To see the other types of publications on this topic, follow the link: Polyurethane.
Journal articles on the topic 'Polyurethane'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Polyurethane.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Zych, Krzysztof, Robert Pełech, and Zbigniew Czech. "Thermal degradation of poly(alkyl methacrylates) and polyurethane pressure-sensitive adhesives." Polish Journal of Chemical Technology 12, no. 4 (January 1, 2010): 40–43. http://dx.doi.org/10.2478/v10026-010-0048-4.
Full textAbstract:
Thermal degradation of poly(alkyl methacrylates) and polyurethane pressure-sensitive adhesives Gas chromatography, coupled with the temperature controlled pyrolysis technique, can be used as a quick method of identification of polymers such as acrylates, methacrylates and polyurethanes. Polymers based on alkyl methacrylates are widely used as construction materials and coatings. Polyurethanes are widely used as self-adhesives, sealants and electrical products (due to polyurethane's low glass transition temperature Tg). The aim of this work is to investigate which products can be obtained from polymethacrylates and polyurethanes.
2
Domańska, Agata, Anna Boczkowska, Marta Izydorzak-Woźniak, Zbigniew Jaegermann, and Małgorzata Grądzka-Dahlke. "Polyurethanes from the crystalline prepolymers resistant to abrasive wear." Polish Journal of Chemical Technology 16, no. 4 (December 1, 2014): 14–20. http://dx.doi.org/10.2478/pjct-2014-0063.
Full textAbstract:
Abstract The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether) glycol (PTMEG), as well as from two different isocyanates 4,4′-methylenebis(cyclohexyl)isocyanate (HMDI) and 4.4′-methylenebis(phenyl isocyanate) (MDI) in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyurethane surface wettability, friction coefficient for different couples of the co-working materials such as polyurethane-polyurethane, polyurethane-titanium alloy, polyurethane-alumina, in comparison to commonly used polyethylene-titanium alloy. Shear strength of polyurethane-alumina joint, as well as viscosity of prepolymers were also measured. The values of friction coefficient were compared to literature data on commercially available polyurethane with the trade name Pellethane. Polyurethanes obtained are characterized by low abrasive wear and low friction coefficient in couple with the titanium alloy, what makes them attractive as possible components of ceramic-polymer endoprosthesis joints.
3
Zagożdżon, Izabela, Paulina Parcheta, and Janusz Datta. "Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors." Materials 14, no. 11 (May 21, 2021): 2699. http://dx.doi.org/10.3390/ma14112699.
Full textAbstract:
Phosphorus-containing polyol applications in polyurethane synthesis can prevent volatilization of flame retardants and their migration on the surface of a material. In this work, novel cast polyurethanes were prepared by a one-step method with the use of different amounts of phosphorus-containing polyol, 4,4′–diphenylmethane diisocyanate and 1,4-butanediol. The chemical structure, thermal, physicochemical and mechanical properties and flame resistance of the prepared materials were investigated. The results obtained for cast flame-retarded polyurethanes were compared with cast polyurethane synthesized with commonly known polyether polyol. It has been shown that with an increasing amount of phosphorus content to polyurethane’s chemical structure, an increased flame resistance and char yield were found during combustion tests. Phosphorus polyol worked in both the condensed (reduced heat and mass exchange) and gas phase (inhibition of flame propagation during burning). The obtained materials contained phosphorus polyol, indicating higher thermal stability in an oxidative environment than an inert atmosphere.
4
Munteanu, Dan, Constantin Bolcu, and Vasile Ostafe. "Polyurethane-Bound Stabilisers." Polymers and Polymer Composites 8, no. 2 (February 2000): 87–100. http://dx.doi.org/10.1177/0967391120000802087.
Full textAbstract:
Addition of antioxidants and light stabilisers into the polyol component before its reaction with the isocyanate com ponent is common practice for polyurethane stabilisation. The stabilisers usually contain single OH and NH groups, which are involved in the mechanisms of stabilisation and the additives may then be regarded as monofunctional stabilisers. The OH and NH groups are very reactive towards the -N=C=O (isocyanate) groups so that a reaction between the stabiliser and the isocyanate groups during the synthesis of the polyurethane may occur to some extent. The stabiliser will become part of the polymer chain but the resulting structure will lose its active groups and consequently will not demonstrate the stabilisation effect. Some stabilisers have an additional OH group, not engaged in the stabilisation mechanisms. Having no constraints, these groups are more reactive towards the isocyanate groups. For these bifunctional stabilisers the resulting structure will bear the unreacted stabilising group, still effective, and a polyurethane-bound stabiliser will be obtained. The reaction of various commercial monofunctional and bifunctional stabilisers with isocyanates has been studied, as well as t heir use for the stahi lisation of polyurethanes, under conditions typical of practical applications. Whereas the reaction yields of the isocyanates with the monofunctional stahi lisers were very low (less than 15%). the reaction yields exceeded 90% for the hifunctional stahilisers. Therefore. commercial products with hi fu nctional structures may he regarded as reactive stabilisers, which yield polyurethan e-bound stabilisers.
5
Carbonell-Blasco, Pilar, Iulian Antoniac, and Jose Miguel Martin-Martinez. "New Polyurethane Sealants Containing Rosin for Non-Invasive Disc Regeneration Surgery." Key Engineering Materials 583 (September 2013): 67–79. http://dx.doi.org/10.4028/www.scientific.net/kem.583.67.
Full textAbstract:
Different polyurethane sealants were prepared by reacting methylene dyísocyanate and polyadipate of 1,4 butane diol (Mw : 2500 daltons) by using the prepolymer method and different mixtures of rosin and 1,4 butane diol were used as chain extenders. The polyurethanes were characterized by plate-plate rheology, molecular weight distribution, Differential Scanning Calorimetry (DSC), and Laser Confocal Microscopy. The tack of the polyurethanes sealants was obtained by using a modified probe tack method, and their adhesion was obtained by T-peel test of leather/polyurethane sealant/leather joints and by single lap-shear tests of aluminium/polyurethane sealant/aluminium joints. Depending on the rosin content in the chain extender the structure of the polyurethanes was different, i.e. more urethane and urethane-amide hard segments were created up to 50 eq% rosin in the chain extender, and separation of domains was prevailing in the polyurethanes with higher rosin content. Furthermore, the addition of rosin caused an increase in the length of the polymer chains and in the storage modulus (particularly in the polyurethane containing 50 eq% rosin), and decrease in the melting enthalpy. Moreover, the crystallinity of the polyurethanes containing up to 50 eq% rosin showed lower number and smaller spherulites, Finally, the tack at 37 °C and the peel strength increased in the joints made with the polyurethane sealants containing rosin whereas the adhesive shear strength decreased when the polyurethane sealant contained 50 eq% rosin or less.
6
Schmidt and Eschig. "Hydrophobilization of Furan-Containing Polyurethanes via Diels–Alder Reaction with Fatty Maleimides." Polymers 11, no. 8 (July 31, 2019): 1274. http://dx.doi.org/10.3390/polym11081274.
Full textAbstract:
We describe new hydrophobic functionalized linear polyurethane resins by combining N-alkyl maleimides via the Diels–Alder reaction with linear furan-modified polyurethanes. This procedure provides the opportunity for the post-polymerization-functionalizing of polyurethanes. Access to furan-bearing polyurethanes is achieved via the reaction of a furan-containing diol, polyethylenglycol (PEG), and different diisocyanates. The furan-containing diol is obtained from the reaction of furfurylamine and two equivalents of hydroxyalkyl acrylate. The resulting furan-bearing polyurethanes are reacted with fatty amine-based N-alkyl maleimides. The maleimide and furan functionalities undergo a Diels–Alder reaction, which allows for the covalent bonding of the hydrophobic side chains to the polyurethane backbone. The covalent bonding of the hydrophobic maleimides to the polyurethane backbone is proven by means of NMR. The influence of the functionalization on the surface properties of the resulting polyurethane films is analyzed via the determination of surface energy via the sessile drop method.
7
Sur, Suk-Hun, Pil-Jun Choi, Jae-Wang Ko, Jae-Yeon Lee, Young-Hee Lee, and Han-Do Kim. "Preparation and Properties of DMF-Based Polyurethanes for Wet-Type Polyurethane Artificial Leather." International Journal of Polymer Science 2018 (September 2, 2018): 1–9. http://dx.doi.org/10.1155/2018/7370852.
Full textAbstract:
DMF-based polyurethanes for wet-type polyurethane artificial leather were prepared using 4,4′-diphenylmethane diisocyanate (MDI) as diisocyanate, 1,4-butanediol (BD)/1,6-hexanediol (HD) as chain extender, and four different macroglycols (MW: 2000): poly(butylene/3-methyl-pentylene adipate) glycol based on 1,4-butanediol/3-methyl-1,5-pentanediol (MPD), poly(butylene adipate) glycol based on BD, polycarbonate glycol based on HD/MPD, and polycarbonate glycol based on HD. The properties of the as-polymerized polyurethane solutions and their films and the size/uniformity of cells of the foam layer of the resulting artificial leather were investigated. The viscosities of as-polymerized polyurethane solutions were significantly high in the range of 7500–15,000 cps, indicating that the molecular weight of the obtained polyurethanes is high. The tensile strengths of polyurethane films based on carbonate-polyol and BD chain extender were found to be higher than those of polyurethane films based on ester-polyol and HD chain extender. The elongation at the break of polyurethane films with the MPD component were higher than that of polyurethane films without the MPD component. The artificial leather containing MPD had smaller cells than the artificial leather without MPD and had higher uniformity. From these results, DMF-based polyurethanes prepared by using MPD components containing polyols are found to be most suitable for wet-type artificial leather.
8
Yeligbayeva, G., M. Khaldun, Abdassalam A. Alfergani, Zh Tleugaliyeva, A. Karabayeva, L. Bekbayeva, D. Zhetpisbay, N. Shadin, and Z. Atabekova. "Polyurethane as a versatile polymer for coating and anti-corrosion applications: A review." Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 331, no. 4 (January 25, 2024): 21–41. http://dx.doi.org/10.31643/2024/6445.36.
Full textAbstract:
The development of polyurethane materials and process optimization are currently the subjects of extensive study. Polyurethane is characterized by high physicochemical and operational properties. Polyurethanes have high wear resistance, and oil and gasoline resistance. They have excellent thermophysical and elastic properties. This allows the use of polyurethanes in many industries where materials with high-performance properties are required. Polyurethanes are widely used in many industrial applications, protective coating manufacturing, and anti-corrosion agent applications. A significant number of studies have been conducted to improve the physical, mechanical, and operational properties of polyurethane polymers, in particular the anti-corrosion properties of modified polyurethane coatings. The properties of polyurethane polymers for various applications can be improved by changing monomers and their ratios and the process of preparations. Preparation of polyurethane polymers based on polyols and isocyanate monomers using a polyaddition process in the presence of a catalyst as well as solvents including toluene, xylene, and acetone. There are different factors affecting the physical and mechanical properties of polyurethane polymers were investigated by different techniques. The factors were types of isocyanates, polyols, OCN/OH ratios, solvents, catalysts, and temperatures. Generally, the polyols are responsible for the flexibility of the polyurethane polymers and isocyanates are responsible for the rigidity of the polyurethane polymer and crosslinking between the backbone of the polymer. Because of the flexibility of its chemistry, they may modify the coating's characteristics based on the intended use. The effects of different polyols and polyisocyanates' chemistry are assessed. The hydrophobicity, thermal stability, and mechanical and anti-corrosion properties of polyurethane polymers were investigated. As a result, the properties of polyurethane polymers such as hydrophobicity, thermal stability, and mechanical and anti-corrosion properties were all enhanced when all the above factors. An outline of the most modern, financially successful methods for creating protective polyurethane coatings and using them as anti-corrosion agents is given in this review article.
9
Chen, Lijun, and Wei Jiang. "Modification of polyurethane with novel blocking agent." Pigment & Resin Technology 43, no. 2 (February 25, 2014): 97–103. http://dx.doi.org/10.1108/prt-04-2013-0030.
Full textAbstract:
Purpose – Fluorinated polyurethane combines some virtues of polyurethane and fluorinated polymer, such as low water absorption, attractive surface properties, good wearability and high weatherability. Fluorocarbon chains have been incorporated into polyurethanes by fluorinated diisocyanates, chain extenders, polyether glycols, polyester glycols and end-cappers. However, the fluorinated polyurethane, which is prepared with monohydric fluorocarbon alcohol, is seldom reported. The purpose of this research is to prepare and apply the novel fluorocarbon alcohols with side chain to modify polyurethane as the blocking agent. Design/methodology/approach – The novel fluorocarbon alcohol with side chain 2-methoxy-3-nonene perfluorinated oxygen propanol (MNPOP) can be prepared via alcoholysis reaction of methanol and 2,3-epoxypropyl perfluorinated nonene ether (EPPNE), which was prepared with etherification of hexafluoropropene trimer (HFPT) and 2,3-glycidol. Structures of EPPNE and MNPOP are confirmed with FTIR and NMR. The polyurethane can be modified when MNPOP is used as blocking agent. Findings – In comparison with the conventional polyurethane, the hydrophobic property of fluorinated polyurethane is improved. However, the increase of tensile strength of modified polyurethane is not obvious because MNPOP belongs to monohydric alcohol. And the function of MNPOP in the modified polyurethane is the blocking agent. The thermal stability of conventional and modified polyurethane is almost the same because MNPOP is de-blocked and fluorocarbon chains have not been incorporated into polyurethanes when the temperature is more than 150°C. Originality/value – The polyurethane is modified with the novel fluorocarbon alcohols with side chain, which functions as the blocking agent. The hydrophobic property of fluorinated polyurethane is improved.
10
Mo, Ya, Xiaoyue Huang, and Chuanqun Hu. "Recent Advances in the Preparation and Application of Bio-Based Polyurethanes." Polymers 16, no. 15 (July 29, 2024): 2155. http://dx.doi.org/10.3390/polym16152155.
Full textAbstract:
Amid environmental pollution and resource depletion, developing and utilizing biomass resources as alternatives to petroleum is a prominent research focus. Driven by environmental protection and sustainable development, the shift from petroleum-based to bio-based polyurethane is a prevailing trend in polyurethane material development. Biomass sources such as vegetable oil, polysaccharides, and lignin offer extensive application prospects in bio-based polyurethane production. Functional modifications of these polyurethanes can further expand their application range. This article explores the preparation of various bio-based polyurethanes, their applications across different fields, and their anticipated future development and uses.
11
Oprea, Stefan, Violeta Otilia Potolinca, and Veronica Oprea. "Physical properties and the ability to disperse into different polar solvents of the new polyurethane–cellulose composites." Journal of Elastomers & Plastics 52, no. 6 (September 24, 2019): 548–72. http://dx.doi.org/10.1177/0095244319877562.
Full textAbstract:
Novel castor oil (CO)-based polyurethane composites which include polyethylene glycol (PEG) as a polyol and cellulose fillers were prepared. The purpose of this article was to render polyurethane composites that can be dispersed in polar solvents (ethyl alcohol, isopropyl alcohol, and water) using bio-based feedstocks such as CO and cellulose. The chemical structures of the polyurethanes and their cellulose composites were studied by Fourier transform infrared spectroscopy and nuclear magnetic resonance of protons. The atomic force microscopy results showed the surface topography of the cellulose–polyurethane composites matrix. The inclusion of cellulose has been found to improve the thermal stability of the materials and their ability to disperse into the studied polar solvents. Cellulose along with PEG plays an important role in increasing the degree of moisture within the polyurethane composite matrix. Thus, we obtained solutions in polar solvents of polyurethane–cellulose composites without the use of waterborne polyurethanes.
12
Okieimen, F. E., I. O. Bakare, and C. Pavithran. "Network Structures, Flexibility and Stability in Thermal and Chemical Environments of Polyurethane Prepared from Rubber Seed Oil." Advanced Materials Research 62-64 (February 2009): 324–34. http://dx.doi.org/10.4028/www.scientific.net/amr.62-64.324.
Full textAbstract:
Rubber seed oil monoglyceride was prepared by glycerolysis and characterized by chemical and spectroscopic methods. The monoglyceride was reacted with excess diisocyanates (hexamethylene -diisocyanate and toluene diisocyanate), and the network structures and molecular mass of the polyurethane were determined from swelling experiments in toluene and size exclusion chromatography respectively. The polyurethane films obtained were characterized in terms of their resistance to chemicals (water, brine, dilute acid and alkali) thermal stability and tensile and flexural strength and modulus. It was found that under the experimental conditions, conversion of the triglyceride content of the rubber seed oil to monoglyceride not quantitative less than 70%. The measured properties of the RSO-based polyurethanes were attributed to the degree of crosslinking and the observed superior properties of the polyurethane obtained with hexamethylene diisocyanate in comparison with polyurethane obtained with toluene diisocyanate were explained in terms of structure-property relationship. The measured properties of RSO-based polyurethanes compare favourably with the properties reported for polyurethanes derived from other vegetable oils.
13
Echarri-Giacchi, María, and José Miguel Martín-Martínez. "Efficient Physical Mixing of Small Amounts of Nanosilica Dispersion and Waterborne Polyurethane by Using Mild Stirring Conditions." Polymers 14, no. 23 (November 25, 2022): 5136. http://dx.doi.org/10.3390/polym14235136.
Full textAbstract:
Good dispersion of nanosilica particles in waterborne polyurethane was obtained by mild mechanical stirring when 0.1–0.5 wt.% nanosilica in aqueous dispersion was added. The addition of small amounts of nanosilica produced more negative Z-potential values, increased the surface tension and decreased the Brookfield viscosity, as well as the extent of shear thinning of the waterborne polyurethane. Depending on the amount of nanosilica, the particle-size distributions of the waterborne polyurethanes changed differently and the addition of only 0.1 wt.% nanosilica noticeably increased the percentage of the particles of 298 nm in diameter. The DSC curves showed two melting peaks at 46 °C and 52 °C, as well as an increase in the melting enthalpy. In addition, when nanosilica was added, the crystallization peak of the waterborne polyurethane was displaced to a higher temperature and showed higher enthalpy. Furthermore, the addition of 0.1–0.5 wt.% nanosilica displaced the temperature of decomposition of the soft domains to higher temperatures due to the intercalation of the particles among the soft segments; this led to a change in the degree of phase separation of the waterborne polyurethanes. As a consequence, improved thermal stability and viscoelastic and mechanical properties of the waterborne polyurethanes were obtained. However, the addition of small amounts of nanosilica was detrimental for the wettability and adhesion of the waterborne polyurethanes due to the existence of acrylic moieties on the nanosilica particles, which seemed to migrate to the interface once the polyurethane was cross-linked. In fact, the final T-peel strength values of the joints made with the waterborne polyurethanes containing nanosilica were significantly lower than the one obtained with the waterborne polyurethane without nanosilica; the higher the nanosilica content, the lower the final adhesion. The better the nanosilica dispersion in the waterborne polyurethane+nanosilica, the higher the final T-peel strength value.
14
Yoo, Hye Jin, and Han Do Kim. "Preparation and Properties of Crosslinked Polyurethane Containing Hydrophilic PEO Component for Biomaterials." Key Engineering Materials 277-279 (January 2005): 82–89. http://dx.doi.org/10.4028/www.scientific.net/kem.277-279.82.
Full textAbstract:
A series of multiblock polyurethanes containing various poly(ethylene oxide) (PEO) contents (0-80 wt%) were prepared from hexamethylene diisocyanate (HDI)/ PEO / poly(tetramethylene oxide) (PTMO)/ polybutadiene diol (PBD)/ 1,4-butanediol (BD) and used as modifying additives (30 wt%) to improve the properties of biomedical grade PelletheneÒ. A hydrophilic PEO component was introduced by the addition of PEO-containing polyurethanes and dicumyl peroxide (DCP) as the crosslinking agents in a PelletheneÒ matrix. As the PEO content (PEO block length) increased, the hydrogen-bonding fraction of the crosslinked polyurethane also increased, indicating an increase in the phase separation with an increase in the PEO content in the crosslinked polyurethane. Using electron spectroscopy for a chemical analysis, the ratio of ether carbon to alkyl carbon in the crosslinked polyurethane film increased remarkably with an increase, in the PEO content. Meanwhile, the water contact angle of the crosslinked polyurethane film surfaces decreased with increasing PEO content. The water absorption and mechanical properties of the crosslinked polyurethane films increased with increasing and the platelet adhesion on the crosslinked polyurethane film surfaces decreased significantly. Accordingly, these results suggest that the crosslinked polyurethane containing a hydrophilic PEO component may be more effective for a biomaterial application that is in direct contact with blood.
15
Zheng, Qin, Shuling Gong, Haiqing Dong, and Yuanyin Chen. "Calix[4]arenes Used as a New Type of Chain Extender in the Preparation of Polyurethanes." Australian Journal of Chemistry 60, no. 3 (2007): 167. http://dx.doi.org/10.1071/ch06387.
Full textAbstract:
A series of polyether– or polyester–polyurethanes based on tetrahydrofuran–propylene oxide copolyether diol (PTMG/PPG) or poly(ethylene terephthalate) diol (PET), toluene diisocyanate (TDI), and three kinds of chain extenders including two calix[4]arene derivatives and 3,3´-dichloro-4,4´-diaminodiphenylmethane (MOCA) were synthesized in toluene. The thermal stability and mechanical properties of solvent-type polyurethanes were investigated. Incorporation of calixarenes into polyurethane backbones improved the thermal properties of the polyurethane as a result of the residual phenol hydroxy groups of the calix[4]arene units. Compared with polyurethane chain-extended by MOCA, the polyurethanes with calix[4]arene derivatives had higher elongation at break, lower elastic modulus, and lower yield strength, as a result of the larger steric cubage of calix[4]arene units and relatively large free volume of the polymer.
16
Ciastowicz, Żaneta, Renata Pamuła, and Andrzej Białowiec. "Utilization of Plant Oils for Sustainable Polyurethane Adhesives: A Review." Materials 17, no. 8 (April 10, 2024): 1738. http://dx.doi.org/10.3390/ma17081738.
Full textAbstract:
The utilization of plant oils as a renewable resource for the production of polyurethane adhesives presents a promising way to improve sustainability and reduce environmental impact. This review explores the potential of various vegetable oils, including waste oils, in the synthesis of polyurethanes as an alternative to conventional petroleum-based raw materials. The investigation highlights the environmental challenges associated with conventional polyurethane production and highlights the benefits of switching to bio-renewable oils. By examining the feasibility and potential applications of vegetable oil-based polyurethanes, this study emphasizes the importance of further research and development in this area to realize the full potential of sustainable polyurethane adhesives. Further research and development in this area are key to overcoming the challenges and realizing the full potential of plant-oil-based polyurethanes in various industrial applications.
17
Jeba, D., and K. R. Sheeja. "Antibacterial Activity of Environmentally Sustainable Polyurethane Based Composites from Castor Oil." Oriental Journal Of Chemistry 37, no. 3 (June 30, 2021): 755–58. http://dx.doi.org/10.13005/ojc/370334.
Full textAbstract:
In this present work, soft and hard antibacterial polyurethane sheets of different composition have been synthesized from castor oil based polyurethane and which was reinforced with natural and synthetic fibres such as jute, sisal, hemp and glass. The activity of polyurethane sheets and selected antibiotics was evaluated against four bacterial pathogens including Staphylococcusaureus, Streptococcus mutans, E.coli, Pseudomonas aeruginosausing modified disc diffusion method. Among the ten samples, hard polyurethanes displayed potential activity against bacterial pathogens E.coli and Streptococcus mutans. Polyurethane sheets showed the highest activity against E.coli which is comparable with zone of inhibition exhibited by streptomycin. Further studies are needed to improve the polyurethane sheets for medical applications.
18
Wang, Kun, Jiping Yang, Chen Gong, and Hao Lu. "Polyurethanes with aggregation-enhanced emission characteristics: preparation and properties." Faraday Discussions 196 (2017): 43–54. http://dx.doi.org/10.1039/c6fd00175k.
Full textAbstract:
An amino-terminated poly(propylene glycol)-modified tetraaryl-buta-1,3-diene derivative (TABDAA) was introduced to synthesize polyurethanes with different ratios of soft/hard segments. A mixture of TABDAA and poly(tetrahydrofuran) 1000 as the soft segments was reacted with 4,4-diphenylmethane diisocyanate and 1,4-butanediol as the hard segments in molar ratios of 1 : 2 : 1, 2 : 3 : 1, and 3 : 4 : 1 to give the desired polyurethanes named TMPU-211, TMPU-321 and TMPU-431, respectively. The three polyurethanes exhibited different aggregation-enhanced emission (AEE) behaviors because of their different soft/hard segment ratios. The polyurethanes with a higher soft segment content tended to form bigger particles in a DMF/water mixture solution, thus causing a sharper increase in their fluorescence intensity. In addition, the polyurethane films exhibited different fluorescence intensities after different heat treatments. After a quenching treatment of the soft segments in the polyurethane films, the fluorescence intensity dropped greatly. When these quenched polyurethane films were thermally annealed at 60 °C for 24 hours, their fluorescence intensity exceeded the initial intensity of the as-prepared films. Differential scanning calorimetry results showed that the polyurethane films in the quenched condition did not present the endothermal melting peak of the soft segments, and the melting peaks appeared again after thermal annealing. AFM experiments showed that an ordered arrangement was achieved after the heat treatment of these AEE polyurethane films. These results demonstrated that the polymer structure had a significant effect on the AEE properties of the polyurethane films, and more importantly, it is of great significance in improving the fluorescence emission of the AEE polymers and also for their potential application in fluorescent probes, stimuli-responsive materials, PLED devices and so on.
19
Alaa, M. A., Kamal Yusoh, and S. F. Hasany. "Comparative Study of Physico-Chemical Properties of Pure Polyurethane and Polyurethane Based on Castor Oil." Advanced Materials Research 983 (June 2014): 39–43. http://dx.doi.org/10.4028/www.scientific.net/amr.983.39.
Full textAbstract:
Petroleum based polyurethanes are contributing major portions in the world requirement. To overcome the environmental issues and price adaptability, there is always a massive demand of utilization of renewable resources for polyurethane synthesis with comparable physico-chemical properties. Castor oil is the only major natural vegetable oil that contains a hydroxyl group (-OH) and unsaturated double bonds (C=C) in its organic chain and therefore can be employed with or without modification due to the excellent properties derived from the hydrophobic nature of triglycerides. In this study, physico-chemical properties of high performance polyurethane synthesized from Poly propylene glycol (PPG) in comparison with a combination of PPG and Castor oil (a renewable source), by in situ polymerization technique has been studied. The variations in properties of both types of polyurethanes are evaluated by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis technique (TGA). Tensile strength properties were investigated by Film Tensile testing equipment. Results indicated the presence of large-CH stretching in castor oil mixed polyurethane with a larger oxidative thermal stability, over a pure PPG polyurethanes. Tensile properties were found almost comparable in pure and mixed polymers, which signify the usage of mixed polymer in coming future, to overcome the environmental and economical crisis in polyurethanes synthesis.
20
Tharanikkarasu, Kannan, and Byung Kyu Kim. "Aqueous Dispersions of Polyurethane Ionomers." Progress in Rubber and Plastics Technology 13, no. 1 (February 1997): 26–55. http://dx.doi.org/10.1177/1477760619971301026.
Full textAbstract:
Studies carried out in the field of aqueous polyurethane dispersions are reviewed. After a brief introduction about polyurethanes and their chemistry, the chemistry of aqueous dispersions are discussed. Manufacturing processes of aqueous polyurethane dispersions such as the acetone process, the prepolymer mixing process, the melt dispersion process, the ketimine and ketazine processes are briefly discussed. The properties of dispersions as well as films derived from dispersions are also discussed. Studies of chemical modifications on polyurethane dispersions through crosslinking, graft and block copolymerization are also reviewed along with applications of aqueous polyurethane dispersions.
21
Kausar, Ayesha, Ishaq Ahmad, Tingkai Zhao, Osamah Aldaghri, Khalid H. Ibnaouf, and M. H. Eisa. "Nanocomposite Foams of Polyurethane with Carbon Nanoparticles—Design and Competence towards Shape Memory, Electromagnetic Interference (EMI) Shielding, and Biomedical Fields." Crystals 13, no. 8 (July 31, 2023): 1189. http://dx.doi.org/10.3390/cryst13081189.
Full textAbstract:
Polyurethane is a multipurpose polymer with indispensable physical characteristics and technical uses, such as films/coatings, fibers, and foams. The inclusion of nanoparticles in the polyurethane matrix has further enhanced the properties and potential of this important polymer. Research in this field has led to the design and exploration of polyurethane foams and polyurethane nanocomposite foams. This review article reflects vital aspects related to the fabrication, features, and applications of polyurethane nanocomposite foams. High-performance nanocellular polyurethanes have been produced using carbon nanoparticles such as graphene and carbon nanotubes. Enhancing the amounts of nanofillers led to overall improved nanocomposite foam features and performances. Subsequently, polyurethane nanocomposite foams showed exceptional morphology, electrical conductivity, mechanical strength, thermal stability, and other physical properties. Consequently, multifunctional applications of polyurethane nanocomposite foams have been observed in shape memory, electromagnetic interference shielding, and biomedical applications.
22
Kaur, Raminder, Pooja Singh, Surya Tanwar, Gunjan Varshney, and Sarla Yadav. "Assessment of Bio-Based Polyurethanes: Perspective on Applications and Bio-Degradation." Macromol 2, no. 3 (July 4, 2022): 284–314. http://dx.doi.org/10.3390/macromol2030019.
Full textAbstract:
Among numerous synthetic macromolecules, polyurethane in its different forms has proven its sheer dominance and established a reputation as a reliable and trusted material due to its proficiency in terms of superior properties, which include: high mechanical strength and abrasion resistance, good durability, good adhesion, good thermal stability, excellent chemical and weathering resistance. Synthetic polyurethane materials are non-biodegradable, poisonous, and use petrochemical-based raw materials, which are now depleting, leading to a surge in polyurethane production costs. Bio-based polyurethanes (PU) have been synthesized by researchers in recent decades and have mostly overtaken petrochemical-based PU in terms of challenges such as solid pollution, economic effectiveness, and availability of raw materials. Enormous kinds of available bio-renewable sources as predecessors for the production of polyols and isocyanates have been explored for the development of “greener” PU materials; these bio-based polyurethanes have significant potential to be used as future PU products, with a partial or total replacement of petroleum-based polyurethanes, due to increasing concern about the environment, their relatively low cost and biodegradability. This critical review concentrates on the possibilities of renewable sources to be used for polyurethane production and gives a clear perspective on the journey, utilization, and recent advancements in the field of different bio-based polyurethane polymers that have arisen over the last decade.
23
Ke, Ruoyi, Zhaowen Lin, Hongbo Zhang, and Shilin Zhou. "Research Progress in Intrinsic Self-healing Polyurethane Materials Based on Dynamic Reversible Non-covalent Bonds." Journal of Physics: Conference Series 2324, no. 1 (August 1, 2022): 012007. http://dx.doi.org/10.1088/1742-6596/2324/1/012007.
Full textAbstract:
Abstract Polyurethane (PU) is a polymer with great capabilities like high elasticity, low-temperature resistance, wear resistance, and corrosion resistance. However, it will inevitably be damaged in processing or long-term use, which will shorten the service life of the material and increase the potential safety hazards. The widespread use of polyurethanes has given researchers more motivation to make polyurethanes self-healing, thereby eliminating material damage and potential safety hazards to a certain extent. This paper mainly reviews the self-healing mechanism and the research progress of intrinsic self-healing polyurethanes based on dynamic reversible non-covalent bonds, including H-bonding, metal-ligand, π-π and host-guest interactions. This paper holds that the non-covalent self-healing polyurethane can repair cracks repeatedly without adding a repair agent by introducing the above non-covalent reversible bonds into the polyurethane with good mechanical properties. Various types of reversible bonds provide a variety of options for self-healing. In addition, through the research on the preparation, mechanical properties, and self-healing ability of various self-healing polyurethanes, this paper summarizes and analyzes the prospect and existing problems of self-healing polyurethanes. In the future, researchers should focus on solving the existing deficiencies. This paper looks forward to finding a better scheme to improve the performance of self-healing polyurethanes and preparing ideal self-healing polyurethane materials that appear in the public’s field of vision. This paper is written to provide help for the research of self-healing PU and accelerate the transformation of the world to green development.
24
Lin, Ling, Haiyan Mao, Ziyin Li, Wenyao Li, and Chaoxia Wang. "Preparation and Characterization of Optically Active Polyurethane from Rotatory Binaphthol Monomer and Polyurethane Prepolymer." Molecules 26, no. 10 (May 18, 2021): 2986. http://dx.doi.org/10.3390/molecules26102986.
Full textAbstract:
Optically active polymers are promising multifunctional materials with great application potentials. Herein, environmentally friendly optically active polyurethanes (OPUs) were obtained by introducing rotatory binaphthol monomer to polyurethane. The influence of binaphthol monomer content on the structure, mechanical properties, infrared emissivity, and thermal insulation of OPUs was studied intensively. Structure characterization indicated that the optically active polyurethanes have been successfully synthesized. The OPU synthesized with BIMOL and BDO at the mole ratio of 1:1 presented better thermal resistance. In addition, OPUs showed enhanced tensile strength and stretchability with the increase of BINOL content to a certain extent due to its rigid structural features and high molecular weight. The optically active polyurethanes showed lower infrared emissivity values (8–14 μm) than waterborne polyurethane (WPU), and the infrared emissivity decreased from 0.850 to 0.572 as the content of the BINOL monomer increased. Moreover, OPU4 exhibited the best heat insulation and cooling ability with about a 7 °C temperature difference. The thus-synthesized optically active polyurethanes provide an effective solution for developing highly effective thermal insulation materials.
25
Ahmad Zubir, Syazana, Ahmad Sahrim, and Ernie Suzana Ali. "Palm Oil Polyol/ Polyurethane Shape Memory Nanocomposites." Applied Mechanics and Materials 291-294 (February 2013): 2666–69. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.2666.
Full textAbstract:
A series of nanoclay reinforced thermoplastic polyurethane with shape memory effect have been successfully synthesized via two-step polymerization process. The polyurethanes are composed of polycaprolactonediol, palm oil polyol, 4,4’-diphenylmethane diisocyanate and 1,4-butanediol. Nanoclay was added in order to improve the overall properties of the pristine polyurethane. Besides, the addition of palm oil polyol is believed to enhance the crosslinking process and further improve the properties. X-ray diffraction result showed that there is a decrease in crystallinity of polyurethane nanocomposites as clay is added. Good shape memory and mechanical properties of resulting polyurethane nanocomposites were obtained in this work.
26
Gunatillake, Pathiraja A., Darren J. Martin, Gordon F. Meijs, Simon J. McCarthy, and Raju Adhikari. "Designing Biostable Polyurethane Elastomers for Biomedical Implants." Australian Journal of Chemistry 56, no. 6 (2003): 545. http://dx.doi.org/10.1071/ch02168.
Full textAbstract:
The chemical structure, synthesis, morphology, and properties of polyurethane elastomers are briefly discussed. The current understanding of the effect of chemical structure and the associated morphology on the stability of polyurethanes in the biological environments is reviewed. The degradation of conventional polyurethanes appears as surface or deep cracking, stiffening, and deterioration of mechanical properties, such as flex-fatigue resistance. Polyester and poly(tetramethylene oxide) based polyurethanes degrade by hydrolytic and oxidative degradation of ester and ether functional groups, respectively. The recent approaches to develop polyurethanes with improved long-term biostability are based on developing novel polyether, hydrocarbon, polycarbonate, and siloxane macrodiols to replace degradation-prone polyester and polyether macrodiols in polyurethane formulations. The new approaches are discussed with respect to synthesis, properties and biostability based on reported in vivo studies. Among the newly developed materials, siloxane-based polyurethanes have exhibited excellent biostability and are expected to find many applications in biomedical implants.
27
Desappan, Venkatesh, and Jaisankar Viswanathan. "Synthesis and Characterization of Biodegradable Jatropha Oil Based Polyurethanes Using Modified Sesame Oil as Cross-Linker Containing Different NCO Groups with Improved Thermal Stability." Asian Journal of Chemistry 31, no. 10 (August 30, 2019): 2375–82. http://dx.doi.org/10.14233/ajchem.2019.22014.
Full textAbstract:
In this work, the modified S-diol were prepared from sesame oil to produce polyol. The thermal responsive vegetable oil-based polyurethane was prepared by polycondensation method. The different diisocyanate react with jatropha-sesame oil polyol to produce higher density with molecular weight of polyurethanes structure and functionality were characterized by Fourier transform spectroscopy, proton nuclear resonance spectroscopy and gel permeation chromatography. The thermal analysis was carried with TG analysis. The kinetic and thermodynamic parameters was calculated by TGA decomposition temperature and compared with PU-1, PU-2 and PU-3. Furthermore, the corresponding decomposition temperature of polyurethanes activation energy were calculated by Coats-Redfern, Sharp-Wentworth and Freeman-Carols methods, and it is investigated with lifetime of polyurethanes. Depending on the physically observed NH and C=O linkages of polyurethane matrix, which enhancing the hard and soft segment to improve their chain mobility. The success of the investigated polyurethanes, the corresponding estimated enthalpy, entropy and pre-exponential factors are much closer with toluene and phenyl based polyurethane matrix
28
Kosyanchuk, Ludmila, Nataly Kozak, Natalia Babkina, Volodymyr Bezrodnyy, and Marina Stratilat. "The dynamic characteristics of polyurethane matrix of dye laser solid-state active elements." French-Ukrainian Journal of Chemistry 4, no. 2 (2016): 40–46. http://dx.doi.org/10.17721/fujcv4i2p40-46.
Full textAbstract:
Investigations of polyurethane matrices for solid-state laser active elements showed that comparison of chain mobility and permeability for low molecular substances of polyurethanes based on glycol and diisocyanate components of various structures allows predict their radiation resistance and choose optimal chemical composition of polyurethane. The correlation was shown of polyurethane dynamic properties with values of their elastic modulus and laser damage threshold under pulsed laser irradiation as well as the weak influence of phenalenone dyes introduction on the above characteristics.
29
Zumbardo-Bacelis, Gualberto Antonio, Laura Peponi, Rossana Faride Vargas-Coronado, Eustolia Rodríguez-Velázquez, Manuel Alatorre-Meda, Pascale Chevallier, Francesco Copes, Diego Mantovani, Gustavo A. Abraham, and Juan Valerio Cauich-Rodríguez. "A Comparison of Three-Layer and Single-Layer Small Vascular Grafts Manufactured via the Roto-Evaporation Method." Polymers 16, no. 10 (May 8, 2024): 1314. http://dx.doi.org/10.3390/polym16101314.
Full textAbstract:
This study used the roto-evaporation technique to engineer a 6 mm three-layer polyurethane vascular graft (TVG) that mimics the architecture of human coronary artery native vessels. Two segmented polyurethanes were synthesized using lysine (SPUUK) and ascorbic acid (SPUAA), and the resulting materials were used to create the intima and adventitia layers, respectively. In contrast, the media layer of the TVG was composed of a commercially available polyurethane, Pearlbond 703 EXP. For comparison purposes, single-layer vascular grafts (SVGs) from individual polyurethanes and a polyurethane blend (MVG) were made and tested similarly and evaluated according to the ISO 7198 standard. The TVG exhibited the highest circumferential tensile strength and longitudinal forces compared to single-layer vascular grafts of lower thicknesses made from the same polyurethanes. The TVG also showed higher suture and burst strength values than native vessels. The TVG withstood up to 2087 ± 139 mmHg and exhibited a compliance of 0.15 ± 0.1%/100 mmHg, while SPUUK SVGs showed a compliance of 5.21 ± 1.29%/100 mmHg, akin to coronary arteries but superior to the saphenous vein. An indirect cytocompatibility test using the MDA-MB-231 cell line showed 90 to 100% viability for all polyurethanes, surpassing the minimum 70% threshold needed for biomaterials deemed cytocompatibility. Despite the non-cytotoxic nature of the polyurethane extracts when grown directly on the surface, they displayed poor fibroblast adhesion, except for SPUUK. All vascular grafts showed hemolysis values under the permissible limit of 5% and longer coagulation times.
30
Xu, Chun Lei, Yi Hu, Jin Qiang Liu, Sheng Peng Wang, Shao Min Qu, and Jian Hua Xu. "The Preparation of Core-Shell Type Acrylic-Polyurethane Composite Emulsions for Pigment Printing." Advanced Materials Research 332-334 (September 2011): 387–90. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.387.
Full textAbstract:
Vinyl-endblocked polyurethanes were prepared from polyether diols(N210), isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and 2-hydroxyethyl acrylate (HEA). The core-shell structure acrylic-polyurethane composite emulsion was prepared by seeded emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) using the polyurethanes emulsions as seeded emulsions. The core and shell regions were occupied by acrylic polymer and polyurethane, respectively. Because polyurethanes were vinyl-endblocked, acrylic monomers could graft partially to them. The formation of core-shell structure was observed by transmission electron microscopy (TEM). The structure and properties of dried film were studied by Fourier-transform infrared spectroscopy (FT-IR) and TGA.
31
Kucinska-Lipka, Justyna, Iga Gubanska, and Helena Janik. "Polyurethanes modified with natural polymers for medical application. Part II. Polyurethane/gelatin, polyurethane/starch, polyurethane/cellulose." Polimery 59, no. 03 (March 2014): 197–200. http://dx.doi.org/10.14314/polimery.2014.197.
Full text
32
Song, Ru Yi, Yong Yan Li, Xin Ping Li, Jing Zhang, and Heng Quan. "Influences of Ion Abundance of Cationic Hydrophilic Polyurethane Modified with Polysiloxane on its Emulsion Properties." Advanced Materials Research 781-784 (September 2013): 2685–89. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2685.
Full textAbstract:
Several cationic water-based polyurethanes end-capped with silicone coupling agent with different ion abundance are prepared. The effects of ion abundance of those polyurethanes on its emulsion particle size distribution, wet rubbing fastness improvement, hydrophility and soft handle are studied. The results show that the sample with moderate cationic ion abundance has optimal efficiency for color fixing of reactive dyes, and the quaterized cationic groups in polyurethane molecule should has positive contribution to hydrophility and soft handle of the treated fabric, especially for the color fabric treated with higher concentration polyurethane emulsion.
33
Yusuf, Ilyas, M. Yunus, and Teuku Rihayat. "Addition of aceh bentonite in an effort to improve the heat resistance properties of polyurethane-based paint coatings." Jurnal Polimesin 21, no. 3 (June 30, 2023): 358–60. http://dx.doi.org/10.30811/jpl.v21i3.3871.
Full textAbstract:
Polyurethane is a polymer compound whose main chain constituent is urethane group (-NHCOO-). Polyurethanes can be mixed with other polymers or other fillers in an effort to enhance and improve the properties of the single polymer. Metal coating materials are needed for metal materials that have properties resistant to heat thermal condition and corrosion that can damage the structure,. The priority and novelty of this research is to utilize the natural bentonite which is very potential in the local area to fill polyurethane-based coating paint in order to improve its properties. This research looked at the effect of mixing Polyurethane with Bentonite filler obtained from Nisam, North Aceh which has been modified with CTAB and AgNO3 surfactants. The sample formulation used is polyurethane and polyurethane with North Aceh Bentonite variations of 1.5, 2.5, and 3.5%. Characterization with the addition of Bentonite produces polymers that have good thermal stability capabilities. The addition of Bentonite filler into polyurethane polymer can affect the mechanical properties of the material. The Polyurethane/Bentonite composite sample has better thermal resistance, where in pure Polyurethane, the initial weight reduction of the pure Polyurethane sample is 50-150 ℃, the decomposition of pure Polyurethane is at 385 ℃. For Polyurethane/Bentonite 98.5:1.5% w/w nanocomposite, the initial weight reduction is 150-300 ℃, decomposition at 416 ℃. For Polyurethane/Bentonite 97.5:2.5 w/w, the initial weight reduction is 150-250 ℃ and decomposition at 430 ℃. Polyurethane/Bentonite 96.5:3.5 w/w initial weight reduction is also at 200-300 ℃ and decomposition at 458 ℃.
34
Zhu, Chun Liu, Can Tao, Jun Jie Bao, Yi Ping Huang, and Ge Wen Xu. "Waterborne Polyurethane Used as Binders for Lithium-Ion Battery with Improved Electrochemical Properties." Advanced Materials Research 1090 (February 2015): 199–204. http://dx.doi.org/10.4028/www.scientific.net/amr.1090.199.
Full textAbstract:
LiFePO4based Lithium-ion batteries are prepared by nonionic waterborne polyurethane with different soft segments which act as binder. FTIR is used to characterize the structure of waterborne polyurethanes .The emulsion viscosity, mechanical properties of films are measured. The result shows that, the emulsion viscosity and tensile strength of polyurethane based polyether glycol are smaller than polyurethane based polyester. Charge-discharge, cycle performance and AC impedance spectroscopy measurement indicat that the first charge-discharge efficiency is 92%, the biggest discharge capacity is 115 mAh/g for lithium-ion batteries based on waterborne polyurethane as adhesive which equaled to PVDF, the batteries have a good cycle performance and high cycle efficiency and the impedance of batteries are small than PVDF.
35
Kemona, Aleksandra, and Małgorzata Piotrowska. "Polyurethane Recycling and Disposal: Methods and Prospects." Polymers 12, no. 8 (August 5, 2020): 1752. http://dx.doi.org/10.3390/polym12081752.
Full textAbstract:
Growing water and land pollution, the possibility of exhaustion of raw materials and resistance of plastics to physical and chemical factors results in increasing importance of synthetic polymers waste recycling, recovery and environmentally friendly ways of disposal. Polyurethanes (PU) are a family of versatile synthetic polymers with highly diverse applications. They are class of polymers derived from the condensation of polyisocyanates and polyalcohols. This paper reports the latest developments in the field of polyurethane disposal, recycling and recovery. Various methods tested and applied in recent years have proven that the processing of PU waste can be economically and ecologically beneficial. At the moment mechanical recycling and glycolysis are the most important ones. Polyurethanes’ biological degradation is highly promising for both post-consumer and postproduction waste. It can also be applied in bioremediation of water and soil contaminated with polyurethanes. Another possibility for biological methods is the synthesis of PU materials sensitive to biological degradation. In conclusion, a high diversity of polyurethane waste types and derivation results in demand for a wide range of methods of processing. Furthermore, already existing ones appear to be enough to state that the elimination of not reprocessed polyurethane waste in the future is possible.
36
Arévalo, Fabián R., Sonia A. Osorio, Nathaly A. Valcárcel, Jeimmy C. Ibarra, and Manuel F. Valero. "Characterization and in vitro Biocompatibility of Binary Mixtures of Chitosan and Polyurethanes Synthesized from Chemically Modified Castor Oil, as Materials for Medical Use." Polymers from Renewable Resources 9, no. 1 (February 2018): 23–38. http://dx.doi.org/10.1177/204124791800900102.
Full textAbstract:
This study aimed to evaluate the effect of the incorporation of chitosan into polyurethane matrices synthesized from chemically modified castor (Ricinus communis) oil by transesterification with pentaerythritol. An additional aim of this study was to determine the degree of acceptance as a biomaterial (obtained from renewable sources), based on the analysis of its mechanical properties (stress/rupture strain), hydrophilic character (contact angle), morphology (SEM) and in vitro compatibility of polyurethanes when in contact with mouse fibroblast L929 cells. No significant changes in mechanical properties were observed with the addition of chitosan to polyurethanes synthesized from chemically modified castor oil. All polyurethane formulas showed morphological changes with increased chitosan concentration. As chitosan/polyurethane binary mixtures do not present a cytotoxicity risk for L929 mouse fibroblasts and possess similar mechanical properties to soft and cardiovascular tissues, their use as a biomedical material is suggested.
37
Nukavarapu, Syam P., Rao S. Bezwada, Deborah L. Dorcemus, Neeti Srivasthava, and Robert J. Armentano. "Novel Absorbable Polyurethane Biomaterials and Scaffolds for Tissue Engineering." MRS Proceedings 1621 (2014): 93–99. http://dx.doi.org/10.1557/opl.2014.359.
Full textAbstract:
ABSTRACTThis study reports a novel class of biodegradable polyurethane biomaterials and three-dimensional scaffolds for tissue engineering. Solvent casted polyurethane films were studied for biocompatibility by seeding with human bone marrow derived stromal cells. In order to develop a three-dimensional and porous structure, a dynamic solvent sintering method was applied to the polyurethanes for the first time. Microstructural studies on the sintered scaffolds reveal porous structure formation with bonding between the adjacent microspheres. In conclusion, this study establishes new polyurethane biomaterials that are fully absorbable for tissue engineering applications.
38
Lee, Dae-Woo, Han-Na Kim, and Dai-Soo Lee. "Introduction of Reversible Urethane Bonds Based on Vanillyl Alcohol for Efficient Self-Healing of Polyurethane Elastomers." Molecules 24, no. 12 (June 12, 2019): 2201. http://dx.doi.org/10.3390/molecules24122201.
Full textAbstract:
Urethane groups formed by reacting phenolic hydroxyl groups with isocyanates are known to be reversible at high temperatures. To investigate the intrinsic self-healing of polyurethane via a reversible urethane group, we synthesized vanillyl alcohol (VA)-based polyurethanes. The phenolic hydroxyl group of vanillyl alcohol allows the introduction of a reversible urethane group into the polyurethane backbone. Particularly, we investigated the effects of varying the concentration of reversible urethane groups on the self-healing of the polyurethane, and we proposed a method that improved the mobility of the molecules contributing to the self-healing process. The concentration of reversible urethane groups in the polyurethanes was controlled by varying the vanillyl alcohol content. Increasing the concentration of the reversible urethane group worsened the self-healing property by increasing hydrogen bonding and microphase separation, which consequently decreased the molecular mobility. On the other hand, after formulating a modified chain extender (m-CE), hydrogen bonding and microphase separation decreased, and the mobility (and hence the self-healing efficiency) of the molecules improved. In VA40-10 (40% VA; 10% m-CE) heated to 140 °C, the self-healing efficiency reached 96.5% after 30 min, a 139% improvement over the control polyurethane elastomer (PU). We conclude that the self-healing and mechanical properties of polyurethanes might be tailored for applications by adjusting the vanillyl alcohol content and modifying the chain extender.
39
Zalina, A. L., J. A. Soboleva, D. V. Zakharova, and I. P. Storozhuk. "Self-healing polyurethane-polypropylene oxide copolymers for the protection of carbon and glass fiber-reinforced composites." E3S Web of Conferences 413 (2023): 02036. http://dx.doi.org/10.1051/e3sconf/202341302036.
Full textAbstract:
Polyurethane-polypropylene oxide block copolymers containing fragments of an adduct capable of self-healing by the Diels-Alder reaction mechanism have been synthesized and studied for the first time. All obtained polyurethane copolymers were characterized by IR spectroscopy. The temperature transitions and thermal stability of copolymer melts were determined by using the methods of differential scanning calorimetry and thermogravimetric analysis. The self-healing effect was confirmed using a thermal cycling procedure on pre-damaged samples of modified polyurethanes and surface morphology studies. The perspective of the work begun on the creation of self-healing protective polyurethane coatings are shown.
40
Kiyanenko, Elena A., Artur D. Nurislamov, Ksenia V. Golovanova, Gulnara I. Amerkhanova, and Lubov A. Zenitova. "Polyurethane filled with modified basalt fiber." Butlerov Communications 63, no. 7 (July 31, 2020): 111–18. http://dx.doi.org/10.37952/roi-jbc-01/20-63-7-111.
Full textAbstract:
The use of basalt fiber as a reinforcing filler is mainly used instead of glass fibers due to its unique properties. Basalt fiber in comparison with glass has a 10-22% greater modulus, higher absolute strength after exposure to 400 °C, superior to glass in alkali and especially acid resistance, approximately identical in water resistance, i.e. close in properties to high-modulus glass fibers. However, it is most often used as a filler for concrete and other building structures. There is much less information about its use as a polymer reinforcing filler. The polymer matrix for creating polymer composite materials is most often epoxy resins, less often polyester. At the same time, there is practically no data on polyurethanes that have a unique combination of high strength indicators with elasticity and hardness, resistance to solvents and aggressive media, abrasion resistance, etc. The use of basalt fiber as a filler that increases the strength characteristics of polyurethanes and gives them specific properties can significantly expand the scope of their application. In this regard, this study attempts to use crushed basalt fiber as a reinforcing filler for polyurethanes. In order to increase the adhesion of the polymer matrix – filler system, an adhesive based on water-based polyurethane dispersion is used. Samples were obtained based on a polyurethane binder filled with basalt fiber in amounts up to 10.0 % by weight, treated with water-polyurethane dispersion with a concentration of 10 to 20 % by weight. The best complex of strength properties is provided by polyurethanes filled with basalt fiber in the amount of 1.0% by weight, treated with 15 % by weight water-based polyurethane dispersion. At the same time, the tensile strength increased by 15% compared to the same filling without processing and by 50% compared to the unfilled analog and amounted to 33.7 MPa. These changes are explained by a more uniform distribution of crushed basalt fiber in the polymer matrix and an increase in the adhesion interaction of fiber-adhesive-polymer matrix due to the biphilicity of the adhesive, as well as the same (polyurethane) nature of the adhesive and the matrix. The developed polymer composite materials have high hydrolytic resistance, as well as resistance to acetone and hexane. At the same time, the greatest degree of swelling did not exceed 0.9 % of the mass.
41
Briz-López, Eva Marina, Rodrigo Navarro, Héctor Martínez-Hernández, Lucía Téllez-Jurado, and Ángel Marcos-Fernández. "Design and Synthesis of Bio-Inspired Polyurethane Films with High Performance." Polymers 12, no. 11 (November 17, 2020): 2727. http://dx.doi.org/10.3390/polym12112727.
Full textAbstract:
In the present work, the synthesis of segmented polyurethanes functionalized with catechol moieties within the hard or the soft segment is presented. For this purpose, a synthetic route of a new catechol diol was designed. The direct insertion of this catechol-free derivative into the rigid phase led to segmented polyurethanes with low performance (σmax ≈ 4.5 MPa). Nevertheless, when the derivative was formally located within the soft segment, the mechanical properties of the corresponding functionalized polyurethane improved considerably (σmax ≈ 16.3 MPa), owing to a significant increase in the degree of polymerization. It is proposed that this difference in reactivity could probably be attributed to a hampering effect of this catecholic ring during the polyaddition reaction. To corroborate this hypothesis, a protection of the aromatic ring was carried out, blocking the hampering effect and avoiding secondary reactions. The polyurethane bearing the protected catechol showed the highest molecular weight and the highest stress at break described to date (σmax ≈ 66.1 MPa) for these kind of catechol-functionalized polyurethanes. Therefore, this new approach allows for the obtention of high-performance polyurethane films and can be applied in different sectors, benefiting from the molecular adhesion introduced by the catechol ring.
42
Grzęda, Dominik, Grzegorz Węgrzyk, Adriana Nowak, Joanna Idaszek, Leonard Szczepkowski, and Joanna Ryszkowska. "Cytotoxic Properties of Polyurethane Foams for Biomedical Applications as a Function of Isocyanate Index." Polymers 15, no. 12 (June 20, 2023): 2754. http://dx.doi.org/10.3390/polym15122754.
Full textAbstract:
Polyurethane foams are widely used in biomedical applications due to their desirable mechanical properties and biocompatibility. However, the cytotoxicity of its raw materials can limit their use in certain applications. In this study, a group of open-cell polyurethane foams were investigated for their cytotoxic properties as a function of the isocyanate index, a critical parameter in the synthesis of polyurethanes. The foams were synthesized using a variety of isocyanate indices and characterized for their chemical structure and cytotoxicity. This study indicates that the isocyanate index highly influences the chemical structure of polyurethane foams, also causing changes in cytotoxicity. These findings have important implications for designing and using polyurethane foams as composite matrices in biomedical applications, as careful consideration of the isocyanate index is necessary to ensure biocompatibility.
43
Grancharov, Georgy, Mariya-Desislava Atanasova, Radostina Kalinova, Pencho Tuleshkov, Petar D. Petrov, Maya K. Marinova, Martin A. Ravutsov, and Svilen P. Simeonov. "Biorenewable Oxypropylated Pentane-1,2,5-triol as a Source for Incorporation in Rigid Polyurethane Foams." Polymers 15, no. 20 (October 19, 2023): 4148. http://dx.doi.org/10.3390/polym15204148.
Full textAbstract:
In this study, as a product from the efficient Achmatowicz rearrangement and mild subsequent hydrogenation–reduction reactions of biorenewable C5 alcohols derived from lignocellulose, pentane-1,2,5-triol was successfully used after oxypropylation in the preparation of rigid polyurethane foams—one of the most important classes of polymeric materials. Despite the broad range of applications, the production of polyurethanes is still highly dependent on petrochemical materials considering the need of renewable raw materials and new process technologies for the production of polyol or isocyanate components as a key point for the sustainable development of polyurethane foams. The synthesized oxypropylated pentane-1,2,5-triol was analyzed using proton NMR spectroscopy, hydroxyl number, and viscosity, whereas the newly obtained foams incorporated with up to 30% biorenewable polyol were characterized using compressive stress, thermogravimetry, dynamic mechanical analysis, and scanning electron microscopy. The modified rigid polyurethanes showed better compressive strength (>400.0 kPa), a comparable thermal degradation range at 325–450 °C, and similar morphological properties to those of commercial polyurethane formulations.
44
Domańska, Agata, Anna Boczkowska, Marta Izydorzak, Zbigniew Jaegermann, and Krzysztof Kurzydłowski. "Polyurethanes used in the endoprosthesis of joints." Polish Journal of Chemical Technology 12, no. 3 (January 1, 2010): 10–14. http://dx.doi.org/10.2478/v10026-010-0025-y.
Full textAbstract:
Polyurethanes used in the endoprosthesis of joints The aim of the studies presented in this paper was the selection of the polyurethanes synthesized from different substrates in order to obtain i) ceramic - biodegradable polymer composite and ii) polyurethane resistant to abrasive wear. The polyurethanes were obtained from the crystalline prepolymers extended by water, because it may have a beneficial effect on the toxicity of the material. The properties of PUs were investigated using infrared spectroscopy, thermogravimetry, differential scanning calorimetry and scanning electron microscopy. In all the tested polyurethanes the peak from the reactive -NCO groups was not observed, which indicates that all the substrates are fully reacted. Such polyurethanes are characterized by interesting properties with the perspective use as components of ceramic-polymer joints endoprosthesis. The designed endoprosthesis should fulfill at least three functions: load bearing function (ceramic core), fastening and stabilizing endoprosthesis to the bone (composite ceramics - biodegradable polymer) and tribologic function allowing mating with parts of the prosthesis (polyurethane layer resistant to abrasive wear).
45
Lee, Jong Baek, Kwang Hyun Lee, Byung Chul Kang, Byung Won Kang, Sang Ll Lee, and Jin Kyung Lee. "Thermal Properties of a Liquid-Crystalline Polyurethanes Containing Biphenyl Mesogen." Key Engineering Materials 321-323 (October 2006): 1385–88. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1385.
Full textAbstract:
A new type of thermotropic main-chain liquid crystalline polyurethanes containing biphenyl units was synthesized by polyaddition reaction of diisocyanates such as 2,6-tolylene diisocyanate, 2,5-tolylene diisocyanate, 2,4-tolylene diisocyanate, and 1,4-phenylene diisocyanate, with 4,4′-Bis(11-hydroxyundeyloxy)biphenyl (BP11). The structure of the monomer and the corresponding polymers were confirmed FT-IR and 1H NMR spectroscopic methods. BP11 exhibited a smectic type mesophase, however, nematic phase was found for all synthesized liquid crystalline polyurethanes except for 1,4-phenylene diisocyanate/BP11 based polyurethane. For example, polyurethane 2,5-TDI/BP11 exhibited monotropic liquid crystallinity in the temperature ranges from 173 to 156 °C on the cooling stage.
46
Correia, Cristina Borges, and João C. Bordado. "Synthesis and Characterization of New Polyurethane Adhesives." Materials Science Forum 514-516 (May 2006): 843–47. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.843.
Full textAbstract:
Polyurethane adhesives provide excellent flexibility, impact resistance and durability. Polyurethanes are formed through the reaction of an isocyanate component with polyether or polyester polyols or other active hydrogen compounds. This paper refers to polyurethane adhesives made from polyester polyols with long aliphatic chains (up to 36 carbon atoms) and MDI (diphenylmethane-4,4’-diisocyanate). The polyester polyols have been made from dimer acids obtained from renewable sources and short chain diols. The polyols that were used presented different degrees of unsaturation. The influence of the different raw materials in the adhesives performance is studied. The polyurethanes were produced by reaction between quasi-stoichiometric quantities of polyol and MDI, at several temperatures. The reaction was carried under inert atmosphere and at temperatures below 100°C. Performance of the adhesives was tested by carrying adhesion, hardness and water absorption tests. Characterization of both the polyester polyols and polyurethane adhesives was carried by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Magnetic Nuclear Resonance (NMR), X-Ray Diffraction (WAXD), Scanning RMN Imaging of 1H of Stray- Field b (MRI) and Brookfield viscometry.
47
Chen, Caihong, Zhening Yang, Fengxian Qiu, Feiyan Ye, Guorong Cao, Yijun Guan, and Dongya Yang. "Novel three chiral azobenzene polyurethanes: Preparation, optical properties and simulation comparisons of two different polymeric thermo-optic switches." Journal of Nonlinear Optical Physics & Materials 24, no. 03 (September 2015): 1550028. http://dx.doi.org/10.1142/s0218863515500289.
Full textAbstract:
Three different structures of chiral side-chain azobenzene polyurethane (CAPU-1), chiral graft azobenzene polyurethane (CAPU-2) and chiral bisazo polyurethane (CAPU-3) were prepared by diazo coupling reaction. The structures, thermal, mechanical properties, refractive index (n) and transmission loss of CAPU-1~3 were investigated. The Y-branch and Mach–Zehnder polymeric thermo-optic switches were simulated based on the synthesized three chiral azo polyurethanes as waveguide materials. The response time differences are owing to the different substituents and structure of the azo compound. The conclusion had potential significance to improve and develop the new digital optical and thermo-optic switch (TOS) with short response time and low driving power.
48
Gomez-Lopez, Alvaro, Fermin Elizalde, Iñigo Calvo, and Haritz Sardon. "Trends in non-isocyanate polyurethane (NIPU) development." Chemical Communications 57, no. 92 (2021): 12254–65. http://dx.doi.org/10.1039/d1cc05009e.
Full textAbstract:
The transition towards safer and more sustainable production of polymers has led to a growing body of academic research into non-isocyanate polyurethanes (NIPUs) as potential replacements for conventional, isocyanate-based polyurethane materials.
49
Nakajima-Kambe, T., Y. Shigeno-Akutsu, N. Nomura, F. Onuma, and T. Nakahara. "Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes." Applied Microbiology and Biotechnology 51, no. 2 (February 25, 1999): 134–40. http://dx.doi.org/10.1007/s002530051373.
Full text
50
Liu, Beibei, Kun Wang, Hao Lu, Mingming Huang, Zhigang Shen, and Jiping Yang. "Thermally responsive AIE-active polyurethanes based on a tetraaniline derivative." RSC Advances 10, no. 68 (2020): 41424–29. http://dx.doi.org/10.1039/d0ra06193j.
Full text