Polylactic acid/polyester alloy and preparation method thereof

The invention relates to a polylactic acid/polyester alloy and a preparation method thereof. The polylactic acid/polyester alloy comprises the following components in percentage by weight: polylactic acid, polyester, a compatilizer, a flexibilizer, an antioxidant and a lubricant. The preparation method comprises the following steps: firstly, proportioning the raw materials and mixing at a room temperature; and respectively carrying out melting extrusion, carrying out ultrasonic treatment at the first late stage, extruding at the second stage and pelletizing, so as to obtain degradable, high-impact-resistant and high-heat-resistant polylactic acid/polyester alloy. Compared with an existing method, the controllable ultrasonic treatment is utilized; and a similar polylactic acid-g-polyester structure is formed by in-situ reaction, so that the heat resistance of the polyester and the biodegradability of the polylactic acid are reserved; and meanwhile, a toughening system with a core-shell structure is formed in an alloy system through interface interaction of a special toughening compatilizer, so that the alloy product with high impact resistance, high heat resistance and high biodegradability can be obtained.