Structure and properties of biodegradable maize starch/chitosan composite films as affected by PVA additions

The aim of this work was to develop environmentally safe multi-purpose composite films based on maize starch (St), low weight chitosan (Chit), and Polyvinyl Alcohol (PVA). To this end the structural features and functional characteristics of the films were evaluated. The PVA content in the blends was varied in the range of 0-40 wt% (based on the total weight of the blend), the St/Chit ratio was fixed at 70/30 in weight. The results of the St/Chit/PVA composite films analysis by X-ray diffraction, FTIR spectroscopy, and SEM methods showed that the PVA concentration increase in the compositions resulted in phase separation between PVA and two other components of the blends, while the intermolecular interactions between St and Chit grew. The mechanical characteristics of the composite films improved with an increase in the PVA concentration. The UV-protective ability and biodegradation rate of St/Chit/PVA films decreased as the PVA content grew. The results of this systematic study enabled us to recommend the 10-20 wt% PVA additions to the St/Chit (70/30) matrix as an optimal supplement ensuring the formation of the films with advanced mechanical and functional characteristics without loss of biodegradability.