Transport properties of coconut shell powder (CSP)-reinforced natural rubber composites in aromatic solvents

The solvent swelling characteristics of natural rubber composites containing both untreated and alkali-treated coconut shell powder (CSP) were investigated in three, aromatic organic solvents (benzene, toluene, and xylene) by conventional weight-gain experiments. The effects of fiber loading, chemical treatment, and filler particle size on solvent sorption were analyzed. Transport parameters such as diffusion coefficient, sorption coefficient, and permeation coefficient have been calculated in terms of CSP content, particle size, nature of solvent, and temperature. All the NR-CSP composites were found to decrease with the uptake of aromatic solvents than NR, but the effect was more significant in the case of alkali-treated CSP composites. The estimated Arrhenius activation energy (E-D) for the processes of sorption, diffusion, and permeation were discussed. The thermodynamic parameters of the sorption process were also evaluated. The mode of transport in all cases was evaluated.