Ecofriendly UV-protective films based on poly(propylene carbonate) biocomposites filled with TiO₂ decorated lignin

It is highly desirable to develop biodegradable UV-shielding materials from the renewable resources as the ever-increasing demand for the sustainable environment. In this work, TiO₂ decorated lignin particles (TiO₂@lignin) were synthesized successfully by hydrothermal method in aqueous solution to improve the UV shielding performance of lignin particles. The poly(propylene carbonate) (PPC) composite films (thickness of ~23 μm) with different contents of TiO₂@lignin were prepared via a blade-casting method. Morphological analysis showed that the TiO₂@lignin dispersed uniformly in the PPC matrix with a good miscibility. UV–vis transmission spectra results revealed that the PPC composite film containing 5 wt% TiO₂@lignin could absorb about 90% of UV light in the full UV band (200–400 nm), indicating the TiO₂@lignin had a good UV-shielding property. Moreover, the presence of TiO₂@lignin could significantly improve the thermal stability of the PPC/TiO₂@lignin composite films. The DMA results showed that the introduction of TiO₂@lignin could enhance the storage modulus and glass transition temperature simultaneously.