Multiblock poly(ether‐ester‐amide)s based on polyamide‐6 and poly(ethylene glycol), 1. Effect of polyether segment length on the properties of poly(ether‐ester‐amide)s with various polyamide/polyether ratios

Abstract

AbstractA series of multiblock poly(ether‐ester‐amide)s (PEEA) based on polyamide‐6 (PA6) and poly(ethylene glycol) (PEG) is synthesized in a two‐step process. The first step represents the hydrolytic polymerization of ε‐caprolactam (CL) in the presence of adipic acid (AA) to carboxyl‐terminated PA6 oligomers of different chain lengths and the second is their polycondensation with PEG of molecular weights 420 (PEG 400) and 1150 (PEG 1000) in the presence of catalyst and thermostabilizer. The formation of the new ester bond between PA6 and PEG is proved by infrared spectroscopy. The content of the hard (PA6) and the soft (PEG) segments in the copolymer is determined by 1H NMR and elemental analysis. The shift in glass transition temperature Tg above that of pure PEG and the depression of the melting temperature Tm assigned to PA6 are characteristic for phase‐separated block copolymers. The degree of crystallinity of the PA6 component does not seem to be affected by the actual weight composition but depends on the different segment lengths. For the copolymers containing PEG‐1000 it is close to that of the respective homopolymer PA6. The tensile parameters of the copolymers studied are similar to those of available PEEA products.