Enhanced mechanical property and water solubility of polyvinyl alcohol film via constructing hydrogen-bond network by adding carboxymethyl chitosan

The slight solubility of polyvinyl alcohol (PVA)/chitosan (CS) blends in water is an unavoidable drawback, which severely limits their applications in controlled drug-release and recycling. In the present work, carboxymethyl chitosan (CMCS) which has a good solubility in a wide PH range was used to modify the mechanical performance and water solubility of PVA-based blends. The results indicated that the PVA/CMCS blends were soluble in an aqueous medium at about PH = 7 and they also demonstrated better thermo-mechanical properties when compared with pure PVA. The PVA/CMCS blend film was compatible at a mid-low percentage of CMCS (i.e., 30% and 50%). The addition of CMCS effectively improved the mechanical strength and glass transition temperature of PVA by constructing intermolecular hydrogen bonds. Moreover, PVA/CMCS blends exhibited excellent solubility in neutral water, which demonstrate promising applications in the coating film industry.