TiO₂-containing PVA/xylan composite films with enhanced mechanical properties, high hydrophobicity and UV shielding performance

Recently, growing interests have been focused on biodegradable films from natural macromolecule, especially great efforts have been made to prepare composite films of xylan with other polymers to improve mechanical properties. In this work, we developed composite films of polyvinyl alcohol (PVA)/xylan with enhanced mechanical properties, the high hydrophobicity and the high UV shielding performance by an addition of TiO₂. Influences of different crystal forms of TiO₂ on the functional properties of composites films such as hydrophilicity/hydrophobicity, water vapor permeability, mechanical properties, solubility and UV transmittance were comparatively investigated. SEM and TGA were used to characterize the morphology and thermal stability of composite films. Results showed that rutile TiO₂ could greatly improve the mechanical properties such as tensile strength (TS). When the amounts of rutile TiO₂ and glycerol was 2 and 10 % based on the weight of PVA and xylan, TS reached to 30.73 MPa and the elongation at break (EAB) was 192.9 %, correspondingly to 115.5° of contact angle for PVA/xylan composite films. PVA/xylan composite films containing TiO₂ had the high UV shielding performance. Therefore, these composite films with excellent properties could have the promising application for food and fruit packaging as preservative films.