Modified polylactic acid material as well as preparation method and application thereof

The invention provides a modified polylactic acid material as well as a preparation method and application thereof. According to the modified polylactic acid material, a repeating unit structure is a linear structure formed by copolymerization of polylactic acid molecules and polysiloxane molecules, a terminal group is an unsaturated grease alcoholysis product, the modified polylactic acid material is formed by block copolymerization of polylactic acid molecular chains and polysiloxane molecular chains, the content of silicon-oxygen bonds is 5-13 wt%, and the content of silicon-oxygen bonds is 5-10 wt%. The mass fraction of the unsaturated grease is 0.5 wt%-1.3 wt%. According to the modified polylactic acid material provided by the invention, a-Si-O-bond is introduced, so that the toughness is improved and the cold resistance of the polylactic acid material is improved; unsaturated bonds are introduced into molecules, the oxidative degradation rate of the polylactic acid material is accelerated, and the biode