Preparation and properties of epoxidized natural rubber/poly(ε-caprolactone) self-vulcanizable blends

Abstract

Curing behaviour as well as mechanical properties of the binary blends of epoxidized natural rubbers (ENR) with end-carboxylated telechelic poly(ε-caprolactone)s (XPCL) has been investigated for development of high-performance self-vulcanizable rubber blends. The binary blends of ENR with different degrees of epoxidation and XPCL of different molecular masses were prepared by using an open two-role mill and subsequently cured at 160–200 °C. It was found that the end-functional and crystallizable XPCLs cured ENR well in the absence of other additives and acted as an effective polymeric crosslinker for ENR to produce self-vulcanizable binary blends. The degree of chemical crosslinking depended on the degree of epoxidation of the ENR as well as the curing time and temperature. The relative contribution of the physical crosslinking via crystallization of poly(ε-caprolactone) chains to that chemical crosslinking was controlled by the molecular mass of the XPCL to give elastomeric materials with various stress–strain curves.