Preparation and properties of chitosan derivative/poly(vinyl alcohol) blend film crosslinked with glutaraldehyde

Novel crosslinked blend films of N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (HTCC) and poly(vinyl alcohol) (PVA) were prepared by mixing their aqueous solutions followed by crosslinking with glutaraldehyde (GA). The effects of the GA content and ratio of HTCC to PVA on the appearance, swelling, gel content, morphology and antibacterial activities of blend films were studied and a possible mechanism of crosslinking was proposed based on the results. It was found that the equilibrium degree of swelling (ESD) increased with the increasing content of HTCC, but decreased with the content of GA. The ESD was a maximum (212%) when the ratio of HTCC/PVA/GA was 60/40/2 (wt). Antibacterial activities against Staphylococcus aureus and Escherichia coli of the blend films were weakened slightly by crosslinking, but still showed substantial antibacterial activity. These results demonstrate that, not only the PVA, but also the HTCC reacted with GA. It was the amino groups on HTCC that was un-substituted by quaternary ammonium salt, which reacted with the aldehyde groups on GA.