CN-120401060-B - Preparation method of nanoscale liquid crystal polyarylester fiber

Abstract

The application relates to a preparation method of nanoscale liquid crystal polyarylate fibers, which comprises the following steps of mixing and extruding high molecular weight polyarylate and low molecular weight polyarylate with a mass ratio of 1 (10-20), carrying out melt spinning by a spinning machine to obtain primary fibers, heating the primary fibers in protective atmosphere to a temperature between the melting points of the high molecular weight polyarylate and the low molecular weight polyarylate, and passing through a filter screen to obtain filter residues, wherein the filter residues are the nanoscale liquid crystal polyarylate fibers. The preparation method has the advantages of simple process, no need of using expensive equipment, higher industrialization value, no need of using alkaline reagent for long-time alkali dissolution treatment, capability of avoiding degradation of the nanofiber caused by the alkaline reagent, higher recovery rate and higher environmental protection benefit.

Inventors

• ZHOU XIAO

Assignees

• 广东星聚材料科技有限公司

Dates

Publication Date

20260512

Application Date

20250506

Claims (9)

1. 1. A preparation method of nanoscale liquid crystal polyarylate fibers is characterized by comprising the following steps of mixing and extruding high molecular weight polyarylate and low molecular weight polyarylate with a mass ratio of 1 (5-20), carrying out melt spinning by a spinning machine to obtain primary fibers, heating the primary fibers in protective atmosphere to a temperature between the melting points of the high molecular weight polyarylate and the low molecular weight polyarylate, and passing through a filter screen to obtain filter residues, wherein the filter residues are the nanoscale liquid crystal polyarylate fibers; The melting point of the high molecular weight polyarylate is 270-275 ℃, the melting point of the low molecular weight polyarylate is 220-230 ℃, and the nascent fiber is heated to 245-255 ℃ in a protective atmosphere.
2. 2. The method of claim 1, wherein the high molecular weight polyarylate is the same monomer as the low molecular weight polyarylate.
3. 3. The method of claim 1, wherein a compatibilizer is added during the mixing extrusion.
4. 4. The method of claim 1, wherein the mass ratio of the high molecular weight polyarylate to the low molecular weight polyarylate is 15:83.
5. 5. The method of claim 1, wherein the aspect ratio of the spinneret orifice of the spinning machine is 10-20.
6. 6. The method of claim 1, wherein the primary fibers are cut into staple fibers having a diameter of 1-3 mm.
7. 7. The method of claim 1, wherein the temperature of the mixing extrusion is 290-310 ℃.
8. 8. The method according to claim 1, wherein the parameters of the melt spinning are a feed zone 230-250 ℃, a melting zone 290-310 ℃, a compression zone 290-310 ℃ and a box temperature 290-310 ℃.
9. 9. The method according to claim 1, wherein the filter residue is subjected to alkali-dissolution treatment.

Description

Preparation method of nanoscale liquid crystal polyarylester fiber Technical Field The application relates to the technical field of liquid crystal polyester fibers, in particular to a preparation method of a nanoscale liquid crystal polyarylate fiber. Background Liquid crystal polyarylate fiber (LCP) is a special fiber with high strength and high modulus, and consists of a rigid aromatic ring and a flexible connecting group. The nano-scale liquid crystal polyarylate fiber refers to a fiber material with the diameter within 1000nm, and the superfine fiber diameter of the fiber material enables the fiber material to have larger specific surface area, so that the fiber material has higher adsorption performance. The preparation method of the nanoscale liquid crystal polyarylate fiber is mainly an electrostatic spinning method, but the production efficiency is low, and the large-scale production is difficult due to a high-voltage electric field. Patent CN103160953a of the university of marchantia discloses a short-process preparation method of thermotropic liquid crystal polyarylate nano-fibrils, which takes alkali-soluble polyester as a dissolution component, and combines and spins thermotropic liquid crystal polyarylate and water-soluble polyester, so that the thermotropic liquid crystal polyarylate is fully oriented in a high-length-diameter ratio spinneret orifice along a melt flow direction to form the nano-fibrils, the alkali-soluble polyester is dissolved and removed by hot alkali liquor, and the thermotropic liquid crystal polyarylate nano-fibrils with excellent comprehensive properties are obtained after separation and drying. The method can prepare the thermotropic liquid crystal polyarylate nano-fibrils in a short process, but has some problems that 1, a large amount of alkaline solution is needed to carry out alkali dissolution on nascent fibers, so that the environment is polluted, the alkali-soluble polyester is difficult to recover, and 2, the alkali dissolution treatment can lead to degradation of the thermotropic liquid crystal polyarylate nano-fibrils, so that the recovery rate is lower, and meanwhile, the structural strength of the nascent fibers is influenced. It is therefore necessary to provide a method for preparing a nano-sized liquid crystalline polyarylate fiber. Disclosure of Invention In order to solve the problems of complex preparation process and serious pollution of the nano-scale liquid crystal polyarylate fiber, it is necessary to provide a preparation method of the nano-scale liquid crystal polyarylate fiber LCP. The first aspect of the application provides a preparation method of nanoscale liquid crystal polyarylate fibers, which comprises the following steps of mixing and extruding high molecular weight polyarylate and low molecular weight polyarylate with a mass ratio of 1 (5-20), carrying out melt spinning by a spinning machine to obtain nascent fibers, heating the nascent fibers in protective atmosphere to a temperature between the melting points of the high molecular weight polyarylate and the low molecular weight polyarylate, and filtering by a filter screen to obtain filter residues, wherein the filter residues are the nanoscale liquid crystal polyarylate fibers. The scheme uses low molecular weight polyarylate (LMW) and high molecular weight polyarylate (HMW) with high mass ratio to be mixed and extruded to form a uniform mixture, then the high molecular chains of the polyarylate are oriented along the flowing direction by a melt spinning process to obtain primary fibers with high orientation, the LMW can also play a role of a plasticizer in the process to promote the molecular chain movement of the HMW, the primary fibers are heated to a temperature between the melting points of the two polyarylates in a protective atmosphere, so that the LMW is melted to form a viscous mobile phase and the HMW component keeps a solid highly oriented structure, the high oriented structure is filtered by a filter screen, the LMW can pass through the filter screen and the HMW has a certain size to be intercepted by the filter screen to form filter residues, namely the nanoscale liquid crystal polyarylate fiber LCP. The preparation method has the advantages of simple process, no need of using expensive equipment, higher industrialization value, no need of using alkaline reagent for long-time alkali dissolution treatment, capability of avoiding degradation of the nanofiber caused by the alkaline reagent, higher recovery rate and higher environmental protection benefit. Further, the high molecular weight polyarylate is the same as the monomer of the low molecular weight polyarylate. The use of polyarylates with the same monomers can avoid phase separation due to chemical structure differences and ensure that a homogeneous system is formed during blending. Further, a compatibilizer is added during the mixing extrusion process. Compatibilizers such as maleic anhydride copolymers and the li