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An efficient route for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages

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Title An efficient route for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages
 
Creator AMBADE, AV
KUMAR, A
 
Subject radical polymerization
star polymers
dendrimers
polyurethanes
chemistry
molecules
monomers
hyperbranched polyurea
carbonyl azide
dendritic polyurea
convergent growth
 
Description A highly efficient synthetic route, based on the quantitative reaction between amine and isocyanate functionalities, was used successfully for the synthesis of hyperbranched polymers and dendritic building blocks based on urea linkages. The thermal decomposition of 3,5-diamino benzoyl azide or 5-amino isophthaloyl azide generated in situ the corresponding phenyl isocyanates, which were then polymerized to give wholly aromatic hyperbranched polyureas. Hyperbranched polyurea with amine chain ends was soluble in common organic solvents. The degree of branching, as calculated with H-1 NMR, was 0.55. Diethyl 5-amino isophthalate and Boc-protected 5-amino isophthaloyl azide were used for the successful stepwise synthesis of dendritic wedges based on urea linkages. The thermal generation of the isocyanate functionality with gaseous nitrogen as the side product and its quantitative reaction with amine groups were the salient features of this convergent synthesis. This eliminated the use of chromatographic purification, an inherent part of other convergent growth approaches, and made it a very efficient synthetic route for the synthesis of dendritic wedges. The products were characterized by H-1 NMR, C-13 NMR, and electron spray mass spectroscopy (ESMS) techniques. (C) 2001 , Inc.
 
Publisher JOHN WILEY & SONS INC
 
Date 2011-08-04T10:16:26Z
2011-12-26T12:54:40Z
2011-12-27T05:42:50Z
2011-08-04T10:16:26Z
2011-12-26T12:54:40Z
2011-12-27T05:42:50Z
2001
 
Type Article
 
Identifier JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 39(9), 1295-1304
0887-624X
http://dx.doi.org/10.1002/pola.1107
http://dspace.library.iitb.ac.in/xmlui/handle/10054/9327
http://hdl.handle.net/10054/9327
 
Language en