Lipophilic modification of T-ZnOw and optical properties of T-ZnOw/PVB composite films

In order to protect the articles in buildings from ultraviolet radiation and save air-conditioning energy, polyvinyl butyral laminated glass are employed and produced in large quantities. Several inorganic particles with blocking effect have been doped into PVB, such as TiO2, ZnO, and ATO. T-ZnOw is a widely used functional structural material with excellent absorption properties. Herein, T-ZnOw was lipophilic modified with silane coupling agent KH-570, and T-ZnOw/PVB composite films were prepared via subsequent solution blending. As per the FTIR spectrum, a characteristic peak of Si–O–Zn at 1165 cm−1 was observed, indicating that T-ZnOw was successfully modified by KH-570. T-ZnOw before and after modification was separately mixed with the St/H2O mixed solution. The modified T-ZnOw could be dispersed in styrene instead of water, displaying a certain lipophilicity. On the other hand, from a microscopic perspective, the SEM images suggest that filling the filler in the form of a suspension can disperse the modified T-ZnOw in PVB in an independent four-needle form, which contributes toward improvement of the agglomeration of T-ZnOw in the PVB matrix. The UV–Vis–NIR spectrum shows that the addition of T-ZnOw reduced the UV transmittance of T-ZnOw/PVB composite films from 50.84 to 25.77%, resulting in a decrease in near-infrared transmittance from 82.14 to 43.22%. The ultraviolet and near-infrared light barrier properties of composite films were more than twice that of the ordinary PVB films. Moreover, the modified T-ZnOw endowed composite films with stronger ultraviolet light and near-infrared light-blocking properties, or better visible light transmittance. And the falling ball impact test proved that there was no clear relationship between the thickness of the film and the adhesion. This work proposes a new solution and preparation method for the production of energy-saving glass. Therefore, it is expected that using composite films instead of traditional PVB films to make laminated glass can greatly contribute toward energy conservation and environmental protection.