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Synthesis and characterization of N-substituted hyperbranched polyureas

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Title Synthesis and characterization of N-substituted hyperbranched polyureas
 
Creator AMBADE, AV
KUMAR, A
 
Subject building-blocks
aromatic polyamides
urea linkages
dendrimers
polymers
polyurethanes
architecture
derivatives
micelles
pyrene
hyperbranched polymers
internal functionalization
n-substitution, polyurea
 
Description N,N'-disubstituted hyperbranched polyureas with methyl, benzyl, and allyl substitutents were synthesized starting from AB(2) monomers based on 3,5-diamino benzoic acid. Carbonyl azide approach, which generates isocyanate group in situ on thermal decomposition, was used for the protection of isocyanate functional groups. The N-substituted hyperbranched polymers can be considered as the new class of internally functionalized hyperbranched polyureas wherein the substituent can function either as receptor or as a chemical entity for selective transformations as a tool to tailor the properties. The chain-ends were also modified by attaching long chain aliphatic groups to fully realize the interior functionalization. This approach opens up a possible synthetic route wherein different functional substituents can be used to generate a library of internally functionalized. hyperbranched polymers. All the hyperbranched polyureas were characterized by FTIR, H-1-NMR, DSC, TGA, and size exclusion chromatography. Degree of branching in these N,N'-disubstituted hyperbranched polyureas, as calculated by H-1-NMR spectroscopy using model compounds, was found to be lower than the unsubstituted hyperbranched polyurea and is attributed to the lower reactivity of N-substituted amines compared to that of unsubstituted amines. (C) 2004 .
 
Publisher JOHN WILEY & SONS INC
 
Date 2011-08-16T15:46:51Z
2011-12-26T12:55:01Z
2011-12-27T05:43:32Z
2011-08-16T15:46:51Z
2011-12-26T12:55:01Z
2011-12-27T05:43:32Z
2004
 
Type Article
 
Identifier JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 42(20), 5134-5145
0887-624X
http://dx.doi.org/10.1002/pola.20295
http://dspace.library.iitb.ac.in/xmlui/handle/10054/9544
http://hdl.handle.net/10054/9544
 
Language en