Curing behaviour and mechanical properties of dicarboxylated telechelic poly(ε-caprolactone)s/styrene-(epoxidized butadiene)-styrene triblock copolymer reactive blends

End-carboxylated telechelic poly(epsilon-caprolactone)s (XPCLs) with different molecular weights were blended into a triblock copolymer of styrene-(epoxidized butadiene)-styrene (ESBS) to investigate the curing behaviour and the mechanical properties of the XPCL/ESBS binary reactive blend. It was found that the time-torque cure curve showed a significant torque increase after a very short induction period, in which the degree of the torque increase depended on the molecular weight of XPCL, This indicates that substantial crosslinking reaction takes place between the XPCLs and the epoxidized polybutadiene of the ESBS. Stress-strain curves of the blends after cure depended on the molecular weight of XPCL and the blend ratio. The XPCL/ESBS blends had sufficient thermal stability to show elastomeric behaviour at elevated temperature above the glass transition of the styrene domains of ESBS because of formation of crosslinking points between unlike polymer components by the reactive blending. (C) 1999 Society of Chemical Industry.