Studying the influence of the addition of nano-titanium dioxide on the rheological, mechanical, thermal, and electrical properties of polycarbonate/wood flour

Abstract

In this work, the thermal stability of wood flour (WF) was modified using a boric acid treatment. To further understand the impacts of incorporating various proportions of titanium dioxide (TiO2) nanoparticles loaded on polycarbonate (PC)/wood flour. The rheological, mechanical, thermal, electrical, and interfacial properties were studied. Various properties of the resultant PC/WF/TiO2 nanocomposites were then characterized. The viscosity of the nanocomposite was shown to decrease with shear rate and temperature. XRD investigation indicated that, by introducing TiO2 nanoparticles into PC/WF, the amorphous phase decreased, and the degree of crystallinity increased, as compared to bare PC/WF, from 65.78 to 42.29. In addition, the TGA profile showed that the nanocomposites have a higher resistance to thermal degradation than PC/WF alone. It was observed that the char residue resulting from the TGA of PC/WF/10%wt TiO2 increased to 5.69% compared to pure PC/WF (1.32%). It was found that an appropriate amount of TiO2 in PC/WF caused a significant increase in tensile strength, elongation at break, and on impact strength. These were attributed to an increase in the interface of the dispersed phase. The incorporation of nanoparticles enhanced the thermal conductivity of the nanocomposites, which was found to be higher when a TiO2 content of ∼3 wt% was used. The electrical conductivity of the PC/WF/TiO2 nanocomposite (<3 wt%) hindered the movement of free-moving ions, therefore reducing the nanocomposite’s electrical conductivity. However, at > 3 wt% of TiO2, due to the aggregation of nanoparticles, TiO2 nanoclusters formed in the PC/WF composite. Therefore, the additional space so created for the movement of conduction ions at the interface may have resulted in increased ion mobility. This could be the one of explanations for the increased electrical conductivity associated with higher wt% of TiO2. Results showed that treating the PC/WF/TiO2 nanocomposites with boric acid decreased both the rate of heat release and the total heat release.