Effect of Activated Palm Kernel Shell Nanoparticles as a Bio-filler on the Mechanical Properties Vulcanized Natural Rubber

Abstract

Oil palm wastes, such as palm kernel shell (PKS), can be beneficially used as value-added additive for natural rubber. Converting PKS into activated palm kernel shell (APKS) and transforming into nano size APKS (n-APKS) can enhance the performance of vulcanizates natural rubber (NR). Performance of n-APKS incorporated NR has been evaluated with different loadings (0 to 10 phr) in several tests, such as cure characteristic, bound rubber content (BRC), swelling, tensile, and abrasion resistance index (ARI). The presence of n-APKS decreased minimum torque from 0.54 dN.m to 0.31 dN.m, indicating enhancement processability. The cure index peaked at n-APKS loading of 5 phr (F4), which indicated the effective crosslinking in NR matrix. The F4 (5 phr) formulation outperformed others, featuring a BRC of 4.08%, a crosslink density of 8.65 x 10^-5 mol/cm³, a tensile strength of 19 MPa, a M₃₀₀ at 3.33 MPa, a reinforcement index of 3.78%, and an ARI of 38% with relatively low elongation at break (648%). The optimum loading of 5 phr is deemed a promising bio-filler option for the rubber industry and it also helps to reduce environmental waste disposal issues.