Effect of LNR-g-MMA on the Mechanical Properties and Lifetime Estimation of PLA/PP Blends

Polylactide (PLA) polymer, polypropylene (PP) polymer, and a PLA/PP (70:30 wt%) blend, with liquid natural rubber-graft-methy methacrylate (LNR-g-MMA) of 0.0, 2.5, 5.0, and 10.0 phr as compatibilizers, were prepared by internal mixing and compression molding. The effect of LNR-g-MMA content on the morphology, mechanical properties, water absorption, thermal degradation, and a lifetime of blends based on PLA and PP was investigated. Scanning electron microscopy (SEM) revealed that the PLA/PP blend underwent phase separation, and the presence of LNR-g-MMA in the PLA/PP blend showed a more homogenized and refined blend morphology. Hence, the addition of LNR-g-MMA was used as a compatibilizer to induce miscibility in the PLA/PP blend. The values of tensile strength, elongation at break, and impact strength of the polymer blends increased, whereas water absorption values decreased with increased LNR-g-MMA content. Thermal degradation kinetics was studied over a temperature range of 50-800 degrees C with multiple heating rates. The results demonstrated that the thermal stability of blends without LNR-g-MMA was greater than that of blends with LNR-g-MMA and that the thermal stability decreased with increasing LNR-g-MMA content. The activation energy (E-a) was calculated by using the Kissinger-Akahira-Sunose method. The E-a value of PLA was much lower than that of PP, and incorporating PP in the PLA matrix increased the E-a. The addition of LNR-g-MMA to the PLA/PP blend decreased the E-a. The lifetime of PLA/PP blends was reduced with the addition of LNR-g-MMA.

Automated summary

Polylactide (PLA) polymer, polypropylene (PP) polymer, and a PLA/PP (70:30 wt%) blend, with liquid natural rubber-graft-methy methacrylate (LNR-g-MMA) of varying concentrations, were studied for their morphology, mechanical properties, water absorption, thermal degradation, and lifetime. The addition of LNR-g-MMA as a compatibilizer improved the homogeneity and refined blend morphology of the PLA/PP blend. Tensile strength, elongation at break, and impact strength increased with increased LNR-g-MMA content, while water absorption values decreased. Thermal stability decreased with increasing LNR-g-MMA content, as indicated by the activation energy (E-a) values. The lifetime of PLA/PP blends was reduced with the addition of LNR-g-MMA.