Film formation and mechanical properties of an opaque titanium dioxide and transparent polyvinyl alcohol composite films

Abstract Mechanical, optical, and film formation properties of titanium dioxide/polyvinyl alcohol (TiO₂/PVA) composites were studied. Two identical experimental sets of % TiO₂ content were prepared that one set is in the range of 1, 3, 5, 7, 10, 13, and 20 wt% for the film formation and the second set is 5 and 50 wt% for the mechanical measurements. Photon transmission technique (PT) at room temperature was used for the film formation process after annealing for 10 min at the temperatures changing from 100 to 270°C. The increase and decrease in the transmission light intensity (I_tr) from the composite films were attributed to void closure and interdiffusion models, respectively. The results were consistent with the data obtained from the film formation processes and mechanical measurements that the addition of TiO₂ in PVA had remarkable improvement on mechanical properties, for example, increment in the Young's modulus and the rigidity as TiO₂ content increased from 5 to 50 wt%, and it had also good film forming especially above 10 wt% TiO₂ for the void closure processes leading to lower the activation energy. It was observed that for the lower content of TiO₂ such as 5 wt%, the tensile strength and Young's modulus increased remarkably for heating temperature increased up to 150°C. However, with the increase of TiO₂ content, the maximum values of the mechanical strength and modulus were shifted to 180°C for 50 wt% TiO₂ from 150°C for 5 wt% TiO₂ because of the thermal stability of TiO₂.