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Thermoplastic polyheterocycles. I: Polyalkylene‐benzoxazoles
Author(s) -
Preston J.,
Tropsha Y.,
Trexler J. W.
Publication year - 1994
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760340411
Subject(s) - materials science , polymer , glass transition , melting point , thermoplastic , melting temperature , polymer chemistry , composite number , viscosity , composite material , chemical engineering , engineering
Polyalkylenebenzoxazoles of high molecular weight (inherent viscosity values from 0.76 to 2.95) were prepared from 4,6‐diaminoresorcinol dihydrochloride and aliphatic diacids in polyphosphoric acid by heating at 180 to 200°C for 3–5 h. Melting points of the polymers ranged from 148 to 423°C, depending on the length of the alkylene chain. Glass transition temperatures were relatively low, ranging from 50 to 100°C and did not show the pronounced odd/even effect noted for melting points. In all cases, rapid weight loss occurred above 400°C. No evidence for the formation of a molecular composite was observed in an attempt to prepare in situ a rod‐like polybenzoxazole in a polyalkylenebenzoxazole.