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In this paper, we melt-blended low density polyethylene (LDPE), thermoplastic starch (TPS), and polylactic acid (PLA). In order to improve the PLA/LDPE/TPS blends compatibility, we used ethylene-x-glycidyl methacrylate block copolymer (E-X-GMA) as PLA/LDPE compatible agent, added starch graft acrylate (Starch-g-X) to increase the dispersion of starch. Microstructure, mechanical properties, crystallization properties and rheological properties of PLA/LDPE/E-X-GMA blends and PLA/LDPE/E-X-GMA/TPS/ Starch-g-X blends was studied, determined the components of the blends, and compared the compatibilization of E-X-GMA and Starch-g-X. Analyzed the compatibilization mechanism of E-X-GMA and Starch-g-X, and the interaction in PLA/LDPE/E-X-GMA/TPS/Starch-g-X blends was studied.Research showed that, LDPE was used as a stress concentration body, which can improve the toughness of PLA, E-X-GMA had compabilization in the PLA/LDPE blends, and ethylene butyl acrylate methl methacrylate glycidyl ester (E-BA-GMA) had the best.compatibilization effect. The compatibility mechanism of E-X-GMA:on the one hand, E segment and LDPE molecular chain can wind with each other; on the other hand, epoxy group in the GMA segment could react with the terminated carboxyl or terminated hydroxyl of PLA, increased the interaction force between PLA and LDPE. Blends of PLA/LDPE/E-BA-GMA (80/20/6) showed the impact strength 55.15 J·m-1, which is about 150% higher than that of PLA/LDPE blends.The dispersion of TPS in PLA/LDPE/E-BA-GMA/TPS blends was not well, which reduced the properties of the blends. Starch-g-X prepared by emulsion grafting method can enhance the dispersion of TPS in blend system, and starch graft butyl acrylate (Starch-g-BA) as the non-reactive compatibilizer performed the best in improving the interface bonding strength and phase dispersion. PLA/LDPE/E-BA-GMA/TPS/Starch-g-BA blends force between components presented crisscross tree model. PLA/LDPE/E-BA-GMA/TPS/ Starch-g-BA blending materials (80/20/6/20/4) can not only meet with good toughness, but also slove the problem of compatibility, meanwhile can reduce the material cost.
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