Antibacterial coating of corona treated Poly(lactic acid) / Poly(butylene succinate) film with Chitosan and Zinc oxide nanoparticle

Abstract

The biodegradable PLA/PBS 90/10 wt% films were extruded and surface treated with corona discharge. Two electrical inputs of the corona treatment were used, 2 or 6 amperes, which the change of the surface tension was evaluated using corona measuring pens. The blend films were coated with the antibacterial mixture between chitosan and zinc oxide nanoparticles (ZnO-NP) in four concentrations: 1.0/0.4, 1.0/0.5, 1.5/0.5, and 1.5/0.5 wt%/wt%. This film could be used to replace transparent disposable packaging in the circular economy. It was found that the surface tension of the blend film was 30 dyne (mN/m) which was much like the neat PLA due to PLA being the main composition. Since the overall coated film thickness was kept constant, there was no significant difference in the coating weight among four coating concentrations. Compared to the uncoated PLA/PBS film, the tensile strength of the coated films tended to be higher with the increase of ZnO-NP content. However, the elongation at break of the coated films decreased significantly, which the stiffer coating layers became the stress concentrators. From SEM, it was seen that the good adhesion between the polymer and the coating layer was achieved. When the coated films were torn apart in the trouser tear testing, the failure was the breakage of the blend film with there was some coating layer delaminated.