CN-122013350-A - Preparation method of polyester imide nanocrystalline fiber with ultra-high length-diameter ratio

Abstract

The invention relates to a preparation method of a super-high length-diameter ratio polyester imide nano-crystalline fiber, which comprises the following steps of S1, mixing trimellitic anhydride and aliphatic amine in a dichloromethane solvent system for reaction, heating and cyclizing to obtain a blocking agent, S2, carrying out prepolymerization reaction on trimellitic anhydride and ethanolamine in an inert atmosphere, adding the blocking agent for full reaction to obtain semi-aromatic polyester imide, S3, dissolving the semi-aromatic polyester imide in tetrahydrofuran solvent, standing for crystallization to obtain a crystallized gel-like product, and S4, centrifuging the crystallized gel-like product to remove free impurities which do not participate in crystallization to obtain the polyester imide nano-fiber with the super-high length-diameter ratio. Compared with the prior art, the preparation method successfully prepares the polyesterimide nanocrystalline fiber with the ultrahigh length-diameter ratio in the single-phase polar solvent, and the polyesterimide nanocrystalline fiber has excellent structural controllability and potential application value.

Inventors

• He zidong
• CAI MINGYA
• ZHOU HUI
• TONG GANGSHENG
• ZHU XINYUAN

Assignees

• 上海化工研究院有限公司
• 上海交通大学

Dates

Publication Date

20260512

Application Date

20260213

Claims (10)

1. 1. The preparation method of the polyester imide nano-crystalline fiber with the ultra-high length-diameter ratio is characterized by comprising the following steps: S1, in a dichloromethane solvent system, mixing trimellitic anhydride and fatty amine for reaction, and then heating for cyclization to obtain a blocking agent; S2, under an inert atmosphere, pre-polymerizing trimellitic anhydride and ethanolamine, adding the end-capping agent in the S1, fully reacting, and purifying the product after the reaction is finished to obtain the long-chain alkane end-capped semi-aromatic polyester imide; S3, dissolving the long-chain alkane end-capped semi-aromatic polyester imide obtained in the S2 in tetrahydrofuran solvent, preparing the semi-aromatic polyester imide into a certain concentration, standing and crystallizing at room temperature to gradually convert the system from clear solution into gel, and obtaining a crystallized gel product; S4, centrifugally separating the crystallized gel product in the S3, dispersing the obtained precipitate in tetrahydrofuran solvent, centrifugally separating again, circulating for a plurality of times to remove free impurities which do not participate in crystallization, and collecting the obtained precipitate to obtain the polyesterimide nanofiber with the ultrahigh length-diameter ratio.
2. 2. The method for preparing the super high aspect ratio polyesterimide nanocrystalline fiber according to claim 1, wherein in S1, the number of carbon atoms of alkyl chain of fatty amine is 8-18.
3. 3. The method for preparing the super high aspect ratio polyesterimide nanocrystalline fiber according to claim 2, wherein the aliphatic amine comprises at least one of stearylamine, n-dodecylamine and n-octylamine.
4. 4. The method for preparing the super high aspect ratio polyester imide nanocrystalline fiber according to claim 1, wherein in S1, the molar ratio of the trimellitic anhydride to the fatty amine is 1 (0.8-1.2).
5. 5. The method for preparing the super high aspect ratio polyester imide nanocrystalline fiber according to claim 1, wherein in the step S1, the temperature of the mixing reaction is 0-30 ℃ and the time is 12-36 h; the temperature of the heating cyclization is 150-170 ℃ and the time is 1-2 h.
6. 6. The method for preparing a super high aspect ratio polyesterimide nanocrystalline fiber according to claim 1, wherein in S1, the chemical structural formula of the end capping agent is: Wherein m is 7 to 17.
7. 7. The method for preparing the super high aspect ratio polyester imide nanocrystalline fiber according to claim 1, wherein in S2, the mole ratio of the trimellitic anhydride, the ethanolamine and the end capping agent is 1 (0.8-1.2): 0.1-0.5.
8. 8. The preparation method of the super high length-diameter ratio polyester imide nanocrystalline fiber according to claim 1, wherein in S2, the prepolymerization reaction process is that the temperature is raised to 100-160 ℃ for 0.5-1 h, and then raised to 200-240 ℃ for 1-2 h; the temperature of the full reaction after adding the end capping reagent is 200-240 ℃ and the time is 2-3 h.
9. 9. The method for preparing the super high aspect ratio polyester imide nanocrystalline fiber according to claim 1, wherein in S2, the chemical structural formula of the long-chain alkane terminated semi-aromatic polyester imide is: wherein m is 7 to 17, and n is 6 to 8.
10. 10. The method for preparing the super high aspect ratio polyester imide nanocrystalline fiber according to claim 1, wherein in S3, the concentration of the semiaromatic polyester imide in the tetrahydrofuran solvent is 0.5-100 mg/ml.

Description

Preparation method of polyester imide nanocrystalline fiber with ultra-high length-diameter ratio Technical Field The invention belongs to the technical field of controllable synthesis and self-assembly of functional polymers, and relates to a preparation method of a polyester imide nanocrystalline fiber with an ultra-high length-diameter ratio. Background The crystallization behavior of the polymer has decisive influence on the performance, such as the key parameters of crystallinity, crystal morphology (such as spherulitic size and distribution, crystal structure) and molecular chain orientation, and the like formed in the crystallization process directly dominates the comprehensive performance of the material, namely, the improvement of the crystallinity can enhance the strength and rigidity of the material, but the too high crystallinity possibly leads to the reduction of toughness, the crystal orientation can lead to the obvious anisotropic strengthening effect of the fiber material, the regular arrangement of the crystallization area can improve the melting temperature and the thermal stability of the material and expand the high-temperature application range of the material, the refractive index difference of the crystal area and the amorphous area can induce light scattering, the fine regulation of the crystal morphology can realize the optimization of the transparency of the material, the processing performance is closely related to the crystallization dynamics, and the crystallization rate and the grain size distribution directly influence the parameter selection and the quality stability of finished products in the molding process such as injection molding, extrusion and the like. Therefore, the precise regulation and control of the crystallization behavior of the polymer is realized, the meaning of the precise regulation and control of the crystallization behavior of the polymer is not only to break through the uncontrollability of the traditional crystallization behavior, but also to provide a brand new paradigm for the rational design of high-performance functional materials, which is always an important research target in the field of material science and one of the core challenges in the field of high-polymer material science. The crystallization-driven self-assembly method is a flexible and efficient self-assembly method, and has wide application in the aspects of nano medicine, nano electronics and the like. Currently, applicable systems for crystallization driven self-assembly are poly ferrocenylsilane, polycaprolactone, polythiophene systems, etc. At present, the crystallization assembly behavior is regulated in the following two ways. One is phase separation driving, such as adding poor solvent into good solvent, and assembling by using lyophobic solvent effect driving system. One is to control the temperature drive, such as heating to above the crystallization temperature of the polymer and cooling to room temperature, to obtain different crystalline nucleus micelles. However, the two modes are traditional crystallization regulation and control means, belong to passive crystallization, cannot react to the original state of a system, depend on passive regulation of macroscopic environmental parameters, are difficult to realize the directional control of crystal nucleation, growth direction and crystal form structure on a molecular scale, and become bottlenecks for restricting the research and application of polymer crystallization self-assembly. Therefore, the ability to effectively regulate the spontaneous crystallization behavior of polymers is a problem to be solved. For example, chinese patent CN113563587A provides a preparation method of polyester imide polymer, firstly, pre-mixing trimellitic anhydride and ethanolamine for a period of time under the atmosphere of low oxygen or inert gas to perform amidation reaction, secondly, raising the temperature, and simultaneously performing melt polyester reaction and imidization reaction under a certain temperature and pressure to obtain the polyester imide polymer after the reaction is finished. However, the polyester imide polymer of this patent does not provide nanofibers. Disclosure of Invention The invention aims to provide a preparation method of a polyester imide nano-crystalline fiber with an ultrahigh length-diameter ratio, and aims to solve the technical problems that the traditional crystallization self-assembly preparation process depends on complex block copolymer design, poor solvent is required to be added or the control is carried out by virtue of a lyophobic solvent effect, so that the preparation process is complicated and the controllability of the crystal morphology is poor. The aim of the invention can be achieved by the following technical scheme: The invention provides a preparation method of a polyester imide nanocrystalline fiber with super-high length-diameter ratio, which is characterized in that a small molecula