Use of dimaleimides as accelerators for the radiation‐induced vulcanization of hydrocarbon polymers

The effect of alkyl and aryl dimaleimides on the rate of crosslinking of natural rubber is described by means of experiments with ionizing radiation. The dose for vulcanization can be reduced from 5 × 10 7 to 2.0 × 10 6 rad by use of purified rubber and 5% of additive, and the reaction is dose‐rate dependent with an intensity exponent of 0.57. The reaction is further accelerated by the addition of small quantities of solvents. By use of C 14 ‐labeled dimaleimides it is shown that there is approximately one dimaleimide unit to each crosslink. Possible chain mechanisms for the reaction are discussed.