@article { ISI:000254587500014,
	title = {Solvent-free and nonisocyanate melt transurethane reaction for aliphatic polyurethanes and mechanistic aspects},
	journal = {Journal of Polymer Science Part A-Polymer Chemistry},
	volume = {46},
	number = {7},
	year = {2008},
	month = {APR},
	pages = {2445-2458},
	publisher = {JOHN WILEY \& SONS INC},
	address = {111 RIVER ST, HOBOKEN, NJ 07030 USA},
	abstract = {<p>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.</p>},
	keywords = {MALDI, melt polymerization, nonisocyanate, Polycondensation, polyurethanes, thermal stability, transurethane},
	issn = {0887-624X},
	doi = {10.1002/pola.22578},
	author = {Deepa, P. and Jayakannan, M.}
}
