Super Toughened and High Heat-Resistant Poly(Lactic Acid) (PLA)-Based Blends by Enhancing Interfacial Bonding and PLA Phase Crystallization

Polycarbonate (PC) was incorporated into poly(lactic acid) (PLA) to prepare the high-PLA-content (>= 66 wt %) PLA/PC blends with high impact strength and heat distortion temperature (HDT) via adding a compatibilizer to tailor the interfacial bonding and annealing to enhance the crystallization of PLA phase with the aid of an impact modifier. On the basis of the tensile test, scanning electron microscope, and transmission electron microscope observations, the change from the yielding behavior dominated by shear-yielding to a coexistence of shear-yielding and crazing should be the leading reason for the significant improvement of impact strength for the annealed PLA/PC blends. The increase of the ability to sustain the high local stress also played an important role in the improvement of impact strength. Meanwhile, the increase of HDT should be resulting from the formation of a rigid three-dimensional framework composed of rigid PC particles and PLA crystals formed in the PLA/PC blends.