Premium
Tolylene Diisocyanate‐Based Poly(imido‐amide)s, 1. Microstructure and Distributions of Amide and Imide Groups studied by 1 H and 13 C NMR
Author(s) -
MaunandTussot Corinne,
Sagnier Cathy,
Pham QuangTho
Publication year - 2001
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 - 10.1002/1521-3935(20010401)202:7<1060::aid-macp1060>3.0.co;2-c
Subject(s) - imide , polymer chemistry , phthalic anhydride , amide , condensation polymer , chemistry , hexamethylene diisocyanate , steric effects , organic chemistry , polyurethane , polymer , catalysis
Thermostable tolylene diisocyanate (D)‐based poly(imide‐amide)s (PIA) are obtained by homogeneous polycondensation at completion between D (a mixture of two isomers) and trimellic anhydride (T) in N , N′ ‐dimethylene urea solvent at 185°C. The study of the microstructures of these PIAs by 1 H and quantitative 13 C NMR is efficiently aided by using (D + phthalic anhydride) and (D + benzoic acid) model condensates. In all cases, imide (I) groups are found to be slightly in deficit and traces of in‐chain amic acid groups (precursors of I) are present. With tolylene 2,4‐diisocyanate (D′), A (amide) and I groups are preferably formed at the ortho (or 2) and at the para (or 4) positions relative to the methyl group of the tolylene cycle respectively. The concentration of A 2 I 4 sequences are found to equal two times that of I 2 A 4 . For tolylene 2,6‐diisocyanate (D″), the concentration of A 2 I 6 mixed sequence amounts to three times that of A 2 A 6 or I 2 I 6 . The variations of the concentrations of A i A j , A i I j , I i I j sequences versus the composition of D (= x D′ + y D′′, x + y = 1) are perfectly linear. I being bulkier than A, the formations of I and A groups on tolylene cycles are found to be mainly governed by steric hindrance effects.