Effect of coconut fibre filler on the cure characteristics physico-mechanical and swelling properties of natural rubber vulcanisates

Investigation into the effect on the rheological, physico - mechanical and swelling properties of natural rubber vulcanizates using coconut fibre as fillers were carried out. The coconut fibre was characterized in terms of pH, moisture content, ash content, loss on ignition, conductivity, particle size and surface area. The physico - mechanical properties as well as the equilibrium swelling characteristics of the vulcanizates in organic solvents were measured as a function of filler loading and compared with the values obtained using commercial grade carbon black (N330). The coconut fibre showed good processing safety in terms of torques and scorch. For coconut fibre filled vulcanizates, optimum tensile strength of 7.35 MPa at 60 ph was recorded. It was found that vulcanizates with 60 ph showed maximum tensile properties. Hardness of filled vulcanizates with coconut fibre increased with filler loading. Abrasion resistance decreases marginally with increasing filler loading. A flex resistance and percentage compression set decreased with increasing filler loading. The equilibrium sorption in organic solvents of natural rubber vulcanizates filled with coconut fibre and carbon black decreased with increasing filler loading. However, the resistance to swelling of natural rubber compound is dependent on the amount of filler loading: the higher the filler content, the lower the equilibrium sorption values obtained.