Antibacterial food packaging sheets prepared by coating chitosan on corona-treated extruded poly(lactic acid)/poly(butylene succinate) blends

Abstract

This research developed antibacterial food packaging sheets from biodegradable poly(lactic acid)/poly(butylene succinate) 90/10 wt% blend. The corona discharge energy via input current (in A) was set at three levels (4, 5, and 6 A) to investigate its influence on the coating content. Physical and chemical characteristics of treated surfaces were studied using scanning electron microscope, X-ray photoelectron spectroscopy, and contact angle measurement. A simple dip coating was carried out by immersing the sheets in chitosan solutions with four different concentrations (0.25, 0.50, 1.00, and 2.00% w/v). Chitosan content, antibacterial activity, and water vapour transmission rate were evaluated. Tensile tests were performed and results were statistically analyzed. We found that the sheets treated at 4 A corona discharge energy obtained the highest chitosan content while the sheets maintained elongation at break values similar to the untreated sheets. Chitosan coating had some water vapour permeation barrier and also mechanically reinforced the corona-treated sheets. Antibacterial activity tests against Staphylococcus aureus and Escherichia coli showed that chitosan coating inhibited the growth of both microorganisms as a function of chitosan coating content.