Preparation of a new polyesteramide by ring-opening copolymerization of ε-caprolactone

Abstract The anionic ring-opening copolymerization of η-capryllactam and ε-caprolactone was studied and a new type of polyesteramide was prepared. The copolymerizations were initiated with ethylmagnesium bromide, resulting in more than 92% copolymer yields at different monomer ratios in the polymerization mixture at 170 °C. The viscosity-average molar mass of the prepared materials ranged from 19 to 34 kg/mol. The glass transition temperature decreased monotonically with increasing content of lactone structural units and confirmed the statistical structure of the copolymer. The thermal stability evaluated by TGA decreased with the content of lactone units. The tensile modulus, yield stress and tensile strength decreased with increasing content of lactone structural units, that is, with decreasing content of crystalline phase. The lowest values of these characteristics were recorded for the sample containing 70 wt% lactone units. The type and content of the α - or γ -crystalline phase were also significantly affected by the polyesteramide composition and the thermal history of the sample.