Application of ionic liquid as a catalyst in the preparation of liquid crystal polyester and a preparation method of liquid crystal polyester

Abstract

The invention discloses uses of an ionic liquid as a catalyst in preparation of liquid crystal polyesters, particularly performing of a polymerization monomer acylation reaction step and / or a meltingcondensation polymerization reaction step after acylation in liquid crystal polyester preparation reaction steps under the catalysis of an ionic liquid, wherein the ionic liquid is obtained by carrying out a reaction on a heterocyclic organic alkali compound containing two or more nitrogen atoms and an anionic functional compound, and the adding amount of the ionic liquid is 5-2000 ppm based on the total amount of all the added polymerization monomer. According to the present invention, the ionic liquid catalyst has advantages of efficient directional catalytic property, obvious catalytic effect and reduced side reaction of polymerization; the ionic liquid has advantages of excellent stability and long-lasting catalytic effect; the prepared ionic liquid can be directly added to the acylation and transesterification reaction system without purification, such that the operation is simple; and the liquid crystal polyester resin prepared under the catalysis of the ionic liquid catalyst hasexcellent tensile strength and excellent notched impact strength.

Description

technical field [0001] The invention relates to the technical field of polymers, in particular to the use of ionic liquids as catalysts in the preparation of liquid crystal polyesters and a method for preparing liquid crystal polyesters. Background technique [0002] Thermotropic liquid crystal polyester (TLCP) has excellent mechanical properties, processing properties, high dimensional stability, high and low temperature resistance, chemical corrosion resistance, self-reinforcing self-flame retardancy and electrical insulation properties, and is currently used in electronic and electrical components and other fields widely. [0003] The known preparation method of liquid crystal polyester is generally divided into two steps. First, under the action of a catalyst, the polymerized monomer is used to acylate the aromatic hydroxyl compound with an acylating agent to improve the reactivity of the hydroxyl group, and then react with the aromatic carboxyl group. Under the action ...

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Problems solved by technology

However, due to the influence of water in the solution and other problems in solution polymerization, it is easy to cause problems such as catalyst deactivation, and the recycling of ionic liquid solution is difficult, and the post-treatment is complicated.