Temperature-resistant pla straw and preparation method therefor

A method for preparing a thermo-resistant PLA straw, wherein the method comprises the following steps:

• (1) subjecting a PLA straw raw material to a tube drawing process via an extruder to prepare a straw preform, wherein the straw preform comprises PLA that is not fully crystallized;
• and
• (2) subjecting the straw preform to a constant-temperature and constant-pressure carbon dioxide soaking treatment, such that the uncrystallized PLA in the straw preform is crystallized, obtaining a PLA straw product with a temperature resistance of 70° C. or above;
• wherein, a method of the carbon dioxide soaking treatment in step (2) comprises:
• placing PLA straw preform in a temperature-adjustable closed container with high temperature and high pressure resistance, injecting the carbon dioxide into the closed container, and soaking at a constant temperature and under retained pressure;
• in step (2), a pressure retaining temperature is 40° C.-105° C., a pressure retaining pressure is 4-13 MPa, a pressure retaining time is 1-30 minutes, and a pressure release speed is 5-45 MPa/s;
• and
• the carbon dioxide is a supercritical carbon dioxide fluid or a subcritical carbon dioxide fluid.