Ozone ageing of rubbers in the presence of antiozonants of different physical nature

摘要

The results of tests, conducted over a period of many years, on tyre sidewall vulcanisates based on polyisoprene rubber SKI-3, natural rubber, or their combinations with SKD polybutadiene rubber show that, irrespective of the nature and composition of the antiageing group, the ozone resistance of the vulcanisafe practically amounts to 2-12 h (at an ozone concentration in the chamber of 5 x 10~(-5) vol% and a strain of the specimen of 20%). From this it follows that the protective oction of p-paraphenylenediomine derivatives is unpronounced, and key to the question of the stability of the vulconisates when exposed to ozone is the nature of the rubber. If account is taken of the fact that the ozone resistance of vulcanisates based on chloroprene rubbers is several times higher, and that of vulcanisates based on ethylene-propylene rubbers practically a whole order of magnitude higher, it is clear that the ozone resistance even of protected vulcanisates based on non-polar and unsaturated rubbers is not so high.