High-transparency and high-toughness polylactic acid and preparation method thereof

The invention discloses high-transparency and high-toughness polylactic acid which is prepared from a lactic acid oligomer, a PLA-PEG copolymer and a cross-linking agent through polymerization reaction. The invention also discloses a preparation method of the high-transparency and high-toughness polylactic acid. The preparation method comprises the following steps of carrying out polycondensation and depolymerization on L-lactic acid (the purity is greater than or equal to 95%) to obtain L-lactide, carrying out copolymerization on the L-lactide and polyglycolic acid to obtain a PLA-PEG copolymer, and further polymerizing the polylactic acid oligomer, the cross-linking agent and the PLA-PEG copolymer to obtain the high-transparency and high-toughness polylactic acid. Compared with common PLLA, the high-transparency and high-toughness polylactic acid has the advantages that a molecular chain is of a more complex three-dimensional network structure, the crystallinity of the molecular chain of the polylactic acid