Radiation crosslinking of vinyl chloride–vinyl stearate copolymer

The crosslinking of internally plasticized polyvinyl chloride–stearate copolymer by irradiation with high‐energy electrons was studied. Based on gel yields and swelling as a measure of relative crosslinking, the effect of added tetra‐functional monomers, and of carbon black and silica fillers are discussed. Crosslinking by dicumyl peroxide a t 170°C. even in the presence of a stabilizer, causes concurrent decomposition (dehydrochlorination) which is avoided in the radiation‐crosslinking process. The heat stability of the copolymer is not impaired by radiation crosslinking under the proper conditions. Results of tensile measurements a t 25 and 150°C. are given for the radiation‐crosslinked copolymer with and without filler reinforcement.