Sieciowanie i reakcje interelastomerowe w mieszaninach kauczukow butadienowo-styrenowego i chlorobutylowego

Abstract

Blends of styrene butadiene and chlorobutyl rubber in various mass ratios were prepared according to standard procedures in a laboratory mill. The blends were heated to 433 K in the presence of a metal ion donor (ZnO, Fe 2 O 3 or zinc powder). The influence of the blend composition and amount of metal ion donor on the degree of interelastomer crosslinking of the rubbers was investigated. Thermal treatment and the resultant crosslinking of the blends led to changes in their morphology. On the basis of IR spectra (Figs. 2, 7, Table 2, 7), it was confirmed that crosslinking proceeds as a result of Friedel-Crafts interelastomer alkylation of the SBR phenyl ring by the CIIR polihalogenic elastomers (Scheme A). Moreover, the autoalkylation of these rings by SBR vinyl side groups and 1,4-cis-butadiene monomers were catalyzed by aprotic Lewis acids (ZnCl 2 , FeCl 3 ) generated in situ in the reaction of CIIR with the metal ion donor. The degree of blend crosslinking increased with an increase in the content of CIIR and the metal ion donor. The best results were obtained for mixtures containing more that 50 % CIIR and 2—4 parts by wt. of ZnO in respect to 100 parts by wt. of CIIR (Figs. 1, 4, 6; Tables 1, 3, 4, 6). The new, unconventional method could be applied for the crosslinking of rubber blends with selected fillers (Fig. 5, Table 5).