Study on Mechanical Properties of Polylactic Acid (PLA) Films

Polylactic acid (PLA) is a thermoplastic, biodegradable, and bioactive polymer obtained from renewable resources such as beets and potatoes. PLA is a brittle polymer, so its use in the packaging industry is limited. Mechanical properties of this polymer can be affected by adding nanoparticles and plasticizers. Zinc oxide nanoparticle (۱ wt % of PLA), Polyethylene glycol ۴۰۰ (۲۰ wt % of PLA), and Polysorbate ۸۰ (۰.۲۵ wt % of the solution) were used in this research to improve the mechanical properties of PLA films. The effect of the materials added to the films was measured in the first and tenth months. The aim was to investigate physical aging, which is a precursor to polymer degradation. Statistical analysis was performed on the mechanical properties measured in the first and tenth months. With the help of statistical analysis, we can find the significant difference between the produced films. Before the statistical analysis, three necessary assumptions for using ANOVA, namely normality of data, independence of samples, and equality of standard deviation of groups were evaluated. Results showed that the highest tensile strength (۸۲.۹۹±۱.۹۰ MPa, neat PLA), elongation (۷۶.۸۲±۲۷.۲۲ %, PLA/PEG/ZnO), toughness (۲۰.۱۳±۷.۸۹ J/cm۳, PLA/PEG/ZnO), and young's modulus (۲.۷۴±۰.۱۰ GPa, neat PLA) belonged to the first month. Based on the stress-strain curves, it was found that the neat PLA film is among the resistant materials. The PLA/Polysorbate/ZnO film had brittle behavior in the tenth month. The rest of the samples behave between resistant and ductile materials in the first and tenth months

کلیدواژه ها:

ANOVA ، Mechanical properties ، PLA ، ZnO nanoparticles