Construction of functional composite films originating from hemicellulose reinforced with poly(vinyl alcohol) and nano-ZnO

Abstract The aim of this study is to prepare functional hemicellulose (HC) films with flexibility, thermoplasticity and UV-shielding ability. HC was firstly esterified with vinyl benzoate and then reinforced with poly(vinyl alcohol) (PVA) and nano-zinc oxide (ZnO). After esterification, the solubility of benzoated HC (BH) increased, while the thermal stability decreased. Moreover, esterification could transform HC into crystalline nature and endow HC with tunable transition temperature ( T g ). Adding equivalent mass of PVA and 1% ZnO increased the thermal stability of BH/PVA/ZnO films. XRD and DSC analyses showed the new crystalline structure and the decreased T g of films, probably due to the interactions among BH, PVA and ZnO. From SEM, the cross sections of films were dense, rough, and were connected to form the network structure, promoting the uniform insertion of ZnO into the matrix. The films showed moderate tensile strength and good flexibility with the maximum elongation at break of 87.18%. In addition, the water vapor permeability (WVP) and oxygen permeability (OP) values of BH/PVA/ZnO film were 2.08 × 10 −10  g/m s Pa and 0.95 cm 3  μm/m 2  d kPa, respectively. Moreover, the film with 1% ZnO exhibited excellent UV-shielding properties with the percentage blocking of UV-A and UV-B of 99.34% and 99.99%, respectively. Graphic abstract