ABSTRACT:The technical viability of using rice husk ashes (RHA) as alternative fillers in polypropylene was studied. Three types of RHA, white rice husk ash (WRHA), black rice husk ash (BRHA) and amorphous rice husk ash (AMRHA) at 10-40wt% filler loading were investigated. The RHA composites were compounded by twin screw compounders and the mechanical properties of the composites evaluated. Incorporation of the RHA fillers increased the flexural modulus of the composites, particularly the BRHA composities. Modulus of the RHA composites were found to be in good agreement with theoretical values predicted by equation of Lewis and Nielsen. The increase in modulus was offset by lowering of the tensile strength, elongation at break and impact properties. Theoretical treatments of the ultimate tensile strength performed based on the model proposed by Nicolai and Nicodemo showed reasonably good agreement. The mechanical properties of the RHA composites were of comparable values with the prepared polypropylene composites filled with commercial Neu burg silica. Transformation of the crystalline RHA to amorphous RHA resulted in composites with improved tensile strength. No coupling agent was used in this study.KEY WORDS Rice Husk Ash / Filler / Polypropylene / Composites / Mechanical Properties/ Incorporation of fillers into a polymer is known to cause substantial changes to the mechanical properties of the composities. As polymer composites are increasingly used in various mechanical applications, the mechanical properties are perhaps the most basic and important behaviors that need to be investigated in order to evaluate the performance of the composities when they are subjected to stress.term of modulus of elasticity, ultimate tensile strength, impact resistance, etc. The term mechanical is applied for this category of properties because they are often used to indicate the suitability of a material for use in mechanical applications, parts that carry a !oak, absorb shock, etc. 1 The principal objective of this study is to investigate the technical viability of using the rice husk ashes which are usually regarded as waste products as alternative low cost fillers in polypropylene. In this investigation, the mechanical properties of the polypropylene/ rice hush ash (RHA) composites are investigated in term of their modulus, tensile and impact properties. Modulus is a measure of The basic characterization of the mechanical properties are usually determined by tests resulting in various deformation versus stress dependencies, for instance the stressstrain diagrams. Examinations of such dependencies yield mechanical characteristics in * To whom correspondence should be addressed. 1002Mechanical Properties of RHA/PP Composites the stiffness of a material subjected to shear loading. Addition of filler normally improves the stiffness of the composities. Tensile test is among the most widely employed test method to characterize the mechanical properties of composites. From such a test, enomorous amount of important information m...

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Incorporation of rick husk ash (RHA) fillers into polypropylene affected some of the thermal properties of polypropylene composites. Addition of the black rice husk ash (BRHA) filler raised the thermal degradation temperature while maintaining the oxidative stability. The thermal degradation temperature of the white rice husk ash (WRHA) composites was found to be independent of filler loading but the oxidative stability deteriorated with increasing filler content. DSC studies indicated that both white and black RHA fillers act as weak nucleation agents and increase the degree of crystallinity of polypropylene by a small margin. Addition of the RHA fillers reduced the linear thermal expansion coefficient of the composites. Dynamic mechanical studies showed that the RHA composites with higher filler content have higher storage modulus. Tan δ curves of the composites indicated that WRHA filler increased the damping property while the BRHA filler had an opposite effect.

Electrochemical impedance spectroscopy (EIS) was employed to study electrochemical behaviors during Li-ion insertion into rice husk carbon. The impedance spectra consist of two depressed semicircles in the high and middle range frequency and an incline line at low frequency. The impedance spectra, obtained in the potential range 2.0 to 0.005 V were analyzed with an equivalent circuit model. Kinetic parameters such as the chargetransfer resistance and surface film resistance were evaluated and discussed.

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