Ring-Opening Polymerization of the Cyclic Ester Amide Derived from Adipic Anhydride and 1-Amino-6-hexanol in Melt and in Solution

摘要

The ring-opening polymerization (ROP) of the cyclic ester amide (cEA) 5 (systematic name, 1-oxa-8-aza-cyclotetradecane-9, 14-dione) - prepared from adipic anhydride and 1-amino-6-hexanol- in the melt at 165°C and in solution at 100°C and 120°C with Bu_2Sn(OMe)_2 or Ti(OBu)_4 as initiator yields the alternating poly(ester amide) (PEA) 4 (systematic name, poly(5-(6-oxyhexylcarbamoyl)-pentanoate) with regular microstructure. Kinetic studies for different monomer-to-initiator ratios, different reaction media, initiators and temperatures reveal that the ROP is a first-order reaction with respect to the monomer. Under suitable polymerization conditions termination and transfer reactions are suppressed. The elementary chain growth reaction proceeds by a coordination insertion mechanism in analogy to the polymerization of lactones. By using monohydroxy- and bishydroxy-functional telechelic poly(ethylene oxide) and Sn(octoate)2 as the initiating system poly(ethylene oxide)-block-poly(ester amide)s and poly(ester amide)-block-poly(ethylene oxide)-block-poly(ester amide)s are obtained. The poly(ester amide) 4 is a semicrystalline material with a melting point of 140°C, the block copolymers are phase separated systems showing two melting points characteristic for the respective homopolymers.