阅读说明：本技术 一种热致性液晶聚酯材料及其制备方法 (Thermotropic liquid crystal polyester material and preparation method thereof ) 是由 张东宝 于冉 徐良 于 2021-07-23 设计创作，主要内容包括：本发明公开了一种热致性液晶聚酯材料及其制备方法,其制备方法包括以下步骤：(1)制备乙酰化单体：将单体分别进行乙酰化反应,得到乙酰化单体；(2)制备热致性液晶聚酯材料：将乙酰化单体、乙酸酐和醋酸锌高温聚合,粉碎,得到热致性液晶聚酯材料；其中所述的乙酰化单体包括乙酰化羟基苯甲酸和乙酰化第一单体。本发明通过单体乙酰化能够提高单体反应活性,避免单体自聚及单体中的羟基被氧化；再通过调整对乙酰化单体的种类和配比,降低规整聚合物分子链的紧密堆积程度,从而降低热致性液晶共聚酯的熔点,使其广泛应用于高分子材料加工助剂领域。(The invention discloses a thermotropic liquid crystal polyester material and a preparation method thereof, wherein the preparation method comprises the following steps: (1) preparing an acetylated monomer: respectively carrying out acetylation on the monomers to obtain acetylated monomers; (2) preparing a thermotropic liquid crystal polyester material: polymerizing the acetylated monomer, acetic anhydride and zinc acetate at high temperature, and crushing to obtain a thermotropic liquid crystal polyester material; wherein the acetylated monomers comprise an acetylated hydroxybenzoic acid and an acetylated first monomer. According to the invention, the monomer reaction activity can be improved through monomer acetylation, and the self-polymerization of the monomer and the oxidation of hydroxyl in the monomer are avoided; and the tight packing degree of regular polymer molecular chains is reduced by adjusting the variety and the proportion of the acetylated monomers, so that the melting point of the thermotropic liquid crystal copolyester is reduced, and the thermotropic liquid crystal copolyester is widely applied to the field of polymer material processing aids.)

1. The preparation method of the thermotropic liquid crystal polyester material is characterized by comprising the following steps of:

(1) preparing an acetylated monomer: respectively carrying out acetylation on the monomers to obtain acetylated monomers;

(2) preparing a thermotropic liquid crystal polyester material: polymerizing the acetylated monomer, acetic anhydride and zinc acetate at high temperature, and crushing to obtain a thermotropic liquid crystal polyester material;

wherein the acetylated monomers comprise an acetylated hydroxybenzoic acid and an acetylated first monomer.

2. The method of claim 1, wherein the acetylated first monomer comprises at least one of acetylated 2-hydroxy-6-naphthoic acid, acetylated 4-hydroxy-3-methoxybenzoic acid and acetylated 4-hydroxyphenylpyruvic acid.

3. The method for preparing the thermotropic liquid-crystalline polyester material according to claim 1, wherein the acetylation reaction comprises: mixing the monomer, acetic anhydride and a catalyst, and carrying out acetylation reaction to obtain an acetylated monomer;

wherein the monomer is p-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-3-methoxybenzoic acid or 4-hydroxyphenylpyruvic acid.

4. The method for producing the thermotropic liquid-crystalline polyester material according to claim 3, wherein the catalyst is concentrated sulfuric acid.

5. The method for preparing the thermotropic liquid-crystalline polyester material of claim 3, wherein the molar ratio of the monomer to the acetic anhydride is 1:1 to 3.

6. The method for preparing the thermotropic liquid-crystalline polyester material according to claim 3, wherein the acetylation reaction conditions are as follows: stirring for 1-3h at the temperature of 150 ℃ and 200 ℃, and then stirring for 0.5-2h in an ice water bath.

7. The method for preparing the thermotropic liquid-crystalline polyester material of claim 1, wherein the molar ratio of the acetylated p-hydroxybenzoic acid to the acetylated first monomer in the acetylated monomers is 1-9: 1.

8. The method for preparing the thermotropic liquid-crystalline polyester material according to claim 1, wherein the molar ratio of the acetylated monomer to the acetic anhydride to the zinc acetate is 1: 0.5-1: 0.001-0.005.

9. The method for preparing the thermotropic liquid-crystalline polyester material according to claim 1, wherein the polymerization conditions at high temperature are as follows: reacting at 190 ℃ for 1-3h under 150-.

10. A thermotropic liquid-crystalline polyester material produced by the method according to any one of claims 1 to 9; the melting point of the thermotropic liquid crystal polyester material is 310-380 ℃.

Technical Field

The invention relates to the technical field of liquid crystal polymers, in particular to a thermotropic liquid crystal polyester material and a preparation method thereof.

Background

Liquid Crystal Polymers (LCP) are polymer materials which lose the fluidity of the material after being heated and melted or dissolved by a solvent, but can still maintain partial ordered arrangement to form a polymer material with the properties of both crystal and liquid parts. Liquid crystal polymers can be further classified into thermotropic liquid crystal polymers and lyotropic liquid crystal polymers according to the different ways of exhibiting a liquid crystal state. The thermotropic liquid crystal is that the material is in a liquid crystal state along with the temperature change in a certain temperature range, and the lyotropic liquid crystal is that the material is in a liquid crystal state in a certain concentration range.

The molecular chain of the thermotropic liquid crystal polyester is composed of rigid straight chains, has higher orientation capability after being melted at high temperature, and generates high orientation along the axial direction after flowing. Therefore, the polymer has excellent mechanical property, high strength and modulus, better heat resistance, excellent processing property and excellent chemical resistance. The thermotropic liquid crystal copolyester has the excellent performance, so that the thermotropic liquid crystal copolyester can be widely applied. The high-strength high-modulus composite material is made into fibers by utilizing the characteristics of high strength and high modulus of the high-strength high-modulus composite material, replaces glass fibers and mineral fillers, can reduce the abrasion to equipment and reduce the specific gravity of the material, can be directly compounded with resin, has the effects of improving the strength and modulus of the material, and can improve the performance of general plastics. The molecular composite material prepared by molecular-level compounding with the high molecular material has more excellent comprehensive performance, and the high fluidity of the molecular composite material can be used as a modifier for plastic fluidity, so that the application range of the thermoplastic plastic is expanded.

The p-hydroxybenzoic acid thermotropic liquid crystal material prepared by taking p-hydroxybenzoic acid as a monomer has a very high melting point due to high molecular chain rigidity and high stacking degree, so that the composite processing of the material and other high polymer materials is influenced, and the application of the material in the field of high polymer material processing aids is limited.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a thermotropic liquid crystal polyester material and a preparation method thereof, and aims to reduce the melting point of the thermotropic liquid crystal polyester and apply the thermotropic liquid crystal polyester material to the field of polymer material processing aids.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a preparation method of a thermotropic liquid crystal polyester material comprises the following steps:

(1) preparing an acetylated monomer: respectively carrying out acetylation on the monomers to obtain acetylated monomers;

(2) preparing a thermotropic liquid crystal polyester material: polymerizing the acetylated monomer, acetic anhydride and zinc acetate at high temperature, and crushing to obtain a thermotropic liquid crystal polyester material;

wherein the acetylated monomers comprise an acetylated hydroxybenzoic acid and an acetylated first monomer.

The preparation method of the thermotropic liquid crystal polyester material comprises the step of preparing an acetylated first monomer, wherein the acetylated first monomer comprises at least one of acetylated 2-hydroxy-6-naphthoic acid, acetylated 4-hydroxy-3-methoxybenzoic acid and acetylated 4-hydroxyphenylpyruvic acid.

The preparation method of the thermotropic liquid crystal polyester material comprises the following steps: mixing the monomer, acetic anhydride and a catalyst, and carrying out acetylation reaction to obtain an acetylated monomer;

wherein the monomer is p-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-3-methoxybenzoic acid or 4-hydroxyphenylpyruvic acid;

the preparation method of the thermotropic liquid crystal polyester material comprises the following steps of (1) preparing a thermotropic liquid crystal polyester material by using a catalyst, wherein the catalyst is concentrated sulfuric acid;

the preparation method of the thermotropic liquid crystal polyester material comprises the step of preparing a thermotropic liquid crystal polyester material, wherein the molar ratio of the monomer to the acetic anhydride is 1: 1-3.

The preparation method of the thermotropic liquid crystal polyester material comprises the following steps of: stirring for 1-3h at the temperature of 150 ℃ and 200 ℃, and then stirring for 0.5-2h in an ice water bath.

The preparation method of the thermotropic liquid crystal polyester material comprises the step of preparing an acetylated p-hydroxybenzoic acid from an acetylated first monomer, wherein the molar ratio of the acetylated p-hydroxybenzoic acid to the acetylated first monomer is 1-9: 1.

The preparation method of the thermotropic liquid crystal polyester material comprises the following steps of (1: 0.5-1): 0.001-0.005;

the preparation method of the thermotropic liquid crystal polyester material comprises the following steps of: reacting at 190 ℃ for 1-3h under 150-.

Meanwhile, the invention also provides a thermotropic liquid crystal polyester material which is prepared by the method; the melting point of the thermotropic liquid crystal polyester material is 310-380 ℃.

Has the advantages that: the invention discloses a thermotropic liquid crystal polyester material and a preparation method thereof, wherein the monomer reaction activity can be improved through monomer acetylation, and the self-polymerization of the monomer and the oxidation of hydroxyl in the monomer are avoided; and the tight packing degree of regular polymer molecular chains is reduced by adjusting the variety and the proportion of the acetylated monomers, so that the melting point of the thermotropic liquid crystal copolyester is reduced, and the thermotropic liquid crystal copolyester is widely applied to the field of polymer material processing aids.

Detailed Description

The invention provides a thermotropic liquid crystal polyester material and a preparation method thereof, and the invention is further detailed below in order to make the purpose, technical scheme and effect of the invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Specifically, the invention provides a preparation method of a thermotropic liquid crystal polyester material, which comprises the following steps:

(1) preparing an acetylated monomer: adding a monomer and acetic anhydride into a three-neck flask, adding concentrated sulfuric acid as a catalyst, stirring for 1-3h at the temperature of 150-;

the monomer is p-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-3-methoxybenzoic acid or 4-hydroxyphenylpyruvic acid;

the molar ratio of the monomer to the acetic anhydride is 1: 1-3.

(2) Preparing a thermotropic liquid crystal polyester material: adding an acetylated monomer, acetic anhydride and zinc acetate into a three-neck flask filled with nitrogen under the stirring condition, reacting for 1-3h at the temperature of 150-;

the acetylated monomers comprise acetylated p-hydroxybenzoic acid and acetylated first monomers;

the molar ratio of the acetylated p-hydroxybenzoic acid to the acetylated first monomer is 1-9: 1;

the acetylated first monomer comprises at least one of acetylated 2-hydroxy-6-naphthoic acid, acetylated 4-hydroxy-3-methoxybenzoic acid and acetylated 4-hydroxyphenylpyruvic acid;

the molar ratio of the acetylated monomer to the acetic anhydride to the zinc acetate is 1: 0.5-1: 0.001-0.005.

Meanwhile, the invention also provides a thermotropic liquid crystal polyester material which is prepared by the method; the melting point of the thermotropic liquid crystal polyester material is 310-380 ℃.

Meanwhile, the invention also provides application of the thermotropic liquid crystal polyester material, which is mainly applied to the field of polymer material processing aids. The thermotropic liquid crystal polyester material can change the polyphenylene sulfide material, thereby improving the crystallization temperature of the polyphenylene sulfide and reducing the viscosity of the polyphenylene sulfide material in the processing process.

The thermotropic liquid crystal polyester material and the preparation method thereof of the present invention are further explained by the following specific examples:

example 1

One embodiment of the invention provides a preparation method of a thermotropic liquid crystal polyester material, which comprises the following steps:

(1) preparing an acetylated monomer: adding 0.1mol of p-hydroxybenzoic acid, 0.15mol of acetic anhydride and 0.2g of concentrated sulfuric acid into a three-neck flask under the condition of stirring, stirring for 3 hours at 160 ℃, stirring for 0.5 hour in an ice-water bath, filtering, washing and drying to obtain the acetylated p-hydroxybenzoic acid.

Adding 4-hydroxy-3-methoxybenzoic acid 0.1mol, acetic anhydride 0.15mol and concentrated sulfuric acid 0.2g into a three-neck flask under stirring, stirring for 3h at 160 ℃, stirring for 0.5h in an ice-water bath, filtering, washing and drying to obtain acetylated 4-hydroxy-3-methoxybenzoic acid.

(2) Preparing a thermotropic liquid crystal polyester material: adding 0.09mol of acetylated p-hydroxybenzoic acid, 0.01mol of acetylated 4-hydroxy-3-methoxybenzoic acid, 10ml of acetic anhydride and 0.05g of zinc acetate into a three-neck flask filled with nitrogen under the stirring condition, reacting at 170 ℃ for 1h, heating to 220 ℃ for reaction for 2h, heating to 260 ℃ for heat preservation for 4h, finally heating to 300 ℃ for reaction for 1h, crushing by a crusher, washing with ethanol, and drying to obtain the thermotropic liquid crystal polyester material.

One embodiment of the present invention provides a thermotropic liquid crystalline polyester material prepared by the method of example 1. The melting point of the chiral liquid crystalline polyester material of example 1 was 346 ℃.

Example 2

One embodiment of the invention provides a preparation method of a thermotropic liquid crystal polyester material, which comprises the following steps:

(1) preparing an acetylated monomer: adding 0.1mol of p-hydroxybenzoic acid, 0.1mol of acetic anhydride and 0.2g of concentrated sulfuric acid into a three-neck flask under the condition of stirring, stirring for 3 hours at 150 ℃, stirring for 2 hours in an ice water bath, filtering, washing and drying to obtain the acetylated p-hydroxybenzoic acid.

Adding 4-hydroxy-3-methoxybenzoic acid 0.1mol, acetic anhydride 0.1mol and concentrated sulfuric acid 0.2g into a three-neck flask under stirring, stirring for 3h at 150 ℃, stirring for 2h in an ice-water bath, filtering, washing and drying to obtain acetylated 4-hydroxy-3-methoxybenzoic acid.

(2) Preparing a thermotropic liquid crystal polyester material: adding 0.05mol of acetylated p-hydroxybenzoic acid, 0.05mol of acetylated 4-hydroxy-3-methoxybenzoic acid, 10ml of acetic anhydride and 0.05g of zinc acetate into a three-neck flask filled with nitrogen under the stirring condition, reacting at 190 ℃ for 1h, heating to 240 ℃ for reacting for 1h, heating to 290 ℃ for preserving heat for 2h, finally heating to 330 ℃ for reacting for 3h, crushing by a crusher, washing with ethanol, and drying to obtain the thermotropic liquid crystal polyester material.

One embodiment of the present invention provides a thermotropic liquid crystalline polyester material prepared by the method of example 2. The melting point of the thermotropic liquid-crystalline polyester material of example 2 was 370 ℃.

Example 3

One embodiment of the invention provides a preparation method of a thermotropic liquid crystal polyester material, which comprises the following steps:

(1) preparing an acetylated monomer: adding 0.1mol of p-hydroxybenzoic acid, 0.3mol of acetic anhydride and 0.2g of concentrated sulfuric acid into a three-neck flask under the condition of stirring, stirring for 1h at 300 ℃, stirring for 0.5h in an ice-water bath, filtering, washing and drying to obtain the acetylated p-hydroxybenzoic acid.

Adding 4-hydroxyphenylpyruvic acid 0.1mol, acetic anhydride 0.3mol and concentrated sulfuric acid 0.2g into a three-neck flask under the condition of stirring, stirring for 1h at 300 ℃, stirring for 0.5h in an ice-water bath, filtering, washing and drying to obtain acetylated 4-hydroxyphenylpyruvic acid.

(2) Preparing a thermotropic liquid crystal polyester material: adding 0.07mol of acetylated p-hydroxybenzoic acid, 0.03mol of acetylated 4-hydroxyphenylpyruvic acid, 10ml of acetic anhydride and 0.05g of zinc acetate into a three-neck flask filled with nitrogen under the stirring condition, reacting at 150 ℃ for 3h, heating to 200 ℃ for reaction for 4h, heating to 250 ℃ for heat preservation for 5h, finally heating to 300 ℃ for reaction for 1h, crushing by a crusher, washing with ethanol, and drying to obtain the thermotropic liquid crystal polyester material.

One embodiment of the present invention provides a thermotropic liquid crystalline polyester material prepared by the method of example 3. The melting point of the chiral liquid crystalline polyester material of example 3 was 365 ℃.

Example 4

One embodiment of the invention provides a preparation method of a thermotropic liquid crystal polyester material, which comprises the following steps:

(1) preparing an acetylated monomer: adding 0.1mol of p-hydroxybenzoic acid, 0.15mol of acetic anhydride and 0.2g of concentrated sulfuric acid into a three-neck flask under the condition of stirring, stirring for 3 hours at 160 ℃, stirring for 0.5 hour in an ice-water bath, filtering, washing and drying to obtain the acetylated p-hydroxybenzoic acid.

Adding 2-hydroxy-6-naphthoic acid 0.1mol, acetic anhydride 0.15mol and concentrated sulfuric acid 0.2g into a three-neck flask under stirring, stirring for 3h at 160 ℃, stirring for 0.5h in an ice-water bath, filtering, washing and drying to obtain the acetylated 2-hydroxy-6-naphthoic acid.

(2) Preparing a thermotropic liquid crystal polyester material: adding 0.07mol of acetylated p-hydroxybenzoic acid, 0.03mol of acetylated 2-hydroxy-6-naphthoic acid, 10ml of acetic anhydride and 0.05g of zinc acetate into a three-neck flask filled with nitrogen under the stirring condition, reacting at 170 ℃ for 1h, heating to 220 ℃ for reaction for 2h, heating to 260 ℃ for heat preservation for 4h, finally heating to 300 ℃ for reaction for 1h, crushing by a crusher, washing with ethanol, and drying to obtain the thermotropic liquid crystal polyester material.

One embodiment of the present invention provides a thermotropic liquid crystalline polyester material prepared by the method of example 4. The melting point of the chiral liquid crystalline polyester material of example 4 was 332 ℃.

Example 5

One embodiment of the invention provides a preparation method of a thermotropic liquid crystal polyester material, which comprises the following steps:

(1) preparing an acetylated monomer: adding 0.1mol of p-hydroxybenzoic acid, 0.15mol of acetic anhydride and 0.2g of concentrated sulfuric acid into a three-neck flask under the condition of stirring, stirring for 3 hours at 160 ℃, stirring for 0.5 hour in an ice-water bath, filtering, washing and drying to obtain the acetylated p-hydroxybenzoic acid.

Adding 2-hydroxy-6-naphthoic acid 0.1mol, acetic anhydride 0.15mol and concentrated sulfuric acid 0.2g into a three-neck flask under stirring, stirring for 3h at 160 ℃, stirring for 0.5h in an ice-water bath, filtering, washing and drying to obtain the acetylated 2-hydroxy-6-naphthoic acid.

(2) Preparing a thermotropic liquid crystal polyester material: adding 0.07mol of acetylated p-hydroxybenzoic acid, 0.03mol of acetylated 2-hydroxy-6-naphthoic acid, 10ml of acetic anhydride and 0.05g of zinc acetate into a three-neck flask filled with nitrogen under the stirring condition, reacting at 170 ℃ for 1h, heating to 220 ℃ for reaction for 2h, heating to 260 ℃ for heat preservation for 4h, finally heating to 300 ℃ for reaction for 1h, crushing by a crusher, washing with ethanol, and drying to obtain the thermotropic liquid crystal polyester material.

One embodiment of the present invention provides a thermotropic liquid crystalline polyester material prepared by the method of example 5. The melting point of the chiral liquid crystalline polyester material of example 5 was 321 ℃.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.