VULCANIZATION REACTION OF SBR RUBBER BY 6-DIBUTYLAMINO-1, 3, 5- TRIAZINE -2, 4- DITHIOL AND 2, 2′- BIS (BENZOTHIAZYL) DISULFIDS

Abstract

Vulcanization reaction of SBR by using 6-dibutylamino-1, 3, 5-triazine-2, 4-dithiol (DB), 2, 2′- bis(benzothiazyl)disulfide (MBTS) and ZnO has been investigated for an apparent rate constant (k_ob), an induction period (t₁₀) and the degree of vucanization (f_max-f_min) at 170°C. The vucanization occured in the case of the co-presence of DB, MBTS and ZnO, and was influenced by the mixing ratio (r) of DB aginst MBTS: k_ob increased with increase in r, and f_max-f_min in l/r; but t₁₀ had an maximum value at r=0.5. These were explained from the results that the reaction products of DB with MBTS differ with r as follows. The crosslinking
DB+MBTS→R(_??_)_nR+_??_=S
r<1; R=_??_-S-, r_??_1; R=H
chain, 2, 4-bis(S-substituent thio)-6-dibutylamino-1, 3, 5-triazine structure was confirmed by the IR spectra measurement and the elemental analyses of the SBR vulcanizates, and seems to be produced by the attack of a thiyl radical aginst the allyl type-methylene structure in SBR rubber, which are formed by the fission of a S-S bond in the reaction products.