Preparation method of degradable high-strength closed-cell polylactic acid foam material

The invention provides a preparation method of a degradable high-strength closed-cell polylactic acid foam material, and belongs to the technical field of high polymer materials. Comprising the following steps: A, preparing modified nano SiO2 particles grafted with acrylic acid; b, mechanically crushing the toughening grade PLA resin particles; c, the refined PLA, thermoplastic starch and modified nano SiO2 particles are mechanically stirred and pre-dispersed in an ethanol solution according to the proportion of 20: 79: 1; d, putting the mixture pre-dispersed in the step C into a fuming cupboard for pumping, and then drying in a drying oven to obtain a mixed material; e, the mixed material obtained in the step D and a certain amount of dispersing agent are processed and granulated through double screws, a modified plate is prepared through a vulcanization forming machine, then the modified plate is placed in a limited foaming mold, the mold is placed in a high-pressure foaming reaction kettle to be subjected