Preparation method for high melt strength poly lactic acid, and extruder thereof

Abstract

The invention relates to a preparation method for high melt strength poly lactic acid, and an extruder thereof. The raw materials comprise, by weight, 100 parts of a poly lactic acid resin, 1-3 parts of a reaction chain extender, and 0.1-3 parts of an antioxidant. The preparation method comprises: drying the poly lactic acid resin, mixing the poly lactic acid resin, the reaction chain extender and the antioxidant according to the weight part ratio, adding the resulting mixture to an extruder, and carrying out extruding through the extruder to obtain the high melt strength poly lactic acid, wherein the extruder comprises a primary stage extruder and a secondary stage extruder, the primary stage extruder and the secondary stage extruder are respectively provided with a temperature sensor and a heating device, the primary stage extruder is a twin screw extruder, the secondary stage extruder is a single screw extruder, the primary stage extruder is provided with a first material inlet and a first material outlet, the secondary stage extruder is provided with a second material inlet and a second material outlet, and the first material outlet is connected with the second material inlet. With the method of the present invention, the production method and the device thereof are provided, wherein the method adopts the double-single series reaction extruder structure to prepare the high melt strength poly lactic acid material, and is suitable for continuous mass production of the poly lactic acid material with the long chain branched structure.

Description

technical field [0001] The present invention relates to a preparation method and equipment of high melt strength polylactic acid. Background technique [0002] Due to the negative impact of traditional plastics on the environment and the limited development of petroleum-based plastic resources, green bioplastics that can be completely biodegraded and synthesized from renewable resources have received close attention. Among them, polylactic acid (PLA) is a kind of thermoplastic aliphatic polyester prepared by chemical synthesis of renewable plant resources through ring-opening polymerization and direct polycondensation. It is currently a widely used green biomaterial. It can be completely decomposed under the action of microorganisms, water, acid, alkali, etc., and the decomposition products are water and carbon dioxide, or degraded into lactic acid under the action of specific enzymes, without causing environmental pollution; it can also be recycled and processed like tradit...

AI Technical Summary

Problems solved by technology

However, due to the characteristics of the structure of this reaction extruder, the residence time of the material in the barrel is very short, and the too short reaction time cannot ensure the sufficient grafting of the PLA molecular chains, and the obtained long-chain branched PLA has low molecular weight, branched Low level of integration, low efficiency of chain extension

Even if the length-to-diameter ratio of the ordinary reaction extruder is increased, the residence time of the material cannot be significantly increased

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