COPOLYESTERAMIDES .7. SEGMENTED AND RANDOM POLYMERS CONTAINING BIS-TEREPHTHALAMATE UNITS

Segmented and random polyesteramides of aliphatic polyesters with hexamethylene bis-terephthalamate (A) units differ markedly in texture and properties from those with trimethylhexamethylene bis-terephthalamate (B) units. In segmented polymers with A units, the polyester component does not crystallize spontaneously from the melt but forms a distinct phase of low T(g) and some degree of sub-crystalline order which crystallizes under stress; those with B units possess a mixed phase structure coexisting with aliphatic polyester crystallinity and are of higher modulus than those with A. The differences, which also occur in the amide group i.r. frequencies, are correlated with the solubility parameters of the sub-species.