EFFECT OF DITHIODIAMINES AND DIBENZOTHIAZYL DISULFIDE AS SYNERGISTIC PAIRS OF SAFE ACCELERATORS IN THE VULCANIZATION OF NR

Some investigations regarding the effect of binary systems of accelera tors comprising three safe dithiodiamines, namely, dithiobis(N-methyl piperazine)(DTMP), dithio bis(N-beta-hydroxyethyl piperazine)(DTEP) an d dithiobis(dibenzyl amine, DTDBz and MBTS on the vulcanization of NR have been carried out. The results have been compared with those obtai ned with conventional bis (N-oxydiethylene) disulfide (ODDS) presently considered as unsafe. The vulcanizates obtained from safe synergistic pairs of accelerators [DTMP-MBTS, DTEP-MBTS and DTDBz-MBTS] possess c omparable mechanical properties (modulus, tensile strength, hardness) and exhibit some small improvements in the heat and age resistance beh avior as compared to those obtained with ODDS-MBTS system. In order to understand cure synergism, some hplc studies have also been made.