Poly(ester amide)s from poly(alkylene succinate)s and rapid crystallizing amido diols

Random poly(ester amide)s are synthesized from succinic acid, ethylene glycol or 1,4-butanediol and different aliphatic amido diols - symmetric a,o-diols containing two amide moieties. The formation of chain-terminating N-succinimide end groups, which limit the molecular weight attainable by common synthetic strategies, is effectively suppressed. Poly(ester amide)s crystallize in a suprastructure similar to that of even-even polyamides. The thermal properties of both types of poly(ester amide)s synthesized are considerably improved and transition temperatures are tunable by changing the ratio of aliphatic diol to rapidly crystallizing amido diol in the feed. Using ethylene glycol as diol component, Tg and Tm of the material could be enhanced from −12 to −2 °C and 97 to 157 °C, respectively, while an increase from −33 to −8 °C and 115-153 °C was observed for their 1,4-butanediol derived counterparts. Furthermore, the slow crystallization rate of poly(ethylene succinate) from molten state could be significantly accelerated by the introduction of amide moieties into the polymer backbone.