MODIFICATION, CHARACTERISATION AND APPLICATION OF COCONUT WASTES AS FILLERS IN RUBBER COMPOUNDING

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Author

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Department of Engineering

ABSTRACT
In this study, coconut palm wastes were obtained, washed to remove sands and debris and then dried at 95oC for 1 hr to remove surface moisture. Filler modifications through carbonisation were done at varying temperatures of 300oC, 400oC, 500oC, 600oC and 700oC. Both raw fillers and carbonised fillers were ground to achieve 100 μm particle sizes, after which they were characterised. Formulations were appropriately drawn for the mixing and compounding process. Rheological determination and flow properties were evaluated. Physico-mechanical measurement of hardness, abrasion resistance index, compressive strength, tensile strength, flexural strength, modulus and elongation at break to ascertain composites reinforcement levels were also carried out. All measurements were according to American Society for Testing and Materials (ASTM) standards. Furthermore, qualitative assessments of modification levels were estimated using Fourier infrared spectroscopic studies (FTIR), X-ray diffraction analysis (XRD), X-ray fluorescence (XRF) of elemental oxides presence, scanning electron microscopic analysis (SEM), thermal gravimetric analysis (TGA) and chemical resistance measurements through sorption inference and analysis. Carbonisation strengthened the polymer-carbon bond and therefore increased reinforcements of the composite matrix effectively at 500oC for the coconut shell and 600oC for the coconut fibre. Optimum formulations of 500oC for the shell and 600oC for the fibre were technically utilised in the engineering design and manufacture of vibration dampeners for motor cycle hub and industrial oil seals for bambury mixers employed in the mixing and mastication of rubbers. Qualitative comparisons in properties such as resilience/rebound study, hysteresis, dynamic flex cracking, flex fatigue, weathering/ozone resistance and chemical resistance showed a comparatively good products when functionally and aesthetically compared to available commercial grades. The formulated products were of high performance quality. Modification through carbonisation therefore created a positive effect and improvements on the morphology, degree of crystallisation/crystallite formations, physico-mechanical properties, chemical resistance, weathering/ozone resistance, and development in resilience/rebound properties, thermal gravimetric degradation/stability, and improvement in active elemental oxides and depletion of lignocelluloses of the coconut shell and fibre through infrared spectroscopic study. The results of mechanical and chemical sorption properties that gave the optimised formulation for the fibre and shell composites used in the modeled products were further theoretically evaluated through predictive and statistical analysis of variance (ANOVA). The new Duncan?s multiple range test (DMRT) was used to verify the significance differences between subject factors of mechanical properties and samples (modification temperatures) at 95% probability and deterministic levels. A great proportion of the properties and samples satisfied the significant measurement levels and therefore positive agreements between theoretical and experimental results were established as a contribution to reinforcements. All these noticed improvements resulted in better filler-rubber adhesion and interactions and specifically leading to the reinforcement of the resulting composites and therefore present the composites as useful materials for predictive product development in engineering designs and applications.