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Low‐molecular‐weight poly(imide‐amide)s obtained by copolycondensation of 4,4′‐methylenedi(phenyl isocyanate), trimellitic anhydride and benzoic acid in N ‐methyl‐2‐pyrrolidone, 2 . Structural defects observed by 1 H and 13 C NMR
Author(s) -
SintèsZydowicz Nathalie,
Pham Quang Tho,
Michaud Philippe
Publication year - 1996
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1996.021970404
Subject(s) - imide , trimellitic anhydride , isocyanate , polymer chemistry , chemistry , benzoic acid , amide , acid anhydride , organic chemistry , polyurethane , epoxy
The in depth examination (by 1 H and 13 C NMR, DSC, SEC and TGA) of the low‐molecular‐weight poly(imide‐amide)s synthesized with the mixture [4,4′‐methylenedi(phenyl isocyanate) (M) + trimellitic acid anhydride (T) + benzoic acid (B)] in N ‐methyl‐2‐pyrrolidone (NMP) at temperatures lower than 180°C allowed the identification and quantitative determinations of all the unexpected and relatively stable structures. While amide functions are readily synthesized, the formation of imide from anhydride and isocyanate functions passes through 4‐amido‐1,2‐benzenedicarboxylic acid (T i ), 1,4‐di‐amido‐2‐benzenecarboxylic acid (T″) and disubstituted urea (u). At 180°C T i completely disappears but traces of T″ and u remain; thus, the formation of imide can never reach its theoretical quantity. Traces of moisture in NMP may play the role of catalyst in the formation of imide, and reaction mechanisms are proposed.