Interconversion of Alternating Poly(ester amide)s and Cyclic Ester Amides from Adipic Anhydride and <i>α</i>,<i>ω</i>‐Amino Alcohols

Abstract

Abstract Poly(esters amide)s from adipic anhydride and α , ω ‐amino alcohols were obtained by polycondensation of α ‐carboxyl‐ ω ‐hydroxyl amides under mild conditions in solution or by bulk polycondensation at elevated temperatures. For the polycondensation in bulk the influence of catalyst and of temperature on the number‐average molecular weight was studied. At a temperature of 170 °C the polycondensation process is followed by a ring‐closing depolymerisation and the formation of cyclic ester amides. Ten‐ to fourteen‐membered cyclic ester amides were obtained and characterized. The ring‐opening polymerisation of these cyclic ester amides leads, in a controlled mode, to poly(ester amide)s. The interconversion of poly(ester amide)s and cyclic ester amides by ring‐closing depolymerisation and ring‐opening polymerisation is possible. The poly(ester amide)s from adipic anhydride and homologous α , ω ‐amino alcohols H 2 N(CH 2 ) x OH ( x = 2–6) are semicrystalline materials, their melting points show the odd/even effect observed for [ n ]‐polyamides and [ n ]‐polyurethanes. Synthesis of alternating poly(ester amide)s. image Synthesis of alternating poly(ester amide)s.