Effect of cation-exchange bentonite on properties of acrylonitrile-butadiene rubber composites

The present work focuses on exchanging the sodium in Na-bentonite by single (Mg, Zn and Sr) and double (Zn–Mg, Mg–Sr and Zn–Sr) cations to induce the cation-exchange process. Different cation-exchange bentonites (CEBs) were used as reinforcing fillers with different loadings in acrylonitrile–butadiene rubber (NBR) composites. Curing characteristics, mechanical properties, morphology and swelling behaviour were determined. The study revealed that the performances of Mg bentonite and Mg–Sr bentonite were the best among the tested groups, while Sr bentonite showed the least performance, indicating that addition of Mg deteriorates the reinforcing efficiency of Sr. Moreover, it was observed that the preparation of some CEBs co-intercalated with a surfactant (cetyl trimethyl ammonium bromide (CTAB)) using cation-exchange process was done, and in this part there was a focus on the effect of CTAB surfactant content ratio (0.5CEC) on the CEBs and their influence on the properties of NBR composites.