Degradation of polyesteramides prepared by the anionic polymerisation of ɛ-caprolactam in the presence of poly(ɛ-caprolactone)

Poly[(ɛ-caprolactam)-co-(ɛ-caprolactone)] was prepared by the anionic polymerisation of ɛ-caprolactam in the presence of poly(ɛ-caprolactone) initiated by ɛ-caprolactam magnesium bromide. Copolymers with 10-25% ɛ-caprolactone structure units were subjected to degradation. After 8-weeks abiotic hydrolysis at 60 °C the molar mass of the copolymer was significantly reduced as seen from viscosity measurements. IR spectroscopy was employed to clarify the mechanism of hydrolysis. Only small changes in molar mass were observed after composting and fungal treatment. Therefore, the effect of degradation temperature was crucial. The thermal properties of polyesteramides were studied by DSC, which showed the shift of melting endotherm and enthalpy of fusion to higher values of degraded samples compared to original one. This indicated an increase in crystalline phase content caused by reorganization of amorphous phase. Physical degradation of films was observed using SEM. Film-surface changes were apparent mainly on samples with 25% ɛ-caprolactone units.