Effect of silica dioxide on natural resistance and morphological study of wood plastic composite against of white rot fungi (Trametes Versicolor)

Abstract

The objective of this study was the evaluation of the addition of silica particles in composite on natural resistance and morphology of wood plastic composite against of white rot fungi (Trametes Versicolor). Wood flour at the ratio of 60% (w/w), polypropylene and 2 per hundred compound (phc) MAPP was mixed. Nano and micro silica at 0, 1, 3 and 5 (phc) were added as filler. The mixing process in internal mixer (HAAKE) was done and test specimens were prepared using injection molding. The test specimens were exposed to Trametes Versicolor fungi for 8, 12 and 16 weeks at 25 oC and 75% humidity according to BS 838:1961. Then the mass loss, long-term water absorption and humidity coefficient diffusion of the samples were measured. The formation of hydrogen bonds between silica and wood flour was determined by Fourier Transform Infrared (FTIR) spectroscopy and the morphology of composite was stydied using scanning electron microscopy (SEM). The result showed that with increasing period of samples exposure to fungi, the mass loss, long-term water absorption and humidity coefficient diffusion in wood plastic composite increased. However at higher silica, decay in the samples was decreased. The effect of silica nanoparticles on natural resistance of wood plastic composite was higher than sample containing silica micro particles. Infrared spectroscopy showed hydrogen bonds between wood flour and silica. The result of scanning electron microscopy showed that with increasing of exposure time to fungi, small and large cracks in composite were created. However increasing silica addition, these cracks were decreased.

Keywords

• Natural resistance
• humidity coefficient diffusion
• TRAMETES VERSICOLOR
• nano and micro silica
• mass loss