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Journal articles on the topic 'Polyurethanes. Polyurethanes Polyurethanes'

Author: Grafiati

Published: 4 June 2021

Last updated: 15 February 2022

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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 (2010): 40–43. http://dx.doi.org/10.2478/v10026-010-0048-4.

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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

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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 (2021): 2699. http://dx.doi.org/10.3390/ma14112699.

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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 syn

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3

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 (1999): 134–40. http://dx.doi.org/10.1007/s002530051373.

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4

Schmidt and Eschig. "Hydrophobilization of Furan-Containing Polyurethanes via Diels–Alder Reaction with Fatty Maleimides." Polymers 11, no. 8 (2019): 1274. http://dx.doi.org/10.3390/polym11081274.

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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 wit

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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.

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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 a

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6

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 (2014): 14–20. http://dx.doi.org/10.2478/pjct-2014-0063.

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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 materia

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Jayakumar, R., S. Nanjundan, and M. Prabaharan. "Developments in Metal‐Containing Polyurethanes, Co‐polyurethanes and Polyurethane Ionomers." Journal of Macromolecular Science, Part C: Polymer Reviews 45, no. 3 (2005): 231–61. http://dx.doi.org/10.1081/mc-200067721.

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8

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 (2010): 10–14. http://dx.doi.org/10.2478/v10026-010-0025-y.

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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.

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9

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.

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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,

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10

Datta, J., and J. T. Haponiuk. "Influence of Glycols on the Glycolysis Process and the Structure and Properties of Polyurethane Elastomers." Journal of Elastomers & Plastics 43, no. 6 (2011): 529–41. http://dx.doi.org/10.1177/0095244311413447.

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In this work, the influence of glycols on the glycolysis process and the properties of obtained polyurethanes were investigated. The glycolysates were produced via glycolysis of waste polyurethane foam in the reaction with one of the following glycols: 1,3-propanediol, 1,5-pentanediol, and 1,6-hexanediol.The reactions were carried out for different mass ratios of polyurethane wastes to glycolysis agent, i.e. 6:1, 8:1, and 10:1. Polyurethanes were synthesized from the obtained intermediates by a one-step method of mixing polymeric di-isocyanate and the glycolysis products with molecular masses

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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 (2019): 2375–82. http://dx.doi.org/10.14233/ajchem.2019.22014.

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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 tempera

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12

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.

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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-

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13

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.

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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 gro

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14

Yeoh, Fang Hoong, Choy Sin Lee, Yew Beng Kang, Shew Fung Wong, Sit Foon Cheng, and Wei Seng Ng. "Production of Biodegradable Palm Oil-Based Polyurethane as Potential Biomaterial for Biomedical Applications." Polymers 12, no. 8 (2020): 1842. http://dx.doi.org/10.3390/polym12081842.

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Being biodegradable and biocompatible are crucial characteristics for biomaterial used for medical and biomedical applications. Vegetable oil-based polyols are known to contribute both the biodegradability and biocompatibility of polyurethanes; however, petrochemical-based polyols were often incorporated to improve the thermal and mechanical properties of polyurethane. In this work, palm oil-based polyester polyol (PPP) derived from epoxidized palm olein and glutaric acid was reacted with isophorone diisocyanate to produce an aliphatic polyurethane, without the incorporation of any commercial

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15

Senthilkumar, Natarajan, and Mohammad Luqman. "Metal-Containing Polyurethanes: An Overview." Materials Science Forum 657 (July 2010): 1–25. http://dx.doi.org/10.4028/www.scientific.net/msf.657.1.

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The combination of the concept of metallopolymers with urethane chemistry offers a versatile approach for the synthesis of new polyurethane materials. Polyurethanes are a distinct class of materials with tremendous industrial importance, and it is of interest to develop these materials with modified thermal and liquid crystalline behavior for advanced applications. Generally, polyurethanes suffer a major disadvantage of poor thermal stability. This can be improved upon by chemical modification of their structures by the incorporation of thermally stable heterocyclic ring structures along with

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16

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.

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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 f

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17

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.

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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, phys

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18

Tran, Tuan, Prasun Kumar, Hak-Ryul Kim, Ching Hou, and Beom Kim. "Microbial Conversion of Vegetable Oil to Hydroxy Fatty Acid and Its Application to Bio-Based Polyurethane Synthesis." Polymers 10, no. 8 (2018): 927. http://dx.doi.org/10.3390/polym10080927.

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New polyurethanes were synthesized based on dihydroxy fatty acid obtained by the microbial conversion of olive oil. Monounsaturated 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was produced from olive oil by Pseudomonas aeruginosa PR3 and reacted with hexamethylene diisocyanate (HMDI) at different ratios to form polyurethanes. Fourier transform infrared spectroscopy and gas chromatography/mass spectrometry confirmed the synthesis of DOD. The thermal and tensile properties of the polyurethanes were investigated by differential scanning calorimetry, thermogravimetric analysis, and a universal tes

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Kim, Jang Soon, Ok Hyoung Lee, and Yun Soo Lim. "AFM Studies on the Effect of Crystalline Interphase on Adhesion of Polyurethane Thin Film to Al Substrate." Materials Science Forum 658 (July 2010): 65–68. http://dx.doi.org/10.4028/www.scientific.net/msf.658.65.

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Polyurethanes crystallized at the aluminum surface, but the crystalline interphase varied with polyol OH number. Early stage of spherulite formation was characterized using AFM after removing amorphous polyurethane. The crystallite shapes of polyurethanes were correlated with the bond strength measured from indentation debonding. Interestingly, the samples involving non-specific shape of crystallites displayed high bond strength, while the polyurethanes with rod-like crystallite poorly adhered to aluminum substrate. Although crystallite shape did not unequivocally relate to bond strength, the

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20

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 (2021): 2986. http://dx.doi.org/10.3390/molecules26102986.

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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 bette

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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.

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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

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22

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.

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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 f

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Lee, Jong Baek, and Byung Won Kang. "Synthesis and Properties of Thermotropic Main-Chain Type Liquid Crystalline Polyurethanes Containing Biphenyl Mesogen." Key Engineering Materials 342-343 (July 2007): 729–32. http://dx.doi.org/10.4028/www.scientific.net/kem.342-343.729.

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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(8-hydroxyoctoxy)biphenyl (BP8). The structure of the monomer and the corresponding polymers were confirmed using FT-IR and 1H-NMR spectroscopic methods. BP8 exhibited a smectic type mesophase, however, nematic phases were found for all synthesized liquid crystalline polyurethanes except for 1,4-phenylene diis

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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.

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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 diff

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Patel, Rasmika, Amin Hirani, and Hitesh Patel. "Flame Retardant Polyurethanes and their Applications for the Improvement in Properties of Conventional Castor Oil Based Polyurethane." Material Science Research India 11, no. 2 (2014): 159–67. http://dx.doi.org/10.13005/msri/110209.

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The urethane polymers of castor oil (COPU) are used in many commercial applications but one of the major limitations of these polymers is their inherent flammability and poor mechanical properties. Polymers containing phosphorous groups belong to the fire retardants, and when blended with castor oil based polyurethane improves the latter’s fire retardant properties. Present work, deals with the synthesis of a monomer bis (m-hydroxy phenyl) phenyl phosphate (BHPPP) and its related polyurethanes. Characterization of the monomer and polyurethanes are discussed. Blending of the polyurethanes with

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Brzeska, Joanna, Agnieszka Tercjak, Wanda Sikorska, Marek Kowalczuk, and Maria Rutkowska. "Morphology and Physicochemical Properties of Branched Polyurethane/Biopolymer Blends." Polymers 12, no. 1 (2019): 16. http://dx.doi.org/10.3390/polym12010016.

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The aim of this study is the analyze the structure of branched polyurethanes based on synthetic poly([R,S]-3-hydroxybutyrate) and their blends with biopolymers and montmorillonite. The properties which would predict the potential susceptibility of these materials to degradation are also estimated. Fourier-transform infrared spectroscopy with attenuated total reflection analysis shows that poly([d,l]-lactide) is on the surfaces of polyurethanes, whereas chitosan and starch are included inside the blend network. Atomic force microscopy images have shown that the surfaces of investigated samples

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Pavlicevic, Jelena, Mirjana Jovicic, Vesna Simendic, Oskar Bera, Radmila Radicevic, and Milena Spírková. "Modification of epoxy resins with thermoplastic segmented polycarbonate-based polyurethanes." Chemical Industry 68, no. 6 (2014): 755–65. http://dx.doi.org/10.2298/hemind130904086p.

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In this work, epoxy hybrid materials were synthesized by addition of thermoplastic segmented aliphatic polyurethanes with good elastic properties. The modified epoxy samples were obtained by curing of previously homogenized mixture of prepared polyurethane melts, epoxy resin and crosslinking agent Jeffamine D-2000. The influence of different weight content of polyurethanes (5, 10 and 15 wt. % compared to pure epoxy resin) as well the influence of different hard segments of elastomers (20, 25 and 30 wt. %) on the curing of modified epoxy systems was studied. The curing was followed by different

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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 (2019): 548–72. http://dx.doi.org/10.1177/0095244319877562.

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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 cellul

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Yakushin, Vladimir, Uldis Stirna, Irina Sevastyanova, Dzintra Vilsone, Viesturs Zeltins, and Mikelis Kirpluks. "Properties of Polyurethanes Based on Tall Oil Fatty Acids Ester with Different Types of Flame Retardants." Key Engineering Materials 559 (June 2013): 115–20. http://dx.doi.org/10.4028/www.scientific.net/kem.559.115.

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To decrease the combustibility of polyurethanes based on tall oil fatty acids ester, additives of five different halogen- and phosphorus-containing flame retardants were used. The efficiency of the flame retardants was evaluated from the change in the thermal, mechanical and combustibility characteristics of the obtained polyurethanes. It has been found that the phosphorus-containing flame retardant Levagard 4090 N decreases the combustibility of polyurethane to the greatest extent.

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Kemona, Aleksandra, and Małgorzata Piotrowska. "Polyurethane Recycling and Disposal: Methods and Prospects." Polymers 12, no. 8 (2020): 1752. http://dx.doi.org/10.3390/polym12081752.

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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 applie

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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 (2020): 2727. http://dx.doi.org/10.3390/polym12112727.

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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 t

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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.

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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 diisoc

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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.

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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 (2019): 2201. http://dx.doi.org/10.3390/molecules24122201.

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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 mobil

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Brzeska, Joanna, Agnieszka Tercjak, Wanda Sikorska, Marek Kowalczuk, and Maria Rutkowska. "Predicted Studies of Branched and Cross-Linked Polyurethanes Based on Polyhydroxybutyrate with Polycaprolactone Triol in Soft Segments." Polymers 12, no. 5 (2020): 1068. http://dx.doi.org/10.3390/polym12051068.

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The number of cross-links in the non-linear polyurethane structure is the basic factor affecting its properties. Selected properties of aliphatic polyurethanes with soft segments made of different amounts of polycaprolactonetriol, polycaprolactonediol and synthetic, telechelic poly([R,S]-3-hydroxybutyrate) were determined. On the basis of changes in polyurethane properties, the correlation between these properties and the construction of soft segments was found. The structure of polyurethanes, their morphology, hydrophilicity, thermal and mechanical properties were examined. These properties w

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Hou, Jinghui, Yifei Ma, Zihan Zhang, Xuanhe Yang, Muhua Huang, and Chunpeng Chai. "The Relationship between Solid Content and Particle Size Ratio of Waterborne Polyurethane." Coatings 9, no. 6 (2019): 401. http://dx.doi.org/10.3390/coatings9060401.

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A series of high solid content carboxylic acid/sulfonic acid waterborne polyurethanes was prepared by the emulsion dispersion method. The particle size and solid content were measured. By changing the particle size of the large particles to achieve different particle size ratios, high solid content waterborne polyurethanes were obtained at specific particle size ratios. When the particle size ratio was >7, 4–5 or 2–3, the aqueous polyurethane could reach a higher solid content (more than 56%). This indicated that solid content is related to particle size distribution in high solid content w

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Vimalasiri, P. A. D. T., R. P. Burford, and J. K. Haken. "Chromatographic Analysis of Elastomeric Polyurethanes." Rubber Chemistry and Technology 60, no. 3 (1987): 555–77. http://dx.doi.org/10.5254/1.3536140.

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Abstract Both alkali and acid fusion reactions can be used to cleave polyurethane polymers successfully. Fusion reaction rates are much faster than conventional aqueous alkali or acid fusion methods. Separation of fragments could be carried out using the liquid-liquid extraction procedures described. After quantitative and qualitative analysis of fragments using GC, SEC, and HPLC, chemical structure of the polymer can be established. Although the work described uses only elastomeric polyurethanes for the development of the analytical schemes, these schemes can be used to analyze other types of

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Zahedifar, Pegah, Lukasz Pazdur, Christophe M. L. Vande Velde, and Pieter Billen. "Multistage Chemical Recycling of Polyurethanes and Dicarbamates: A Glycolysis–Hydrolysis Demonstration." Sustainability 13, no. 6 (2021): 3583. http://dx.doi.org/10.3390/su13063583.

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The use of polyurethanes and, therefore, the quantity of its scrap are increasing. Considering the thermoset characteristic of most polyurethanes, the most circular recycling method is by means of chemical depolymerization, for which glycolysis is finding its way into the industry. The main goal of polyurethane glycolysis is to recover the polyols used, but only limited attempts were made toward recovering the aromatic dicarbamate residues and derivates from the used isocyanates. By the split-phase glycolysis method, the recovered polyols form a top-layer phase and the bottom layer contain tra

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Li, Ying, Sichong Chen, Jun Shen, et al. "Preparation and Properties of Biobased, Cationic, Waterborne Polyurethanes Dispersions from Castor Oil and Poly (Caprolactone) Diol." Applied Sciences 11, no. 11 (2021): 4784. http://dx.doi.org/10.3390/app11114784.

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Biobased cationic waterborne polyurethanes (WPUs) were prepared using isophorone diisocyanate (IPDI), N-methyl diethanolamine (N-MDEA), polycaprolactone (PCL) diol, hydrochlotic acid (HCl), and 1,4-butanediol (BDO). To improve the mechanical performance and adhesive strength of the waterborne polyurethane films, different amounts of castor oil (CO) acting as a cross-linking agent were incorporated in the polyurethane structure. The structures of the waterborne polyurethanes were assessed by Fourier-transform infrared spectroscopy (FTIR). The combination of CO had a positive effect on the dispe

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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 (2018): 23–38. http://dx.doi.org/10.1177/204124791800900102.

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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

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Chalid, Mochamad, Hans J. Heeres та Antonius A. Broekhuis. "A Study on the Structure of Novel Polyurethanes Derived from γ-Valerolactone-Based Diol Precursors". Advanced Materials Research 789 (вересень 2013): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amr.789.274.

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As versatile biomass-based diol precursors, N,N'-1,2-ethanediylbis-(4-hydroxy-pentanamide) (1) and 4-hydroxy-N-(2-hydroxyethyl)-pentanamide (2) are potential monomers to synthesize novel polyurethanes through adding di-isocyanates. This study reported the structural analysis and molecular behavior of polyurethanes obtained from polymerization of the diol precursors with aliphatic and aromatic di-isocyanates (hexamethylene diisocyanate, HDI (3), and phenyl-diisocyanate, PDI (4)) in (N,N-dimethylacetamide (DMA) solvents with triethylamine (TEA) catalysts.1H-NMR,13C-NMR and Elemental Analysis con

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Sajkiewicz, P., J. Brzeska, P. Denis, W. Sikorska, M. Kowalczuk, and M. Rutkowska. "The preliminary studies of a structure and electrospinning of new polyurethanes based on synthetic atactic poly[(R, S)-3-hydroxybutyrate]." Bulletin of the Polish Academy of Sciences: Technical Sciences 62, no. 1 (2014): 55–60. http://dx.doi.org/10.2478/bpasts-2014-0006.

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Abstract Novel polyurethanes based on synthetic, atactic poly[(R, S)-3-hydroxybutyrate] (a-PHB) and polycaprolactone (PCL) or polyoxytetramethylene (PTMG) diols were synthesized. It was shown that the presence of a-PHB within soft segments reduces crystallinity of PUR. Because of the low melting temperature for polyurethanes with PCL in soft segments, at this stage of work, electrospinning was limited to polyurethanes containing PTMG and a-PHB. Polyurethane containing 80% of PTMG and 20% of a-PHB was electrospun at various parameters from hexafluoro-2-propanole solution, resulting in formation

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Oprea, S., V. O. Potolinca, and C. D. Varganici. "Synthesis and properties of polyurethane urea with pyridine-2,6-dicarboxamide moieties in their structure." RSC Advances 6, no. 108 (2016): 106904–13. http://dx.doi.org/10.1039/c6ra23660j.

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The inclusion of 2,6-pyridinedicarboxamide into polyurethanes structure strongly influenced their morphology, surface and thermo-mechanical properties. The 2,6-pyridinedicarboxamide units adopt syn-syn conformations into polyurethane matrix.

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Mitsuzuka, Masahiko, Yuho Kinbara, Mizuki Fukuhara, et al. "Relationship between Photoelasticity of Polyurethane and Dielectric Anisotropy of Diisocyanate, and Application of High-Photoelasticity Polyurethane to Tactile Sensor for Robot Hands." Polymers 13, no. 1 (2020): 143. http://dx.doi.org/10.3390/polym13010143.

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Eight types of polyurethane were synthesized using seven types of diisocyanate. It was found that the elasto-optical constant depends on the concentration of diisocyanate groups in a unit volume of a polymer and the magnitude of anisotropy of the dielectric constant of diisocyanate groups. It was also found that incident light scattered when bending stress was generated inside photoelastic polyurethanes. A high sensitive tactile sensor for robot hands was devised using one of the developed polyurethanes with high photoelasticity.

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Jalili Marand, Maryam, Mostafa Rezaei, Amin Babaie, and Reza Lotfi. "Synthesis, characterization, crystallinity, mechanical properties, and shape memory behavior of polyurethane/hydroxyapatite nanocomposites." Journal of Intelligent Material Systems and Structures 31, no. 14 (2020): 1662–75. http://dx.doi.org/10.1177/1045389x20932212.

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Herein, polycaprolactone diols with diverse molecular weights were synthesized by ring-opening method. Then, polyurethanes were synthesized through two-step pre-polymerization method by polyaddition of hydroxyl and –NCO groups. Afterward, a set of polyurethanes/hydroxyapatite nanocomposites were synthesized through solution casting as well as in situ polycondensation methods. The exact nominal molecular weights of the synthesized polycaprolactones were determined by proton nuclear magnetic resonance (hydrogen-1 nuclear magnetic resonance). Hydrogen bonding index of ester and urethane carbonyl

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Li, Yue Ting, Hui Qin Lian, Yan Ou Hu, et al. "Synthesis and Shape Memory Property of a MDI Based Liquid Crystalline Polyurethane." Materials Science Forum 848 (March 2016): 132–39. http://dx.doi.org/10.4028/www.scientific.net/msf.848.132.

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Liquid crystalline polyurethanes (LCPU) were prepared from 4,4’-methylenediphenyl diisocyanate (MDI), 1,6-hexanediol (HDO), 2,2-dimethylol propionic acid (DMPA) and polytetramethylene ether glycol (PTMG). The experiments synthesized three liquid crystalline polyurethane films with different soft/hard segment ratio. Chemical and structural characterization of the polyurethanes were investigated by Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimeter and polarized microscopy respectively. Swelling rate and shape memory property were tested.

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Xiaoxia, Jian, Hu Yiwen, and Zheng Qilong. "Effect of thermal processing temperature on the microphase separation and mechanical properties of BAMO/THF polyurethane." Journal of Polymer Engineering 37, no. 2 (2017): 169–76. http://dx.doi.org/10.1515/polyeng-2015-0509.

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Abstract This paper describes the influence of thermal processing temperature on the microphase separation, hydrogen bonding, phase transitions and mechanical properties of 3,3-bis(azidomethyl)oxetane (BAMO)/tetrahydrofuran (THF) polyurethane binder, which is used for propellant. Fourier transform infrared (FTIR) spectroscopy confirmed that the intended polyurethane was synthesized and was used to determine the state of the local hydrogen bonding in these polyurethanes. The results showed that the thermal processing clearly imparts significant changes to the H-bonded environment and this was c

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Ali, Alaa, Kamal Yusoh, and S. F. Hasany. "Synthesis and Physicochemical Behaviour of Polyurethane-Multiwalled Carbon Nanotubes Nanocomposites Based on Renewable Castor Oil Polyols." Journal of Nanomaterials 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/564384.

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Polyurethanes (PUs) are high performance materials, with vast industrial and engineering applications. In this research, effects of Multiwalled Carbon Nanotubes (MWCNTs) on physicochemical properties of Castor Oil based Polyurethanes (COPUs) were studied. MWCNTs were added in different weight percentages (0% to 1% wt) in a castor oil based polyurethane (COPUs-MWCNTs) nanocomposites. The composition, structure, and morphology of polyurethanes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning

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Lin, Zhaojun, Qianqiong Zhao, Ruilan Fan, Xiaoxue Yuan, and Fuli Tian. "Flame retardancy and thermal properties of rigid polyurethane foam conjugated with a phosphorus–nitrogen halogen-free intumescent flame retardant." Journal of Fire Sciences 38, no. 3 (2020): 235–52. http://dx.doi.org/10.1177/0734904119890685.

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In this work, a halogen-free intumescent combining phosphorus and nitrogen, flame-retardant 2-((2-hydroxyphenyl)(phenylamino)methyl5,5-dimethyl-1,3,2-dioxaphosphinane 2-oxide (HAPO) was successfully synthesized. It had been synthesized by reaction of 5,5-dimethyl-1,3, 2-dioxphosphinane 2-oxide with Schiff base. Its chemical structure was characterized in detail by Fourier transform infrared spectroscopy, 1H NMR, and 31P NMR spectrum. The flame-retardant polyurethanes were prepared with different loadings of HAPO. The thermal properties, flame retardancy and combustion behavior of the pure poly

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Brzeska, Joanna. "Biodegradable Polyurethanes Cross-Linked by Multifunctional Compounds." Current Organic Synthesis 14, no. 6 (2017): 778–84. http://dx.doi.org/10.2174/1570179414666161115155149.

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Background: Cross-linking structure of polyurethanes determines no degradability of these materials. However, introducing the hydrolysable substrates (of natural or synthetic origin) into the cross-linked polyurethanes structure makes them biodegradable. Moreover compounds (such as polycaprolactone triol, glycerin, lysine triisocyanate, etc.) that are used for polyurethane cross-linking are degraded in non-toxic products. All these kinds of compounds can be introduced into soft or hard segments via urethane bonds. Objective: The review focuses on kind of multifunctional polyols and isocyanates

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