<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Deepa, P.</style></author><author><style face="normal" font="default" size="100%">Jayakannan, M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Solvent-free and nonisocyanate melt transurethane reaction for aliphatic polyurethanes and mechanistic aspects</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Polymer Science Part A-Polymer Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">MALDI</style></keyword><keyword><style  face="normal" font="default" size="100%">melt polymerization</style></keyword><keyword><style  face="normal" font="default" size="100%">nonisocyanate</style></keyword><keyword><style  face="normal" font="default" size="100%">Polycondensation</style></keyword><keyword><style  face="normal" font="default" size="100%">polyurethanes</style></keyword><keyword><style  face="normal" font="default" size="100%">thermal stability</style></keyword><keyword><style  face="normal" font="default" size="100%">transurethane</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">APR</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">7</style></number><publisher><style face="normal" font="default" size="100%">JOHN WILEY &amp; SONS INC</style></publisher><pub-location><style face="normal" font="default" size="100%">111 RIVER ST, HOBOKEN, NJ 07030 USA</style></pub-location><volume><style face="normal" font="default" size="100%">46</style></volume><pages><style face="normal" font="default" size="100%">2445-2458</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;A novel melt transurethane polycondensation route for polyurethanes under solvent-free and nonisocyanate condition was developed for soluble and thermally stable aliphatic or aromatic polyurethanes. The new transurethane process was investigated for A + 13, A-A + B, and A-A + B-B (A-urethane and B-hydroxyl) type condensation reactions, and also monomers bearing primary and secondary urethane or hydroxyl functionalities. The transurethane process was confirmed by H-1 and C-13 NMR, and molecular weight of the polymers were obtained as M-n = 10-15 X 10(3) and M-w = 15-45 X 10(3) g/mol. The mechanistic aspects of the melt transurethane process and role of the catalyst were investigated using model reactions, H-1 NMR, and MALDI-TOF-MS. The model reactions indicated the occurrence of 97% reaction in the presence of catalyst, whereas its absence gave only less than 2% of the product. The polymer samples were subjected for end-group analysis using MALDI-TOF-MS, which confirms the Ti-catalyst mediated nonisocyanate pathway in the melt transurethane process. Almost all the polyurethanes were stable up to 280 degrees C, and the T-g of the polyurethanes can be easily fine-tuned from -30 to 120 degrees C by using appropriate diols in the melt transurethane process. (C) 2008 Wiley Periodicals, Inc.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">3.894</style></custom4></record></records></xml>