Morphologies and mechanical properties of polylactic acid / polypropylene carbonate (PLA/PPC) blends by solvent casting method

Polylactic acid (PLA), which is biodegradable, biocompatible, risk-free and eco-friendly is being used extensively in numerous applications such as in food packaging, pharmaceutical, and biomedical. However, PLA is brittle by nature. Hence, this study aimed to investigate the effect of polypropylene carbonate (PPC) contents on the morphologies and mechanical properties of PLA/PPC blends. PLA and PPC with five different compositions blends (100%PLA; 75%PLA/25%PPC; 50%PLA/50%PPC; 25%PLA/75%PPC; and 100%PPC) were prepared by using solvent casting method. The mechanical properties and morphologies of the blends were investigated systematically. The results showed that the elongation at break of PLA was increased from less than 10% to 63% as 25% PPC were added and kept on increasing up to 1000% elongation without a break as the amount of PPC were increased from 75% to 100%. SEM image verified that PPC dispersed as spheres or islands inside the PLA matrix when 25% of PPC were added. Co-continuous morphology was observed in 50%PLA/50%PPC blends. As the amount of PPC increased to 75%, the PLA formed an island phase in PPC matrix. In conclusions, adding PPC to PLA via solvent casting may be an effective way to improve the toughness of PLA and the SEM image verified that there was a clear phase separation in all three PLA/PPC blends which further prove the partial miscibility of the blends.