Effect of Varied Cure Temperature on the Cure Behavior, Mechanical Properties and Heat Build-Up of Solid Tire Tread Compound Containing Different Particles Sizes of Ground Tire Rubber

Abstract

This work investigates the effect of variation in vulcanization temperature on the cure behavior, tensile properties, tear strength, hardness, Akron abrasion loss and heat build-up of vulcanized tire tread compound in which the total rubber was replaced with 10% and 20% ground tire rubber (GTR) of 40, 60 and 80 mesh sizes. The first step was the characterization of the GTR using optical microscopy and a thermogravimetric analyzer. The first step of mixing each rubber compound was carried out using an internal mixer (Brabender) at 60°C and 40 rev/min rotor speed and the second step was done on a two-roll mill. The mooney viscosity of each rubber compound was investigated. the cure behavior of the rubber compounds was studied at 140°C, 150°C, and 160°C respectively. Results show that the introduction of GTR reduced vulcanization time, while increased cure temperature resulted in a lower vulcanization time. No significant difference was observed in the vulcanization time at a particular temperature of the rubber sample with different particle sizes and varied amounts of GTR. The introduction of ground tire rubber in the rubber vulcanizate however resulted in decreased tensile strength, tear strength and elongation, and increased hardness, abrasion resistance, modulus and heat build-up. An increase in the vulcanization temperature from 140°C to 150°C and 160°C did not impart a significant reduction in the tensile strength of the vulcanizates containing GTR. Vulcanization at higher temperatures resulted in reduced hardness, and modulus, slightly increased abrasion loss and increased elongation of the vulcanizates containing GTR. The heat build-up increased as the cure temperature increased. Generally, the control sample with no content of ground tire rubber exhibited the best properties. If GTR is to be introduced in rubber matrix at an amount up to 20%, the results suggest that 60 mesh size particles will impart better properties. The optimal vulcanization temperature recommended based on the findings from the work is 150°C.