Appraisal of the Insulation Potential of Rice Husk Ash Reinforced Calabash-Epoxy Composite for Vehicle Firewall Application

This paper presents the appraisal of the insulation potential of rice husk ash-reinforced calabash-epoxy composite. Calabash and rice husks were collected from the agrarian communities in Eastern Nigeria and then processed into composite-compatible particles. The dried calabash fibres were pulverized into powder with the aid of a laboratory-scale hammer mill, while the rice husks were carbonized into ash in a furnace at about 500 0C. Samples of composites were developed with varying ratios of calabash powder (CP) and rice husk ash (RHA) for the investigation of their thermal and other material properties regarding insulation potential. Four combinations with design ratios, CPːRHA, 0ː20, 10ː10, 20ː0 and 15ː5 were considered whereas at every stage of the mixture formulation, the content of the epoxy resin was maintained as 80% of the overall mixture. The thermal properties of the developed samples had been characterized by differential scanning calorimetry and the result of this procedure revealed that the best formulation of the composite would have a mean thermal conductivity of 0.049Wm-1K-1. Furthermore, the Response Surface Methodology (RSM) provided a clear insight into how the proportion of the component of the adopted mixtures would influence the thermal and mechanical properties of the developed composites. This method determined a very close alignment of the actual and predicted values of the material properties of the composites. Also, results from the optimization process suggested that the best-fit model of the novel insulation composites would constitute 15% calabash fibre, 5% rice husk ash and 80% epoxy resin, with the resultant material density of 1.055g/cm3, thermal conductivity of 0.151Wm-1K-1, thermal resistivity of 0.183Wm-1K-1 and material hardness value of 61.046 shores D. The statistical significance of the developed model and its reliability was reinforced through a regression analysis indicating a considerable agreement between the empirical values and expected results of optimization. Comparatively, the overall results of the optimization infer adequately that the new composite would be capable of navigating the design space successfully and would also be more suitable for light-weight applications as well as have a higher potential for thermal reduction than the pressed-steel insulators whose thermal conductivity and density have been found higher. Finally, this study concludes that the developed model of RHA Reinforced Calabash – Epoxy composite possesses adequate insulation potential and would be quite suitable for application in the firewall system of automotive.