Preperation of Antimicrobial and Biodegradable Packaging Based on Poly Lactic Acid PLA

Antimicrobial packaging has been very successful and well received due to its ability to inhibit food contaminating microorganisms and thus maintain product quality, in addition to increasing shelf life in meeting customer needs. In this project, antimicrobial and biodegradable films based on linear polyethylene/light polyethylene/poly lactic acid (blends of LLDPE/LDPE/PLA)containing potassium sorbate were prepared by blowing film method. First, linear polyethylene / light polyethylene blend was prepared with different percentages of poly lactic acid (10, 20 and 30%) and 3% component of polyethylene maleic anhydride. The sample of 20% lactic acid was selected as optimal  based on mechanical properties test. In the next step, 4% potassium sorbate was used as an antimicrobial agent to produce biodegradable and antimicrobial films and the films were prepared by blowing film method. The mechanical properties test results showed that the presence of potassium sorbate improved the tensile strength from 7.93 to 11.71 MPa and elongation to rupture from 282.57 to 551.57%. Also, the 72-hour microbial test results showed that the film contains 4% potassium sorbate against Staphylococcus aureus and Aspergillus Niger completely inhibited bacterial activity and inhibited their growth by affecting the essential enzymes in the growth of microorganisms. Also, the 2-month biodegradability results for linear polyethylene/ light polyethylene films and films containing 20% poly lactic acid and 4% potassium sorbate films showed that by adding 20% poly Lactic acid and 4% potassium sorbate improved the biodegradability of the films after 2 months by 1.11% and 2.07%, respectively, however the figure is expected to grow further if time increase.