Characterization and sliding wear performance of PMMA reinforced with SiO ₂ nanoparticles

Abstract

The characterization and wear sliding performance of the poly(methyl methacrylate) (PMMA) reinforced with hydrophilic and hydrophobic nanoparticles of silicon dioxide (SiO 2 ) was studied. The final polymer matrix was treated in a water bath at a temperature of 100°C for 6 h. Steel balls were used to slide against the surface of PMMA specimens reinforced with SiO 2 nanoparticles. Sliding wear tests were carried out in wet sliding conditions applying a drop of distilled water between the specimen and the ball. The tests were carried out up to 9000 cycles at room temperature. A frequency of 5 Hz, a stroke amplitude of 3 mm, and a maximum contact pressure of 1.087 GPa were selected. Fourier transform infrared spectroscopy spectrum, scanning electron microscopy, and microhardness and roughness of the pure PMMA and PMMA/SiO 2 were obtained. The coefficient of friction and wear rates were calculated, and the main wear mechanisms found were adhesion wear, plastic deformation, ploughing, and pitting. The results showed that the addition of hydrophobic nanoparticles of SiO 2 may be employed to enhance the wear resistance of external automotive parts made of polymeric compound matrix. Finally, the specimens showed a hydrophilic behavior (angular contact < 90°) due to the high polarity of the PMMA matrix and the incorporation of the SiO 2 nanoparticles.