PREPARATION AND PROPERTIES OF EPOXIDIZED NATURAL RUBBER POLY(EPSILON-CAPROLACTONE) SELF-VULCANIZABLE BLENDS/

Curing behaviour as well as mechanical properties of the binary blends of epoxidized natural rubbers (ENR) with end-carboxylated telechelic poly(epsilon-caprolactone)s (XPCL) has been investigated for developme nt of high-performance self-vulcanizable rubber blends. The binary ble nds of ENR with different degrees of epoxidation and XPCL of different molecular masses were prepared by using an open two-role mill and sub sequently cured at 160-200 degrees C. It was found that the end-functi onal and crystallizable XPCLs cured ENR well in the absence of other a dditives and acted as an effective polymeric crosslinker for ENR to pr oduce self-vulcanizable binary blends. The degree of chemical crosslin king depended on the degree of epoxidation of the ENR as well as the c uring time and temperature. The relative contribution of the physical crosslinking via crystallization of poly(epsilon-caprolactone) chains to that chemical crosslinking was controlled by the molecular mass of the XPCL to give elastomeric materials with various stress-strain curv es.