阅读说明：本技术 一种亲水阻燃改性聚酰亚胺纤维 (Hydrophilic flame-retardant modified polyimide fiber ) 是由 陈智水 李志强 廖颖 于 2021-09-17 设计创作，主要内容包括：本发明提供一种亲水阻燃改性聚酰亚胺纤维,涉及纺织品技术领域,该亲水阻燃改性聚酰亚胺纤维制备过程：首先利用硅烷偶联剂对二氧化硅进行改性,不仅增加硅烷偶联剂在有机试剂中的分散性,且在二氧化硅表面接枝氨基,再利用改性后的硅烷偶联剂与二酐反应接枝,二酐与二胺反应制备改性聚酰胺酸,最后改性聚酰氨酸经过亚酰胺化制备得到改性聚酰亚胺。得到的改性聚酰亚胺为亲水阻燃改性聚酰亚胺纤维。改性聚酰亚胺通过制备含硅氧烷的二酐来制备含硅氧烷的嵌段共聚物,硅氧键的键能较高,热稳定性好,成型加工性及柔韧性得到改善,可以提高聚合物分子链的柔顺性显著改善材料的粘附性能,且增加材料的亲水性能,便于材料水洗。(The invention provides a hydrophilic flame-retardant modified polyimide fiber, which relates to the technical field of textiles, and the preparation process of the hydrophilic flame-retardant modified polyimide fiber comprises the following steps: firstly, modifying silicon dioxide by using a silane coupling agent, not only increasing the dispersibility of the silane coupling agent in an organic reagent, but also grafting amino on the surface of the silicon dioxide, then reacting and grafting by using the modified silane coupling agent and dianhydride, reacting the dianhydride and diamine to prepare modified polyamic acid, and finally performing imidization on the modified polyamic acid to prepare the modified polyimide. The obtained modified polyimide is hydrophilic flame-retardant modified polyimide fiber. The modified polyimide is used for preparing the siloxane-containing block copolymer by preparing the siloxane-containing dianhydride, the bond energy of a siloxane bond is higher, the thermal stability is good, the molding processability and the flexibility are improved, the flexibility of a polymer molecular chain can be improved, the adhesion performance of the material is obviously improved, the hydrophilic performance of the material is increased, and the material is convenient to wash.)

1. The hydrophilic flame-retardant modified polyimide fiber is characterized in that the preparation method of the hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(1) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano silicon dioxide and toluene by ultrasonic waves to obtain a nano silicon dioxide suspension, preparing a pre-hydrolysis solution from a proper amount of silane coupling agent, deionized water and acetic acid, heating the nano silicon dioxide suspension and the pre-hydrolysis solution to 60-70 ℃ in a reaction kettle A, stirring for 1-2h under heat preservation, refluxing for 7-8h under heat preservation, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into the reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, reacting for 4-6h at the reaction temperature of-10-30 ℃, sequentially washing the filtered solid with water, washing with tetrahydrofuran, washing with ethanol, filtering and drying to obtain modified polyamic acid;

(3) preparing modified polyimide: and (2) immersing the modified polyamide acid into a catalyst, adding a proper amount of acetic anhydride, heating to 30-40 ℃, preserving heat, immersing for 14-18h, washing with water, and drying to obtain the hydrophilic flame-retardant modified polyimide fiber.

2. The hydrophilic flame-retardant modified polyimide fiber according to claim 1, wherein the nano silica: toluene: silane coupling agent: the mass ratio of the deionized water is 1 (150) -250): (0.4-1): 1, adjusting the pH of the prehydrolysis solution to 3.5-4 by using the acetic acid.

3. The hydrophilic flame-retardant modified polyimide fiber according to claim 1, wherein the silane coupling agent in step (1) is any one of gamma-aminopropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, N-beta (aminoethyl) -gamma-aminopropyltrimethoxysilane and N-beta (aminoethyl) -gamma-aminopropylmethyldimethoxysilane.

4. The hydrophilic flame-retardant modified polyimide fiber according to claim 1, characterized in that: the N-methylpyrrolidone in the step (2): aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: and 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at intervals of 0.2-0.3 h.

5. The hydrophilic flame-retardant modified polyimide fiber according to claim 1, wherein the catalyst in the step (3) is a mixture of a catalyst and a water-soluble polymer in a mass ratio of 5: 4, and the catalyst is prepared by mixing triethylamine and pyridine: modified polyamic acid: molar ratio of acetic anhydride (0.02-0.5): 1: 1.

6. the hydrophilic flame-retardant modified polyimide fiber according to claim 1, wherein the reaction of step (2) and step (3) are performed under a nitrogen atmosphere.

Technical Field

The invention relates to the technical field of textiles, in particular to a hydrophilic flame-retardant modified polyimide fiber.

Background

The polyimide has a very stable aromatic heterocyclic structure in the molecule, so that the polyimide has high-temperature resistance and low-temperature resistance which cannot be compared with other high polymer materials, has excellent flame retardant property and low smoke rate, can meet the flame retardant requirements of most fields, and polyimide fibers which are industrially produced in China have high-strength high-modulus physical characteristics, so that the polyimide fibers have wide market prospect in developing outer-layer fabrics of fire-fighting suits.

However, because polyimide fibers belong to chemical fibers, belong to high polymer materials, have long molecular chains, compact structures and lack of hydrophilic groups, the chemical fibers generally have the defects of poor moisture absorption capacity, poor air permeability, easy accumulation of static electricity, easy dust absorption, difficult dyeing and the like, and the development of synthetic fibers is restricted to a certain extent; therefore, the problems of poor mechanical property of the fabric and the like need to be solved in the development process of the fabric. The synthetic fibers must be modified as necessary. The prepared differential fiber has special performance, good hand feeling and comfortable wearing. The hydrophilic flame-retardant polyimide fiber has the advantages of simple synthesis process, lower production cost, stable performance and wide application range, thereby having good application prospect and being suitable for mass processing production.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the hydrophilic flame-retardant modified polyimide fiber, which is prepared by grafting the pyromellitic anhydride on the modified silicon dioxide, preparing the modified polyamic acid by reacting the grafted dianhydride with the diamine and preparing the modified polyimide by imidizing the modified polyamic acid.

(II) technical scheme

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

a preparation method of hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(1) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano silicon dioxide and toluene by ultrasonic waves to obtain a nano silicon dioxide suspension, preparing a pre-hydrolysis solution from a proper amount of silane coupling agent, deionized water and acetic acid, heating the nano silicon dioxide suspension and the pre-hydrolysis solution to 60-70 ℃ in a reaction kettle A, stirring for 1-2h under heat preservation, refluxing for 7-8h under heat preservation, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into the reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, reacting for 4-6h at the reaction temperature of-10-30 ℃, sequentially washing the filtered solid with water, washing with tetrahydrofuran, washing with ethanol, filtering and drying to obtain modified polyamic acid;

(3) preparing modified polyimide: and (2) immersing the modified polyamide acid into a catalyst, adding a proper amount of acetic anhydride, heating to 30-40 ℃, preserving heat, immersing for 14-18h, washing with water, and drying to obtain the hydrophilic flame-retardant modified polyimide fiber.

Preferably, the nano-silica in step (1): toluene: silane coupling agent: the mass ratio of the deionized water is 1 (150) -250): (0.4-1): 1, adjusting the pH of the prehydrolysis solution to 3.5-4 by using the acetic acid.

Preferably, the silane coupling agent in the step (1) is any one of gamma-aminopropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, N-beta (aminoethyl) -gamma-aminopropyltrimethoxysilane and N-beta (aminoethyl) -gamma-aminopropylmethyldimethoxysilane.

Preferably, the ratio of N-methylpyrrolidone in step (2): aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: and 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at intervals of 0.2-0.3 h.

Preferably, the mass ratio of the catalyst in the step (3) is 5: 4, and the catalyst is prepared by mixing triethylamine and pyridine: modified polyamic acid: molar ratio of acetic anhydride (0.02-0.5): 1: 1.

preferably, the step (2) and step (3) reactions are both carried out under a nitrogen atmosphere.

(III) advantageous effects

The invention aims to overcome the problems in the prior art and provide a hydrophilic flame-retardant modified polyimide fiber.

According to the invention, the silicon dioxide is modified by using the silane coupling agent, so that the dispersibility of the silane coupling agent in an organic reagent is increased, amino groups are grafted on the surface of the silicon dioxide, the modified silane coupling agent is reacted with dianhydride for grafting, the dianhydride is reacted with diamine for preparing modified polyamic acid, and the modified polyimide is prepared by imidization of the modified polyamic acid. The modified polyimide is used for preparing the siloxane-containing block copolymer by preparing the siloxane-containing dianhydride, the bond energy of a siloxane bond is higher, the thermal stability is good, the molding processability and the flexibility are improved, the flexibility of a polymer molecular chain can be improved, the adhesion performance of the material is obviously improved, the hydrophilic performance of the material is increased, and the material is convenient to wash.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

a preparation method of hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(1) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano-silica and toluene by ultrasonic to obtain a nano-silica suspension, and preparing a pre-hydrolysis solution from a proper amount of gamma-aminopropyltriethoxysilane, deionized water and acetic acid, wherein the nano-silica: toluene: gamma-aminopropyltriethoxysilane: the mass ratio of the deionized water is 1: 150: 0.4: 1, adjusting the pH value of a prehydrolysis solution to 3.5 by using acetic acid, heating a nano silicon dioxide suspension and the prehydrolysis solution to 60 ℃ in a reaction kettle A, keeping the temperature, stirring for 1h, keeping the temperature, refluxing for 7h, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into a reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, and reacting for 4 hours at the reaction temperature of-10 ℃, wherein the reaction temperature is as follows: aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at an interval of 0.2h, sequentially washing the filtered solid with water, washing with tetrahydrofuran and ethanol, filtering and drying to obtain modified polyamic acid, and reacting in a nitrogen atmosphere;

(3) preparing modified polyimide: immersing the modified polyamic acid into a solution with a mass ratio of 5: 4 triethylamine and pyridine, adding proper amount of acetic anhydride, catalyst: modified polyamic acid: molar ratio of acetic anhydride 0.02: 1:1, heating to 30 ℃, preserving heat, soaking for 14h, washing and drying to obtain the hydrophilic flame-retardant modified polyimide fiber, and reacting in a nitrogen atmosphere.

Example 2:

a preparation method of hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(1) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano-silica and toluene by ultrasonic to obtain a nano-silica suspension, and preparing a pre-hydrolysis solution from a proper amount of gamma-aminopropyltriethoxysilane, deionized water and acetic acid, wherein the nano-silica: toluene: gamma-aminopropyltriethoxysilane: the mass ratio of the deionized water is 1: 250: 1:1, adjusting the pH value of a prehydrolysis solution to 4 by using acetic acid, heating a nano silicon dioxide suspension and the prehydrolysis solution to 70 ℃ in a reaction kettle A, keeping the temperature and stirring for 2 hours, keeping the temperature and refluxing for 8 hours, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into a reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, and reacting for 6 hours at the reaction temperature of 30 ℃, wherein the reaction temperature is as follows: aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at an interval of 0.3h, sequentially washing the filtered solid with water, washing with tetrahydrofuran and ethanol, filtering and drying to obtain modified polyamic acid, and reacting in a nitrogen atmosphere;

(3) preparing modified polyimide: immersing the modified polyamic acid into a solution with a mass ratio of 5: 4 triethylamine and pyridine, adding proper amount of acetic anhydride, catalyst: modified polyamic acid: molar ratio of acetic anhydride 0.5: 1:1, heating to 40 ℃, preserving heat, soaking for 18h, washing and drying to obtain the hydrophilic flame-retardant modified polyimide fiber, and reacting in a nitrogen atmosphere.

Example 3:

a preparation method of hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(1) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano-silica and toluene by ultrasonic to obtain a nano-silica suspension, and preparing a pre-hydrolysis solution from a proper amount of gamma-aminopropyltriethoxysilane, deionized water and acetic acid, wherein the nano-silica: toluene: gamma-aminopropyltriethoxysilane: the mass ratio of the deionized water is 1: 150: 1:1, adjusting the pH value of a prehydrolysis solution to 3.5 by using acetic acid, heating a nano silicon dioxide suspension and the prehydrolysis solution to 70 ℃ in a reaction kettle A, keeping the temperature and stirring for 1h, keeping the temperature and refluxing for 8h, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into a reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, and reacting for 4 hours at the reaction temperature of 30 ℃, wherein the reaction temperature is as follows: aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at an interval of 0.2h, sequentially washing the filtered solid with water, washing with tetrahydrofuran and ethanol, filtering and drying to obtain modified polyamic acid, and reacting in a nitrogen atmosphere;

(3) preparing modified polyimide: immersing the modified polyamic acid into a solution with a mass ratio of 5: 4 triethylamine and pyridine, adding proper amount of acetic anhydride, catalyst: modified polyamic acid: molar ratio of acetic anhydride 0.5: 1:1, heating to 30 ℃, preserving heat, soaking for 18h, washing and drying to obtain the hydrophilic flame-retardant modified polyimide fiber, and reacting in a nitrogen atmosphere.

Example 4:

a preparation method of hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(1) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano-silica and toluene by ultrasonic to obtain a nano-silica suspension, and preparing a pre-hydrolysis solution from a proper amount of gamma-aminopropyltriethoxysilane, deionized water and acetic acid, wherein the nano-silica: toluene: gamma-aminopropyltriethoxysilane: the mass ratio of the deionized water is 1: 250: 0.4: 1, adjusting the pH value of a prehydrolysis solution to 4 by using acetic acid, heating a nano silicon dioxide suspension and the prehydrolysis solution to 60 ℃ in a reaction kettle A, keeping the temperature and stirring for 2 hours, keeping the temperature and refluxing for 7 hours, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into a reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, and reacting for 6 hours at the reaction temperature of-10 ℃, wherein the reaction temperature is as follows: aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at an interval of 0.3h, sequentially washing the filtered solid with water, washing with tetrahydrofuran and ethanol, filtering and drying to obtain modified polyamic acid, and reacting in a nitrogen atmosphere;

(3) preparing modified polyimide: immersing the modified polyamic acid into a solution with a mass ratio of 5: 4 triethylamine and pyridine, adding proper amount of acetic anhydride, catalyst: modified polyamic acid: molar ratio of acetic anhydride 0.02: 1:1, heating to 40 ℃, preserving heat, soaking for 14h, washing and drying to obtain the hydrophilic flame-retardant modified polyimide fiber, and reacting in a nitrogen atmosphere.

Example 5:

a preparation method of hydrophilic flame-retardant modified polyimide fiber comprises the following steps:

(2) preparing modified silicon dioxide: uniformly dispersing a proper amount of nano-silica and toluene by ultrasonic to obtain a nano-silica suspension, and preparing a pre-hydrolysis solution from a proper amount of gamma-aminopropyltriethoxysilane, deionized water and acetic acid, wherein the nano-silica: toluene: gamma-aminopropyltriethoxysilane: the mass ratio of the deionized water is 1: 200: 0.5: 1, adjusting the pH value of a prehydrolysis solution to 3.7 by using acetic acid, heating the nano silicon dioxide suspension and the prehydrolysis solution to 65 ℃ in a reaction kettle A, keeping the temperature, stirring for 1.5h, keeping the temperature, refluxing for 7.5h, filtering, washing and drying in vacuum to obtain aminated silicon dioxide;

(2) preparing modified polyamic acid: adding a proper amount of N-methyl pyrrolidone into a reaction kettle B, adding aminated silicon dioxide, uniformly stirring, adding a proper amount of 4,4' -diaminodiphenyl ether and phthalic anhydride, uniformly stirring, and reacting for 5 hours at the reaction temperature of 0 ℃, wherein the reaction temperature is as follows: aminated silica: 4,4' -diaminodiphenyl ether: the mass ratio of the phthalic anhydride is 12: 4: 3: 2, adding the benzenedicarboxylic acid glycoside into the reaction kettle B for three times at an interval of 0.25h, sequentially washing the filtered solid with water, washing with tetrahydrofuran and ethanol, filtering and drying to obtain modified polyamic acid, and reacting in a nitrogen atmosphere;

(3) preparing modified polyimide: immersing the modified polyamic acid into a solution with a mass ratio of 5: 4 triethylamine and pyridine, adding proper amount of acetic anhydride, catalyst: modified polyamic acid: molar ratio of acetic anhydride 0.5: 1:1, heating to 30 ℃, preserving heat, soaking for 16h, washing and drying to obtain the hydrophilic flame-retardant modified polyimide fiber, and reacting in a nitrogen atmosphere.

Content of the experiment

Hydrophilic flame-retardant modified polyimide fibers were prepared according to the compositions and methods of examples 1 to 5, respectively.

(1) Contact Angle testing

In this experiment, a contact angle measuring instrument of JC200C model in Shanghai and Mediterranean morning was used to measure the contact angle of the coating by the pendant drop method. Approximately 3 μ L of liquid was dropped on the hydrophilic flame-retardant modified polyimide fiber using a syringe, the profile of the drop was photographed using a camera with a CCD, and the contact angle was evaluated by a method of measuring an angle, and the contact angle of 5 points was measured, and the average value was taken as the surface contact angle of the hydrophilic flame-retardant modified polyimide fiber.

Table 1:

	example 1	Example 2	Example 3	Example 4	Example 5
						Contact Angle/(°)	57.4	56.1	55.7	57.6	56.7

As can be seen from Table 1, the hydrophilic flame retardant modified polyimide fibers prepared in examples 1 to 5 of the present invention have excellent hydrophilic properties. Can meet the requirements of the industry and has better application prospect.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.