Curing characteristics, tensile properties, fatigue life, swelling behavior, and morphology of waste tire dust (WTD)/carbon black (CB) hybrid filler filled natural rubber (NR) compounds were studied. The WTD/CB hybrid filler filled NR compounds were compounded at 30 phr hybrid filler loading with increasing partial replacement of CB at 0, 10, 15, 20, and 30 phr. The curing characteristics such as scorch time, t 2 and cure time, t 90 decreased and increased with increment of CB loading in hybrid filler (30 phr content), respectively. Whereas maximum torque (M HR ) and minimum torque (M L ) increased with increasing CB loading. The tensile properties such as tensile strength, elongation at break, and tensile modulus of WTD/CB hybrid filler filled NR compounds showed steady increment as CB loading increased. The fatigue test showed that fatigue life increased with increment of CB loading. Rubber-filler interaction, Q f /Q g indicated that the NR compounds with the highest CB loading exhibited the highest rubber-filler interactions. Scanning electron microscopy (SEM) micrographs of tensile and fatigue fractured surfaces and rubber-filler interaction study supported the observed result on tensile properties and fatigue life.

Waste tyre dust (WTD)/kenaf fibre (Ke) hybrid filler filled natural rubber (NR) compounds having constant 30 phr loading were prepared with increasing partial replacement of WTD by kenaf fibre at 0, 10, 15, 20, and 30 phr. Curing characteristics, mechanical properties, rubber-fibre interaction, and morphology of the NR compounds were studied after the compounds were obtained. The curing characteristics such as t2 and t90 increased with increment of kenaf fibre loading. For MHR, the increasing partial replacement of WTD by kenaf fibre showed increasing MHR value. For tensile properties, the value of tensile strength and elongation at break value decreased with increasing kenaf fibre loading. The values of M100 and M300 increased but then decreased after the addition of 15 phr of kenaf fibre loading. Besides, fatigue life value also showed a decreasing trend with increasing kenaf fibre loading. For rubber-fibre interaction, the values of Qf/Qg showed a small increment with increasing kenaf fibre loading. The SEM micrographs obtained for fractured surface of WTD/kenaf fibre hybrid filled NR compounds supported the results for the mechanical properties.