Thermal and mechanical properties of poly(lactic acid)/natural rubber blend using epoxidized natural rubber and poly(methyl methacrylate) as co-compatibilizers

In order to improve the toughness of poly(lactic acid) (PLA), the incorporation of natural rubber (NR), which has a high elasticity and flexibility, can be used. However, the phase incompatibility between PLA and NR can cause poor mechanical properties of the final product in the absence of a compatibilizer because of their different polarities. In this research, epoxidized NR (ENR) and poly(methyl methacrylate) (PMMA) were used as co-compatibilizers for linking PLA/NR blends (PLA 100: NR 15 parts by weight per hundred parts of resin (phr)). Therefore, the aim of this research was to study the effect of the ENR/PMMA co-compatibilizer contents on the mechanical, thermal and morphological properties of the 100:15 phr PLA/NR blend. With 3 phr of ENR and 1 phr of PMMA, the elongation at break and impact strength of the 100:15 phr PLA/NR blend was significantly improved up to 1,813% and 362%, respectively. The thermal stability of the PLA/NR blend was also increased when using the co-compatibilizers. Interestingly, the PLA/NR blend containing the co-compatibilizer showed a high ultimate tensile strength after thermal aging at 100 A degrees C for 1 h with good mechanical properties. However, the percentage of crystallinity and glass transition temperature were decreased by the added co-compatibilizer. Finally, a good compatibility between the PLA and NR matrices could be clearly observed by scanning electron microscopy in the presence of the co-compatibilizer.