阅读说明：本技术 聚丙烯纤维强化亲油改性方法 (Polypropylene fiber reinforced oleophylic modification method ) 是由 王炳捷 白志山 田涛 杨晓勇 赵生豪 古文全 于 2019-12-10 设计创作，主要内容包括：本发明属于材料改性技术领域,具体涉及聚丙烯纤维强化亲油改性方法,利用分子自组装技术和化学接枝共聚技术,强化聚丙烯纤维的亲油性能。包括以下步骤：1)对原料聚丙烯纤维进行硫酸浸泡处理得到微孔聚丙烯纤维；2)对微孔聚丙烯纤维进行梯度双氧水溶液浸泡处理得到羟基改性聚丙烯纤维；3)基于多巴胺分子自组装得到氨基改性聚丙烯纤维；4)基于化学接枝共聚技术,配合硅烷偶联剂,获得强化亲油改性聚丙烯纤维。本发明通过在聚丙烯纤维表面预留微孔结构和接枝憎水性超支化聚合物,提高界面对有机相的亲和性能和贮存作用,明显改善聚丙烯纤维的亲油特性。(The invention belongs to the technical field of material modification, and particularly relates to a polypropylene fiber reinforced oleophylic modification method, which utilizes a molecular self-assembly technology and a chemical graft copolymerization technology to reinforce the oleophylic property of polypropylene fibers. The method comprises the following steps: 1) carrying out sulfuric acid soaking treatment on the raw material polypropylene fiber to obtain microporous polypropylene fiber; 2) carrying out gradient hydrogen peroxide solution soaking treatment on the microporous polypropylene fibers to obtain hydroxyl modified polypropylene fibers; 3) based on dopamine molecule self-assembly, amino modified polypropylene fiber is obtained; 4) based on a chemical graft copolymerization technology, the reinforced oleophylic modified polypropylene fiber is obtained by matching with a silane coupling agent. The invention improves the affinity performance and the storage function of the interface to an organic phase and obviously improves the oleophylic property of the polypropylene fiber by reserving a microporous structure and grafting a hydrophobic hyperbranched polymer on the surface of the polypropylene fiber.)

1. A polypropylene fiber reinforced lipophilic modification method is characterized by comprising the following steps:

the method comprises the following steps: soaking the polypropylene fiber after the pre-cleaning treatment in sulfuric acid solution to obtain microporous polypropylene fiber;

step two: soaking the microporous polypropylene fiber in a gradient hydrogen peroxide solution to obtain hydroxyl modified polypropylene fiber;

step three: carrying out polydopamine amination treatment on the hydroxyl modified polypropylene fiber to obtain amino modified polypropylene fiber;

step four: and (3) carrying out polymer grafting silanization treatment on the amino modified polypropylene fiber to obtain the reinforced oleophylic modified polypropylene fiber.

2. The polypropylene fiber reinforced lipophilic modification method as claimed in claim 1, wherein the polypropylene fiber pre-cleaning treatment process in the first step is as follows: soaking raw material polypropylene fiber in 40-60% volume fraction acetone solution and 20-30% volume fraction ethanol solution for 1-2 hours, and then transferring the raw material polypropylene fiber into deionized water for ultrasonic cleaning for 10-20 minutes;

the sulfuric acid solution soaking treatment comprises the following steps: soaking the polypropylene fiber after the pre-cleaning treatment in a sulfuric acid solution with the mass fraction of 30-50% for 1-2 hours, repeatedly washing the polypropylene fiber for 2-3 times by using an ethanol solution with the volume fraction of 20-30% and deionized water in sequence, and then placing the polypropylene fiber in a thermostat and drying the polypropylene fiber for 6-12 hours at the temperature of 60-80 ℃.

3. The polypropylene fiber reinforced lipophilic modification method as claimed in claim 1 or 2, wherein the diameter of the polypropylene fiber in the first step is 20-200 μm.

4. The method for lipophilic modification of polypropylene fiber reinforcement according to claim 1, wherein the hydroxylation modification process in the second step is: and (2) sequentially placing the microporous polypropylene fiber obtained in the step one in hydrogen peroxide solution with the mass fraction of 2-5%, 5-10% and 10-20% for stirring reaction at a constant temperature, controlling the temperature to be 95-100 ℃, reacting for 2-3 hours, washing with excessive deionized water for 2-3 times, placing in a constant temperature box, and drying at 40-60 ℃ for 4-6 hours, wherein 500mL of the hydrogen peroxide solution is required for soaking each 100g of the microporous polypropylene fiber.

5. The method for lipophilic modification of polypropylene fiber reinforcement according to claim 1, wherein the amino modification in step three is: and (2) fully stirring the dihydroxylated and modified polypropylene fiber in the step (b) in a Tri-HCl buffer solution, wherein every 100g of hydroxyl modified polypropylene fiber needs 500mL of the Tri-HCl buffer solution for treatment, adding dopamine hydrochloride accounting for 2-5 wt% of the Tri-HCl buffer solution, controlling the stirring speed to be 200-300rpm, reacting for 8-10 hours, washing the hydroxyl modified polypropylene fiber for 2-3 times by using deionized water after the reaction is finished, and drying the hydroxyl modified polypropylene fiber for 3-5 hours in a constant temperature box at the temperature of 30-40 ℃.

6. The method for lipophilic modification of polypropylene fiber reinforcement according to claim 5, wherein the Tri-HCl buffer solution in step three is prepared by: mixing trihydroxymethyl aminomethane and deionized water according to the mass ratio of (1:4.5) - (1:7.5) to be uniform. Adjusting pH of the solution to 7.2-7.6 with concentrated hydrochloric acid, sterilizing at high temperature under high pressure, and storing at room temperature.

7. The method for lipophilic modification of polypropylene fiber reinforcement according to claim 1, wherein the polymer graft-silanization treatment in step four is: adding the amino modified polypropylene fiber obtained in the step three into an acetone solution containing 10-15% of silane coupling agent KH-550 by mass fraction for silanization modification, wherein 500mL of the acetone solution is required for each 100g of the amino modified polypropylene fiber for silanization modification treatment, the modification process is carried out for 4-6 hours at 80-90 ℃ under the constant-temperature stirring of 150-200rpm, and saturated glutaraldehyde n-octanol solution accounting for 1-2% of the mass fraction of the acetone solution is used as a cross-linking agent to realize the silane group graft copolymerization on the surface of the amino modified polypropylene fiber; and then sequentially utilizing 10-20% volume fraction ethanol solution and deionized water to clean the silanized modified polypropylene fiber for 2-3 times, and then placing the silanized modified polypropylene fiber in a thermostat for drying for 10-12 hours at the temperature of 30-40 ℃ to obtain the reinforced oleophylic modified polypropylene fiber.

8. The polypropylene fiber reinforced lipophilic modification method as claimed in claim 7, wherein the saturated glutaraldehyde n-octanol solution is prepared by the following steps: placing 25% mass fraction glutaraldehyde aqueous solution and n-octanol into a separating funnel according to the volume ratio of 1:1 for full shaking and mixing, standing for layering, and taking supernatant to obtain saturated glutaraldehyde n-octanol solution.

Technical Field

The invention relates to polypropylene fiber reinforcement, in particular to a modification method for reinforcing the lipophilic property of polypropylene fiber by utilizing a molecular self-assembly technology and a chemical graft copolymerization technology. Belongs to the technical field of material modification.

Background

In recent years, with the rapid development of processing and manufacturing industries, large-volume, high-toxicity and difficult-to-degrade industrial wastewater has a continuous and serious influence on the ecological environment of China. The oily emulsified wastewater is taken as typical nondegradable industrial wastewater, the pollution of the oily emulsified wastewater is mainly from nondegradable organic pollutants formed by decomposed emulsified oil and an emulsifier, the organic pollutants are mutually combined with water molecules in an emulsified micro-oil drop form in a water body, the stability is extremely high, and the treatment difficulty is extremely high. In a plurality of oil-water separation technologies, the fiber coalescence method based on the hydrophilic and hydrophobic characteristics of the material micro-interface can capture micro-oil drops in a wastewater system through the high hydrophobic (oleophilic) characteristics of the fiber material, and gradually gather and grow on the surface of the fiber, thereby effectively realizing the separation and resource recovery of the micro-oil drops. However, the oleophilic property of the fiber material itself is difficult to meet the high requirements of the current complex system oily wastewater treatment. Therefore, the enhancement of the oleophylic property of the material by using the low-cost material as the matrix and combining with the corresponding modification method becomes a hot spot of current research. The polypropylene fiber has the characteristics of high strength, strong plasticity, corrosion resistance, heat resistance, aging resistance and the like, and has certain oleophylic property, so that the polypropylene fiber becomes an ideal modified matrix material.

Chinese invention patent (CN106012526B) reports a two-step method for enhancing the oleophilic property of polypropylene fiber. The first step of the method adopts strong acid modification and carbonization treatment, so that a large number of micropores are distributed on the surface of the polypropylene fiber, and the specific surface area and the oil storage capacity are increased. In the second step, single-component or multi-component alkyl methacrylate is used as a monomer, an initiator and a swelling agent are matched, and oleophilic groups are introduced on the surface of the fiber, so that the oleophilic adsorption performance of the fiber is improved. However, since the first modification step in this method involves strong acid modification and carbonization, high-temperature and high-pressure equipment such as a batch-type carbonization furnace is required, which is expensive. Meanwhile, the second step of modification in the method relates to a complex chemical modification reaction with participation of various modified monomers and additives, and is not suitable for the requirement of high-efficiency oleophylic modification of polypropylene fibers. In addition, chinese invention patent (CN106823470B) reports a composite coalescent material for water deoiling combined with co-weaving of modified polypropylene fibers and 304 stainless steel wires. The invention takes potassium permanganate and sulfuric acid solution as initiators and combines with ethyl acrylate solution to modify the fiber. However, the method has poor stability in the modification process of the polypropylene fiber, and the modified polypropylene fiber has hydrophilic and oleophobic properties, so that the method is not suitable for the requirement of high-efficiency oleophylic modification of the polypropylene fiber.

Graft copolymerization is a chemical modification method of polymers, and the principle is that a side chain with characteristic groups is introduced into a macromolecular chain of a base material based on chemical bonds, so that the functional modification of the macromolecular chain is realized. Two polymers with different properties can be assembled together by graft copolymerization, and the physicochemical characteristics of the material are obviously improved.

The chemical grafting method is a surface grafting process for introducing a specific functional group to a grafted monomer or a macromolecular chain through a chemical bond by utilizing a reactive group on the surface of a material. Wherein, the coupling grafting refers to the grafting reaction process of the grafting group and the grafted group realized by means of the coupling characteristic of a specific substance. The coupling grafting modification has the advantages of simple process, low requirements on equipment and environment, stable modification performance, no pollution and the like, and becomes a practical and effective method for improving material performance and expanding the application field. Dopamine has excellent biocompatibility, a stable and compact attachment layer can be formed on the surfaces of various materials through molecular self-assembly of dopamine, and secondary modification can be realized by combining a coupling agent based on active free radicals such as amino, hydroxyl and the like which are rich in the dopamine, so that the physicochemical properties of the original materials are changed or improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a polypropylene fiber reinforced oleophylic modification method with excellent and reliable performance and simple and flexible process.

In order to solve the problems, the invention adopts the following technical scheme.

A polypropylene fiber reinforced lipophilic modification method is characterized by comprising the following steps:

the method comprises the following steps: soaking the polypropylene fiber after the pre-cleaning treatment in sulfuric acid solution to obtain microporous polypropylene fiber;

step two: soaking the microporous polypropylene fiber in a gradient hydrogen peroxide solution to obtain hydroxyl modified polypropylene fiber;

step three: carrying out polydopamine amination treatment on the hydroxyl modified polypropylene fiber to obtain amino modified polypropylene fiber;

step four: and (3) carrying out polymer grafting silanization treatment on the amino modified polypropylene fiber to obtain the reinforced oleophylic modified polypropylene fiber.

The diameter of the polypropylene fiber in the first step is 20-200 μm.

The polypropylene fiber pre-cleaning treatment process in the first step comprises the following steps: soaking raw material polypropylene fiber in 40-60% volume fraction acetone solution and 20-30% volume fraction ethanol solution for 1-2 hours, and then transferring the raw material polypropylene fiber into deionized water for ultrasonic cleaning for 10-20 minutes;

the sulfuric acid solution soaking treatment in the first step comprises the following steps: soaking the polypropylene fiber after the pre-cleaning treatment in a sulfuric acid solution with the mass fraction of 30-50% for 1-2 hours, repeatedly washing the polypropylene fiber for 2-3 times by using an ethanol solution with the volume fraction of 20-30% and deionized water in sequence, and then placing the polypropylene fiber in a thermostat and drying the polypropylene fiber for 6-12 hours at the temperature of 60-80 ℃.

The hydroxylation modification process in the second step is as follows: and (2) sequentially placing the microporous polypropylene fiber obtained in the step one in hydrogen peroxide solution with the mass fraction of 2-5%, 5-10% and 10-20% for stirring reaction at a constant temperature, controlling the temperature to be 95-100 ℃, reacting for 2-3 hours, washing with excessive deionized water for 2-3 times, placing in a constant temperature box, and drying at 40-60 ℃ for 4-6 hours, wherein 500mL of the hydrogen peroxide solution is required for soaking each 100g of the microporous polypropylene fiber.

The amino modification in the third step is as follows: and (2) fully stirring the dihydroxylated and modified polypropylene fiber in the step (2) in a Tri-HCl buffer solution, wherein every 100g of hydroxyl modified polypropylene fiber needs 500mL of the Tri-HCl buffer solution for treatment, adding dopamine hydrochloride accounting for 2-5 wt% of the Tri-HCl buffer solution, controlling the stirring speed to be 200-300rpm, reacting for 8-10 hours, washing the hydroxyl modified polypropylene fiber for 2-3 times by using deionized water after the reaction is finished, and drying the hydroxyl modified polypropylene fiber for 3-5 hours in a constant temperature box at the temperature of 30-40 ℃ to obtain the amino modified polypropylene fiber.

The preparation process of the Tri-HCl buffer solution in the third step comprises the following steps: mixing trihydroxymethyl aminomethane and deionized water according to the mass ratio of (1:4.5) - (1:7.5) to be uniform. Adjusting pH of the solution to 7.2-7.6 with concentrated hydrochloric acid, sterilizing at high temperature under high pressure, and storing at room temperature.

The polymer graft silanization treatment in the step four is as follows: adding the amino modified polypropylene fiber obtained in the step three into an acetone solution containing 10-15% of silane coupling agent KH-550 by mass fraction for silanization modification, wherein 500mL of the acetone solution is required for each 100g of the amino modified polypropylene fiber for silanization modification treatment, the modification process is carried out for 4-6 hours at 80-90 ℃ under the constant-temperature stirring of 150-200rpm, and saturated glutaraldehyde n-octanol solution accounting for 1-2% of the mass fraction of the acetone solution is used as a cross-linking agent to realize the silane group graft copolymerization on the surface of the amino modified polypropylene fiber; and then sequentially utilizing 10-20% volume fraction ethanol solution and deionized water to clean the silanized modified polypropylene fiber for 2-3 times, and then placing the silanized modified polypropylene fiber in a thermostat for drying for 10-12 hours at the temperature of 30-40 ℃ to obtain the reinforced oleophylic modified polypropylene fiber.

The preparation process of the saturated glutaraldehyde n-octanol solution is as follows: placing 25% mass fraction glutaraldehyde aqueous solution and n-octanol into a separating funnel according to the volume ratio of 1:1 for fully shaking and mixing. And (4) standing for layering, and taking supernatant to obtain saturated glutaraldehyde n-octanol solution.

Principle of the invention

Firstly, the surface of the polypropylene fiber is subjected to micropore treatment by sulfuric acid solution, so that the specific surface area of the fiber is improved while the micropore oil storage characteristic of the fiber is given, and a good surface foundation is provided for the adhesion of a subsequent modified layer. And secondly, activating the hydroxyl on the surface of the fiber by using a hydrogen peroxide solution with a concentration gradient, so as to improve the stability of a subsequent polydopamine modified layer. Then, the self-assembly of dopamine molecules under acidic conditions is utilized to impart a uniform and large number of hydrophobic silane-based grafting sites to the fiber surface. And finally, by using a chemical graft copolymerization technology and using glutaraldehyde molecules as a cross-linking agent, coupling amino groups from dopamine molecules and silane groups of a silane coupling agent KH-550 to realize the enhanced oleophylic modification of the polypropylene fibers.

Advantageous effects

Compared with the prior art, the polypropylene fiber reinforced oleophylic modification method has the characteristics of simple and flexible process, low material cost, no toxicity, stable and reliable reinforced oleophylic performance, low requirement on experimental equipment and the like. The storage characteristic of the micro-oil drop fiber surface is realized by endowing the fiber microporous structure, and meanwhile, the stable grafting of the hydrophobic hyperbranched polymer on the polypropylene fiber surface is realized by utilizing the molecular self-assembly and chemical graft copolymerization technology, so that the interface energy of the fiber surface to an oil phase is reduced, and the oleophylic characteristic of the polypropylene fiber is improved. The composite fiber is woven into a fiber net or fiber cloth in combination with a post-treatment process, is suitable for treating various complex oil-water mixed liquids, and has wide application prospect.

Drawings

FIG. 1 is a process flow chart of a polypropylene fiber reinforced lipophilic modification method.

FIG. 2 shows the mechanism of lipophilic modification reinforced by polypropylene fibers.

Fig. 3 is a graph showing the spreading behavior of micro-oil droplets on the surface of modified polypropylene fibers in an aqueous phase.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

In figure 2, dopamine molecules are self-polymerized into long chain-shaped polydopamine molecules under acidic conditions. In the subsequent silanization modification process, aldehyde groups at two ends of a glutaraldehyde molecule are respectively combined with free amino groups in a polydopamine molecule and free silane groups of a silane coupling agent KH-550 by participating in Schiff base reaction, so that the graft copolymerization of hydrophobic silane groups on the surface of the polypropylene fiber is realized, and the oleophylic property of the polypropylene fiber is enhanced.

As shown in the attached figure 3, the collision process of the micro-oil drops and the modified polypropylene fibers from bottom to top is observed by means of a high-speed camera, and the observation result proves that the micro-oil drops finally realize the complete spreading of the modified polypropylene fibers under the action of interfacial tension.