Stabilization of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends

In order to improve the positive effect of irradiation, the stability of po ly (vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends was studied with particular attention to stabilization of the PVC phase. Stability of 7 0/30 PVC/ENR blends was studied by examining evidence from brabender torque -time curves, tensile strength, yellowness index, hardness and gel fraction . The observation on the trend shown in the above properties has confirmed that among the common PVC stabilizers employed in this studies, tribasic le ad sulfate is efficient in stabilizing PVC/ENR blends as well as enhancing the blend properties upon irradiation. Addition of zinc octoate proved to p lay a major role in providing good color retention and radiation stability to the blends although the improvement on the blend properties through irra diation was found to be relatively low. Studies also revealed that the init ial stability of the blend during processing is of prime importance in orde r to further stabilize the blends upon irradiation. Possible stabilization of the blends by oxirane group present in ENR is also discussed. (C) 1999 E lsevier Science Ltd. All rights reserved.