Influence of Urea and Sorbitol on Packaging Properties of Biodegradable PVA/Hemicellulose Blend Films

Abstract

In recent years, numerous studies have focused on biodegradable biomass-derived materials for packaging applications. To improve the mechanical and barrier properties, biodegradable hemicellulose extracted from bagasse pith blend films containing poly (vinyl alcohol) (PVA) were elaborated by casting method in this study. A series of blend films at a PVA/hemicellulose weight ratio of 4:1 under the addition of sorbitol and urea were investigated. Influences of the sorbitol and urea amounts on the packaging properties of blend films were analyzed. Results showed that increasing the sorbitol amount led to a decrease in tensile strength and OP, and an increase in elongation at break, contact angle and WVP, While the urea amount led to a decrease in WVP and OP, and an increase in tensile strength, elongation at break and contact angle. The addition of 1.5 % urea in blend films without sorbitol had a positive impact on improving the moisture barrier performance and oxygen barrier properties of blend films，the values of PV and OP were 4.13×10-13·g·cm/cm2·s·Pa and 0.08×10-4·cm3/m·24h·0.1MPa, respectively. Moreover, FTIR and XRD were used to confirm the compatibility of the PVA and hemicellulose components. FTIR analysis displayed the intensity of hydroxyl groups of blend films became stronger with increasing amounts of sorbitol, while the opposite results were obtained with an increase of the amount of urea. These indicated that sorbitol could improve the miscibility between PVA and hemicellulose, and urea could improve the moisture barrier performance of blend films. This study shows potential applications of biopolymer extracted from agriculture and forestry biomass as future barrier packaging films.