Physical Properties and Antibacterial Efficacy of Biodegradable Chitosan/PVA Blend Films

publisher[Synopsis] In this study, fabrication of chitosan/PVA blend films was fabricated, and their mechanical properties and antibacterial efficacy were examined. The maximum draw ratio of the chitosan/PVA blend films increased with increasing PVA content. Only diffraction from PVA could be observed from a wide angle and X-ray diffraction measured from the through view of drawn films. The diffraction arcs from PVA crystal planes (110) and (110) for the composite with 22/78 composition (λ＝7) become spots indicating high orientation of molecular chains of PVA. Furthermore, the value of Young's modulus increased significantly by elongation because of the preferential orientation of PVA and chitosan crystallites with respect to the stretching direction. The E' reached ca. 20GPa at room temperature for the 22/78 composite at draw ratio of 7 times which is higher than the pure PVA film at λ＝8. The contact angle increased with increasing of the chitosan content, and the film became more hydrophilic. The antibacterial activity for the chitosan/PVA blend films was better for Staphylococcus aureus NBRC 12732 (ATCC 6538P) rather than Escherichia coli NBRC 3972 (ATCC 8739) but the activity became worse (less effective) with increasing draw ratio. The activity become more effective for the blend films treated by quaternary ammonium chitosan and became hardly affected by the neutralization. This indicates that the drawing of the treated blends provide the possibility to expand the applications as industrial materials became of an increase in Young's modulus and tensile strength