Rice Husks - Structure, Composition and Possibility of Use them at Surface Treatment

Abstract

Rice husks (RH) are characterized by a high content of silicon dioxide up to 23 wt. %. Silica in the form of nanoparticles creates surface layers formed in various plant parts which ensure protective properties and mechanical stability. These nanoparticles with a dimension in the range of tens of nanometers, are formed during biochemical processes and photosynthesis. Individual nanoparticles are interconnected between themselves and between layers with organic phase via cellulose fibres. Accompanying ions mainly potassium, calcium, sodium, magnesium and aluminium extremely important for plant growth have also been identified in rice husks. In this research paper we investigated mechanical properties of composite epoxy resin material, which was composed of ChS Epoxy 520 filled with silica obtained from rice husks. Nanoparticles of silicon dioxide with the size in dozen of nanometers were prepared by calcination of raw plant parts. We found that the 0.1 phr of filling (0.01 g of filler + 10 g of epoxy) demonstrated a significant increase of wear resistance and decrease of coefficient of friction. An excellent adhesion between epoxy resin and silica nanoparticles was also observed. The silicon dioxide in epoxy resin plays the role of the hard phase, which transfers part of the load and protects the surface of polymer against wear. The presence of this filler does not change the mechanical properties of the original resin.