Polylactic acid composite material and preparation method thereof

The invention discloses a polylactic acid composite material and a preparation method thereof. Raw materials required in a preparing process of the polylactic acid composite material comprises polylactic acid, a polyester toughening agent, a chain extender, talcum powder, an anti-aging agent, an antioxidant and a plasticizer. Through the chain extender used in the raw materials for preparing the polylactic acid composite material, in a twin-screw extruding process, the chain extender reacts with a functional group on a polylactic acid chain, so that the polylactic acid molecular chain can form a long branched chain structure, the molecular weight of the polylactic acid can be increased, and the prepared polylactic acid composite material has improved toughness and better thermal stability and mechanical properties; and relative to the polylactic acid, the using amount of each additive in the raw materials used in the preparing process of the polylactic acid composite material is relatively small, so that the prepared polylactic acid composite material is obvious in toughening effect, high in transparency and high in tensile strength.