Abstract
BR and SBR-Sulfur vulcanizates containing various kinds of rubber chemicals, all of which were filled with HAF black, were irradiated with Co-60 gamma radiation. The same procedures as in previous papers were applied in this paper also. The following results were obtained.
(1) An extreme increase of stress at 100% elongation was observed with irradiation of 1×107r, and hence BR seemed to be a polymer of typical crosslinking type.
(2) Antirad improved slightly the properties of BR and SBR vulcanizates after irradiation. However, even in the presence of antirad, BR vulcanizates were deteriorated with irradiation from 5×107 to 1×108r and SBR vulcanizates were deteriorated from 1×108 to 5×108r.
(3) Generally speaking, antirad in BR and SBR vulcanizates was more effective than one in NR vulcanizate.
(4) Little difference in changes of 100% stress of BR and SBR vulcanizates was observed between irradiation in air and that in nitrogen.
(5) Changes of physical properties of BR-Oxime and peroxide vulcanizates after irradiation indicated a similar tendency to those of the corresponding NR vulcanizates.
