Effects of Lauroyl Peroxide on Structural Modification and Physical Properties of Polylactic Acid

Improving the inherent brittleness and melt strength of polylactic acid using branching agents is essential to make it suitable for industrial applications. Hence, different percentages (0.1, 0.3, and 0.5 wt%) of lauroyl peroxide were used to modify the polylactic acid structure. For this purpose, lauroyl peroxide was added to polylactic acid in a melt state. Then, the effect of different percentages of lauroyl peroxide on the crystallinity, rheological, and mechanical properties of polylactic acid was investigated. The rheological results showed that the complex viscosity of the branched samples increased with the addition of more peroxide. The DSC results indicated that the addition of 0.3 wt% peroxide could enhance the crystallinity of polylactic acid. The results of mechanical properties showed that the addition of 0.5 wt% peroxide significantly increases the elongation at the break of polylactic acid, while the branched sample containing 0.3 wt% peroxide showed the highest yield strength compared to the pure PLA. The results of crystallinity, rheological and mechanical properties of branched samples showed that the structural modification of polylactic acid depends on the amount of lauroyl peroxide.