Abstract: Block copolymers of lactic acid and methyl methacrylate (PLA-b-PMMA) with different block lengths were synthesized, which were used as a macromolecular compatibilizer to improve the compatibility of polycarbonate (PC) and poly(lactic acid) (PLA). Fourier transform infrared spectrometer (FTIR) and nuclear magnetic resonance spectroscopy (NMR) were used to characterize the structure of PLAbPMMA. Differential scanning calorimeter (DSC)，scanning electron microscopy (SEM) and mechanical property tester were used to characterize the structure and properties of PC/PLA blends．It showed that PLA-b-PMMA improved the compatibility of PC and PLA, and the degree of compatibility mainly depended on the block length in PLA-b-PMMA. A PC/PLA blend with satisfied morphology and mechanical properties was obtained when the content of PLAbPMMA was 6 %. With PMMA chain length in PLA-b-PMMA being 60000, the compatibility of PC and PLA in the blends continued to get better as the PLA chain length increased from 3390 to 9780. However, with PLA chain length in PLA-b-PMMA being 9780, the compatibility of PC/PLA blends came down as the PMMA chain length increased from 20680 to 99680.

Key words: polycarbonate, block copolymer of lactic acid and methyl methacrylate, compatilizer