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Chain extenders for polyesters. I. Addition‐type chain extenders reactive with carboxyl end groups of polyesters
Author(s) -
Inata Hiroo,
Matsumura Shunichi
Publication year - 1985
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1985.070300815
Subject(s) - polyester , oxazoline , intrinsic viscosity , polymer chemistry , ethylene , chain (unit) , poly ethylene , chemistry , polymer , materials science , organic chemistry , catalysis , physics , astronomy
Effective chain extenders for linear polyesters were investigated among some bis‐heterocycles, which were capable of coupling carboxyl terminals of the polyesters through addition reaction. Consequently, 2,2′‐bis(2‐oxazoline), 2,2′‐bis(5,6‐dihydro‐4H‐1,3‐oxazine) and N , N′ ‐hexamethylenebis(carbamoyl‐2‐ oxazoline) were found to be the most effective chain extenders. Starting from a poly(ethylene terephthalate) (PET) having intrinsic viscosity ([η]) of 0.66 and carboxyl content (CV) of 46 eq/10 6 g, one could obtain polyesters with [η] of above 1.0 and CV of below 5 eq/10 6 g in the presence of the chain extenders. Typical reaction condition for the coupling of PET was heating PET under atmospheric nitrogen above its melting temperature with 0.5 mol % of a chain extenders only for several minutes. Bis‐2‐thiazolines showed no effect under the condition investigated, while in case of bis‐2‐imidazolines definite degradation was observed. Bis‐ N ‐acylaziridines and bisiminocarbonates resulted in some gell formation, indicative of side reactions.