Abstract: A type of foaming materials based on poly（lactic acid） （PLA）/poly（butylene adipate-co-terephthalate） （PBAT） blends modified with an epoxy-type chain extender （ADR） was prepared through a hot press foaming process using azodicarbonamide as a foaming agent and nano-silica （SiO2） as a nucleating agent. The chain extension reaction of ADR with PLA and PBAT was confirmed by FTIR. The experimental results from melting flow tests indicated that the addition of ADR improved the melt strength of the foam precursor effectively. The cell morphology of the foaming materials was studied by SEM. When 0.3 phr of ADR and 2 phr of SiO2 were added， the cell average diameter of the foaming materials decreased to 48.63 μm and their cell density increased to 3.717×106 cells/cm3. Moreover， their bulk density decreased from 1.156 to 0.75 g/cm3 compared to that of pure PLA. The DSC， XRD， and DMA test results indicated that the addition of PBAT and SiO2 improved the crystallinity of PLA effectively， providing a better environment for the foaming process. The mechanical test results indicated that the addition of PBAT and ADR improved the tensile properties of the foaming materials， and the presence of bubbles improved their impact properties. The foaming materials presented impact strength of 25.94 kJ/cm2， which was 23.52 % higher than that of pure PLA.

Key words: poly（lactic acid）, poly（butylene adipate-co-terephthalate）, foam, crystallinity, mechanical property