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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, 3. Absolute number‐average molecular weights and glass transition temperatures
Author(s) -
SintèsZydowicz Nathalie,
Pham Quang Tho,
Dubois Jacque,
Michaud Philippe
Publication year - 1997
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.1997.021980702
Subject(s) - imide , trimellitic anhydride , polymer chemistry , chemistry , isocyanate , amide , glass transition , benzoic acid , organic chemistry , polymer , polyurethane
In depth study of low molecular weight poly(imide‐amide)s (PIA) obtained by copolycondensation of 4,4′‐methylenedi(phenyl isocyanate), trimellitic anhydride and benzoic acid by 1 H and 13 C NMR spectroscopy and size‐exclusion chromatography allows the determination of their absolute number‐average molecular weights M̄ n, abs . Viscosimetric measurements reveal that, dissolved in N ‐methyl‐2‐pyrrolidone, these low molecular weight PIAs should be semi‐rigid because of the presence of very short crystalline chains. By using the semi‐empirical Fox‐Flory relation, the extrapolated glass transition temperature equals 300°C for high molecular weight.