the ICTAC were also investigated. The TG / DTG-DTA curves showed that the polymerization was incomplete in all resins indicating the need for process adjustments. The reaction proposal for the UF and MDI resins is in agreement with the data of the TG curves and MIR spectra. From the polymerization of MDI resin the formation of carbodiimides was suggested as the final product. At the end of the research, some improvements were proposed, such as the increase in the temperature of the press and the decrease of the resin concentration, since in the current situation the polymerization is incomplete and leaves residues in the MDF sheets. It has also been proven that non-specification sheets can be used as biomass fuel in boilers instead of eucalyptus chips, as they release more heat when they are in combustion.
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Tran, Ngoc-Buu. "Huile de ricin : polycondensation tridimensionnelle en masse avec des diisocyanates : gélification." Lyon 1, 1993. http://www.theses.fr/1993LYO10302.
Full textAbstract:
L'huile de ricin (hr) melange complexe de triglycerides naturels s'utilise comme polyol dans la synthese des polyurethanes (pu) reticules. En presence de diisocyanate (di) la reticulation de l'hr est uniquement due au triol triricinoleate de glycerol, composant majoritaire (67%). La cinetique de polycondensation en masse ne suit l'ordre 2 qu'en deca de 50% de conversion. La reaction-fortement ralentie pres du point de gel (pg) s'annule pratiquement au-dela. Du fait probable des cyclisations, les conversions critiques (p#c) observees aux pg sont superieures a celles calculees selon la relation de flory-stockmeyer. L'utilisation de la relation macosko-miller a permis la mise au point d'une methode de determination graphique de fw(oh), valeur generalement inconnue pour nombre de prepolymeres industriels. Fw(oh) peut aussi s'extrapoler des taux de gonflement a l'equilibre des gels de pu obtenus a differents rapports nco/oh. Aux temps critiques de transition sol-gel localises par cisaillement, les conversions different peu des p#c precedemment determines bien qu'il y ait presence de sol. Selon la nature des di, la tangente de l'angle de perte varie de 1 a 2. Enfin, les variations des taux de gel, de la densite de reticulation et du temps de relaxation magnetique transversale des protons en fonction de nco/oh passent des maxima aux alentours de nco/oh=1
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Larsen, Anna. "Återanvändning av kemiska riskbedömningar : Förutsättningar, fördelar och svårigheter." Thesis, KTH, Ergonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262023.
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Kemiska arbetsmiljörisker förekommer inom ett flertal branscher och behöver förebyggas för att skydda arbetstagare mot ohälsa, sjukdom och olycksfall. Det förebyggande arbetet görs genom att identifierade risker bedöms och kontrolleras med ändamålsenliga åtgärder, med målet att riskerna minskar eller helt försvinner. Att genomföra kemiska riskbedömningar är dock ofta både svårt och komplext med många olika aspekter att beakta och kräver både tid och kunskap. Som ett sätt att förenkla och effektivisera processen kring kemisk riskbedömning önskar Skanska, ett företag inom bygg- och anläggningsbranschen, se över om det är möjligt att återanvända kemiska riskbedömningar. Syftet med detta examensarbete blev därmed att utreda möjligheten i återanvändning av redan genomförda kemiska riskbedömningar där de kemiska produkterna ska användas igen. Utredningen har fokuserat på fördelar, hinder eller svårigheter och förutsättningar för återanvändning. Europeiskt och svenskt regelverk och vetenskaplig litteratur har genomlysts och data har samlats in från intervjuer med olika nyckelpersoner på tre arbetsplatser inom Skanska samt utifrån riskbedömningar av några utsedda produkter. Resultatet har därefter jämförts med svenskt regelverk, för att därigenom dra slutsatser om möjligheten i återanvändning av kemiska riskbedömningar. Examensarbetet har resulterat i slutsatsen att återanvändning av kemiska riskbedömningar bör vara möjlig, under förutsättning att de mallar eller checklistor som används som stöd uppfyller de krav som finns för kemisk riskbedömning. Det behöver säkerställas genom ändamålsenliga rutiner av personal med rätt kompetens om kemiska arbetsmiljörisker. Det behöver också stämmas av att exempelvis arbetssätt, omgivning och tillgången av åtgärder är likvärdiga på den arbetsplats som först genomfört riskbedömningen, och den arbetsplats som därefter återanvänder riskbedömningen, eller att dessa faktorer kan bli likvärdiga genom vidtagna åtgärder. Några risker eller hinder för återanvändning har identifierats. En av de mest framträdande riskerna är att kemiska arbetsmiljörisker förbises i samband med återanvändningen och därigenom också de åtgärder som behöver vidtas. Orsaker till detta kan vara bristande kunskap och engagemang eller möjligen fusk och slarv. I situationer där arbete ska ske med farligare kemiska produkter kan det vara svårare med återanvändning av riskbedömningar. Några fördelar med återanvändning bedöms vara förkortad tidsåtgång för kemiska riskbedömningar, en effektivare hantering, samt ett ökat stöd och lärande om kemiska arbetsmiljörisker genom att man lär av varandra och tidigare riskbedömningar. Möjligen kan återanvändning också bidra till att fler riskbedömningar genomförs, för att därigenom trygga yrkesarbetarnas säkerhet och hälsa.<br>Chemical risks in the work environment occur in several industries, and need to be prevented to protect workers from ill-health, illness and accidents. By performing risk assessments and taking appropriate measures, it is possible to reach the goal to reduce or even eliminate chemical risks. However, performing chemical risk assessments is often a quite difficult and complex issue with several different aspects to consider, requiring both time and knowledge. As a way to simplify and streamline the process of chemical risk assessment, Skanska, a company within the construction industry, wants to investigate whether it is possible to reuse chemical risk assessments. The purpose of this thesis was thus to investigate the possibility of reusing already performed chemical risk assessments in situations where the chemical products will be used again. The investigation has focused on the advantages, obstacles or difficulties and prerequisites for reuse. European and Swedish regulations and scientific literature have been reviewed and data have been collected from interviews with managers, safety representatives and employees at three workplaces at Skanska and from performed risk assessments of some selected products. Thereafter, the results have been compared with Swedish regulations, in order to draw conclusions about the possibility of reusing chemical risk assessments. The conclusion is that it should be possible to reuse chemical risk assessments, provided that the templates or checklists used as a support meet the requirements for chemical risk assessments. This needs to be ensured through appropriate routines by personnel with the right expertise about chemical risks in the work environment. It must also be ensured that some factors, as way of working, the work environment and measures taken, need to be similar for the workplace first performing the risk assessment, and the workplace that will reuse the same risk assessment, or at least that these factors can become similar after measures taken. Some risks or obstacles of reusing chemical risk assessments have been identified. One of the most prominent risks is that chemical hazards will be missed and thereby also the measures that need to be taken. This may be due to lack of knowledge and commitment or possibly cheating or carelessness. In situations where more hazardous chemical products are being used, it may be more difficult to reuse risk assessments. Some benefits of reusing risk assessments may be less time required for chemical risk assessments, more efficient management and increased support and learning about chemical hazards by learning from each other and previous risk assessments. Possibly, reuse can also contribute to more risk assessments being carried out, thereby ensuring the safety and health of professional workers.
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Sagnier, Cathy. "Polyimide-amides - polycondensation avec les diisocyanates : microstructure - mécanismes de formation - mécanismes de dégradation thermo-oxydante." Lyon 1, 1995. http://www.theses.fr/1995LYO10260.
Full textAbstract:
Des polyimide-amides (pia) aromatiques de hautes masses s'obtiennent par polycondensation simultanee d'un diisocyanate, d'un acide-anhydride et de deux diacides dans la n-methyl pyrrolidone (nmp) ou la dimethyl-n,n' ethylene uree (dmeu) a 185c. La rmn #1h et #1#3c a haute temperature permet l'etude de la microstructure et de la composition des pia. Elle conclut a une distribution statistique des motifs imide et amide, a la presence de structures intermediaires en tres faible quantite qui induisent un deficit en fonction imide par rapport a la theorie. Il n'y a pas de difference d'ordre microstructural entre les pia synthetises dans la dmeu ou la nmp. Par sec, la distribution quasi-gaussienne des masses molaires du pia-dmeu indique une polycondensation classique tandis que le chromatogramme du pia-nmp est plurimodal. Sa masse moyenne en poids est superieure a celui du pia obtenu dans la dmeu. En utilisant un detecteur a diffusion de la lumiere, on montre que le pia-nmp est tres compacte. L'etude par rmn #1#3c et dosage chimique de prelevements au cours de la polycondensation permet de suivre l'evolution des fonctions (anhydride + isocyanate), acide, amide, imide et uree. On montre que les fonctions amide se forment plus rapidement que les fonctions imide. Ces dernieres sont toujours en deficit du fait de la presence de structures intermediaires. Ces resultats permettent de proposer des mecanismes reactionnels de formation des amides (reaction acide + isocyanate) et des imides (reaction anhydride + isocyanate). Les mecanismes de degradation thermo-oxydante sont reveles par l'identification des produits volatils et par l'evolution de la structure du pia au cours d'un vieillissement thermique. Les fonctions methyleniques du modif mdi - instables - se degradent tres tot selon deux mecanismes. Nous avons principalement oxydation des ch#2 en co cetone mais aussi rupture de la liaison ch#2-phenyle pour former des fins de chaines en methyle. Nous avons pu montrer egalement que le pia est moins sensible a la chaleur qu'a l'action conjuguee de la chaleur avec l'oxygene de l'air
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Maratini, Federica. "Monitoraggio ambientale e biologico per la determinazione dell'esposizione occupazionale a diisocianati." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424948.
Full textAbstract:
The research project focused on the development and validation of an analytical method for the combined determination of the concentration in ambient air of 3 of the most used diisocyanates in the workplace: 1,6-hexamethylene diisocyanate (1,6-HDI) , 4,4'-diphenylmethane diisocyanate (4,4'-MDI) and 2,6-toluen diisocyanate (2,6-TDI). The analytical method was developed based on procedures indicated by the Occupational Safety and Health Administration (OSHA, ID OSHA 42 and ID OSHA 47) using high performance liquid chromatography coupled with a fluorimetric detector. The method has been validated and has been shown to have adequate sensitivity and precision for the analysis of real samples, in the context of environmental monitoring for the determination of the airborne concentrations of these substances. The method was then applied in determining the environmental concentration levels of 1.6-HDI, 4,4'-MDI and 2,6-TDI, as part of two monitoring campaigns, in two different work contexts.
A further aim of the research project was the development and validation of analytical methods for the determination of urinary concentrations of 1,6-HDI, 4,4'-MDI and the two TDI isomers, 2, 4- and 2,6-TDI, or the corresponding diamines. For this purpose, gas chromatography coupled to the mass spectrometer detector was used as a separation and analytical identification technique. The method was identified starting from a comparison of the scientific literature on the subject and the indications provided by one of the most important sector agencies, the American Conference of Governmental Industrial Hygienists (ACGIH). The optimal analytical conditions were identified by conducting a series of tests, first in organic solvent and then in the urinary matrix of subjects not professionally exposed to diisocyanates or solvents. The urinary test matrix was treated by high temperature acid hydrolysis, as indicated by the majority of the work reported in the literature and in accordance with the indications in the ACGIH Documentation for the analysis of urinary samples of workers exposed to TDI and HDI. The 3 methods developed have been validated and have returned a sensitivity and precision appropriate to the determination of the concentration levels of the diamines of diisocyanates covered by the present research project. To date, it has been possible to apply these methods for the evaluation of the recorded internal dose for samples of patients exposed to bronchial provocation tests specific for the diagnosis of occupational asthma.<br>Il progetto di ricerca si è incentrato sulla messa a punto e sulla validazione di una metodica analitica per la determinazione combinata della concentrazione in aria ambiente di 3 dei diisocianati maggiormente utilizzati in ambito lavorativo: 1,6-esametilen diisocianato (1,6-HDI), 4,4’-difenilmetano diisocianato (4,4’-MDI) e 2,6-toluen diisocianato (2,6-TDI). Il metodo analitico è stato sviluppato a partire da procedure indicate dall’Occupational Safety and Health Administration (OSHA; ID OSHA 42 e ID OSHA 47) utilizzando la cromatografia liquida ad alte prestazioni accoppiata a un rivelatore fluorimetrico. Il metodo è stato validato e ha dimostrato di avere sensibilità e precisione adeguate per l’analisi di campioni reali, nell’ambito di monitoraggi ambientali per la determinazione delle concentrazioni aerodisperse di tali sostanze. Il metodo è stato quindi applicato nella determinazione dei livelli di concentrazione ambientale di 1,6-HDI, 4,4’-MDI e 2,6-TDI, nell’ambito di due campagne di monitoraggio, in due diversi contesti lavorativi.
Ulteriore scopo del progetto di ricerca è stata la messa a punto e la validazione di metodiche analitiche per la determinazione delle concentrazioni urinarie dei metaboliti dell’1,6-HDI, del 4,4’-MDI e dei due isomeri del TDI, 2,4- e 2,6-TDI, ovvero le corrispondenti diammine. A tal fine è stata utilizzata come tecnica di separazione ed identificazione analitica la gascromatografia accoppiata al rivelatore spettrometro di massa. La metodica è stata individuata a partire da una comparazione della letteratura scientifica sull’argomento e dalle indicazioni fornite da una delle agenzie di settore di maggiore rilievo, l’American Conference of Governmental Industrial Hygienists (ACGIH). Le condizioni analitiche ottimali sono state individuate conducendo una serie di prove, prima in solvente organico quindi in matrice urinaria di soggetti non esposti professionalmente a diisocianati o a solventi. La matrice urinaria delle prove è stata trattata mediante idrolisi acida ad alta temperatura, come indicato dalla maggioranza dei lavori riportati in letteratura ed in accordo con quanto indicato nella Documentation ACGIH per l’analisi dei campioni urinari dei lavoratori esposti a TDI e a HDI. I 3 metodi messi a punto sono stati validati ed hanno restituito una sensibilità ed una precisione adeguate alla determinazione dei livelli di concentrazione delle diammine dei diisocianati oggetto del presente progetto di ricerca. Ad oggi è stato possibile applicare tali metodiche per la valutazione della dose interna registrata per campioni di pazienti esposti a test di provocazione bronchiale specifici per la diagnosi di asma professionale.
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Holánová, Iveta. "Detekce a laboratorní kontrola úniků nebezpečných chemických látek do životního prostředí s nutností výjezdu chemické laboratoře HZS." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-232723.
Full textAbstract:
The diploma thesis is focused on a detection and a laboratory control of hazardous substances’ leak into the environment. These hazardous substances are classified. Further, it aims to chemical laboratories of the fire-brigade of the Czech Republic, as well as which place they hold in the fire-brigade system, and it indicates their main duties. This diploma thesis contains a review of some essential types of devices and mediums, which are in terms of the fire-brigade of the Czech Republic usable to practice the detection, determination and assessment of the hazardous substances in various figures of the environment in terrain, i.e. filling of duties of the chemical survey. The output of this diploma thesis is simulation of leaks of the toluene diisocyanate using ALOHA software, TerEx software and Rozex Alarm software. Further on, the proposal of another methodical sheet focused on leak actions of the concrete hazardous industrial substance – toluene diisocyanate. This methodical sheet could therefore broaden pro tempore elaborated sheets for chlorine and ammonia.
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Zhang, Tianle. "Synthesis, characterization and properties of new low-valent palladium and platinum clusters of diarsine and diisocyanide ligands." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0018/NQ57012.pdf.
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Lin, Hsi-Chen, and 林希貞. "Evaluation of Samplers for Toluene Diisocyanate." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/92222910812711769946.
Full textAbstract:
碩士<br>國立交通大學<br>環境工程所<br>91<br>This study was carried-out to compare the performance of five kinds of sampler for toluene diisocyanate (TDI), i.e. triple filter system (TFS), annular denuder system (ADS), dual filter system (DFS), open-face filter cassette (OFFC) and closed-face filter cassette (CFFC). Laboratory tests showed that there was no obvious difference between two relative humidities with different media. Further, it can say that the lon-ger the sampling time, the faster the concentration of 2,4-TDI decreased. The loss rate of TDI during the chamber runs followed first order decay behavior.
The field comparison study was carried-out in a polyurethane foam factory situ-ated in Taichung, Taiwan during September to October 2002. Sampling was perform-ed at different time intervals to study the time effect on sampling concentrations. The results show that the concentrations of total TDI estimated by the TFS are comparable to those by the ADS and other filter systems. The comparison with ADS shows that TFS works well with 15-min sampling period, which is the standard duration for TDI sampling. The test data prove the reliability of TFS in the field sampling of TDI. It is a convenient system for the simultaneous sampling of vapor- and aerosol-phase TDI, and derivatives of other isocyanates
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Chen, Hseuh-Yong, and 陳學永. "Non-phosgene Route to 4,4''-Methylenediphenylene Diisocyanate." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/54394495260539543874.
Full textAbstract:
碩士<br>國立中興大學<br>化學工程學系所<br>99<br>A two-step non-phosgene process of making 4,4’-methylene diphenylene diisocyanate (4,4’-MDI) from 4,4’-methylene dianiline (4,4’-MDA) has been developed in this research. In the first step, MDA was treated with diphenyl carbonate (DPC) in the presence of a carboxylic acid to form N,N’-diphenyl-4,4’- methylenediphenylene biscarbamate (4,4’-DP-MDC). This was followed by a hermolysis step to convert into 4,4’-MDI and phenol.
In the first carbonylation step of 4,4’-MDA, catalytic behaviors of carboxylic acids were investigated by checking the effects of pKas of the acids used, dosages of the acid, concentration of DPC and recyclability of the acid. Above all, the catalytic mechanism of carboxylic acid in the carbonylation process was clarified and realized that “carbonic carboxylic anhydride” intermediate might be involved and was in-directly proven by the addition of a tertiary amine. Now, in the new improved synthesis, 99% of 4,4’-DP-MDC has been prepared at 45 ℃ instead of 80 ℃.
In the second themolysis step, 4,4’-MDI was successfully cracked into MDI and phenol in n-dodecane solution at 210 ℃ over 2.5 hours. A small amount of benzoyl chloride seems essential in preventing MDI from forming carbodimide side-products at 100% conversion. Pure MDI in over 75% were isolated either by vacuum distillation under reduced pressure or through a low temperature crystallization step. About 95% of n-dodecane and phenol could be recovered from the process.
Through this non-phosgene route, we have successfully avoided using phosgene completely from the process. It appears that quality of 4,4’-MDI also has been improved showing little halogenated by-products. During this safety and pollution highly conscious time, we hope that this process can be practically applied in the industrial scale.
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Kao, Ming-Jen, and 高名人. "The Assessment of the Relationships Between Toluene Diisocyanate and Occupational Asthma." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/28622918076848112686.
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碩士<br>國立成功大學<br>環境醫學研究所<br>86<br>In Taiwan area, it thinks highly of occupational health
day by day. But , until now, it is not sure about the incidence
of occupational asthmaand there is no any study about this. The
relationship between occupational exposure and asthma is not
mere, it dependent on human sensitivity, exposure density,
exposure time, exposure channel...etc. Toluene diisocyanate
(TDI) is a highly reactive chemical used primarily in the
polyurethane industry. A number of important medical
consequences of TDI are neurological sequelae and pulmonary
toxicity. The diagnosis of TDI-induced asthma largely relies on
a comprehensive history and physical examination. In addition to
obtaining a detailed occupational history, specific laboratory
test can be helpful. This study was done in randomsampling at 7
plants that use TDI in the manufacture of polyurethane. The
assessment included a respiratory symptom questionnaire,
spirometry, Eotaxin. Recommendations include a stepwise approach
to diagnosing TDI-induced asthma in exposured workers and
differential diagnosis between TDI-induced asthma and common
asthma. 2 of these 58exposured workers(3.45%) had a significant
cross-shift decrease in forcedexpiratory volume in one second
and had sympyion of occupational asthma. 3 of 80 exposure
worker(3.75) had positive reaction in eotaxin, but normal in
pulmonary. In addition, assessment of exposure rectified by
expert system was used in this study It may utilized widely in
future epidemiological studies.
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Pan, Jun-Ming, and 潘俊銘. "Determination of diisocyanate-related diamines by liquid chromatography-tandem mass spectrometry." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/w3f433.
Full textAbstract:
碩士<br>高雄醫學大學<br>醫藥暨應用化學研究所<br>102<br>Isophorone diisocyanate(IPDI), 2,6-toluene diisocyanate(2,6-TDI), 2,4-toluene diisocyanate (2,4-TDI), 4,4’-methylene diphenyldiisocyanate (MDI) and 1,5-naphthalene diisocyanate (NDI) are important sources of polyurethane(PU) productions. Diisocyanates have been researched about occupational asthma and respiratory diseases. Currently, the main methods for determination of diisocyanate exposure are determination of the concentration of diisocyanate in air or the diisocyanate metabolites which are diisocyanate related diamines protein adduct in human urine. The main diisocyanate-related diamines are Isophorone diamine(IPDA), 2,6-toluene diamine(2,6-TDA), 2,4-toluene diamine(2,4-TDA), 4,4′-diaminodiphenylmethane(MDA) and 1,5-diamino naphtha-lene(NDA).
In this study, we developed microwave method for diisocyanate related diamines protein adduct hydrolysis and a simple and sensitive method with liquid chromatography-tandem mass spectrometry to determine the diisocyanate-related diamines, IPDA, 2,6-TDA, 2,4-TDA, MDA and NDA.
In the study, there are many effects of intensity for determination of IPDA, 2,6-TDA, 2,4-TDA, MDA and NDA, such as the formic acid addition in solvent, the solvent proportion of methanol and H2O. There are many effects of work-up procedure for urine sample, such as equivalent of acid and base, microwave power and irradiation time, volume of toluene. All were discussed in this study. The application of the method for human urine which determine IPDA, 2,6-TDA, 2,4-TDA, MDA and NDA were evaluated the concentrations over range of 1-50 ng/mL IPDA, 2,6-TDA, 2,4-TDA, NDA and 0.5-25 ng/mL MDA. The linear correlation coefficient are greater than 0.999. The detection limit are 0.025 ng/mL IPDA, 0.4 ng/mL 2,6-TDA, 0.1 ng/mL 2,4-TDA, 0.025 ng/mL NDA and 0.025 ng/mL MDA (S/N=3, injection volume 10 μL) The intra-day relative standard deviation (R.S.D) and the inter-day intra-day relative standard deviation (R.S.D) were below 6.5 % and 11.7 %, the relative error (R.E) were below 7.1 % and 7.0 %
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Li-MingChin and 秦禮銘. "Redox Modulation for the Treatment of Toluene Diisocyanate-induced Lung Inflammation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/98928332696548792208.
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YUAN, YANG MIN, and 楊敏原. "Study of Mechanical Properties of Polyurethane Based on Polyols and Toluene Diisocyanate." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/84040663559600044337.
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碩士<br>靜宜大學<br>應用化學系<br>89<br>Polyurethanes have been prepared from TDI and two kinds of polyols, PPG and PTMEG, based on two polyols PPG (polypropylene glycol) (diol or triol) or PTMEG (polytetramethylene ether glycol) and TDI(toluene diisocyanate) were synthesized in various concentrations of extender MOCA(3,3’-dichloro-4,4’-diamino-diphenylmethane) with different equivalent ratio NCO/OH 1.04~1.44, and at different temperature .The mechanical and physical properties including tensile strength, hardness, tear strength, elasticity ,resistant abrasion, resistant acid and alkali properties, etc. were examined.
PTMEG/TDI system illustrates highest tensile strength, tear strength, and elongation at break; however, PTMEG/TDI prepolymer system shows highest viscosity. Increasing NCO/OH equivalent ratio tends to increase the tensile strength and to decrease elongation
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Tung, J. C., and 董人傑. "Studies on the synthesis and properties of polyamide-imide (by diisocyanate method)." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/94242443233099408007.
Full textAbstract:
碩士<br>中原大學<br>化學工程研究所<br>82<br>Polyimides have excellent mechanical properties and thermal
stablilty. It has been widely used in electronic products,
aerospace and enamelled wires. The disadvatages of polyimides
are expensive and processing difficulty due to the high glass
transition temperature (Tg) and poor solubility. In this
study, we use diisocyanate method to form polyamide-imides, to
improve the processing ability with less adversely effects on
the mechanical properties and thermal stability. Six different
diisocyanates : TODI, MDI, TDI, XDI, H12MDI and HDI were used
as the raw material to react with trimellitic anhydride, TMA,
in N-methylpyrrolidone (NMP) at 160oC to prepare polyamide-
imides. The dynamic-mechanical, thermal and thermal stability
properties were characterised by using DMA, DSC and TGA,
respectively. The electric properties will examined on
enamelled wires by following the JIS C 3003 standards. From DSC
results, the polymer with higher imide content (TDI-TMA) and
good structure symmtry (MDI-TMA) display higher Tg than that
with lower imide group content and poor structure symmetry
(TODI-TMA). The DMA data show the dynamic-mechanical
properties of (TDI-TMA) and (MDI-TMA), they have storage
modulus of 2×109 N/m2 at 50oC and fall to 1×108 N/m2 at
200oC. The TGA data show the polymer based on aromatic
diisocyanates have better high temperature stability than those
based on aliphatic diisocyanates. The electric properties
test on MDI-TMA based enamelled wires display good electric
properties with no pin holes, low dissipation factor, tand, and
good dielectric strength(4.8 kV).
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Lin, Wei-Hsing, and 林維興. "An Efficient One-Pot Synthesis of Aliphatic Diisocyanate from Diamine and Diphenyl Carbonate." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/8dy5z5.
Full textAbstract:
博士<br>國立中興大學<br>化學工程學系所<br>103<br>A non-phosgene route (NPR) of making aliphatic diisocyanates has been developed through synthesis and thermolysis of diphenyl N,N’-alkenylbiscarbamates (diphenyl biscarbamates). Four diphenyl biscarbamates were prepared readily by carbonylation of three aliphatic diamines and one aryl aliphatic mixed diamine with the carbonylation reagent diphenyl carbonate (DPC) in 1,2-diethoxyethane (EGDEE) under mild conditions. Pure diphenyl biscarbamates were isolated in >90% for each case. Thermolysis of individual diphenyl biscarbamate in diphenyl ether solution at 240~255 oC readily cracked them into four respective diisocyanates and recovering phenol. In this study, 1,12-dodecamethylene diisocyanate (DDI) gave the highest isolation yields (84 %) through fractionation. The yields of 1,6-hexamethylene diisocyanate (HDI), 1,4-butamethylene diisocyanate (BDI) and 1-isocyanato-4-(isocyanatomethyl)benzene (4-IBPI) were slightly lower (~76 %) with by-products consisting of isocyanate oligomers. More notable than high yields, we succeeded in developing a one-pot two-stage NPR process in diphenyl ether solution by first synthesis of biscarbamate followed immediately by thermolysis in the same solution. Excellent yields of DDI (80 %) and isophorone diisocyanate (86 %) along with HDI (71 %) were prepared in the one-pot synthesis. Thus, a general green-chemical process has been developed for aliphatic diisocyanate without using toxic phosgene or any undesirable metal catalysts.
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Yeh, Hui-Jung, and 葉慧容. "Investigation of the relationship between the exposure to toluene diisocyanate (TDI) and biomarker." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74894806363285371221.
Full textAbstract:
博士<br>國立成功大學<br>基礎醫學研究所<br>95<br>Toluene diisocyanates (TDIs) are widely used in the production of polyurethane (PU). TDIs have been documented to cause occupational asthma. Up to the present time, three issues, however, are still waiting for further investigation with respect to TDI-related occupational health: (1) to determine the general exposure scenario among various TDI-related industries; (2) to develop a method accelerating the urine analysis in biological monitoring of TDIs exposure； and (3) to affirm skin absorption of TDIs.
In summary, the objectives of this study were to determine the nationwide 2,4- and 2,6-TDIs exposure profile on an industry-specific basis by a systematic survey. The results showed a significant difference in TDIs concentrations among three industries and PU foam with the highest TDIs concentration. Moreover, the TDIs could easily expose workers to TDIs via skin contact during the manufacturing processes e.g. charging and foaming. The findings hypothesized that TDIs skin exposure could results in skin absorption, but warrant a more thorough study to affirm. A rat model was used to evaluate the skin absorption to explore the dose-response pattern and determine the kinetic characteristics of U-TDAs during skin exposure. We confirmed that skin absorption of TDIs through skin contact and there is a clear dose-response fashion. U-TDAs concentrations via skin exposure reveal the first-order elimination kinetics and the apparent half-lives are about 20 hr. An attempt is made to apply microwave-assisted heating (MAH) to reduce the duration in analysis. The hydrolysis efficiency obtained from MAH procedure is significantly greater than that from conventional one. Hydrolysis by MAH required only 20 minutes, 48 times faster than with conventional heating. The use of the MAH method in hydrolysis was demonstrated to be a reproducible, timesaving and efficient technique in measuring the concentration of urinary TDAs. This method could be applied for analysis of U-TDAs in occupational health.
46
Chang, Wei-Yao, and 張偉瑤. "Synthesis and Characterization of Novel Polyimide via Methylene Diphenyl Diisocyanate (MDI) and Their Nanocomposites." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/58694009886201369527.
Full textAbstract:
博士<br>國立臺灣大學<br>高分子科學與工程學研究所<br>104<br>In this thesis, it is composed of two major parts: The first part is synthesis the kinds of polyimide by Methylene diphenyl diisocyanate (MDI). By adjust the molar ratio of Pyromellitic Dianhydride (PMDA), Trimellitic Anhydride (TMA), 4’4-Oxydianline (ODA), Bisphenol-A (BPA), and Diglycidyl Ether of Bisphenol A (DGEBA) to synthesis polyurea-imide (PUI), polyurea-amide-imide (PUAI), polyurea-imide-ester (PUIE), polyimide-epoxy (PIE), and polyamide-imide-epoxy (PAIE). The purpose of this study is using much cheaper materials to synthesis high thermal properties and low dielectric constant polymers. The thermal properties are measure by Thermal Gravimetric (TGA), Differential Scanning Calorimetry (DSC), and Thermomechanical Analysis (TMA); the morphologies of polymer/nano-clay are observed by Scanning Electronic Microscopy (SEM) and Transmission Electron Microscopy (TEM); and also measured the mechanical and electronic properties. The results of this study are shown that when imide groups are more, it will have good thermal and mechanical properties. The best polymer of this study is polyimide-epoxy (PIE), the degradation temperature is over 500 oC, and the dielectric constant is between 3.3-3.5. Therefore, polyimide-epoxy (PIE) polymer is much cheaper and also has higher performance as Kapton®.
The second part is synthesis the new soluble polyimides which were synthesized from different 4,4''-diaminodiphenylmethane monomers with different alkyl substituents (4’4’-diamino-3,3’-dimethyl-diphenyl-methane, DDMDPM; 4,4’-methylene -bis(2-ethyl-6-methylaniline), MBEMA; and 4,4’-methylene-bis(2,6-diethylaniline), MBDEA)) in one-step with the poly(amic acid)s prepared from the polyaddition of 4,4’-oxydiphthalic anhydride (ODPA) and 4,4''-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA). These polyimides exhibited excellent thermal stability, and they also possessed relatively low coefficients of thermal expansion and dielectric constants.
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高意芸. "The chemical structure of 2,4-toluene diisocyanate conjugating with human serum albumin and it's cytotoxicity." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/70242713140939751618.
Full textAbstract:
碩士<br>東吳大學<br>微生物學系<br>92<br>Toluene diisocyanate (TDI) is a widely used as a chemical intermediate in the production of polyurethane products such as foams, coatings, and elastomers. In exposed workers, inhalation exposure TDI leads its binding with human serum albumin (HSA) and results significant decreases in lung function and asthma-like reaction. Firstly, investigated the conjugation of TDI-HSA and found the possible binding position of TDI was lysine on the 373 and 437 amino acid sequence of HSA. These binding sites are evidenced by the peptide fragments analysis by Maldi-TOF MS. In most affected workers, TDI-induced asthma is characterized by specific airway hyperresponsiveness to acetylcholine or methacholine. Therefore, we investigated the possible mechanisms involved in TDI-induced airway hyperresponsiveness to acetylcholine by observation [Ca2+]c changes under the stimulation of nicotinic and muscarinic acetylcholine receptors in the present or absent of TDI in human neuroblastoma cells. The results shows TDI can induce internal calcium release and capacitative calcium entry. Under the stimulation of nicotinic and muscarinic receptors, TDI suppressed their [Ca2+]c rise. We also found TDI was capable to inhibit P2X receptors, GABA receptors and voltage-sensitive calcium channels. However, the inhibition of TDI on muscarinic receptors was most dominant. We suggest that the suppression of TDI on muscarinic receptors was due to its capability releasing calcium from internal pools. In airways, TDI is possibly to act at the muscarinic receptors on the epithelial cells to suppress smooth muscle relaxation by shutting down the NO-signaling pathway that is initiated by the activation of muscarinic receptors on epithelial cells.
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Lai, Jian-Zei, and 賴建志. "Curing Reaction of One-Component Aqueous-Based PU System with Di-Aziridinyl Derivatives from Hexamethylene Diisocyanate." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/13004994349644407724.
Full textAbstract:
碩士<br>淡江大學<br>化學學系<br>87<br>Title of Thesis: Curing Reactions of One-Component Tolal page:
Aqueous-Based PU System With
Di-Aziridinyl Derivatives from
Hexamethylene Diisocyanate
Key Words: aqueous-based PU, aliphatic, aromatic
Name of Institute: Tamkang University, Department of Chemistry
Graduate date: June, 1999 Degree conferred: Master
Name of student: Jian-Zei Lai Advisor: Prof. Kwei-Ju Chen
賴 建 志 陳 桂 珠
Abstract
A di-acylaziridinyl curing agent was prepared for a single-component aqueous-based PU curing system. The modification of aqueous-based PU by this self-curable system was developed in this report.
Di-acylaziridinyl curing agent was prepared by an addition of hexamethylene diisocyanate with aziridine. This prepared curing agent was added into PU prepolymer before water dispersion, and resulted a single-component self-curable aqueous-based PU dispersion. This curing agent is also added into aliphatic (IPDI) and aromatic(TDI) aqueous-based PU dispersions separately as a stable self-curing PU system. The performance properties of aqueous-based PU before and after the curing reaction were investigated and discussed in this report.
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Spies, Adri. "Assessment of exposure associated health effects to hexamethylene diisocyanate (HDI) in automotive spray painting processes in small,medium and micro enterprises." Thesis, 2006. http://hdl.handle.net/10539/1560.
Full textAbstract:
Student Number : 0110634H -
MPH research report -
School of Public Health -
Faculty of Sciences<br>During October 1996 to December 1999, isocyanates were the most frequently reported causative agent for occupational asthma cases (16.7% of all cases) submitted to the Surveillance of Work-Related and Occupational Respiratory Diseases in South Africa registry (SORDSA). Occupational disease surveillance registries in other countries also identified isocyanates as the most important occupational sensitiser. Asthma caused by isocyanates exposure may be severe and may persist even after exposure ceases. For this reason, it is important to identify the potentially hazardous isocyanate exposure settings, and to prevent sensitisation and asthma development where possible.
Auto body repair shops, typically small, medium or micro enterprises (SMMEs), were the focus group in this study. Due to the paucity of medical surveillance and occupational hygiene programmes, there is likely to be over-exposure to isocyanates in such workplaces. The aim of this study was to identify and quantify exposure to HDI in auto body repair shops, and secondly, to describe the control measures currently used in these repair shops.
The study investigated hexamethylene diisocyanate (HDI) exposure in the spray-painting processes of automotive repair shops in Gauteng. The repair shops were selected from the Highveld South African Motor Body Repairers’ Association (SAMBRA) membership list. Ten repair shops were included in this cross sectional study. Twelve subjects directly or indirectly involved in spray-painting in each repair shop had HDI exposure measured, resulting in a total of 113 HDI measurements. HDI monomers, prepolymers and total isocyanates determined using the National Institute for Occupational Safety and Health (NIOSH) draft method 5525 for analysis of monomeric and TRIG aliphatic isocyanates.
Eighty one percent of workers were over-exposed to HDI monomers (exposure limit of 0.02mg/m3) and 3.4% to HDI prepolymers (exposure limit of 0.5mg/m3). Ninety percent of the establishments’ HDI monomer airborne concentration exceeded the OEL and 30% the prepolymer HDI concentrations.
Workers were divided into 12 occupation categories according to the extent of their direct contact with the HDI-based paint and the three highest exposed groups were panel beaters, spray painters and dent-fillers. Workers directly and indirectly in contact with paint, in the auto body repair shops registered with SAMBRA were exposed to high levels of HDI during the spray painting operation. Insufficient and incorrect control measures were in place to control HDI exposure. The findings of this study confirm the risk of exposure to HDI in the automotive repair industry and the need for occupational hygiene control measures.
In conclusion, high concentrations of HDI were common and even indirectly exposed workers were at risk of excessive exposure to HDI. Inadequate exposure control methods were widespread.
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CHEN, MEI-LIAN, and 陳美蓮. "The determination of toluene diisocyanate in the ambient air of workplace by derivatization and electron-capture gas chromatography." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/81430841468208958859.
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