EXPERIMENTAL AND MODELING STUDY ON THE EFFECT OF CARBON BLACK SUBSTITUTION WITH MODIFIED AND RAW BENTONITE ON THE TENSILE PROPERTIES OF NATURAL RUBBER COMPOSITES

Abstract

The effect of carbon black (CB) substitution with modified (M-BNT) and raw (BNT) bentonite on the tensile properties of natural rubber (NR) composites is investigated in this paper. NR composites are prepared using a third degree simplex lattice mixture design of experiment, where proportions of CB, M-BNT, and BNT are varied in the rubber formulations. M-BNT is produced by modifying sodium-activated bentonite with tetradecyl dimethylamine (TDA) salt and cocamide diethanolamine (CDEA). Results from tensile testing of NR composites reveal the optimum composition of mixture filler to be 10 phr CB, 5 phr M-BNT, and 0 phr BNT for tensile modulus, tensile strength and stresses at different strains (100, 200 and 300 %). Observed synergistic effect on tensile properties can be attributed to the formation of dual filler system between CB and M BNT. Better dispersion of clay fillers in the rubber matrix was achieved due to organic modification of bentonite. Generated contour plots based on reduced hierarchical models show same trend demonstrating synergy between CB and M-BNT