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Ester Urethane (ester + urethane)
Selected AbstractsStudies on thermoplastic polyurethanes based on new diphenylethane-derivative diols.JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Abstract Two series of poly(ether urethane)s and one series of poly(ester urethane)s were synthesized, containing, respectively, poly(oxytetramethylene) diol (PTMO) of Mn = 1000 and 2000 and poly(,-caprolactone) diol of Mn = 2000 as soft segments. In each series the same hard segment, i.e., 4,4,-(ethane-1,2-diyl)bis(benzenethiohexanol)/hexane-1,6-diyl diisocyanate, with different content (, 14,72 wt %) was used. The polymers were prepared by a one-step melt polymerization in the presence of dibutyltin dilaurate as a catalyst, at the molar ratio of NCO/OH = 1 (in the case of the polymers from PTMO of Mn = 1000 also at 1.05). For all polymers structures (by FTIR and X-ray diffraction analysis) and physicochemical, thermal (by differential scanning calorimetry and thermogravimetric analysis), and tensile properties as well as Shore A/D hardness were determined. The resulting polymers were thermoplastic materials with partially crystalline structures (except the polymer with the highest content of PTMO of Mn = 2000). It was found that the poly(ether urethane)s showed lower crystallinity, glass-transition temperature (Tg), and hardness as well as better thermal stability than the poly(ester urethane)s. Poly(ether urethane)s also exhibited higher tensile strength (up to 23.5 MPa vs. 20.3 MPa) and elongation at break (up to , 1950% vs. 1200%) in comparison with the corresponding poly(ester urethane)s. Among the poly(ether urethane)s an increase in soft-segment length was accompanied by an increase in thermal stability, tensile strength, and elongation at break, as well as a decrease in Tg, crystallinity, and hardness. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Poly(ester urethane)s with polycaprolactone soft segments: A morphological studyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2002Juliana Kloss Abstract Two series of poly(ester urethane)s were prepared, containing polycaprolactone (PCL) as the soft segment with molecular weights of 530 and 2000. In each series, the soft-segment/hard-segment ratio was varied, and the morphological changes were monitored with differential scanning calorimetry, dynamic mechanical thermal analysis, wide-angle X-ray scattering, and scanning electron microscopy techniques. The polyurethanes with longer PCL segments retained their crystallinity, whereas those with shorter PCL segments did not. A morphological model is proposed, in which a continuous PCL-rich matrix contains both PCL crystallites and domains of urethane hard segments. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4117,4130, 2002 [source] Preparation and characterization of polyurethane,gold nanocomposites prepared using encapsulated gold nanoparticlesPOLYMER INTERNATIONAL, Issue 7 2010Chao-Ching Chang Abstract Gold nanoparticles (GNPs) have been widely studied due to their unique properties. Although many research groups have developed the synthesis of GNPs using various polymers as stabilizing or reducing agents, the effects of GNPs on the structures and properties of polymer matrices have been less reported. We propose a new design for the preparation of polyurethane,gold (PU,Au) nanocomposites. 11-Mercapto-1-undecanol-coated GNPs acted as the chain extenders and reacted with isocyanates to form covalent bonds between PU and GNPs. PU,Au nanocomposites were successfully synthesized, and the effects of multifunctional GNPs on the structures, morphology and properties of poly(ester urethane) were investigated. Scanning electron microscopy images suggested the GNPs can be dispersed uniformly in the PU matrix. Maltese-cross of spherical crystals was observed in the PU,Au nanocomposites, and the size of the crystals decreased with an increase in gold content. As the gold content increased, the thermal decomposition temperature and the temperature of the maximum decomposition rate increased. The glass transition temperature, crystal melting temperature and melting enthalpy of the soft segment also increased progressively. The results showed that multifunctional GNPs concentrated hard segments and resulted in an increase of heterogeneous nucleation, phase separation and elasticity. Copyright © 2010 Society of Chemical Industry [source] Surface tension of poly(ester urethane)s and poly(ether urethane)sPOLYMER INTERNATIONAL, Issue 3 2007Mihaela Lupu Abstract The correlation between the surface tension parameters and the chemical composition of poly(ester urethane) and poly(ether urethane) thin films with different soft and hard segments, both before and after plasma treatment, was investigated. Calculations are based on the geometric mean approach of Owens and Wendt (Owens DK and Wendt RC, J Appl Polym Sci13:1741 (1969)), Rabel (Rabel W, Physikalische Blätter33:151 (1977)) and Kälble (Kälble DH, J Adhesion1:102 (1969)), on the Lifshitz,van der Waals acid/base approach of van Oss and co-workers (van Oss CJ, Good RJ and Chaudhury MK, Langmuir4:884 (1988); van Oss CJ, Ju L, Chaudhury MK and Good RJ, Chem Rev88:927 (1988); van Oss CJ, Interfacial Forces in Aqueous Media. Marcel Dekker, New York (1994)) and on the theoretical methods involving quantitative structure,property relationships (Bicerano J, JMS Rev Macromol Chem PhysC36:161 (1996)). For all investigated films, the polar terms contribute significantly to the total surface tensions, as due to the large electron donor, , interactions. Plasma treatment alters the surface energy of samples by changing their surface polarity and hydrophilicity. The hydrophilicity trends for polyurethanes were also studied by means of the free energy of hydration between compounds and water. Preliminary blood contact tests of the selected polyurethane sample with higher hydrophilicity were developed for biomedical applications. Copyright © 2006 Society of Chemical Industry [source] | ||||||||||