Articles de revues : « Aromatic polyurethanes »

1

Morgan, Paul W. « Polyurethanes from aromatic bischlorformates ». Journal of Applied Polymer Science 40, n^o 910 (5 novembre 1990) : 1771–82. http://dx.doi.org/10.1002/app.1990.070400930.

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Chalid, Mochamad, Hans J. Heeres et Antonius A. Broekhuis. « A Study on the Structure of Novel Polyurethanes Derived from γ-Valerolactone-Based Diol Precursors ». Advanced Materials Research 789 (septembre 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 confirmed structure of the polyurethanes built from both diols and di-isocyanates and FTIR indicated interaction among polyurethane molecules showed at lower wave numbers such as 2855-2976 cm-1for hydrogen-bonded NH groups and 1621-1643 cm-1for hydrogen-bonded C=O groups. Furthermore a study on influence of the inter-and intra-molecular hydrogen bonding on the thermal and mechanical properties of the polyurethanes would be an interesting investigation for the next study.

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Briz-López, Eva Marina, Rodrigo Navarro, Héctor Martínez-Hernández, Lucía Téllez-Jurado et Ángel Marcos-Fernández. « Design and Synthesis of Bio-Inspired Polyurethane Films with High Performance ». Polymers 12, n^o 11 (17 novembre 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 the degree of polymerization. It is proposed that this difference in reactivity could probably be attributed to a hampering effect of this catecholic ring during the polyaddition reaction. To corroborate this hypothesis, a protection of the aromatic ring was carried out, blocking the hampering effect and avoiding secondary reactions. The polyurethane bearing the protected catechol showed the highest molecular weight and the highest stress at break described to date (σmax ≈ 66.1 MPa) for these kind of catechol-functionalized polyurethanes. Therefore, this new approach allows for the obtention of high-performance polyurethane films and can be applied in different sectors, benefiting from the molecular adhesion introduced by the catechol ring.

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Zahedifar, Pegah, Lukasz Pazdur, Christophe M. L. Vande Velde et Pieter Billen. « Multistage Chemical Recycling of Polyurethanes and Dicarbamates : A Glycolysis–Hydrolysis Demonstration ». Sustainability 13, n^o 6 (23 mars 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 transreacted carbamates, excess glycol, amines, urea, and other side products. The hydrolysis of carbamates results in amines and CO2 as the main products. Consequently, the carbamates in the bottom layer of polyurethane split-phase glycolysis can also be hydrolyzed in a separate process, generating amines, which can serve as feedstock for isocyanate production to complete the polyurethane material cycle. In this paper, the full recycling of polyurethanes is reviewed and experimentally studied. As a matter of demonstration, combined glycolysis and hydrolysis led to an amine production yield of about 30% for model systems. With this result, we show the high potential for further research by future optimization of reaction conditions and catalysis.

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Jayasuriya, A. C., S. Tasaka et N. Inagaki. « Pyroelectric properties of linear aromatic polyurethanes ». IEEE Transactions on Dielectrics and Electrical Insulation 3, n^o 6 (1996) : 765–69. http://dx.doi.org/10.1109/94.556557.

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Gouveia, Júlia Rocha, Cleber Lucius da Costa, Lara Basílio Tavares et Demetrio Jackson dos Santos. « Synthesis of Lignin-Based Polyurethanes : A Mini-Review ». Mini-Reviews in Organic Chemistry 16, n^o 4 (19 mars 2019) : 345–52. http://dx.doi.org/10.2174/1570193x15666180514125817.

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Lignin is a natural polymer composed primarily of phenylpropanoid structures with an abundance of reactive groups: aliphatic and aromatic hydroxyls, phenols, and carbonyls. Considering the large quantity of hydroxyl groups, lignin has significant potential as a replacement for petroleum-based polyols in polyurethane (PU) synthesis and as a value-added, renewable raw material for this purpose. Several methods of lignin-based polyurethane synthesis are reviewed in this paper for reactive and thermoplastic systems: direct lignin incorporation, chemical lignin modification and depolymerization. Despite the unmodified lignin low reactivity towards diisocyanates, its direct incorporation as polyol generates highly brittle PUs, but with proper performance when applied as adhesive for wood. PU brittleness can be reduced employing polyols obtained from lignin/chain extender blends, in which glass transition temperature (Tg), mechanical properties and PU homogeneity are strongly affected by lignin content. The potential applications of lignin can be enhanced by lignin chemical modifications, including oxyalkylation and depolymerization, improving polyurethanes properties. Another PU category, lignin- based thermoplastic polyurethane (LTPU) synthesis, emerges as a sustainable alternative and is also presented in this work.

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Mendelsohn, Morris A., Francis W. Navish et Dongsik Kim. « Characteristics of a Series of Energy-Absorbing Polyurethane Elastomers ». Rubber Chemistry and Technology 58, n^o 5 (1 novembre 1985) : 997–1013. http://dx.doi.org/10.5254/1.3536110.

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Abstract Compositional effects were measured on a series of polyurethanes prepared by extending MDI-terminated PTMG prepolymers with dihydric alcohols and MCHDI-terminated prepolymers with diamines. The tensile and compressive stiffness and hysteretic loss increased while the resilience decreased with a decrease in the isocyanate equivalent weight of the prepolymer. Polyol chain extenders having an aromatic structure provided greater rigidity and increase in temperature on compressive cycling than did their aliphatic counterparts. Structural linearity and symmetry of both the aliphatic and aromatic extenders promoted greater rigidity and resiliency and less damping. Although direct replacement of MDI with MCHDI gives softer polyurethanes, use of the aromatic diamine extenders with the MCHDI-terminated prepolymers gave materials displaying the least resilience and greatest rigidity under static test conditions and the highest increase in temperature on compressive cycling. However, a significant increase in the chain length of the aromatic diamine-extended prepolymer provided properties quite similar to those obtained with the aliphatic diol systems.

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Jourdain, Antoine, Iurii Antoniuk, Anatoli Serghei, Eliane Espuche et Eric Drockenmuller. « 1,2,3-Triazolium-based linear ionic polyurethanes ». Polymer Chemistry 8, n^o 34 (2017) : 5148–56. http://dx.doi.org/10.1039/c7py00406k.

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We report the synthesis and detailed characterization of a series of ionic polyurethanes issued from the polyaddition of a 1,2,3-triazolium-functionalized diol monomer having a bis(trifluoromethylsulfonyl)imide counter-anion with four aliphatic, cycloaliphatic or aromatic commercial diisocyanates.

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Rapone, Irene, Vincenzo Taresco, Valerio Di Lisio, Antonella Piozzi et Iolanda Francolini. « Silver- and Zinc-Decorated Polyurethane Ionomers with Tunable Hard/Soft Phase Segregation ». International Journal of Molecular Sciences 22, n^o 11 (7 juin 2021) : 6134. http://dx.doi.org/10.3390/ijms22116134.

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Segmented polyurethane ionomers find prominent applications in the biomedical field since they can combine the good mechanical and biostability properties of polyurethanes (PUs) with the strong hydrophilicity features of ionomers. In this work, PU ionomers were prepared from a carboxylated diol, poly(tetrahydrofuran) (soft phase) and a small library of diisocyanates (hard phase), either aliphatic or aromatic. The synthesized PUs were characterized to investigate the effect of ionic groups and the nature of diisocyanate upon the structure–property relationship. Results showed how the polymer hard/soft phase segregation was affected by both the concentration of ionic groups and the type of diisocyanate. Specifically, PUs obtained with aliphatic diisocyanates possessed a hard/soft phase segregation stronger than PUs with aromatic diisocyanates, as well as greater bulk and surface hydrophilicity. In contrast, a higher content of ionic groups per polymer repeat unit promoted phase mixing. The neutralization of polymer ionic groups with silver or zinc further increased the hard/soft phase segregation and provided polymers with antimicrobial properties. In particular, the Zinc/PU hybrid systems possessed activity only against the Gram-positive Staphylococcus epidermidis while Silver/PU systems were active also against the Gram-negative Pseudomonas aeruginosa. The herein-obtained polyurethanes could find promising applications as antimicrobial coatings for different kinds of surfaces including medical devices, fabric for wound dressings and other textiles.

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Kimura, Akihiro, Haruka Hayama, Jun-ya Hasegawa, Hassan Nageh, Yue Wang, Naofumi Naga, Mayumi Nishida et Tamaki Nakano. « Recyclable and efficient polyurethane-Ir catalysts for direct borylation of aromatic compounds ». Polymer Chemistry 8, n^o 47 (2017) : 7406–15. http://dx.doi.org/10.1039/c7py01509g.

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Hoyle, Charles E., et Kyu-Jun Kim. « Photolysis of aromatic diisocyanate-based polyurethanes in solution ». Journal of Polymer Science Part A : Polymer Chemistry 24, n^o 8 (août 1986) : 1879–94. http://dx.doi.org/10.1002/pola.1986.080240811.

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Khan, Ajmir, Muhammad Naveed et Muhammad Rabnawaz. « Melt-reprocessing of mixed polyurethane thermosets ». Green Chemistry 23, n^o 13 (2021) : 4771–79. http://dx.doi.org/10.1039/d1gc01232k.

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Herein we have developed melt-reprocessing of mixed aromatic and aliphatic polyurethanes (PUR) thermosets. This study will enable post-consumer mixed PURs with immense benefits for science, the economy, and the environment.

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Fan, Wuhou, Yong Jin, Liangjie Shi, Rong Zhou et Weining Du. « Developing visible-light-induced dynamic aromatic Schiff base bonds for room-temperature self-healable and reprocessable waterborne polyurethanes with high mechanical properties ». Journal of Materials Chemistry A 8, n^o 14 (2020) : 6757–67. http://dx.doi.org/10.1039/c9ta13928a.

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Visible-light-induced dynamic aromatic Schiff base bond was developed for waterborne polyurethanes, which possess a desirable room-temperature self-healability and excellent mechanical properties (tensile stress: 14.32 MPa; toughness: 64.80 MJ m⁻³).

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Liu, Yahao, Jian Zheng, Xiao Zhang, Yu Zhang, Guibo Yu et Yunfei Jia. « Self-healable Hydroxyl-terminated Polybutadiene based Polyurethane for Sustainable Development ». IOP Conference Series : Earth and Environmental Science 966, n^o 1 (1 janvier 2022) : 012009. http://dx.doi.org/10.1088/1755-1315/966/1/012009.

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Abstract Self-healing technology provides a promising road for the sustainable development of the environment, which can extend the service life of materials, thereby reducing the waste of natural resources. As is known to all, it is difficult to obtain a polymer with fast room-temperature self-healing properties without any external stimuli. In this work, a series of polyurethanes with fast room-temperature self-healing capability were designed and prepared by combining the hydrogen bonds and the aromatic disulfide bonds. Owing to their synergistic effect, the obtained polyurethane exhibited high self-healing efficiency of 95.2% for SPU-1, and 98.4% for SPU-2. It is excepted that this design strategy may be potential applications in sustainable development for applied materials.

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15

Casey, J. P., B. Milligan et M. J. Fasolka. « Aromatic Diamine Chain Extender Structure-Activity Relationships in Polyurethanes ». Journal of Elastomers & ; Plastics 17, n^o 3 (juillet 1985) : 218–32. http://dx.doi.org/10.1177/009524438501700306.

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Chalid, Mochamad. « Synthesis and Characterization of Novel Polyurethanes Based on N,N'-1,2-Ethanediylbis-(4-Hydroxy-Pentanamide) and 4-Hydroxy-N-(2-Hydroxyethyl)-Pentanamide ». Advanced Materials Research 277 (juillet 2011) : 112–19. http://dx.doi.org/10.4028/www.scientific.net/amr.277.112.

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As diols, N,N'-1,2-ethanediylbis-(4-hydroxy-pentanamide) (1) and 4-hydroxy-N-(2-hydroxyethyl)-pentanamide (2)) are versatile precursors for the manufacture of bio-polymers. Polymer design, by exploiting the variation in structure of both diol and di-isocyanate monomers, such as backbone structure and presence of functional groups, appears to be a promising biopolymer engineering pathway to synthesize polyurethanes. Both diols (1) and (2) were then polymerized by reaction with aliphatic and aromatic di-isocyanates at 140 °C in (N,N-dimethylacetamide (DMA) solvents using triethylamine (TEA) catalysts, to obtain novel polyurethanes. The products were characterized by FTIR, 1H-NMR, 13C-NMR, and Elemental Analysis. This working has created a new chance to synthesis bio-polyurethanes based on levulinic acid, as one of biomass compounds

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Ostanin, Stepan, Maxim Mokeev, Dmitry Pikhurov, Aleksandr Sakhatskii et Vjacheslav Zuev. « Interplay of Structural Factors in Formation of Microphase-Separated or Microphase-Mixed Structures of Polyurethanes Revealed by Solid-State NMR and Dielectric Spectroscopy ». Polymers 13, n^o 12 (14 juin 2021) : 1967. http://dx.doi.org/10.3390/polym13121967.

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A set of aromatic-oxyaliphatic polyurethanes (PUs) with different mass fractions of components also containing fluorinated fragments was synthesized and studied using various solid-state NMR techniques and dielectric spectroscopy. In contrast to the common model suggested by Cooper and Tobolsky in 1966, the rigid domains of microphase separated PUs are formed, not only by units containing urethane bonds, but also by oxyethylene fragments that form a common rigid phase. The urethane bonds and oxyethylene fragments are incorporated into both rigid and soft phases. Good agreement with the Cooper and Tobolsky model is observed only when solubility parameters are significantly different for the hard and soft segments, such as hydrocarbon aromatics and perfluoroaliphatic blocks.

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Acetti, Daniela, Paola D'arrigo, Carmen Giordano, Piero Macchi, Stefano Servi et Davide Tessaro. « New Aliphatic Glycerophosphoryl-Containing Polyurethanes : Synthesis, Platelet Adhesion and Elution Cytotoxicity Studies ». International Journal of Artificial Organs 32, n^o 4 (avril 2009) : 204–12. http://dx.doi.org/10.1177/039139880903200404.

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In this study new poly(ether)urethanes (PEUs) based on aliphatic diisocyanates were synthesized with phospholipid-like residues as chain extenders. The primary objective was to prepare new polyurethanes from diisocyanates that are less toxic than the aromatic ones widely used in medical-grade polyurethanes, in order to investigate the effect of the different aromatic or aliphatic hard segment content on the final properties of the materials. Some glycerophospho residues were simultaneously introduced to enhance the hemocompatibility of these materials. Polymers were prepared by a conventional two-step solution polymerization procedure using hexamethylene diisocyanate (HDI) and dodecametilendiisocyanate (DDI) and poly(1,4-butanediol) with molecular weight 1000 to form prepolymers, which were subsequently polymerized with 1-glycerophosphorylcholine (1-GPC) or glycerophosphorylserine (GPS) to act as chain extenders. The reference polymers bearing 1,4-butandiol (BD) were also synthesized. The polymers obtained were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H NMR), and differential scanning calorimetry (DSC). The hemocompatibility of synthesized segmented polyurethanes was preliminarily investigated by platelet-rich plasma contact studies and related scanning electron microscopy (SEM) photographs as well as by cell viability assay after cell exposure to material elutions to assess the effect of any toxic leachables coming out from the samples. Two of the polymers gave interesting results, suggesting the desirability of further investigation into their possible use in biomedical devices.

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Olszewska, E., S. Pikus, A. Kultys et P. Wolski. « Powder diffraction investigations of some derivatives of benzophenone : Monomers for synthesis of new polyurethanes ». Powder Diffraction 22, n^o 3 (septembre 2007) : 259–67. http://dx.doi.org/10.1154/1.2770470.

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Four aliphatic-aromatic diols with ether linkages [4, 4′-Bis(2-hydroxyethoxy)benzophenone, 4, 4′-Bis(3-hydroxypropoxy)benzophenone, 4, 4′-Bis(6-hydroxyhexyloxy)benzophenone, 4, 4′-Bis(11-hydroxyundecyloxy)benzophenone] and two aliphatic-aromatic diols with sulfur linkages [4, 4′-Bis[(2-hydroxyethyl)thio]benzophenone, 4, 4′-Bis[(3-hydroxypropyl)thio]benzophenone] have been characterized by X-ray powder diffraction. These diols can be used for synthesis of thermoplastic nonsegmented polyurethanes. Experimental 2θ peaks positions, relative peak intensities, values of d, and Miller indices as well as unit-cell parameters are presented.

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Didenko, A. L., D. A. Kuznetsov, A. G. Ivanov, V. E. Smirnova, G. V. Vaganov, A. M. Kamalov, V. M. Svetlichnyi, V. E. Yudin et V. V. Kudryavtsev. « Synthesis and properties of aromatic polyimides chemically modified by polyurethanes ». Russian Chemical Bulletin 71, n^o 6 (juin 2022) : 1085–110. http://dx.doi.org/10.1007/s11172-022-3510-6.

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Brecl, Marko, Gabriela Ambrožič et Majda Žigon. « Aromatic side-chain liquid-crystalline polyurethanes with azobenzene mesogenic units ». Polymer Bulletin 48, n^o 2 (1 avril 2002) : 151–58. http://dx.doi.org/10.1007/s00289-002-0027-x.

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SZCZEPKOWSKI, LEONARD, STANISLAW HERNACKI et LESZEK GAJZLER. « Determination of trace amounts of aromatic amines in foamed polyurethanes ». Polimery 57, n^o 11/12 (novembre 2012) : 861–64. http://dx.doi.org/10.14314/polimery.2012.861.

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Wei, Xin, Yan Ying et Xuehai Yu. « A novel synthetic strategy to aromatic-diisocyanate-based waterborne polyurethanes ». Journal of Applied Polymer Science 70, n^o 8 (21 novembre 1998) : 1621–26. http://dx.doi.org/10.1002/(sici)1097-4628(19981121)70:8<1621 ::aid-app20>3.0.co;2-o.

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Zhao, Changbo, Caijuan Huang, Qin Chen, Ian D. V. Ingram, Xiankui Zeng, Tianhua Ren et Haibo Xie. « Sustainable Aromatic Aliphatic Polyesters and Polyurethanes Prepared from Vanillin-Derived Diols via Green Catalysis ». Polymers 12, n^o 3 (5 mars 2020) : 586. http://dx.doi.org/10.3390/polym12030586.

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The design and preparation of polymers by using biobased chemicals is regarded as an important strategy towards a sustainable polymer chemistry. Herein, two aromatic diols, 4-(hydroxymethyl)-2-methoxyphenol and 2-(4-(hydroxymethyl)-2-methoxyphenoxy)ethanol, have been prepared in good yields through the direct reduction of vanillin and hydroxyethylated vanillin (4-(2-hydroxyethoxy)-3-methoxybenzaldehyde) using NaBH4, respectively. The diols were submitted to traditional polycondensation and polyaddition with acyl chlorides and diisocyanatos, and serials of new polyesters and polyurethanes were prepared in high yields with moderate molecular weight ranging from 17,000 to 40,000 g mol−1. Their structures were characterized by 1H NMR, 13C NMR and FTIR, and their thermal properties were studied by TGA and differential scanning calorimetry (DSC), indicating that the as-prepared polyesters and polyurethanes have Tg in the range of 16.2 to 81.2 °C and 11.6 to 80.4 °C, respectively.

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Pikus, S., E. Olszewska, W. Podkościelny, M. Rogulska et A. Kultys. « Powder diffraction data for the new aliphatic-aromatic thiodiols ». Powder Diffraction 18, n^o 3 (septembre 2003) : 240–43. http://dx.doi.org/10.1154/1.1578651.

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Five new aliphatic-aromatic thiodiols: 1,2-bis[4-(2′-hydroxyethylthio)phenyl]ethane (C18H22O2S2), 1,2-bis[4-(3′-hydroxypropylthio)phenyl]ethane (C20H26O2S2), 1,2-bis[4-(6′-hydroxyhexylthio)phenyl]ethane (C26H38O2S2), 1,2-bis[4-(10′-hydroxydecylthio)phenyl]ethane (C34H54O2S2), 1,2-bis[4-(11′-hydroxyundecylthio)phenyl]ethane (C36H58O2S2) have been characterized by X-ray powder diffraction. These thiodiols can be used for synthesis of thermoplastic nonsegmented polyurethanes. Experimental 2θ peaks positions, relative peak intensities, values of d and Miller indices as well as unit cell parameters are reported.

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Vieira, Fernanda Rosa, Sandra Magina, Dmitry V. Evtuguin et Ana Barros-Timmons. « Lignin as a Renewable Building Block for Sustainable Polyurethanes ». Materials 15, n^o 17 (5 septembre 2022) : 6182. http://dx.doi.org/10.3390/ma15176182.

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Currently, the pulp and paper industry generates around 50–70 million tons of lignin annually, which is mainly burned for energy recovery. Lignin, being a natural aromatic polymer rich in functional hydroxyl groups, has been drawing the interest of academia and industry for its valorization, especially for the development of polymeric materials. Among the different types of polymers that can be derived from lignin, polyurethanes (PUs) are amid the most important ones, especially due to their wide range of applications. This review encompasses available technologies to isolate lignin from pulping processes, the main approaches to convert solid lignin into a liquid polyol to produce bio-based polyurethanes, the challenges involving its characterization, and the current technology assessment. Despite the fact that PUs derived from bio-based polyols, such as lignin, are important in contributing to the circular economy, the use of isocyanate is a major environmental hot spot. Therefore, the main strategies that have been used to replace isocyanates to produce non-isocyanate polyurethanes (NIPUs) derived from lignin are also discussed.

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Bayrak, Fatih, Emriye Ay, Ayhan Oral, Tamer Karayıldırım et Kadir Ay. « Synthesis of 1,2,3-triazole group-containing isomannide-based aromatic new polyurethanes ». Iranian Polymer Journal 31, n^o 4 (30 novembre 2021) : 413–23. http://dx.doi.org/10.1007/s13726-021-01001-z.

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Lee, Jong-Baek. « Synthesis and Characterization of Liquid Crystalline Polyurethanes Containing Aromatic Ring Moiety ». Elastomers and Composites 48, n^o 2 (30 juin 2013) : 141–47. http://dx.doi.org/10.7473/ec.2013.48.2.141.

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Ates, Burhan, Suleyman Koytepe, Merve Goksin Karaaslan, Sevgi Balcioglu et Selam Gulgen. « Biodegradable non-aromatic adhesive polyurethanes based on disaccharides for medical applications ». International Journal of Adhesion and Adhesives 49 (mars 2014) : 90–96. http://dx.doi.org/10.1016/j.ijadhadh.2013.12.012.

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Javni, Ivan, Doo Pyo Hong et Zoran S. Petrović. « Polyurethanes from soybean oil, aromatic, and cycloaliphatic diamines by nonisocyanate route ». Journal of Applied Polymer Science 128, n^o 1 (10 juillet 2012) : 566–71. http://dx.doi.org/10.1002/app.38215.

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Wang, L. F., K. S. Su, E. C. Wang et J. S. Chen. « Synthesis and characterization of segmented polyurethanes containing aromatic diol chain extenders ». Journal of Applied Polymer Science 64, n^o 3 (18 avril 1997) : 539–46. http://dx.doi.org/10.1002/(sici)1097-4628(19970418)64:3<539 ::aid-app10>3.0.co;2-t.

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Alinejad, Mona, Christián Henry, Saeid Nikafshar, Akash Gondaliya, Sajad Bagheri, Nusheng Chen, Sandip Singh, David Hodge et Mojgan Nejad. « Lignin-Based Polyurethanes : Opportunities for Bio-Based Foams, Elastomers, Coatings and Adhesives ». Polymers 11, n^o 7 (18 juillet 2019) : 1202. http://dx.doi.org/10.3390/polym11071202.

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Polyurethane chemistry can yield diverse sets of polymeric materials exhibiting a wide range of properties for various applications and market segments. Utilizing lignin as a polyol presents an opportunity to incorporate a currently underutilized renewable aromatic polymer into these products. In this work, we will review the current state of technology for utilizing lignin as a polyol replacement in different polyurethane products. This will include a discussion of lignin structure, diversity, and modification during chemical pulping and cellulosic biofuels processes, approaches for lignin extraction, recovery, fractionation, and modification/functionalization. We will discuss the potential of incorporation of lignins into polyurethane products that include rigid and flexible foams, adhesives, coatings, and elastomers. Finally, we will discuss challenges in incorporating lignin in polyurethane formulations, potential solutions and approaches that have been taken to resolve those issues.

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Davletbaeva, I. M., I. I. Zaripov, R. S. Davletbaev et F. B. Balabanova. « Polyurethanes based on anionic macroinitiators, aromatic isocyanates, and 4,4′-dihydroxy-2,2-diphenylpropane ». Russian Journal of Applied Chemistry 87, n^o 4 (avril 2014) : 468–73. http://dx.doi.org/10.1134/s10704272140400120.

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Kausar, Ayesha, Sonia Zulfiqar et Muhammad Ilyas Sarwar. « High performance segmented polyurethanes derived from a new aromatic diisocyanate and polyol ». Polymer Degradation and Stability 98, n^o 1 (janvier 2013) : 368–76. http://dx.doi.org/10.1016/j.polymdegradstab.2012.09.004.

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Hoyle, Charles E., C. P. Chawla et Kyu-Jun Kim. « The effect of flexibility on the photodegradation of aromatic diisocyanate-based polyurethanes ». Journal of Polymer Science Part A : Polymer Chemistry 26, n^o 5 (mai 1988) : 1295–306. http://dx.doi.org/10.1002/pola.1988.080260504.

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Byrne, Catherine A., Daniel P. Mack et James M. Sloan. « A Study of Aliphatic Polyurethane Elastomers Prepared from Diisocyanate Isomer Mixtures ». Rubber Chemistry and Technology 58, n^o 5 (1 novembre 1985) : 985–96. http://dx.doi.org/10.5254/1.3536109.

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Abstract Linear polyurethane elastomers are block copolymers which are elastomeric because they are phase separated. The soft block is derived from a hydroxy terminated telechelic polymer, frequently a polyether or polyester of a molecular weight less than 3000 and a glass transition temperature well below room temperature. The hard block, having a Tg above room temperature, consists of a diisocyanate and a diol. Most frequently the diisocyanate is aromatic and the diol is 1,4-butanediol. The elastomers produced are frequently opaque and then yellow in storage due to the presence of the aromatic rings. For applications where transparency and nonyellowing are important, aliphatic diisocyanates are the compounds of choice. One such diisocyanate is methylene bis(4-cyclohexyl-isocyanate), which is conveniently called H12MDI. It is prepared from the same diamine as methylene dianiline diisocyanate (MDI), but the aromatic rings are hydrogenated before phosgenation. The hydrogenation leads to a mixture of three aliphatic diamine isomers. Phosgenation leads to a diisocyanate which is a mixture of the three isomers shown in Figure 1. The isomer content is adjusted by the manufacturer, and the product received is a liquid. Another example of a diisocyanate which is marketed as a mixture is toluene diisocyanate, an 80:20 mixture of the 2,4:2,6 isomers being the most common. The aromatic diisocyanates are planar molecules or bent planar molecules like MDI. The H12MDI is also bent, but does not contain planar rings. Even if polymers from one pure diisocyanate isomer are examined, the cycloaliphatic compounds are much less likely to form highly ordered or crystalline regions in the hard-segment phase due to the greater difficulty in packing correctly. A desire to know the isomer composition of the diisocyanate and what effect the isomer composition has on the properties of the elastomers led to this study. Mixtures of the isomers varying from approximately 10% of the trans-trans isomer up to 95% (t-t) have been prepared and the properties of polyurethanes prepared from them have been studied.

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Takahashi, Akira, Taichi Watanabe, Shinji Ando et Atsushi Kameyama. « Refractive Index Modulation by Photo-Fries Rearrangement of Main Chain-Type Aromatic Polyurethanes ». Journal of Photopolymer Science and Technology 32, n^o 2 (24 juin 2019) : 243–47. http://dx.doi.org/10.2494/photopolymer.32.243.

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RENMAN, L., C. SANGÖ et G. SKARPING. « Determination of Isocyanate and Aromatic Amine Emissions from Thermally Degraded Polyurethanes in Foundries ». American Industrial Hygiene Association Journal 47, n^o 10 (octobre 1986) : 621–28. http://dx.doi.org/10.1080/15298668691390340.

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Antonino, Leonardo Dalseno, Júlia Rocha Gouveia, Rogério Ramos de Sousa Júnior, Guilherme Elias Saltarelli Garcia, Luara Carneiro Gobbo, Lara Basílio Tavares et Demetrio Jackson dos Santos. « Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI ». Molecules 26, n^o 8 (7 avril 2021) : 2131. http://dx.doi.org/10.3390/molecules26082131.

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Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

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Rosenberg, Christina, Kirsi Nikkilä, Maj-Len Henriks-Eckerman, Kimmo Peltonen et Kerstin Engström. « Biological monitoring of aromatic diisocyanates in workers exposed to thermal degradation products of polyurethanes ». J. Environ. Monit. 4, n^o 5 (2002) : 711–16. http://dx.doi.org/10.1039/b206340a.

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Carré, Camille, Hugo Zoccheddu, Stéphane Delalande, Pascal Pichon et Luc Avérous. « Synthesis and characterization of advanced biobased thermoplastic nonisocyanate polyurethanes, with controlled aromatic-aliphatic architectures ». European Polymer Journal 84 (novembre 2016) : 759–69. http://dx.doi.org/10.1016/j.eurpolymj.2016.05.030.

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Emamikia, Mohammad, Mehdi Barikani et Gholamreza Bakhshandeh. « Relationship between structure and aromatic solvent permeability of crosslinked polyurethanes based on hyperbranched polyesters ». Polymer International 64, n^o 9 (20 février 2015) : 1142–54. http://dx.doi.org/10.1002/pi.4882.

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Wang, Fu Cai, Michel Feve, Thanh My Lam et Jean-Pierre Pascault. « FTIR analysis of hydrogen bonding in amorphous linear aromatic polyurethanes. I. Influence of temperature ». Journal of Polymer Science Part B : Polymer Physics 32, n^o 8 (juin 1994) : 1305–13. http://dx.doi.org/10.1002/polb.1994.090320801.

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Yuan, C. Y., S. Y. Chen, C. H. Tsai, Y. S. Chiu et Y. W. Chen-Yang. « Thermally stable and flame-retardant aromatic phosphate and cyclotriphosphazene-containing polyurethanes : synthesis and properties ». Polymers for Advanced Technologies 16, n^o 5 (2005) : 393–99. http://dx.doi.org/10.1002/pat.593.

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BRZESKA, JOANNA, PIOTR DACKO, HENRYK JANECZEK, MAREK KOWALCZUK, HELENA JANIK et MARIA RUTKOWSKA. « The influence of synthetic polyhydroxybutyrate on selected properties of novel polyurethanes for medical applications. Part I. Polyurethanes with aromatic diisocyanates in hard segments ». Polimery 55, n^o 01 (janvier 2010) : 41–46. http://dx.doi.org/10.14314/polimery.2010.041.

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Lemaire, Jacques, Jean-Luc Gardette, Agnès Rivaton et Agnès Roger. « Dual photo-chemistries in aliphatic polyamides, bisphenol A polycarbonate and aromatic polyurethanes—A short review ». Polymer Degradation and Stability 15, n^o 1 (janvier 1986) : 1–13. http://dx.doi.org/10.1016/0141-3910(86)90002-9.

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Wang, Yuanmeng, Xiangnan Liu, Yikun Wang et Jingbo Zhao. « Epoxy-free synthesis of aromatic dicyclocarbonates and the related strong epoxy hybrid non-isocyanate polyurethanes ». Materials Today Communications 34 (mars 2023) : 105263. http://dx.doi.org/10.1016/j.mtcomm.2022.105263.

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Su, Shuenn-Kung, Jia-Hao Gu, Hsun-Tsing Lee, Shu-Huei Yu, Cheng-Lung Wu et Maw-Cherng Suen. « Effects of an Aromatic Fluoro-Diol and Polycaprolactone on the Properties of the Resultant Polyurethanes ». Advances in Polymer Technology 37, n^o 4 (29 septembre 2016) : 1142–52. http://dx.doi.org/10.1002/adv.21773.

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Wang, Fu Cai, Michel Feve, Thanh My Lam et Jean-Pierre Pascault. « FTIR analysis of hydrogen bonding in amorphous linear aromatic polyurethanes. II. Influence of styrene solvent ». Journal of Polymer Science Part B : Polymer Physics 32, n^o 8 (juin 1994) : 1315–20. http://dx.doi.org/10.1002/polb.1994.090320802.

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Santana, Jeferson Santos, Elisangela Silvana Cardoso, Eduardo Rezende Triboni et Mário José Politi. « Polyureas Versatile Polymers for New Academic and Technological Applications ». Polymers 13, n^o 24 (15 décembre 2021) : 4393. http://dx.doi.org/10.3390/polym13244393.

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Polyureas (PURs) are a competitive polymer to their analogs, polyurethanes (PUs). Whereas PUs’ main functional group is carbamate (urethane), PURs contain urea. In this revision, a comprehensive overview of PUR properties, from synthesis to technical applications, is displayed. Preparative routes that can be used to obtain PURs using diisocianates or harmless reagents such as CO2 and NH3 are explained, and aterials, urea monomers and PURs are discussed; PUR copolymers are included in this discussion as well. Bulk to soft components of PUR, as well as porous materials and meso, micro or nanomaterials are evaluated. Topics of this paper include the general properties of aliphatic and aromatic PUR, followed by practical synthetic pathways, catalyst uses, aggregation, sol–gel formation and mechanical aspects.

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