Radiation Processing of Natural Rubber with Vinyl Plastics
Radiation processing is a very convenient tool for imparting desirable effects in polymeric materials for a variety of applications. The irradiation of polymeric materials with ionizing radiation (gamma rays, X-rays, accelerated electrons, ion beams) may lead to several important reactions such as crosslinking, polymerization (graft polymerization and curing) and degradation. The use of high-energy radiation using electron beam (EB) accelerators has been well established for crosslinking of polymers as it results in a product that offers distinct advantages over chemically crosslinked polymeric materials. Crosslinking is a reaction where polymer chains are joined and a network is formed. Natural rubber (NR) can be crosslinked by irradiation. This chapter briefly outlines the radiation crosslinking of NR, with emphasis on dry rubber, epoxidized natural rubber with 50 mol% epoxidation (ENR-50), NR latex and NR based blends. Recent scope of work in EB irradiation modification of PVC/ENR, EVA/ENR and PVC/NR blends will be discussed in detail. The focus will be given on the effect of irradiation on the physical, morphological and dynamic mechanical properties of the blends. The acceleration of crosslinking by the addition of multifunctional monomers, MFA and the influence of EB radiation in improving the compatibility of PVC/ENR and EVA/ENR blends will also be reported.