Fig. 2 shows SEM micrographs of cryofracture surfaces of pure PLA, ENR20/PLA and ENR50/PLA blends. In our previous work, the NR/PLA blend revealed a spherical-particle-dispersed morphology, because the non-polar NR was immiscible with the polar PLA and led to phase separation. However, obvious spherical rubber particles are not observed in the epoxidized natural rubber/PLA blends. Instead, the rubber domain for blends containing 5 wt% ENR20 and ENR50 appeared as smooth patches. This morphology is different from the 10% ENR25/PLA blend reported by Jaratrotkamjorn et al. [21] probably due to different material and mixing technique. Comparison between Fig. 2b1 and Fig. 2c1 also confirms that ENR with higher degree of epoxidation can induce more molecular interaction and entanglements with PLA because polarity of the ENR increases with epoxidation content, so the 5 wt% ENR50/PLA blend appears larger patches than 5 wt% ENR20/PLA. Both the 20 wt% ENR20/PLA and ENR50/PLA blends present quite coarse phase morphology with large amount of elongated and flattened rubber domains. This is ascribed to the coalescence of ENR at high rubber content. Compared to the blend containing 20 wt% ENR20 (Fig. 2b2), the 20 wt% ENR50/PLA blend (Fig. 2c1) shows a better compatible morphology with obscure interphase. Interfacial adhesion for the ENR50/PLA blend seemed to be better than that of ENR20/PLA blend.