Fig. 9 presents the frequency dependences of the storage modulus (G′) and loss modulus (G″) of pure PLA, ENR20/PLA and ENR50/PLA blends. The storage modulus represents the elastic or in-phase response of the material and the loss modulus reflects the viscous or out-of-phase response. At high frequencies (> 10 rad/s), the viscoelastic behaviors of all the samples are the same. At low frequencies (< 10 rad/s), the addition of ENR to PLA resulted in enhanced G′ and G″, this indicates that the epoxidized natural rubber is well dispersed in PLA matrix because of the interaction between the epoxy groups of ENR and carbonyl groups of PLA, this well dispersion produces a percolation network which prevents the PLA chains from free moving, and leads to the increase of G′ and G″. It can be seen that the terminal region slope of G′ and G″ for all blends are lower than that of pure PLA. The lower terminal slope and higher storage and loss modulus indicate a solid-like behavior of the ENR/PLA blends, which is originated from the network structure of the blends as a consequence of the crosslinking of each phase as well as interchain crosslinking between the components in the blends. It is also seen from