Effect of Carbon Black Substitution with Raw and Modified Bentonite on the Thermal Aging Resistance of Natural Rubber Composites

Abstract

The effect of carbon black (CB) substitution with raw (BNT) and modified (M-BNT) bentonite on the thermal aging resistance of natural rubber (NR) composites was investigated in this study. NR composites were prepared at varied proportions of CB, M-BNT, and BNT using a three-component, third degree simplex lattice mixture design of experiment (DOE). M-BNT was produced by modifying sodium-activated bentonite with tetradecyldimethylamine (TDA) salt and cocamide diethanolamine (CDEA). Thermal aging was performed at 70 and 100°C for 168 and 336 h. Substitution of CB with 5 phr M-BNT gave the highest values of tensile properties (modulus and strength) for both unaged and aged samples. This is attributed to the synergistic effect of CB and M-BNT fillers on the tensile properties of NR composites. In terms of property retention (%), composites filled with M-BNT and BNT clay fillers attained the highest values which signified their excellent thermal aging resistance. This observation proves the barrier effect of clay platelet structure which hinders oxygen diffusion in the rubber. Reduced hierarchical models as function of CB, M-BNT, and BNT proportions were used to generate contour plots for tensile properties of NR composites after 168 h of aging at 70 and 100°C.

Experimental and Modeling Study on the Curing Properties of Natural Rubber Composites Filled with Varying Proportions of Carbon Black, Modified Bentonite and Raw Bentonite

“…Plain NR and thirteen NR composites with varying mixture filler proportions of CB, M-BNT and BNT were prepared for this study using a third-degree simplex lattice mixture design of experiment augmented by center and axial points [9]. The process of modifying BNT and rubber compounding are discussed in [1]. Measurement of Rheometric Properties.…”

“…Numerous studies have already presented the positive effect of adding organoclay to different rubber matrices [1][2][3][4][5], but very few have considered the feasibility of using organoclay to replace conventional fillers such as carbon black (CB). Today, researchers and rubber manufacturers aim to lessen their dependence on CB due to its color limitation and the devastating effect of its production on the environment [1,6].…”

“…It is important to evaluate cure responses for it indicates the quality and processability of rubber compounds during vulcanization [8]. In this study, carbon black (CB) is mixed with a natural clay mineral, bentonite (BNT) together with its organically modified form (M-BNT) producing a ternary filler at different proportions based on a previous study [1]. This paper aimed to investigate the effect of CB/M-BNT/BNT mixture filler on the curing properties of natural rubber (NR) composites.…”

Effect of Replacing Carbon Black with Organo-Modified Bentonite and Acid-Activated Zeolite on Vulcanization Characteristics of Natural Rubber Tire Tread

“…Formulations 1 -10 are the design points of the simplex-lattice, while formulations 11 -13 are the augmented axial points. Organo-modified bentonite was produced from sodium-activated natural bentonite (using 5 wt% NaCl) treated with tetradecyldimethylamine chloride salt (1 equivalent times the cation exchange capacity of natural bentonite) and coconut diethanolamide (3 wt% of bentonite) [2,3,9,10]. Acid-activated zeolite was synthesized from natural zeolite modified with 3 M hydrochloric acid solution [6,11].…”

Effect of Silica/M-BNT/BNT Ternary Filler Loading on the Curing Properties of Natural Rubber Vulcanizates

“…The most widely used reinforcing filler is carbon black. However, carbon black (CB) is polluting in nature, petroleum-dependent, and expensive [1][2][3][4]. Because of the color restriction and other limitations, rubber manufacturers are forced to employ non-black fillers.…”