RICE HUSK ASH AS A NANO-FILLER TO SYNTHESIZE THERMOSETTING POLYMER NANOCOMPOSITES AND EVALUATION OF ITS TRIBOLOGICAL BEHAVIOR

This paper deals with synthesizing of nanocomposites of unsaturated polyester (UP) filled with nano silica and investigation the effect of silica content on the tribological behavior of UP and nanocomposites . Silica nanoparticles were prepared by burning rice husk ash (RHA) as an agricultural waste material. Three different percentages as 2%, 6% and 10% of nano silica were added to the unsaturated polyester and dispersed by using ultrasonic waves method. As a result of agglomeration and sedimentation of nano RHA particles, dispersing by ultrasonic waves was very effective to terminate these challenges. X-Rays diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) technics were used for characterization of materials. RHA-UP nanocomposites were tested for their tribo-performance by pin-on-disc machine. XRD demonstrated that white rice husk ash consists of amorphous silica. SEM demonstrated that silica particles were distributed uniformly and well embedded within the polyester matrix. Results showed an improvement in wear resistance with relatively stable friction coefficient with the addition of 10% nano silica. Adding 2 wt% nano RHA negatively affected the wear resistance of RHA-UP nanocomposite .The best tribological performance of 10% RHA-UP nanocomposites achieved at load 10N. Incorporation of RHA with unsaturated polyester has advantages of reducing pollution, making the pollutant RHA as a valuable material to produce low cost and lightweight products with modified properties. Silica enriched RHA could prove to be cheaper anti-wear additives for producing high performance unsaturated polyester composites such as brake pads.