In situ generated silica reinforced polyvinyl alcohol/liquefied chitin biodegradable films for food packaging.

In previous report, polyvinyl alcohol/liquefied ball-milled chitin (PVA/LBMC) blend films with good antibacterial activity were successfully prepared. To further develop a biodegradable food packaging material, various amounts of nano-silica were introduced in situ by the hydrolysis of Na2SiO3 to give a series of silica-reinforced PVA/LBMC blend films. Their structure, morphology, mechanical and thermal properties, food preservation and degradation behavior in soil were comprehensively characterized. The results showed that when the content of Na2SiO3 was 0.2 wt %, the blend film 4PVA-LBMC-0.2Si displayed the optimized performance. Its tensile strength, and the maximum weight loss rate temperature reached 51 MPa and 307 ℃, respectively, which were significantly improved than those of silica-free film. The preservation tests of cherries showed its good fresh keeping performance. Although the degradation rate of silica-reinforced blend films in the soil was slightly decreased, it remained at a good level of 43 % after 30 days of burial.