To see the other types of publications on this topic, follow the link: Urethanne polymere.
Journal articles on the topic 'Urethanne polymere'
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 'Urethanne polymere.'
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
Ferraro, Luiz Gustavo, Felipe Bastos de Souza Alvarenga, Maria Virginia Gelfuso, and Daniel Thomazini. "Investigation to Obtain Polyols from Residual Frying Oil." Materials Science Forum 775-776 (January 2014): 351–56. http://dx.doi.org/10.4028/www.scientific.net/msf.775-776.351.
Full textAbstract:
. Polymeric materials based on petroleum have generated a major problem for the environment because they are produced by non-renewable sources. Many studies are being conducted to propose alternatives to obtain polymers from renewable raw materials sources. The disadvantage of this alternative is the use of food sources for polymer production but this is avoided when using the residual frying oil. Aiming to obtain polymer-based urethanes, pretreated residual frying oil samples were submitted to various conditions of hydroxylation and analyzed by FT-IR, where it was possible to observe the presence of-OH groups. To optimize the process of hydroxylation a new research was conducted to determine the concentrations of formic acid and hydrogen peroxide that can generate polyols with high levels of hydroxylation index, suitable for the formation of urethanes.
2
Didenko, Andrei, Danila Kuznetcov, Gleb Vaganov, Valentina Smirnova, Elena Popova, Alexey Ivanov, Boris Chernitsa, Valentin Svetlichnyi, Vladimir E. Yudin, and Vladislav Kudryavtsev. "The Thermal Stability and Mechanical Properties of Non-Segregating Blends of Polyimides with Copoly(Urethane-Imide)s." Key Engineering Materials 869 (October 2020): 280–95. http://dx.doi.org/10.4028/www.scientific.net/kem.869.280.
Full textAbstract:
The series of compositions containing thermodynamically incompatible flexible blocks of aliphatic polyesters and rigid blocks of aromatic bis (urethane) imides in the volume of polymers was obtained on the basis of multiblock (segmented) poly (urethane-imides) and related aromatic polyimides. The series includes segmented poly (urethane-imides) with different relative content of flexible and rigid blocks, non-segregating mixtures of poly (urethane-imides) and thermoplastic partially crystalline polyimide, statistical copolymers of poly (urethane-imide) with imide, and non-segregating mixtures of statistical copolymers with thermoplastic polyimide. The derived polymer systems were studied using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The deformation and strength properties of film samples are determined. It is shown that the properties of the studied polymers change as their content of imides blocks increases, and the transition from thermoplastic poly (urethane-imide) elastomers to thermoplastic polyimides is observed.
3
KUZMENKO, S. M., E. O. SPORYAGIN, O. M. KUZMENKO, and A. YA PUZENKO. "SYNTHESIS AND PROPERTIES OF OLIGODIURETANEDIOLS BASED ON A MIXTURE OF (2,4–2,6) TOLUILENDIISOCYANATE." Polymer journal 43, no. 3 (September 20, 2021): 198–203. http://dx.doi.org/10.15407/polymerj.43.03.198.
Full textAbstract:
The paper describes the synthesis, the reaction of a mixture of isomers (2,4–2,6) of toluilendiisocyanate with a double molar excess of aliphatic individual or oligomeric diols, a number of previously unknown oligodiuretanediols and their physicochemical constants. It is shown that with an increase in the synthesis temperature from 50 to 70 °C, the reaction time to complete depletion in the mixture of free NCO-groups decreases from 8–9 hours to 3–4 hours. The reaction temperature of 70–2 °С should be considered optimal, because at higher temperatures side reactions of free NCO-groups with already formed urethane ones are possible. Because the presence of even a small amount of moisture in the diols can provoke side effects during the urethane formation reaction, all of the above diols were dried from the adsorbed moisture by azeotropic distillation with toluene before use in the reaction. Since the final products are even at the synthesis temperature (68–70 °C) viscous liquids, and there are difficulties with the homogenization of the reaction mass during synthesis, and when unloading the finished product from the reaction plant, in all cases, the synthesis was performed in solution cyclohexanone by 50 % by weight of the final product. Control of the reaction was performed by changing the % wt. free NCO-groups in time. The reaction was considered complete if the measured % wt. free NCO-groups in the reaction mixture for at least one hour twice showed zero. The isolated oligodiuretanediols range from solid at room temperature to very viscous products, which significantly depends on the molecular weight of the diol used in the reaction (ie the concentration of urethane groups formed). They are homogeneous, transparent compounds that are readily soluble in esters, ethers, aromatic and halide-containing, aprotic solvents, ketones, poorly or completely insoluble in aliphatic saturated hydrocarbons. The structure of the synthesized oligomeric products is confirmed by functional analysis, IR–spectra. In the IR-spectra of each of the synthesized oligodiuretanediols there are no absorption bands in the region of 2270 cm-1, which confirms the complete completion of the reaction of urethane formation according to the scheme. At the same time, the absorption bands in the region of 3450 cm-1, 1720 cm-1, 1540 cm-1 are fixed, which are characteristic of the presence of urethane groups in the structure of the target products. As the chain length of the diol component –R– increases in the target product (which synchronously leads to an increase in molecular weight), the intensity of these absorption bands decreases, which is associated with a decrease in the concentration of formed urethane groups in the structure of oligodiuretanediols. The refractive index also decreases synchronously. Synthesized series of oligodiuretanediols can be used for synthesis on its basis of other classes of oligomers with the simultaneous presence in the structure of urethane groups. The ability of such compounds to be soluble in solvents of different nature has been studied, which provides information for the directions of their further use (varnishes, enamels, primers).
4
Jalal, Mahir A. "Synthesis and Evaluation of Urethane Polymers from PET Waste." Journal of Zankoy Sulaimani - Part A 17, no. 2 (January 25, 2015): 51–62. http://dx.doi.org/10.17656/jzs.10380.
Full text
5
Laurano, Rossella, Monica Boffito, Claudio Cassino, Francesco Liberti, Gianluca Ciardelli, and Valeria Chiono. "Design of Injectable Bioartificial Hydrogels by Green Chemistry for Mini-Invasive Applications in the Biomedical or Aesthetic Medicine Fields." Gels 9, no. 1 (January 11, 2023): 59. http://dx.doi.org/10.3390/gels9010059.
Full textAbstract:
Bioartificial hydrogels are hydrophilic systems extensively studied for regenerative medicine due to the synergic combination of features of synthetic and natural polymers. Injectability is another crucial property for hydrogel mini-invasive administration. This work aimed at engineering injectable bioartificial in situ cross-linkable hydrogels by implementing green and eco-friendly approaches. Specifically, the versatile poly(ether urethane) (PEU) chemistry was exploited for the development of an amphiphilic PEU, while hyaluronic acid was selected as natural component. Both polymers were functionalized to expose thiol and catechol groups through green water-based carbodiimide-mediated grafting reactions. Functionalization was optimized to maximize grafting yield while preserving group functionality. Then, polymer miscibility was studied at the macro-, micro-, and nano-scale, suggesting the formation of hydrogen bonds among polymeric chains. All hydrogels could be injected through G21 and G18 needles in a wide temperature range (4–25 °C) and underwent sol-to-gel transition at 37 °C. The addition of an oxidizing agent to polymer solutions did not improve the gelation kinetics, while it negatively affected hydrogel stability in an aqueous environment, suggesting the occurrence of oxidation-triggered polymer degradation. In the future, the bioartificial hydrogels developed herein could find application in the biomedical and aesthetic medicine fields as injectable formulations for therapeutic agent delivery.
6
Кулікова, І. О., Г. В. Міщенко, О. В. Міщенко, О. О. Венгер, and Т. А. Попович. "НАДАННЯ ПІДВИЩЕНОЇ ЗНОСОСТІЙКОСТІ ТКАНИНАМ ДЛЯ ЗАХИСНОГО ОДЯГУ." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 128, no. 6 (April 9, 2019): 47–55. http://dx.doi.org/10.30857/1813-6796.2018.6.5.
Full textAbstract:
The purpose of the work is to increase the wear resistance of textile materials by forming composite polymer films on their surfaces. Methodology. The problem was solved by the use of a mixture of polymers and due to their ability to formulate composite polymer systems that combine the properties of individual polymers and exhibit new ones. One of them was used in the form of aqueous dispersion of the finished polymer of urethane type, and the second one was synthesized from pre-condensates of thermosetting resins (PTSR) in the process of finishing, namely, at the stage of heat treatment of the fabric after impregnation and drying, by providing conditions for the course of the condensation reaction.
7
Didenko, A. L., A. G. Ivanov, V. E. Smirnova, G. V. Vaganov, E. N. Popova, D. A. Kuznetsov, L. A. Myagkova, V. M. Svetlichniy, V. E. Yudin, and V. V. Kudryavtsev. "Comparative characteristics of products of processing of fusible copoly (urethane-imides) from the solutions and melts formed by them." Plasticheskie massy, no. 9-10 (November 29, 2022): 20–24. http://dx.doi.org/10.35164/0554-2901-2022-9-10-20-24.
Full textAbstract:
Self-supporting films and thick-walled moldings (blades) were obtained from solutions and melts of multiblock (segmental) copoly(urethane-imides). The initial copoly(urethane-imides) were obtained on the basis of aliphatic polyesters: poly(propyleneglycol), poly(diethyleneglycoladipinate) and polycaprolactone, dianhydride of 1,3-bis(3’,4-dicarboxyphenoxy) benzene and aromatic diamines: 4,4’-bis-(4”-aminophenoxy)biphenyl and 1,4-bis(4’-aminophenoxy)diphenylsulfone. Samples of films and moldings were studied by IR spectroscopy, TGA, DSC and mechanical analysis under static and dynamic (DMA) experimental conditions. It is assumed that the diff erences in the properties of films and moldings are due to an increase in the proportion of aromatic blocks due to microdestruction of polymer chains and increased interfacial interactions of polyester and urethanimide microphases (blocks) in polymer systems during the processing of polymers from the melt by injection molding.
8
Simioni, F., and M. Modesti. "Glycolysis of Flexible Polyurethane Foams." Cellular Polymers 12, no. 5 (September 1993): 337–48. http://dx.doi.org/10.1177/026248939301200501.
Full textAbstract:
Flexible water blown polyurethanes are polymers with repeating urethane and urea groups. When they undergo heating in the presence of glycols the reaction of these groups leads to soluble products. The transesterification reaction of the urethane groups, that leads to the formation of new carbamate is faster than that of the urea groups. Carbamates in turn undergo aminolysis due to the amines formed in the glycolysis of the urea groups. The use of ethylene glycol (EG) allows the process to be carried out with high polymer/glycol ratio (up to 4:1). A polyphase product is obtained with a top liquid phase mainly formed by the polyether polyol from the polymer, an intermediate liquid phase formed by the solution of carbamates, ureas and amines in EG and a bottom solid phase with compounds with prevalent urea bonds.
9
Gonchar, Oleksii, YURI SAVELYEV, and ТAMARA TRAVINSKAYA. "Polyurethaneacrylate/montmorillonite nanocomposites." Polymer journal 43, no. 1 (March 9, 2021): 03–11. http://dx.doi.org/10.15407/polymerj.43.01.003.
Full textAbstract:
In order to create polymer nanocomposites with high performance on the basis of polyurethaneacrylates (PUA) with montmorillonite (MMT), three methods of chemical modification of the layered silicate surface have been developed. The first modification method is based on using of two different functional modifiers (organophilic and reactive), the second method is based on modification with synthesized by us compound which contains urethane groups, and the third one in based on using synthesized by us modifier containing urethane and other reactive groups. Exchange capacity of the MMT surface was determined by adsorption of indicator “methylene blue”. Intercalation of modifier into the interlayer space of MMT was confirmed by X-ray analysis; the content of organic component in the modified MMT (MMT/M) was determined by thermogravimetric analysis. The resulting organoclay is purposed for the formation of nanostructured composites based on cross-linked polyurethane acrylates with improved physical and mechanical properties. The obtained polyurethaneacrylate nanocomposites with different type MMT/M exhibit the increased in 1,6–2,6 times tensile strength as compared to original polymer matrix. WAXS method has proved an intercalation of modifier into MMT interlayer space (increased distance between layers after modification), as well as the total exfoliation of MMT in PUA matrix, characterized by the disappearance of the absorption peak which is responsible for layered structure.
10
Aranberri, Ibon, Sarah Montes, Itxaso Azcune, Alaitz Rekondo, and Hans-Jürgen Grande. "Flexible Biocomposites with Enhanced Interfacial Compatibility Based on Keratin Fibers and Sulfur-Containing Poly(urea-urethane)s." Polymers 10, no. 10 (September 21, 2018): 1056. http://dx.doi.org/10.3390/polym10101056.
Full textAbstract:
Feathers are made of keratin, a fibrous protein with high content of disulfide-crosslinks and hydrogen-bonds. Feathers have been mainly used as reinforcing fiber in the preparation of biocomposites with a wide variety of polymers, also poly(urea-urethane)s. Surface compatibility between the keratin fiber and the matrix is crucial for having homogenous, high quality composites with superior mechanical properties. Poly(urea-urethane) type polymers are convenient for this purpose due to the presence of polar functionalities capable of forming hydrogen-bonds with keratin. Here, we demonstrate that the interfacial compatibility can be further enhanced by incorporating sulfur moieties in the polymer backbone that lead to new fiber-matrix interactions. We comparatively studied two analogous thermoplastic poly(urea-urethane) elastomers prepared starting from the same isocyanate-functionalized polyurethane prepolymer and two aromatic diamine chain extenders, bis(4-aminophenyl) disulfide (TPUU-SS) and the sulfur-free counterpart bis(4-aminophenyl) methane (TPUU). Then, biocomposites with high feather loadings (40, 50, 60 and 75 wt %) were prepared in a torque rheometer and hot-compressed into flexible sheets. Mechanical characterization showed that TPUU-SS based materials underwent higher improvement in mechanical properties than biocomposites made of the reference TPUU (up to 7.5-fold higher tensile strength compared to neat polymer versus 2.3-fold). Field Emission Scanning Electron Microscope (FESEM) images also provided evidence that fibers were completely embedded in the TPUU-SS matrix. Additionally, density, thermal stability, and water absorption of the biocomposites were thoroughly characterized.
11
Guo, Xinru, Feng Liu, Meng Lv, Fengbiao Chen, Fei Gao, Zhenhua Xiong, Xuejiao Chen, Liang Shen, Faman Lin, and Xuelang Gao. "Self-Healable Covalently Adaptable Networks Based on Disulfide Exchange." Polymers 14, no. 19 (September 21, 2022): 3953. http://dx.doi.org/10.3390/polym14193953.
Full textAbstract:
Introducing dynamic covalent bonding into thermoset polymers has received considerable attention because they can repair or recover when damaged, thereby minimizing waste and extending the service life of thermoset polymers. However, most of the yielded dynamic covalent bonds require an extra catalyst, high temperature and high-pressure conditions to trigger their self-healing properties. Herein, we report on a catalyst-free bis-dynamic covalent polymer network containing vinylogous urethane and disulfide bonds. It is revealed that the introduction of disulfide bonds significantly reduces the activation energy (reduced from 94 kJ/mol to 51 kJ/mol) of the polymer system for exchanging and promotes the self-healing efficiency (with a high efficiency of 86.92% after being heated at 100 °C for 20 h) of the material. More importantly, the mechanical properties of the healed materials are comparable to those of the initial ones due to the special bis-dynamic covalent polymer network. These results suggest that the bis-dynamic covalent polymer network made of disulfide and inter-vinyl ester bonds opens a new strategy for developing high-performance vitrimer polymers.
12
Puszka, Andrzej, and Janusz W. Sikora. "Synthesis and Characterization of New Polycarbonate-Based Poly(thiourethane-urethane)s." Polymers 14, no. 14 (July 20, 2022): 2933. http://dx.doi.org/10.3390/polym14142933.
Full textAbstract:
The new segmented poly(thiourethane-urethane)s (PTURs) based on 1,1′-methanediylbis(4-isocyanatocyclohexane) (HMDI, Desmodur W®), polycarbonate diol (PCD, Desmophen C2200) and (methanediyldibenzene-4,1-diyl)dimethanethiol were synthesized by one-step melt polyaddition method. The obtained PTURs, with a content of 30–60 wt% of the hard segments (HS), were tested in which the influence of changes in the HS content on their properties was determined. The polymers were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), thermal analysis (DSC, TGA) and thermomechanical analysis (DMTA). Additionally, tensile strength, optical (refractive index, UV-VIS and color) and surface properties of the obtained polymers (contact angle and surface free energy) and adhesion to copper were examined. FTIR analysis verified the supposed structure of the polymers obtained and showed a complete conversion of the isocyanate groups. TGA analysis confirmed the relatively good thermal stability of the polymers. On the other hand, after performing the DSC analysis, it was possible to state that the obtained materials were partially or completely amorphous, and the microphase separation decreased with increasing HS content in the polymer. Similar observations were made from the DMTA data. In addition, the hardness, tensile strength, modulus of elasticity, storage modulus, adhesion to copper, refractive index and total free surface energy increased with increasing HS content in the polymer.
13
Król, Piotr, Paweł Chmielarz, Bożena Król, and Kinga Pielichowska. "Comparison of Hydrolytic Resistance of Polyurethanes and Poly(Urethanemethacrylate) Copolymers in Terms of their Use as Polymer Coatings in Contact with the Physiological Liquid." Polish Journal of Chemical Technology 16, no. 2 (June 26, 2014): 16–26. http://dx.doi.org/10.2478/pjct-2014-0024.
Full textAbstract:
AbstractPU elastomers were synthesized using MDI, PTMO, butane-1,4-diol or 2,2,3,3-tetrafiuorobutane-1,4-diol. Using the same diisocyanate and polyether reagents urethane segments were prepared, to be inserted in the poly(urethane-methacrylate) copolymers. Bromourethane or tetraphenylethane-urethane macroinitiators were used as transitional products reacting with MMA according to the ARGET ATRP. 1H and 13C NMR spectral methods, as well as DSC and TGA thermal methods, were employed to confirm chemical structures of synthesised elastomers and copolymers. To investigate the possibility of using synthesized polymers as biomaterials a research on keeping them in physiological liquid at 37°C was performed. A loss in weight and ability to sorption of water was determined and by using GPC the molecular weight changes were compared. Additionally, changes in the thermal properties of the samples after exposure in physiological liquid were documented using both the TGA and DSC methods. The studies of surface properties (confocal microscopy and SFE) of the obtained polymers were performed. The structure of the polymer chains was defined by NMR. Possible reasons of hydrolysis were discussed, stating that new copolymers are more resistant and polar biomaterials can be less interesting than elastomers.
14
Madhi, Abbas, and Behzad S Hadavand. "Eco-friendly castor oil-based UV-curable urethane acrylate zinc oxide nanocomposites: Synthesis and viscoelastic behavior." Journal of Composite Materials 54, no. 1 (June 29, 2019): 101–10. http://dx.doi.org/10.1177/0021998319858017.
Full textAbstract:
Attention to environmental problems and the importance of maintaining it have caused the researchers to pay more attention in this regard. The production of polymers and resins has increased in recent years and has affected by environmental pollution due to their long-term degradation. An appropriate solution to this problem is the synthesis of degradable and environmentally friendly polymers and resins. Using natural materials in the synthesis of polymers and resins can help them to be environmentally friendly. The purpose of this research is to synthesize urethane acrylate resins using natural resources. For this purpose, the urethane acrylate pre-polymer was synthesized with castor oil. Then, using modified zinc oxide nanoparticles with 1, 3 and 5 wt% urethane acrylate zinc oxide nanocomposites were produced. The use of castor oil as a degradable part and lack of organic solvent in radiation systems led to the creation of an environmentally friendly resin. Subsequently, the viscoelastic behavior of the prepared nanocomposite was evaluated. Spectrometry results confirm the synthesized resin structure. The morphology of nanocomposites confirmed the proper particle size distribution in a 3 wt.% sample. The results of the dynamic mechanical thermal analysis test showed that increasing the amount of modified nano ZnO could increase the glass transition temperature, and the maximum value was observed in 5 wt.% modified nano ZnO (69.7℃).
15
Malysheva, T. L., and A. L. Tolstov. "Miscibility of poly(urethane-urea) elastomers with chlorinated poly(vinyl chloride)." Polymer journal 43, no. 1 (March 9, 2021): 19–25. http://dx.doi.org/10.15407/polymerj.43.01.019.
Full textAbstract:
Effect of a chemical structure of poly(ether-urethane-urea) (PUU) elastomers on a miscibility of their blends with chlorinated poly(vinyl chloride) (cPVC) has been studied by FTIR and DSC. The segmented PUU were synthesized by prepolymer approach in N,N-dimethylformamide (DMF) solution. PUU-1 was synthesized using poly(propylene glycol) (PPG) of Mn = 1000, mixture of 2,4- and 2,6-isomers of tolylenediisocyanate (TDI) in a ratio of 65:35 (by weight) and 4,4´-methylenedianiline as a chain extender at a molar ratio of 1:2:1. PUU-2 was prepared based on poly(tetramethylene glycol) (PTMG) of Mn = 1000, TDI and cyanoethylated ethylene diamine at a molar ratio of 2:3:1. The polymer-polymer blends were obtained via solution casting technique using DMF as a solvent. It was found a miscibility of the polymers enhances due to a formation of hydrogen or donor-acceptor bonding between polar NH urethane-urea or nitrile groups of hard PUU segments and chlorine of cPVC. According to DSC results the polymer-polymer systems stabilized by stronger donor-acceptor bonding are characterized by single glass transition temperature, Tg, a position of which is higher than that of the theoretical one, TFg, calculated in full composition range via Fox’s equation. When stabilization of polymer-polymer blend with 30 % (by weight) of cPVC performs by weaker hydrogen bonding we observed a formation of mixed phase and the composite is characterized by appearance of three relaxation transitions. Increasing cPVC content reduces a miscibility of the components and biphasic structure of the composites forms. Comparative analysis of experimental and theoretical (additive) tensile strength vs composition dependencies demonstrates an impact of donor-acceptor interface interactions on strength of the polymer composites obtained.
16
Boiko, V. P. "Kinetic features of an urethane formation reaction of hydroxyl-containing oligodienes." Polymer journal 37, no. 2 (June 20, 2015): 115–30. http://dx.doi.org/10.15407/polymerj.37.02.115.
Full text
17
Rodriguez, JE, DH Giraldo, JC Restrepo, and HA Colorado. "Cross-linked ethylene-vinyl acetate – poly(urethane) temperature-memory composite actuator." Journal of Composite Materials 54, no. 28 (June 17, 2020): 4441–55. http://dx.doi.org/10.1177/0021998320933664.
Full textAbstract:
Semicrystalline polymeric systems are a type of Shape Memory Polymer (SMP), which are more straightforward to synthesize in comparison with other class of stimulus-responsive polymers. On these systems, the shape memory is triggered by temperature and partially driven by crystallization-induced elongation, heating-induced contraction, and elastic entropy. However, a stable temporary and permanent shape through cycling is not easy to achieve. For that reason, a laminar composite made based in the encapsulation of ethylene vinyl acetate (EVA) inside a PU matrix was developed, with the aim of obtaining an actuator with a preferred deformation direction and stable change of shape. In this study, chemically cross-linked ethylene vinyl acetate copolymer (cEVA) as SMP was synthesized and functionalized as a reinforcing strip. A temperature-memory actuator composite was manufactured by the encapsulation of a shape memory programmed strip in an elastomer matrix. The shape memory properties and thermocycling assessment were evaluated using differential scanning calorimetry and dynamic mechanical analysis. Results show the ability of the actuator to bend and unbend, following multiple consecutive heating-cooling cycles. The relationship between the strip, the matrix, and the interface is critical in the bending and shape memory maintenance.
18
Hicks, D. A., M. Krommenhoek, D. J. Soderberg, and J. F. G. Hopper. "Polyurethanes Recycling and Waste Management." Cellular Polymers 13, no. 4 (July 1994): 259–76. http://dx.doi.org/10.1177/026248939401300401.
Full textAbstract:
Almost everybody in the urethanes industry is by now familiar with the different options for the recycling of urethane-based materials. Physical recycling (fillers in the polyol), chemical recycling (glycolysis, hydrolysis) and energy recovery are the main options under development. The actual process, however, is only a part of the equation. Disassembly, logistics, applications for recycled materials and market size are other vital elements for success. In this paper, progress is presented on the different recycling options, in conjunction with a cost model which has been developed especially for the purpose.
19
Istratov, V. V., V. I. Gomzyak, O. V. Yamskova, G. D. Markova, L. G. Komarova, B. A. Izmaylov, and V. A. Vasnev. "Novel polymer surfactants based on the branched silatrane-containing polyesters and polyethers." Fine Chemical Technologies 14, no. 5 (November 14, 2019): 61–70. http://dx.doi.org/10.32362/2410-6593-2019-14-5-61-70.
Full textAbstract:
Objectives. Biologically active polymeric surfactants are a new promising class of macromolecules that can find application in medicine, cosmetology, and agriculture. In this study, a number of new biologically active amphiphilic polymers based on branched silatrane-containing polyesters and polyethers were obtained, and their surface-active properties were investigated.Methods. The branched polymers were represented by polyethers and polyesters, obtained respectively via the anionic polymerization of 1,2-epoxypropanol or a combination of equilibrium polycondensation and ring opening polymerization. The polymers were modified with 3-isocyanopropylsilatrane and trimethylethoxysilane to obtain the amphiphilic compounds containing silatrane groups bonded to the polymer backbone by the urethane bond. The structure of the synthesized polymer silatranes was confirmed via nuclear magnetic resonance spectroscopy and gel permeation chromatography. The surface active properties of all the copolymers obtained were investigated in connection with their obvious amphiphilicity. In particular, the formation of micelles in aqueous solutions is such a property. The critical micelle concentrations were determined by a method of quenching the fluorescence of the polymers.Results. It was shown that the values of the critical micelle concentrations and the hydrophilic-lipophilic balance values of polymers determined by the Griffin equation correlate well with each other. A linear relationship between the hydrophilic-lipophilic balance and the critical micelle concentrations was established. At the same time, polyether-based polymers generally showed higher critical micelle concentrations than polyester-based polymers, although the hydrophilic-lipophilic balance values for polymers of different series, but with close degrees of substitution, were close. It was found that the use of all synthesized polymers as stabilizers of direct and reverse emulsions leads to an increase in the aggregative stability of both types of emulsions. The stability of emulsions depended both on the degree of substitution of peripheral hydroxyl groups of polymers by silatranes and on the molecular weight and structure of the branched block of polymers. The stability of direct emulsions increased for all polymers, while that of inverse emulsions decreased with an increasing degree of substitution of hydroxyl groups by silatranes. The increase of the branched block molecular weight led to an increase of droplet sizes for both direct and inverse emulsions. The smallest droplet size for direct and inverse emulsions was obtained using polymers with low molecular weight branched polyester blocks as surfactants.Conclusions. The results obtained prove the possibility of creating polymer surfactants containing silatrane groups. By varying the structure of the polymer, its molecular weight and the degree of substitution of peripheral functional groups, it is possible to obtain surfactants with desired surface properties.
20
Fiket, Lucija, Marin Božičević, Lana Brkić, Patricia Žagar, Anamarija Horvat, and Zvonimir Katančić. "Intrinsically Stretchable Poly(3,4-ethylenedioxythiophene) Conducting Polymer Film for Flexible Electronics." Polymers 14, no. 12 (June 9, 2022): 2340. http://dx.doi.org/10.3390/polym14122340.
Full textAbstract:
The aim of this study was to synthesize an intrinsically stretchable conductive polymer (CP) by atom transfer radical polymerization (ATRP). For this purpose, poly(3,4-ethyilenedioxythiophene) (PEDOT) was synthesized as a backbone, while poly(acrylate-urethane) (PAU) was grafted onto the PEDOT backbone to form graft polymers PEDOT-g-PAU. Different concentrations of acrylate-urethane (AU) were used to synthesize PAU side chains of different lengths. The successful synthesis of the obtained intermediates and products (PEDOT-g-PAU) was confirmed by infrared spectroscopy and nuclear magnetic resonance. Thermal properties were evaluated by differential scanning calorimetry and thermogravimetric analysis, while conductivity was determined by four-point probe measurement. A simple tensile test was performed to characterize the ductility of the samples. PEDOT-g-PAU has shown high stretchability of up to 500% and, therefore, could potentially be used in skin-worn flexible electronics, while additional subsequent doping is required to improve the deterioration of electrical properties after the addition of the insulating urethane layer.
21
Idrees, Mohanad, Heedong Yoon, Giuseppe R. Palmese, and Nicolas J. Alvarez. "Engineering Toughness in a Brittle Vinyl Ester Resin Using Urethane Acrylate for Additive Manufacturing." Polymers 15, no. 17 (August 22, 2023): 3501. http://dx.doi.org/10.3390/polym15173501.
Full textAbstract:
Thermosetting polymers tend to have a stiffness–toughness trade-off due to the opposing relationship of stiffness and toughness on crosslink density. We hypothesize that engineering the polymer network, e.g., by incorporating urethane oligomers, we can improve the toughness by introducing variations in crosslink density. In this work, we show that a brittle methacrylated Bis-GMA resin (known as DA2) is toughened by adding a commercial urethane acrylate resin (known as Tenacious) in different proportions. The formulations are 3D printed using a vat photopolymerization technique, and their mechanical, thermal, and fracture properties are investigated. Our results show that a significant amount of Tenacious 60% w/w is required to produce parts with improved toughness. However, mechanical properties drop when the Tenacious amount is higher than 60% w/w. Overall, our results show that optimizing the amount of urethane acrylate can improve toughness without significantly sacrificing mechanical properties. In fact, the results show that synergistic effects in modulus and strength exist at specific blend concentrations.
22
Markovska, L. A., N. Y. Parkhomenko, A. V. Rudenko, O. A. Savelyeva, S. M. Ostapyuk, and Yu V. Saveliev. "Investigation of the structure and properties of polyurethane compositions modified with metal-containing compounds." Polymer journal 42, no. 4 (December 10, 2020): 283–91. http://dx.doi.org/10.15407/polymerj.42.04.283.
Full textAbstract:
New cross–linked and linear polyurethane compositions with different content of various reactive metal[Ni,Zn,Cu]inorganic modifiers (MIM) were synthesized. The results of IR spectroscopy confirm the reaction and structural reorganization in the system under the influence of MIM. Thus, in the region of stretching vibrations of NH groups of the urethane fragment, a shoulder increase was noted in the region of weakly bound stretching vibrations of NH groups at 3456 cm-1 and a new band at 4314 cm-1 appears, which indicates the presence of hydrogen bonds with the chlorine ion CuCl2. The presence of MIM in polyurethane leads to a shift of valence vibration of urethane group band νС =O to the region of 1723 cm-1 and the appearance of an intensive shoulder 1711 cm-1, which indicates the formation of a coordination bond C = O → Cu[Cl2]. The appearance in the IR spectrum of the polymer with MENM content of three new bands with maximums (530, 558 and 637) cm–1 indicates the formation of a coordination bond N → Cu. It was shown that the presence of transition metals dichlorides in the polymer structure provides opportunities for target production of polyurethane compositions with a set of specified properties, namely: fungicide properties, which were provided by the presence of Zn- and Cu-chlorides, photostability which was provided by the presence of Ni-chloride. In this case, the incorporation of active compounds into the structure of the polymer excludes the diffusion of MIM on the surface of the material with subsequent removal and thus prolongs the protective functions of the coating – resistance to biocorrosion, UV radiation, chemical agents, heat resistance while maintaining high adhesion / cohesion. Keywords: polyurethane compositions, cross-linked, linear, inorganic modifiers, coatings, adhesion, stabilyty, environment.
23
KARABANOVA, L. V., L. A. HONCHAROVA, N. A. BUSKO, and S. M. OSTAPIUK. "THE STUDY OF INTERMOLECULAR INTERACTIONS IN THE POSS-CONTAINING NANOCOMPOSITES BASED ON POLYURETHANE AND POLYURETHANE/POLY(HYDROXYPROPYL METHACRYLATE) MATRICES." Polymer journal 44, no. 4 (December 15, 2022): 304–15. http://dx.doi.org/10.15407/polymerj.44.04.304.
Full textAbstract:
The nanocomposites based on polyurethane matrix and multicomponent polymer matrices consisting of polyurethane and poly(hydroxypropyl methacrylate) with different contents of the last, and 1,2-propanediolisobutyl polyhedral oligomeric silsesquioxane (1,2-propanediolisobutyl-POSS), which was used as a functionalized nanofiller, were synthesized. The influence of the content of 1,2-propanediolisobutyl-POSS on intermolecular interactions and structural features of the nanocomposites was investigated by the method of IR-spectroscopy with Fourier transformation and attenuated total reflection (FTIR-ATR). The study of thermal curing of the model system, which consists of the adduct of trimethylolpropane with toluene diisocyanate and 1,2-propanediolisobutyl-POSS, made it possible to conclude that 1,2-propanediolisobutyl-POSS participates in the reaction of urethane formation using of one of the terminal hydroxyl groups, and it is incorporated into the polymer chain between cross-linking of polyurethane networks. The investigation of multicomponent polymer matrices by FTIR-ATR spectroscopy was done and was shown that photopolymerization of second polymer poly(hydroxypropyl methacrylate) in the matrix of polyurethane was completed by the opening of a double bond and the formation of a linear polymer in the composition of semi-IPN. Studies of nanocomposites based on multicomponent polymer matrices consisting of polyurethane and poly(hydroxypropyl methacrylate) with 15 and 30 % of the last by FTIR-ATR spectroscopy demonstrated the presence of POSS in the nanocomposites and the influence of POSS content on the structure of the studied systems and on the degree of phase separation. The POSS is "embedded" into the polymer chain between cross-linking of the polyurethane networks, with the additional formation of a complex system of intermolecular hydrogen bonds between the carboxyl and amine components of urethane groups in the nanocomposites.
24
Slepchuk, Inna, Olga Ya Semeshko, Tatyana S. Asaulyuk, and Yuliya G. Saribyekova. "INVESTIGATION OF PHYSICOCHEMICAL PROPERTIES OF STYRENE-ACRYLIC AND URETHANE POLYMERS USED IN FINISHING OF TEXTILE MATERIALS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, no. 3 (March 8, 2020): 88–93. http://dx.doi.org/10.6060/ivkkt.20206303.6091.
Full textAbstract:
The results of the study of the physicochemical properties of styrene-acrylic and urethane polymer films, as well as polymer compositions based on the studied polymers with the addition of crosslinking agents are presented. Aqueous dispersions of styrene-acrylic polymers Lacritex 309, Lacritex 430, Lacritex 640 and polyurethane polymer Aquapol 14 were used for the formation of films. Triglycidyl esthers of polyoxypropylene triol and trimethylolpropane — Laproxid 703 and Laproxid TMP — were used as crosslinking agents. The stability of polymer films to hydrolytic destruction was evaluated after treatment at 20, 40 and 100 °C, and to the soap-soda treatment — at 40 °C. It was found that the most resistant to hydrolysis and soap-soda treatment are films from styrene-acrylic polymer Lacritex 309 and compositions Lacritex 640 / Laproxid 703, Aquapol 14 / Laproxid TMP, Aquapol 14 / Laproxid 703. The tensile load, elongation at break, stiffness and surface tackiness were also determined for the studied polymer films. It was found that polymer films based on Lacritex 309 and compositions Lacritex 640 / Laproxid 703, Aquapol 14 / Laproxid 703 are characterized by the greatest strength and elongation, non-rigid and non-tacky surface. Adding Laproxid TMP to polyurethane Aquapol 14 provides creation of a solid and inelastic film. To assess the effect of polymer coatings on the textile material rigidity, a cotton fabric with twill weave was used, which is used for special work clothes. Polymers and their compositions were applied to the fabric from a solution with a concentration of 150 g/l, followed by drying and heat setting. For dressed cotton fabric, rigidity and breaking load were determined. The rigidity of the treated cotton fabric was determined by the method of console. It has been established that the use of polyurethane Aquapol 14 and compositions based on it, as well as styrene-acrylic dispersions Lacritex 309 and Lacritex 430 will result in hard handle of textile materials. The composition based on Lacritex 640 with the addition of Laproxid 703 as a crosslinker provides an elastic and strong textile material.
25
A Alshuiref, Abubker, Mahmoud M Bin Mahmoud, Ahmed A Maraie, Salem M Alburki, and Nagi G Greesh. "SURFACE AND ADHESION PROPERTIES OF URETHANE ACRYLATE GRAFT COPOLYMERS." International Journal of Engineering Applied Sciences and Technology 6, no. 10 (February 1, 2022): 77–83. http://dx.doi.org/10.33564/ijeast.2022.v06i10.009.
Full textAbstract:
A solvent –based adhesive in which a continuous phase includes a solvent for an acrylic based adhesive or a solvent for a urethane based adhesive and wherein adhesive molecules and dissolved in the solvent to form said continuous phase, the adhesive being characterised in in that adhesive molecules include graft polymer where in a major partof the molecule is either acrylic based or urethane based such that the major part is of sufficient size to provide the adhesive molecule with a required solubility in said solvent and wherein a minor part of the molecule is based on the other of said acrylic or urethane thereby providing said molecule with attributes of both acrylic based and urethane based adhesives.Adhesion increased as the content of urethane macromonomers (UMs) increased in graft copolymer. The graft copolymer prepared using a high UM feed for both PMMA and PnBMA showed improved in adhesion compared to the pure methacrylate polymers. The adhesion was better whether for leather and for vinyl. Surface and adhesive properties were improved as the amount of UM content increased in the graft copolymer. Smaller contact angles result giving a surface with a higher surface energy and increase in T-peel strength was observed as the amount of UM content increased in the graft copolymer.
26
OKAMURA, HIROKAZU, KAORI SUZUKI, TAKESHI MORI, KEIJI MINAGAWA, SEIZO MASUDA, and MASAMI TANAKA. "CHAIN BEHAVIOR IN MODEL HOMOGENEOUS ER FLUIDS DEPENDING ON TEMPERATURE." International Journal of Modern Physics B 16, no. 17n18 (July 20, 2002): 2385–91. http://dx.doi.org/10.1142/s0217979202012402.
Full textAbstract:
Water-soluble urethane-modified polyethers were prepared by addition of poly(ethylene oxide)-co-poly(propylene oxide) and aromatic isocyanate compounds. These polymers were found to dissolve in water at lower temperature and separate from solution upon heating. The temperature showing this unusual solubility change is called lower critical solution temperature (LCST). These chemical structures of thermo-responsive polymers were similar to those of urethane-modified ER active polymers containing poly(tetramethylene oxide) and aromatic urethane moiety. The thermo-responsive and ER polymers may have various intra- and intermolecular interactions through the urethane moiety. It is considered that both thermo-responsivility and ER effect are dependent on the conformational stability of the polymers under different conditions possibly related to these stimuli-responsivility through the molecular interactions. In order to clarify molecular motion of thermo-responsive polymers near the LCST, 1 H-NMR spin-lattice relaxation time ( T 1) was measured in D 2 O . The result indicated that hydrophobic interaction of terminal urethane moiety would strongly affect the LCST behavior.
27
GONCHARUK, V. V., V. M. OGENKO, L. V. DUBROVINA, O. A. VYSHNEVSKYI, I. V. DUBROVIN, and I. M. KRUCHKO. "MODIFICATION OF CERAMIC MEMBRANES BY PYROCARBON FROM CARBONIZED POLY(URETHANE UREA)S." Polymer journal 44, no. 3 (September 16, 2022): 198–204. http://dx.doi.org/10.15407/polymerj.44.03.198.
Full textAbstract:
Modification of tubular ceramic membranes made of clay minerals, which were obtained by slip casting (produced by the Dumansky Institute of Colloid Chemistry and Water Chemistry of the National Academy of Sciences of Ukraine) was carried out. The membranes were modified with pyrocarbon, which was obtained by carbonization of a precursor – poly(urethane urea)s. The carbonization precursor was synthesized from polyisocyanate (average functionality 2.7) and laprol grade 5003, which was introduced into the membrane by impregnation of the corresponding solutions in ethylacetate. When laprol reacts with polyisocyanate, three-dimensional polyurethane is formed. Since undried reagents were used, water entered the pores of the membrane, which reacted with the NCO groups of the polyisocyanate to form polyurea. The parallel course of these reactions leads to the formation of poly(urethane urea)s in the pores of the membrane. Carbonization was carried at 800 °C in an argon flow. The apparent density and open porosity of the membranes were determined by CCl4 uptake. After modification, the open porosity of the membrane decreased from 29.9 to 27.3 %, the apparent density increased from 1.86 to 1.87 g/cm3. The composition and structure of the membranes were studied by X-ray diffraction analysis and SEM. It is shown that the obtained modifier is pyrocarbon - the relative intensity of reflexes increases at 26,0 - 26,4 and 41,3 and 44,2° 2Θ. Pyrocarbon covers the surface of the pores with a continuous layer, and there are also three-dimensional formations of various shapes and sizes from several nm to several microns. Testing of modified membranes was carried out by water purification from direct scarlet dye and from Ca2+ of calcium chloride using the baromembrane method at a working pressure of 0.7 MPa. The unmodified membrane does not retain direct scarlet dye and Ca2+ at all. Tests of modified membranes have shown that the membranes acquire ultrafiltration properties. The retention factor (R) for direct scarlet dye is 100 % and 25 % for Ca2+.
28
Rezvova, M. A., and E. A. Ovcharenko. "POLYMERIC HEART VALVE PROSTHESES: CONDITION AND PERSPECTIVES." Russian Journal of Transplantology and Artificial Organs 20, no. 2 (June 27, 2018): 100–111. http://dx.doi.org/10.15825/1995-1191-2018-2-100-111.
Full textAbstract:
The idea of creating a polymer heart valve, which has high strength and biocompatibility, occurs in the 60’s. Since then, many polymer compounds have been investigated, but no solution has been found for this problem. In recent years, in connection with the development of technologies for the synthesis of high-molecular compounds, new polymers have appeared that can solve this problem, as evidenced by a number of publications describing experimental and clinical data. Nevertheless, the search for a polymer for the valve stem of the valvular valve body does not lose its relevance due to the defi ciencies studied and the lack of evidence confi rming the long-term safety of such products. This review presents the fi rst results of a study of polymer heart valves prostheses based on a nanocomposite polymer from polyhedral oligomeric nanoparticles of silicosioxane and polycarbonate urethane polymer POSS-PCU, polystyrene block-isobutylene-block-styrene SIBS, PTFE polytetrafl uoroethylene, copolymers and composites based on olefi n polymers series and polyesters, the idea of creating a material with a given three-dimensional microarchitecture that determines the anisotropy and the necessary mechanical properties.
29
Amarasekara, Ananda S., and Rocio Garcia-Obregon. "Vanillin based polymers: V. Poly(hydrovanilloin–urethane)." Polymers from Renewable Resources 12, no. 1-2 (February 2021): 35–45. http://dx.doi.org/10.1177/2041247921989898.
Full textAbstract:
Renewable resources based hydrovanilloin [1,2- bis(4-hydroxy-3-methoxyphenyl)-1,2-ethanediol] was synthesized in 86% yield by electrochemical dimerization of vanillin in aqueous NaOH. This symmetrical bis-phenol monomer was then used for the preparation of urethane polymers by two different methods. In the first method a 1:2 mole ratio mixture of hydrovanilloin and diisocyanate was polymerized in DMF using 1,4-diazabicyclo[2,2,2]octane as the catalyst at 60°C, for 1 h to give poly(hydrovanilloin–urethane)s. In the second method diisocyanates were first reacted with polyethylene glycol-400 to give pre-polymers. Then prepolymers were reacted with equivalent amount of hydrovanilloin at 60°C for 4 days to produce poly(hydrovanilloin-ethylene glycol-urethane)s. The first method resulted hard poly(hydrovanilloin–urethane)s showing Tg values in the range of 121–172°C. The second method yielded softer poly(hydrovanilloin-ethylene glycol-urethane)s and these polymers failed to show distinct glass transition temperatures in the DSC analysis. However, poly(hydrovanilloin-ethylene glycol-urethane)s showed better thermal stabilities than polymers without polyethylene glycol units.
30
Nadzeyka, Ingo, Eleonore Bolle, Martin Moos, Paula Kunitz, Ulrich Steinseifer, and Thomas Schmitz-Rode. "Process analysis of spray atomization of dissolved polymers for manufacturing of blood-compatible textile implants." Journal of Industrial Textiles 48, no. 5 (December 9, 2017): 926–40. http://dx.doi.org/10.1177/1528083717747336.
Full textAbstract:
The use of porous polymer materials for vascular prostheses demonstrates promising results. Fleece-like non-woven structures can be generated by atomization of dissolved polycarbonate urethanes. This article focuses on the manufacturing process for the fleece structures. The solution is atomized through a high-volume low-pressure nozzle. The solvent evaporates during time of flight to target, so that small fibres are formed from each drop of solution. By using different rotating molds and positioning systems, tubular shapes or open surfaces can be generated. The manufacturing process is described in detail. The usability of different grades of polycarbonate urethane is tested and the time necessary for evaporation of the solvent from the mesh is assessed. The influence of several basic parameters on the mechanical properties of the generated non-woven material is analysed and discussed.
31
Pavelková, Alena, Pavel Kucharczyk, Zdenka Kuceková, Jiří Zedník, and Vladimír Sedlařík. "Non-toxic polyester urethanes based on poly(lactic acid), poly(ethylene glycol) and lysine diisocyanate." Journal of Bioactive and Compatible Polymers 32, no. 3 (November 23, 2016): 225–41. http://dx.doi.org/10.1177/0883911516672239.
Full textAbstract:
Poly(lactic acid)-based polymers are highly suitable for temporary biomedical applications, such as tissue support or drug delivery systems. Copolymers of different molecular weight based on poly(lactic acid) and poly(ethylene glycol) were prepared by polycondensation, catalysed by hydrochloric acid. A chain-extension reaction with l-lysine ethyl ester diisocyanate was employed afterwards to obtain polyester urethanes with enhanced properties. The GPC results showed that the molecular weights of the products reached about 50,000 g·mol−1 and the hydrolytic progress was rapid in the first 2 weeks; the drop in Mn equalled approximately 70%. Additionally, elemental analysis of the buffer medium proved that hydrolytic degradation was more rapid in the first stage. Tensile-strength testing revealed that ductility increased alongside reduced molecular weight of poly(ethylene glycol), also suggesting that polymer branching occurred due to side reactions of isocyanate. Based on the envisaged biomedical applications for these polymers, cytotoxicity tests were carried out and the cytotoxic effect was only moderate in the case of 100% polymer extract prepared according to ISO standard 10993-12. In their research, the authors focused on preparing metal-free, catalysed synthesis of polyester urethanes, which could prove useful to numerous biomedical applications.
32
Didenko, Andrey, Danila Kuznetcov, Valentina Smirnova, Gleb Vaganov, Alexey Ivanov, Vladimir Yudin, and Vladislav Kudryavtsev. "The Co-Poly(Urethane-Imide) Heat Resistant Thermoplastic Elastomers." Nano Hybrids and Composites 34 (February 23, 2022): 23–28. http://dx.doi.org/10.4028/p-rcjpez.
Full textAbstract:
Co-Pоly (Urethane-Imide) s (CPUI) based on pоly (diethyleneglycol) adipate diol, tolylenediisocyanate, multinucleate dianhydrides and diamines were synthesized. The films and moldings from CPUI were processed and their mechanical characteristics were evaluated. Distinctions of specifications of the films formed from polymer solutions and the moldings formed from melt polymers are indicated when using the same starting CPUI. It appears that films and moldings possess typical properties of elastomers. The reprocessing of studied copolymers by using the injection molding method allows to assign CPUI to the thermoplastic elastomers or so-called thermoelastoplasts.
33
Hitchcock, A. P., S. G. Urquhart, H. Ade, E. G. Rightor, and W. Lidy. "Quantitative Chemical Speciation of Multi-Phase Polymers Using Zone Plate x-ray Microscopy." Microscopy and Microanalysis 4, S2 (July 1998): 808–9. http://dx.doi.org/10.1017/s1431927600024168.
Full textAbstract:
Phase segregation is important in determining the properties of many complex polymers, including polyurethanes. Achieving a better understanding of the links between formulation, chemical nature of segregated phases, and physical properties, has the potential to aid development of improved polymers. However, the sub-micron size of segregated features precludes detailed chemical analysis by most existing methods. Zone-plate based, scanning transmission X-ray microscopes (STXM) at NSLS and ALS provide quantitative chemical analysis (speciation) of segregated polymer phases at ∼50 nm spatial resolution. Image sequences acquire much more data with less radiation damage, than spot spectra. After alignment, they provide high quality near edge spectra, and thus quantitative analysis, at full spatial resolution.Fig. 1 shows an image and spectra acquired with the NSLS STXM of a macro-phase segregated TDI polyurethane. Spectral decomposition using model polymer spectra is used to measure the local urea, urethane and polyether content.
34
Mersha, Desalegn A., and Zenamarkos B. Sendekie. "High-Temperature Performance Enhancement of Bitumen by Waste PET-Derived Polyurethane." Advances in Materials Science and Engineering 2022 (October 14, 2022): 1–15. http://dx.doi.org/10.1155/2022/9567197.
Full textAbstract:
Bitumen performance enhancement through modification by reactive polymers gained significant attention in the road construction industry. Polymeric bitumen additives, such as polyurethane, improve bitumen properties at low and high in-service temperatures. This research aimed to increase the polymer content (polyurethane) from 3% to 5%wt of bitumen by introducing cross-linking agent, sulfur. Synthesis of polyurethane was via in situ polymerization of bis (2-hydroxyethyl) terephthalamide (BHETA) in the presence of bitumen with sulfur as a cross-linking agent. BHETA was produced from polyethylene terephthalate (PET) by an aminolysis reaction. Penetration and softening point, frequency sweep test, performance grade (PG) and multiple stress creep recovery (MSCR) were evaluated to compare base and modified bitumen. Results show that the penetration and softening point of modified binders were reduced and increased, respectively, the frequency sweep test indicated improvement in viscoelastic properties of modified bitumen, PG of base bitumen was enhanced by two grades, i.e., from 58°C to 70°C, and the nonrecoverable creep compliance was increased by 81.82% at polymer content of 4% and sulfur content of 0.2%. The FTIR spectra of modified bitumen confirmed the formation of urethane linkages. Therefore, aminolysis of waste PET and in-situ polymerization to produce polyurethane can be applied to improve the performance of bitumen at high temperatures.
35
MALYSHEVA, T. L., and A. L. TOLSTOV. "STUDYING OF THE NANOSTRUCTURIZED POLY(URETHANE-UREA) – POLY(VINYL CHLORIDE) BLEND MODIFIED BY AEROSILS." Polymer journal 44, no. 1 (May 1, 2022): 61–67. http://dx.doi.org/10.15407/polymerj.44.01.061.
Full textAbstract:
An influence of surface adsorption-active centers of fine amorphous silica on physical hydrogen bonding (H-bonding) network in polyurethaneurea (PUU) and nanostructurized polymer blend (PUU/30PVC) was studied by FTIR spectroscopy. PUU was synthesized by prepolymer approach in N,N-dimethylformamide (DMF) solution using poly(propylene glycol) of Mn = 1000, 2,4-tolylene diisocyanate and 2,4-tolylene diamin as a chain extender at a molar ratio of 1:2:1. The compositions were obtained by solution-casting technique using DMF as a solvent. It was found introducing fine silica with hydroxylated surface into PUU matrix enhances segregation of hard urethane-urea segments in oligoether matrix. The maximum of strengthening of the filled composites was observed when silica A-300 content reaches 2–3 % (by weight). Oppositely, introducing silica AM-300 with silylated (by (CH3)2SiCl2) surface into PUU initiates degrading domain structure of elastomer due to interactions between polar groups of chemisorbed molecules of chlorine-containing modifier and proton-donor groups of rigid segments. Modified surface of silica has minor destabilization effect on H-bonding network in nanostructurized polymer-polymer blend. As a result, for producing filled composites without weakening interface interactions and, respectively, reducing the strength and optimal filler content (silica AM-300 or A-300) should be selected as high as 1 % (by weight).
36
Budzinska, V. L., T. M. Nogina, and E. V. Lebedev. "Biodegradable organo-inorganic composites on the basis on sodium silicate, urethane oligomer carboxymethyl cellulose." Polymer journal 37, no. 3 (September 20, 2015): 306–12. http://dx.doi.org/10.15407/polymerj.37.03.306.
Full text
37
Rimdusit S, Rimdusit S., Kasemsiri P. Kasemsiri P., and Okhawilai M. Okhawilai M. "Thermomechanical Properties of KevlarTM Reinforced Benzoxazine-Urethane Alloys." ASEAN Journal of Chemical Engineering 13, no. 1 (September 25, 2013): 11. http://dx.doi.org/10.22146/ajche.49720.
Full textAbstract:
Ballistic armor is one of an important application which required high performance of fiber-reinforced polymer due to its outstanding specific mechanical properties. Therefore, KevlarTM reinforced benzoxazine-urethane alloys as ballistic impact resistance composites were developed in this research. The polybenzoxazine alloy composites were fabricated by compression molding at 200ºC and 5 MPa by a compression molder. The amount of urethane fraction in the alloy matrix was ranging from 0-40wt% while the fiber content was kept constant at 80wt%. The mechanical properties of the matrix alloys and their KevlarTM fiber composites were characterized by dynamic mechanical analysis and universal testing machine. The results revealed that storage modulus at room temperature of the composites was reduced from 16.82 GPa when using the neat polybenzoxazine as a matrix to the value of 11.89 GPa at 40wt% of urethane content in the alloy matrix. Moreover, the more urethane in the alloy matrix resulted in lower flexural modulus of the KevlarTM composites i.e. 22 GPa when using the neat polybenzoxazine as a matrix to the value of 12 GPa when using 40wt% of urethane in the alloy matrix. Interestingly, glass transition temperature (Tg) obtained from the maximum peak of the loss modulus was observed to be in the range of 187-247ºC, which was significantly higher than those of the two parent polymers. Furthermore, the activation energy of the alloys was found to increase with increasing urethane content, which corresponded to the observed Tg value enhancement. The observed synergism in Tg of KevlarTM reinforced benzoxazine-urethane was an outstanding characteristic for a wide range of applications, which requires high thermal stability.
38
Davydov, Evgeny, Irina Gaponova, Georgy Pariiskii, Tatyana Pokholok, and Gennady Zaikov. "Reactivity of Polymers on Exposure to Nitrogen Dioxide." Chemistry & Chemical Technology 4, no. 4 (December 15, 2010): 281–90. http://dx.doi.org/10.23939/chcht04.04.281.
Full textAbstract:
The mechanism of reactions of nitrogen dioxide with polymers of different classes is considered. In reactions with carbon-chain polymers at 298 K, nitrogen dioxide can only add to extrinsic double bonds that are formed in the synthesis of the polymers. The mechanism of reactions of nitrogen dioxide with polymers of different classes is considered. In reactions with carbon-chain polymers at 298 K, nitrogen dioxide can only add to extrinsic double bonds that are formed in the synthesis of the polymers. These reactions resulted in dinitro compounds and nitro nitrites. At elevated temperatures, carbonyl and hydroxyl groups are formed in these polymers along with nitration products. Active participants of NO2 reactions with rubbers are double bonds converting into nitroalkyl and alkyl radicals initiating then free radical conversions of these polymers. Polymers containing amide, urethane and imide groups are rather sensitive to NO2. These materials undergo essential changes in the chemical structure with formation of stable nitrogen-containing radicals. The reactions of nitrogen dioxide provide a simple method of the spin-labeled polymer preparation.
39
Lim, Won-Bin, Ju-Won Kim, Ju-Hong Lee, Ji-Hong Bae, Jin-Gyu Min, and PilHo Huh. "Synthesis of a Room-Temperature Curable Acrylic-Urethane Polymer Binder for Road Markings with High Transmittance." Materials 16, no. 3 (February 3, 2023): 1322. http://dx.doi.org/10.3390/ma16031322.
Full textAbstract:
Triol acrylic-urethane (t-AU) was synthesized from an addition reaction using trimethylolpropane, hexamethylene diisocyanate, and 2-hydroxyethyl methacrylate. The novel acrylic-urethane polymer was applied to a high-performance binder to prepare a reliable road marking paint. Acrylic-urethane polymer binder formulations were designed to optimize the effect of t-AU on the physical properties. The t-AU content in the formulation affected the adhesion and optical properties. The improvement in the adhesive performance and transparency ability for road markings was attributed to the optimal chemical structure or design of the acrylic-urethane polymer. The synthesis of t-AU was confirmed by Fourier transform infrared spectroscopy, and molecular weight and polydispersity index (PDI; PDI = Mw/Mn) measurements. The tensile and shear strength, hardness, gel fraction, crosslink density, contact angle, and transmittance of the acrylic-urethane polymer binder (AUP) were evaluated by curing at room temperature using a redox initiator system. An optimized AUP by adding 5 wt.% t-AU provides a viable alternative to high-performance binders in road marking paints.
40
Marconi, W., I. Francolini, A. Piozzi, and R. Di Rosa. "Antibiotic Releasing Urethane Polymers for Prevention of Catheter Related Infections." Journal of Bioactive and Compatible Polymers 16, no. 5 (September 2001): 393–407. http://dx.doi.org/10.1106/g5eb-ll73-k59a-7ybf.
Full textAbstract:
In order to improve the resistance of catheters to microbial infections (particularly Staphylococci), a cephalosporin type antibiotic (cefamandole, CEF), and a glycopeptidic antibiotic (vancomycin), were adsorbed onto functionalized polyurethane films. The polymers were characterized by chemical, FT-IR and 'H-NMR analysis. The amounts of antibiotic adsorbed were higher than the ones reported in the literature. The kinetics of release, under standard conditions, was evaluated by in vitro tests; both the adsorption yield and the antibiotic release from the polymer surface depended on the type of the surface-antibiotic interactions. In particular, matrix hydrophilicity, formation of strong ionic bonds, existence of "spacing arms" between antibiotic and matrix bonding site play a role. The antimicrobial activity of the treated films was evaluated by optical microscopy and the Kirby-Bauer test. When exhausted polymer films, previously treated with CEF were submitted to a second adsorption, a superior antibacterial activity was observed.
41
Hudzenko, N. V., V. G. Sisyuk, V. K. Grishchenko, N. G. Ugro, and L. I. Zel. "INVESTIGATION OF THE PROPERTIES OF POLYMER COATINGS BASED ON MELAMINE ALKYD RESIN AND OLIGOMERIC URETHANE MALEATES." Polymer journal 42, no. 3 (September 2, 2020): 183–90. http://dx.doi.org/10.15407/polymerj.42.03.183.
Full text
42
Chisnoiu, Radu Marcel, Alexandrina Muntean, Ovidiu Păstrav, Andrea Maria Chisnoiu, Stanca Cuc, Laura Silaghi Dumitrescu, Mihaela Păstrav, Doina Prodan, and Ada Gabriela Delean. "Polymer Mixtures for Experimental Self-Limited Dental Burs Development—A Preliminary Approach (Part 1)." Journal of Functional Biomaterials 14, no. 9 (August 29, 2023): 447. http://dx.doi.org/10.3390/jfb14090447.
Full textAbstract:
Alternative techniques have been investigated for effectiveness in caries removal because conventional metallic dental burs can lead to an excessive loss of sound tissue. The aim of the present study is to realize a preliminary approach in obtaining effective polymer mixtures for polymeric bur development, capable of removing primary dental caries using combinations of polymers to ensure the requirements for such instruments, but also a greater compatibility with the teeth structure. This study assessed the main mechanical properties, water sorption, solubility and microscopic structure of four new polymer mixture recipes to provide essential features in obtaining experimental self-limited dental burs. Two mixtures have in their composition polymer mixtures of Bis-phenol A diglycidyl ether dimethacrylate/Triethylene glycol dimethacrylate/Urethane dimethacrylates (R1, R2), and two other mixtures have Bis-phenol A diglycidyl ether dimethacrylate/Polymethyl methacrylate/Methyl methacrylates (R3, R4). The incorporation of nanoparticles into the polymer matrix has become essential due to the need of polymer biocompatibility increasing along with teeth surface remineralization, so that the powder charge was added to four recipes, such as 5% glass with BaF2 and 0.5% graphene with silver particles. All data sets were analyzed using the One-Way ANOVA test. R3, R4 showed higher compressive strength and diametrical compression values; these values increased when glass and graphene were added. Moreover, the addition of glass particles lead to an increase in flexural strength. Regarding the sorption, sample R3 had the most significant differences between day 69 and the rest of the investigation days, while the solubility varied at different intervals. From the mechanical evaluation, we could conclude that the Bis-GMA/PMMA/MMA mixtures fit the mechanical characteristics supported by polymer burs, following future studies regarding their use on the affected dentin.
43
Bors, Adriana-Mariana, Marius-Eduard Lungulescu, Nicoleta Oana Nicula (Butoi), Alina-Ruxandra Caramitu, and Iosif Lingvay. "Ageing of Some Lacquers Due to Microbiological Stress." Materiale Plastice 56, no. 2 (June 30, 2019): 330–36. http://dx.doi.org/10.37358/mp.19.2.5181.
Full textAbstract:
This paper shows the ageing study of some coatings and / or impregnation lacquers due to microbiological stress through fungal attack. Dielectric spectroscopy has shown that the dielectric losses of the investigated materials increase as result of microbiological ageing. The mean recorded increases are about 4 times for the alkyl-epoxy-melamine copolymer, 2 times for epoxy polymer and 1.5 times for urethane polymer in agreement with the mould coverage degree of about 20 %, 10 %, and 3 %, respectively. The fungal attack of the investigated polymers led to a decrease in volume resistivity of about 65 % for the alkyl-epoxy-melamine copolymer, 45 % for the epoxy polymer, and 14 % for polyurethane, in agreement with the increase of dielectric losses and degree of mold coverage of the samples. FTIR determinations have shown that fungal attack significantly increased the number of aliphatic -OH and C-H bonds and decreased the number of C-O bonds, respectively of C-O-C oxiran groups and C-C aromatic bonds. DSC thermograms recorded at different temperature ranges and the activation energies calculation for first major oxidation process indicate that after the fungal attack the thermooxidative reactivity of the investigated polymers increases.
44
Boiko, V. P., V. K. Grishchenko, G. B. Gruzevich, G. A. Kozlova, and S. M. Ostapyuk. "Investigation of the kinetics of the urethane formation reaction of some industrial oligodienes with terminal hydroxyl groups." Polymer journal 37, no. 1 (March 20, 2015): 85–92. http://dx.doi.org/10.15407/polymerj.37.01.085.
Full text
45
Ardelean, Lavinia Cosmina, Cristina Maria Bortun, Angela Codruta Podariu, and Laura Cristina Rusu. "Polymeric Alternatives in Manufacturing Removable Partial Dentures." Materiale Plastice 54, no. 4 (December 30, 2017): 754–56. http://dx.doi.org/10.37358/mp.17.4.4938.
Full textAbstract:
Traditionally, removable partial dentures consist of a metallic framework, covered by acrylic saddles, which support acrylic or ceramic teeth. Because their shortcomings, new classes of resins/macromolecular compounds which promise better quality are nowadays available for manufacturing removable partial dentures: urethane-based resins, polyamides, acetal resins, high-performance polymers. Manufacturing these new materials implies alternative technologies like: injection, milling, light-curing. Using these alternative polymeric materials results in dentures with better resistance, elasticity, appearance and lower weight, which provide much more comfort to the patient.
46
MALYSHEVA, T. L., and O. L. TOLSTOV. "STUDYING THE MODIFICATION OF NANOSTRUCTURED POLYURETHANE ELASTOMER/POLYVINYL CHLORIDE BLEND BY LOW-MOLECULAR PLASTICIZERS." Polymer journal 45, no. 4 (December 20, 2023): 278–85. http://dx.doi.org/10.15407/polymerj.45.04.278.
Full textAbstract:
The effect of chemical structure of low molecular weight plasticizers (LMWP) on intermolecular interactions and mechanical properties of nanostructured polyurethane elastomer (PU)/polyvinyl chloride (PVC) was investigated. Polymer composite films were prepared by solution casting technique using dimethylformamide (DMF) or by rolling the melt. FTIR data showed a maximum level of intermolecular hydrogen bond degradation for PU or the polymer blend modified with trichloroethyl phosphate (TCEP) due to the formation of H-bonds between NH of rigid urethane/urea fragments of PU elastomer and chlorine of TCEP. The low compatibility of di-(2-ethylhexyl)-о-phthalate (DOP), compared with di-n-butyl-о-phthalate (DBP), and PU elastomer provided a minor effect of plasticizer on intramolecular and interfaсial interactions in PU or polymer blend. The resulting composites are characterized by increased tensile strength in the whole composition range. The results of DSC analysis of melt-rolled blends of PU/PVC modified by DOP had one wide glass relaxation transition range and their thermal and mechanical properties could be controlled by changing the ratio of initial components. The aforementioned results provide new possibilities of manufacturing the novel nanostructured thermoplastic elastomers with improved mechanical properties.
47
Sukhanova, Tatyana E., Andrey L. Didenko, Ilya L. Borisov, Tatyana S. Anokhina, Aleksey G. Ivanov, Anna S. Nesterova, Ilya A. Kobykhno, Alexey A. Yushkin, Vladimir V. Kudryavtsev, and Alexey V. Volkov. "Morphological Analysis of Poly(4,4′-oxydiphenylene-pyromellitimide)-Based Organic Solvent Nanofiltration Membranes Formed by the Solution Method." Membranes 12, no. 12 (December 7, 2022): 1235. http://dx.doi.org/10.3390/membranes12121235.
Full textAbstract:
Poly-(4,4′-oxydiphenylene) pyromellitimide or Kapton is the most widely available polyimide with high chemical and thermal stability. It has great prospects for use as a membrane material for filtering organic media due to its complete insolubility. However, the formation of membranes based on it, at the moment, is an unsolved problem. The study corresponds to the rediscovery of poly(4,4′-oxydiphenylene–pyromellitimide)-based soluble copoly(urethane-imides) as membrane polymers of a new generation. It is shown that the physical structure of PUI films prepared by the solution method becomes porous after the removal of urethane blocks from the polymer, and the pore size varies depending on the conditions of thermolysis and subsequent hydrolysis of the membrane polymer. The film annealed at 170 °C with a low destruction degree of polycaprolactam blocks exhibits the properties of a nanofiltration membrane. It is stable in the aprotic solvent DMF and has a Remasol Brilliant Blue R retention coefficient of 95%. After the hydrolysis of thermally treated films in acidic media, ultrafiltration size 66–82 nm pores appear, which leads to an increase in the permeate flow by more than two orders of magnitude. This circumstance provides opportunities for controlling the membrane polymer structure for further optimization of the performance characteristics of filtration membranes based on it. Thus, we proposed a new preparation method of ultra- and nanofiltration membranes based on poly(4,4′-oxydiphenylene–pyromellitimide) that are stable in aprotic solvents.
48
Puszka, Andrzej, and Janusz W. Sikora. "New Segmented Poly(Thiourethane-Urethane)s Based on Poly(ε-Caprolactone)Diol Soft Segment: Synthesis and Characterization." Materials 15, no. 14 (July 15, 2022): 4940. http://dx.doi.org/10.3390/ma15144940.
Full textAbstract:
New segmented poly(thiourethane-urethane)s (SPTURs) were synthesized by the reaction of 1,1′-methanediylbis (4-isocyanatocyclohexane) (Desmodur W®, HMDI) and poly(ε-caprolactone)diol (PCL) and (methanediyldibenzene-4,1-diyl)dimethanethiol as nonconventional polymer chain extender. FTIR spectroscopy was used for the structural analysis of obtained polymers. The molecular weight distribution was examined by GPC chromatography. Based on the measured contact angles, free surface energy parameters were calculated. Thermal properties of polymers were examined by DSC and TGA, while viscoelastic properties were measured by DMTA. The tensile, adhesive and optical properties were also investigated for the obtained polymers. It was shown that SPTURs were transparent or partially transparent solids with high molar masses up to 84,300 Da. These polymers showed a good resistance to hydrolysis during incubation in Optylite® physiological saline over 8 weeks. Obtained polymers possessed a tensile strength of up to 43.26 MPa, hardness of up to 96.25/59.00 Sh A/D and adhesion to copper of 14.66 MPa. The surface properties of the obtained polymers show that all obtained SPTURs were hydrophilic (CAs for water between 64.07° and 73.12°) with calculated SFE up to 46.69 mN/m.
49
Bakirova, Indira N. "Thermal stability of polyurethane coating prepared by using diphenylolpropane." Butlerov Communications 62, no. 4 (April 30, 2020): 81–87. http://dx.doi.org/10.37952/roi-jbc-01/20-62-4-81.
Full textAbstract:
Thermal stability of polyurethane varnish coating prepared by using diphenylolpropane, polyetherpolyol and polyisocyanate with an equimolar ratio of isocyanate and hydroxyl groups was assessed in the air. The polyurethane weight loss thermogram shows three temperature regions: I – (217-275)°С, II – (275-380)°С, and III – above 380°С. For interpreting thermogram of the polyurethane under study the model substances simulating the urethane groups of a polymer were synthesized. The substance containing the urethane group formed by phenolic hydroxyl of diphenylolpropane was shown to demonstrate relatively low thermal stability and gets broken down into isocyanate and bisphenol. Decomposition of the substance containing the urethane group formed by alcoholic hydroxyl occurs at the higher temperature. The data obtained allow interpreting the occurrence of thermal decomposition step I in TGA curve by structural changes in the blocks formed by diphenylolpropane and polyisocyanate being the least stable when exposed to elevated temperatures. The next step can be attributed to decomposition of more thermostable urethane groups formed by functional groups of oligooxypropylenetriol and polyisocyanate. Transition to the step III accompanied by severe sample weight loss due to decomposition of urethane groups is explained by thermal oxidation of oligoether units of polymer. Based on the data obtained the conclusion was made that the presence of urethane groups formed by phenolic hydroxyl of diphenylolpropane in polymer structure results in the decreased thermooxidative decomposition onset temperature of polymer. At the same time, a deceleration of thermooxidative processes due to the stabilizing effect of diphenylolpropane released at the beginning of thermal decomposition of polyurethane is observed in a high-temperature region. The proposed polyurethane coating is inferior to commercial counterparts in thermal decomposition onset temperature but superior to them in the temperature corresponding to a 50% polymer weight loss.
50
Tolstov, A. L., V. F. MATYUSHOV, E. V. LEBEDEV, and D. A. KLIMCHUK. "FORMATION AND CHARACTERIZATION OF SILVER-CONTAINING COMPOSITES BASED ON IONOMERIC POLY(URETHANE-ACRYLATE)S PREPARED VIA DIFFUSION/SORPTION APPROACH." Polymer journal 42, no. 1 (April 14, 2020): 3–10. http://dx.doi.org/10.15407/polymerj.42.01.003.
Full text