Method and device for directly preparing foamed polylactic acid (pla) product from pla melt

A device for directly preparing a foamed PLA product from a PLA melt, comprising:

• a PLA polymerization unit, a first-stage twin-screw extruder, and a second-stage single-screw extruder, wherein
• the PLA polymerization unit is connected to the first-stage twin-screw extruder, and the first-stage twin-screw extruder is connected to the second-stage single-screw extruder;
• the first-stage twin-screw extruder is provided with a main feeding port, a side feeding port, and a gas injection port in sequence along a feeding direction, and the gas injection port is located at the latter half of the first-stage twin-screw extruder;
• a sealing thread is provided between the side feeding port and the gas injection port;
• the first-stage twin-screw extruder is connected to the second-stage single-screw extruder via a connection buckle, and a filter screen is provided between the first-stage twin-screw extruder and the second-stage single-screw extruder;
• the PLA polymerization unit communicates with the first-stage twin-screw extruder via a melt pipe;
• a feeding pump is further provided between the PLA polymerization unit and the melt pipe;
• the melt pipe communicates with an inside of the first-stage twin-screw extruder via the main feeding port;
• and
• a tail end of the second-stage single-screw extruder is connected to a die head via a static mixer.