The present application relates to a supercritical fluid injection foaming polylactide foam material and a preparation method therefor. The method includes: first obtaining a surface-modified cellulose nanofiber aqueous solution; then melting and blending the cellulose nanofiber aqueous solution and a polylactide twice; passing same through extrusion, cooling under water, and granulation so as to obtain a polylactide/cellulose nanofiber composite material; then plasticizing and melting the polylactide/cellulose nanofiber composite material in a microporous foaming injection molding machine; uniformly mixing same with a supercritical fluid foaming agent in the injection molding machine; injecting same into a mold cavity; and subjecting the resultant to post-treatment so as to obtain a polylactide foam material. The polylactide foam material has a sandwich structure, in which two outer surface layers are solid layers that do not contain any foam, and the sandwiched layer is a foam layer having a cellular structure.

The extruder includes: a cylinder having a first end portion and a second end portion respectively formed at two ends of the cylinder in an axial direction, and an ejection port formed in the first end portion; a screw including a shaft that is configured to rotate within the cylinder, and a screw blade that is provided on an outer circumferential surface of the shaft; a supplier that is attached to the second end portion side of the cylinder and is configured to supply a kneading target to an inside of the cylinder; and a plurality of protruding members that protrude from an inner wall surface of the cylinder.

Provided are a preparation method of a thermoplastic resin composition and a thermoplastic resin composition prepared therefrom. The preparation method includes: feeding a first thermoplastic resin in a molten state into a first hopper and feeding an impact reinforcing agent including a predetermined content of moisture into a second hopper, followed by kneading and extruding processes, and removing the moisture in a first vent port and a second vent port, wherein the first hopper, the first vent port, the second hopper, a first kneading zone, and the second vent port are sequentially formed in a moving direction of an extruder. The thermoplastic resin composition prepared therefrom can have improved appearance property and improved color property by removing moisture of an impact reinforcing agent added to the thermoplastic resin composition.

A process for the processing of an undried particulate polymer or polymer mixture by means of a single- or multiscrew extruder comprising a barrel comprising one or more screws, a feed section intended for the polymer and provided on the barrel and, provided on the barrel, a melting region in which the polymer or polymer mixture melts, where the undried polymer or polymer mixture introduced by way of the feed section into the barrel is devolatilized in at least one vacuum devolatilization region downstream of the feed section and upstream of the melting region in the barrel.