Radiation crosslinking of poly(vinyl chloride)/epoxidized natural rubber blend: effect of lead stabilization of the poly(vinyl chloride) phase

Abstract

The irradiation crosslinking of 50/50 poly(vinyl chloride)/epoxidized natural rubber blend was investigated in the presence of 1–5 parts per hundred resin (phr) tribasic lead sulfate (TBLS) with blends prepared at various mixing temperatures. The blends were irradiated using a 3.0 MeV electron accelerator at 0, 100 and 200 kGy irradiation doses. Changes in tensile strength, elongation at break and stress-strain curves of the blends with the increase TBLS content and blending temperatures were observed before and after irradiation. The results on the tensile properties revealed the inhibition of the irradiation-induced crosslinking by the TBLS although it stabilizes the blend against thermal and irradiation-induced degradation. The Fourier transform infrared spectroscopy studies further confirmed these observations. Control on the thermal degradation of the blend during blending found to be crucial in achieving maximum enhancement in blend properties upon irradiation. Evidence from dynamic mechanical analysis was also used to support this contention. Addition of 2 phr TBLS and blending at 150 °C found to be adequate in order to achieve the best enhancement in blend properties through irradiation-induced crosslinking. © 2001 Society of Chemical Industry