| Abstract: | A simple method to determine the chain scission mechanism of the oxidative degradation of rubber vulcanizates is proposed. The method involves the measurement of oxidative stress decay and the change in sol fraction, which allow us to distinguish whether scission occurs randomly along the main chain, near crosslinks or of crosslinks. The applicability of this method was well established using natural rubber vulcanizates as the reference samples. The chain scission of cis-1,4-polyisoprene vulcanizaties was proved to take place randomly along the main chain irrespective of their crosslink structure. On the other hand, the chain scission of dicumyl peroxide cured cis-1,4-polybutadiene takes place selectively near crosslinks. It is suggested that the unusual behavior of cis-1,4-polybutadiene vulcanizates is due to the characteristic structure of the crosslinks. |
