EFFECT OF PALMYRA PALM FIBER FILLER ON THE PROPERTIES OF NATURAL RUBBER VULCANIZATE

AUTHOR: EZEONYEBUCHI JULIET AZUKA

DEPARTMENT: CHEMICAL ENGINEERING

AFFILIATION: NNAMDI AZIKIWE UNIVERSITY, AWKA

The effect of partial replacement of carbon black by Palmyra palm fiber on the cure characteristics, physico-mechanical and swelling properties on natural rubber vulcanizates was studied. The Palmyra palm fibers were extracted, treated and characterized in terms of pH, moisture content, and ash content, loss on ignition, conductivity, cellulose, lignin, Hemicellulose, cellulose/lignin ratio and Acid soluble lignin. The functional groups in the Palmyra palm fiber was also determined using FTIR. The Palmyra palm powder with an average particle size of 75μm was used in this study. The Natural rubber, carbon black and Palmyra palm fiber (NR/CB/PPF) composites with eight different loadings i.e. 0/70, 10/60, 20/50, 30/40, 40/30, 50/20, 60/10, 70/0 were prepared using a laboratory size two roll mill. Results showed that the maximum Torque of NR/CB/PPF composites increased with increasing commercial filler loading ratio. The scorch time and cure time of NR/CB/PPF composites decreased as the ratio of Carbon black (CB) loading was increased. The tensile strength, modulus of elongation and Tear strength of all the composites increased as the commercial filler loading ratio increased. This is due to the presence of the commercial filler which brought a better filler interaction. The hardness increases as the Palmyra palm fiber loading increases. The abrasion resistance decreases as Palmyra palm fiber loading increases and the elongation at break showed an irregular pattern of increase with PPF filler loading. The effect of filler loading on the swelling behavior of NR/CB/PPF composites was also investigated in aromatic and aliphatic solvents. The uptake of the aromatic solvent is higher than that of aliphatic solvents. Both solvents have the same trend of increase towards CB loading. Optimization of the process was performed using design expert 8.0.7.1 trial version to maximize the vulcanization process parameters. The simultaneous effects of process variables such as time (7-10 minutes), temperature (140-160oC), and fiber length (short and long length) were evaluated. A central composite design (CCD) and Response surface methodology (RSM) were used for the optimization of the vulcanization process. Based on the CCD, quadratic models were developed to correlate the vulcanization process variables with the responses such as tensile strength, elongation at break and Modulus of elongation at 100% and the models were analyzed using appropriate statistical methods (ANOVA). Statistical analysis showed that all the models developed were found to be adequate for the prediction of the respective responses because the predicted values and the actual experimental values were in good agreement confirming the adequacy of the model. The optimum process variables for the maximum tensile strength was found to be 5.05261Mpa,elongation at break, 721.739% and Modulus at 100% elongation, 0.728254Mpa at 7.00 minutes, 150oC and long fiber length. The model was validated using the optimum parameters and the following results were obtained, tensile strength 5.4Mpa, Elongation at break,739% and Modulus at100% elongation, 0.7Mpa.

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