Method and system for continuously preparing liquid crystal polymer with adjustable molecular structure

Abstract

The invention relates to the technical field of polymer material preparation, in particular to a method and system for continuously preparing a liquid crystal polymer with a controllable molecular structure. The method at least comprises the following steps: 1) carrying out multistage tandem acetylation reaction and / or pre-polymerization reaction on a first acetylation reaction material to providea first acetylation monomer and / or a prepolymer with a polymerization degree of Xn; 2) carrying out multistage tandem acetylation reaction and / or pre-polymerization reaction on the second acetylationreaction material to provide a second acetylation monomer and / or a prepolymer with a polymerization degree of X'n; and 3) carrying out polymerization reaction on the first acetylated monomer and / or the prepolymer with the polymerization degree of Xn in the step 1) and the second acetylated monomer and / or the prepolymer with the polymerization degree of X'n in the step 2), removing small moleculesand acetic acid in vacuum, and performing extruding and pelletizing to provide the liquid crystal polymer. According to the invention, the molecular structure can be regulated and controlled; and meanwhile, the generation of small molecular by-products and branched chains is inhibited, and the product performance is improved.

Description

technical field [0001] The invention relates to the technical field of polymer material preparation, in particular to a method and system for continuously preparing liquid crystal polymers with adjustable molecular structure. Background technique [0002] Thermotropic liquid crystal polymer (TLCP), as a high-performance special engineering plastic, has a series of excellent properties, such as high strength, outstanding heat resistance, chemical corrosion resistance, small linear expansion coefficient, low hygroscopicity Excellent electrical insulation, etc., are currently more and more widely used in the fields of aerospace, electronic appliances, and small precision thin-walled parts. [0003] Typical steps for preparing thermotropic liquid crystal polymers are usually as follows: [0004] (1) Reaction monomer, acetic anhydride and catalyzer are carried out acetylation reaction in reactor by a certain ratio; [0005] (2) Carry out temperature rise melt polycondensation r...

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Problems solved by technology

Due to the high viscosity of the reaction system in the post-melt polycondensation stage, internal parts such as internal coils are usually not used in traditional tank-type polymerization reactors. The heat transfer process mainly depends on the heat transfer of the tank wall, but the specific surface area of ​​the tank-type polymerization reactor is small. The temperature rise rate is slow; at the same time, due to the stirring mode of the polymerization tank reactor, the material is mixed unevenly, especially when the viscosity of the polymerization system rises in the late stage of the reaction, the difficulty of material mixing is further increased, and it is easy to cause the concentration of local monomers to be too high, which will intensify the aroma. The self-polymerization of hydroxycarboxylic acid monomers, resulting in uneven molecular weight distribution of polymer products, resulting in deterioration of processability and reduction of mechanical properties

[0008]In addition, the kettle polymerization is mostly a one-pot cooking method. On the one hand, it is difficult to achieve continuous production, and the capacity utilization rate is low; on the other hand, with TLCP in 5G electronics The application requirements of components are getting higher and higher. Therefore, how to precisely control the molecular structure of the polymer to essentially improve the material properties of injection molding grade resins, fiber grade resins and film grade resins has become a hot research topic in the industry.

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