CN116356567A - A kind of preparation method of hydrophobic fabric, hydrophobic fabric and application - Google Patents

Abstract

The invention provides a method for preparing a hydrophobic fabric, the hydrophobic fabric and its application in oil-water separation, belonging to the modification technology of the hydrophobic coating. In the present invention, the hydroxyl, carboxyl, and methoxy groups of alkali lignin react with metal ions, and then form hydrogen bonds with the hydroxyl groups on the fabric to increase the roughness of the fabric surface and modify the surface to obtain a hydrophobic fabric. It is beneficial to provide a utilization path of alkali lignin, and at the same time, the hydrophobic fabric prepared by modification has oil-water separation performance, which can solve the environmental pollution problem caused by oil spills to a certain extent, which is of great significance.

Description

A kind of preparation method of hydrophobic fabric, hydrophobic fabric and application

technical field

The invention relates to a modification technology of a hydrophobic coating, in particular to a preparation method of a hydrophobic fabric, a hydrophobic fabric prepared by the preparation method and an application of the hydrophobic fabric in oil-water separation, wherein the fabric is preferably a waste fabric.

Background technique

In recent years, frequent oil spills and discharge of industrial organic pollutants have caused long-term damage to the ecological environment and human safety. It remains a challenge to develop low-cost, stable, and reusable materials for efficient oil/water separation. Since ancient times, the lotus leaf's "out of mud but not stained, clean ripples without demon" has been widely praised by the world. Researchers have found that "out of mud but not stained" is due to the rough microscopic morphology and hydrophobic epidermal wax on the surface of lotus leaves. , so that the lotus leaf has a unique wettability. Studies have found that the preparation of hydrophobic surfaces is mainly based on the construction of surface roughness and the reduction of surface energy. Generally, it can be measured by water contact angle (WCA), and WCA > 90° is hydrophobic.

Lignin is a natural polymer substance with a phenolic structure. It is widely found in woody plants, herbaceous plants, and vascular plants. It is the second largest natural polymer material in nature after cellulose in quantity. It is environmentally friendly. , pollution-free, renewable and other characteristics. Lignin undergoes a certain amount of alkaline hydrolysis in an alkaline environment to increase its solubility, and is extracted, separated by precipitation, and the obtained lignin is called alkali lignin. Alkali lignin contains functional functional groups such as hydroxyl, carboxyl, carbonyl and methoxy, and the existence of these functional groups provides the possibility for the modification of lignin.

Contents of the invention

In view of this, in order to realize the high-value utilization of alkali lignin and the application of oil-water separation of hydrophobic fabrics, on the one hand, the present invention provides a method for preparing hydrophobic fabrics, which uses the hydroxyl, carboxyl, formazan of alkali lignin Oxygen and other groups react with metal ions, and then form hydrogen bonds with the hydroxyl groups on the fabric, increasing the roughness of the fabric surface, and surface modification to obtain a hydrophobic fabric, which is conducive to providing the utilization of alkali lignin. At the same time, the modified The prepared hydrophobic fabric has oil-water separation performance and can solve the environmental pollution problem caused by oil spills to a certain extent, which is of great significance.

Without achieving the above object, the present invention provides the following technical solutions:

A method for preparing a hydrophobic fabric, using the groups contained in the alkali lignin to react with metal ions, and then form hydrogen bonds with the hydroxyl groups on the fabric to increase the surface roughness of the fabric and modify the surface to obtain a hydrophobic fabric.

Preferably, said groups include hydroxyl, carboxyl and methoxy.

Preferably, it specifically includes the following steps:

1) uniformly mixing the alkali lignin aqueous solution and the metal ion aqueous solution to obtain a co-solution system of the two;

2) placing the fabric in the co-solvent system in step 1), followed by impregnation, removal, and drying to obtain a hydrophobic fabric;

The fabric is preferably a pretreated fabric, and the pretreatment steps are as follows:

The fabric is washed with deionized water, ethanol and deionized water in sequence, and dried.

Preferably, the metal ion is one of Fe ²⁺ and Fe ³⁺ .

Preferably, Fe ²⁺ is from ferrous sulfate heptahydrate and Fe ³⁺ is from ferric chloride.

Preferably, the mass concentration of the alkali lignin is 2g/L; the mass concentration of the ferrous sulfate heptahydrate and the ferric chloride solution are both 3g/L.

Preferably, in step 2), the dipping temperature is 50°C, the time is 24h, and the fabric is turned over every 4h;

In step 2), the drying temperature is 50°C.

Preferably, the fabric is one of 100% pure cotton, polyester-cotton a and polyester-cotton b;

The polyester-cotton a is 35% cotton+65% polyester fiber, and the polyester-cotton b is 20% cotton+80% polyester fiber.

In another aspect, the present invention provides a hydrophobic fabric, which is prepared by the method for preparing the hydrophobic fabric.

In another aspect, the present invention also provides the application of the above-mentioned hydrophobic fabric in oil-water separation.

Compared with the prior art, the present invention has the following beneficial effects:

1) The preparation method of the hydrophobic fabric provided by the present invention, it reacts with metal ions by utilizing groups such as the hydroxyl group of alkali lignin, carboxyl group, methoxyl group and metal ion, then forms hydrogen bond connection with the hydroxyl group on the fabric, increases the roughness of fabric surface surface modification to obtain hydrophobic fabrics, which is beneficial to provide the utilization of alkali lignin. At the same time, the modified hydrophobic fabrics have oil-water separation properties, which can solve the environmental pollution problems caused by oil spills to a certain extent. Significance.

2) The present invention reacts alkali lignin with metal ions to obtain a hydrophobic coating that is environmentally friendly and applicable to various substrates, and the coating is modified on the surface of different waste fabrics to obtain durable hydrophobic coatings. The fabric realizes self-cleaning and oil-water separation of the fabric, and the invention does not use any fluorine-containing substances, long-chain silanes and organic solutions. At the same time, it provides a theoretical and practical basis for improving the added value of alkali lignin.

Description of drawings

Fig. 1 is the water contact angle of the hydrophobic fabric prepared by reacting alkali lignin with FeⅡ(Fe ²⁺ ), FeⅢ(Fe ³⁺ ), CuⅡ(Cu ²⁺ ) ions respectively with pure cotton as the base in ^Example 1;

Fig. 2 is in embodiment 2 with polyester cotton a as base, the water contact angle of the hydrophobic fabric that alkali lignin and FeII (Fe ²⁺ ) ion reaction makes;

Fig. 3 is the water contact angle of the hydrophobic fabric prepared by the reaction of alkali lignin and FeⅢ(Fe ³⁺ ) ions with polyester cotton b as the base;

Fig. 4 is a friction experiment device;

Fig. 5 is the relationship between the friction times and water contact angle of AL/FeⅢ@cotton fabric in Example 1;

Fig. 6 is oil-water separation experiment;

Fig. 7 is the oil-water separation efficiency of AL/FeⅢ@ polyester cotton b in embodiment 2;

Among them, the original in Fig. 1-3 refers to the pure cotton fabric.

Detailed ways

The invention provides a method for preparing a hydrophobic fabric, which uses the groups contained in the alkali lignin to react with metal ions, and then forms hydrogen bonds with the hydroxyl groups on the fabric to increase the roughness of the fabric surface and modify the surface to obtain a hydrophobic fabric. .

In the present invention, the fabric is preferably waste fabric.

Alkali lignin contains functional functional groups such as hydroxyl, carboxyl, carbonyl and methoxy, and the existence of these functional groups provides the possibility for the modification of lignin. In the present invention, the groups include hydroxyl, carboxyl and methoxy base.

In the present invention, specifically include the following steps:

1) uniformly mixing the alkali lignin aqueous solution and the metal ion aqueous solution to obtain a co-solution system of the two;

2) placing the fabric in the co-solvent system in step 1), followed by impregnation, removal, and drying to obtain a hydrophobic fabric;

The fabric is preferably a pretreated fabric, and the pretreatment steps are as follows:

The fabric is washed with deionized water, ethanol and deionized water in sequence, and dried.

In the present invention, the metal ion is at least one of Fe ²⁺ and Fe ³⁺ , Cu ²⁺ can also be selected.

In the present invention, Fe ²⁺ comes from ferrous sulfate heptahydrate, Fe ³⁺ comes from ferric chloride, and Cu ²⁺ comes from copper sulfate.

In the present invention, the mass concentration of the alkali lignin is 2g/L; the mass concentration of the ferrous sulfate heptahydrate and the ferric chloride aqueous solution are both 3g/L, if Cu ²⁺ is selected, the copper sulfate aqueous solution The mass concentration is 3g/L.

In the present invention, in step 2), the dipping temperature is 50° C., the time is 24 hours, and the fabric is turned over every 4 hours;

In step 2), the drying temperature is 50°C.

In the present invention, the fabric is one of 100% pure cotton, polyester-cotton a and polyester-cotton b;

The polyester-cotton a is 35% cotton+65% polyester fiber, and the polyester-cotton b is 20% cotton+80% polyester fiber.

In another aspect, the present invention provides a hydrophobic fabric, which is prepared by the method for preparing the hydrophobic fabric.

In another aspect, the present invention also provides the application of the above-mentioned hydrophobic fabric in oil-water separation.

The technical solution of the present invention will be described clearly and in detail below in combination with specific embodiments.

Example 1

(1) Wash the pure cotton fabric with deionized water for 2 minutes, then soak it in absolute ethanol, and then continue to rinse it with deionized water to remove dust and other impurities on the surface of the fabric. After taking it out, dry it at 50°C for later use ;

(2) get 0.30g alkali lignin and be dissolved in 100ml deionized water, obtain alkali lignin aqueous solution; Get 0.45g ferrous sulfate heptahydrate and ferric chloride, copper sulfate respectively and dissolve in 50ml deionized water, obtain FeII ( Fe ²⁺ ) aqueous solution, FeIII (Fe ³⁺ ) aqueous solution and CuII (Cu ²⁺ ) aqueous solution. Then, the alkali lignin aqueous solution is uniformly mixed with the above-mentioned metal ion solution respectively, and the volume is constant to obtain a co-solution system of the two;

(3) Put the pure cotton fabrics pretreated in (1) into the alkali lignin aqueous solution prepared in (2) respectively with FeII (Fe ²⁺ ) aqueous solution, FeIII (Fe ³⁺ ) aqueous solution and CuII (Cu ^{2 +} ) In the eutectic system formed by the aqueous solution, immerse at 50°C for 24 hours, and turn the fabric over every 4 hours to ensure uniform deposition, and take it out;

(4) Place the fabric treated in step (3) in a constant temperature oven and dry at 50°C for 4 hours to obtain AL/FeⅡ@cotton fabric, AL/FeⅢ@cotton fabric and AL/CuⅡ@cotton fabric, respectively.

(5) Use an optical contact angle measuring instrument (OCA50) to test the water contact angle (WCA) on the surface of the modified fabric, control the syringe to drop 8 μL of water on the surface of the test sample, take pictures of the droplets, and measure their corresponding contact angles. The average value of the tests is taken as the test result, and the results are shown in Figure 1.

It can be seen from Figure 1 that the contact angles of pure cotton fabrics increased after alkali lignin and FeII (Fe ²⁺ ), FeIII (Fe ³⁺ ) and CuII (Cu ²⁺ ). The unmodified pure cotton fabric is super-hydrophilic, with an initial contact angle of 75.6° and water droplets are absorbed after 6s. The modified pure cotton fabrics are all hydrophobic, and the initial contact angle of AL/FeⅢ@cotton fabric can reach 131.9°, and the water droplets stay for 30 minutes without being absorbed, which has good hydrophobic stability. AL/FeⅡ@cotton fabric also has higher contact angle and better hydrophobic stability. Therefore, AL/FeⅢ and AL/FeⅡ coatings have good hydrophobicity and stability, and can be used for oil-water separation.

Example 2

(1) Wash polyester cotton a and polyester cotton b with deionized water for 2 minutes, then soak in absolute ethanol, and then continue to rinse with deionized water to remove dust and other impurities on the surface of the fabric. After taking them out, dry them at 50°C Dry down for later use;

(2) Get 0.30g alkali lignin and dissolve it in 100ml deionized water to obtain an alkali lignin aqueous solution; respectively get 0.45g ferrous sulfate heptahydrate and ferric chloride and dissolve it in 50ml deionized water to obtain FeII (Fe ²⁺ ) aqueous solution and FeIII (Fe ³⁺ ) aqueous solution. Then, the alkali lignin aqueous solution is uniformly mixed with the FeII (Fe ²⁺ ) aqueous solution and the FeIII (Fe ³⁺ ) aqueous solution respectively, and constant volume is obtained to obtain a co-solution system of the two respectively;

(3) Place the pretreated polyester cotton a and polyester cotton b in (1) respectively in the alkali lignin aqueous solution prepared in (2) and FeII (Fe ²⁺ ) aqueous solution and FeIII (Fe ³⁺ ) aqueous solution to form In the co-solvent system of 50°C for 24 hours, the fabric was turned over every 4 hours to ensure uniform deposition, and then taken out.

(4) Place the fabric treated in step (3) in a constant temperature oven and dry at 50°C for 4 hours to obtain AL/FeⅢ@polyester-cotton a, AL/FeⅢ@polyester-cotton b, AL/FeⅡ@polyester-cotton b and AL /FeⅡ@polyester cotton a.

Use an optical contact angle measuring instrument (OCA50) to test the water contact angle (WCA) on the surface of the modified fabric, control the syringe to drop 8 μL of water on the surface of the test sample, take pictures of the droplets, and measure their corresponding contact angles. The average value is used as the test result, as shown in Figure 2-3.

It can be seen from Figure 2-3 that alkali lignin/FeII and alkali lignin/FeIII hydrophobic coatings can improve the hydrophobicity of different substrates. After the surface modification of cotton fabric, polyester-cotton a, and polyester-cotton b by alkali lignin/FeⅢ hydrophobic coating, compared with the unmodified fabric, the initial contact angle increased, and the contact angle of AL/FeⅢ@polyester-cotton a reached 126.6°. Moreover, the water droplets stay on the three kinds of fabrics for more than 30 minutes, which has good hydrophobic stability and can separate oil and water. Therefore, the hydrophobic coating can be used to improve the hydrophobicity of different waste fabrics.

In the above-mentioned Examples 1-2 of the present invention, AL is alkali lignin.

Friction resistance test

(1) Place the AL/FeⅢ@cotton fabric and AL/FeⅡ@cotton fabric prepared in Example 1 on a smooth plane.

(2) Place a 100-gram weight on the AL/FeⅢ@cotton fabric and AL/FeⅡ@cotton fabric, and use the weight to pull the cotton fabric to move on the table, making it rub repeatedly.

(3) Each sliding 40cm is set as a cycle, respectively to measure the static contact angle between cotton fabric and water after 0, 50, 100, 150, 200, 250, and 300 continuous cycles. According to the test results of the contact angle, Judge the stability of the fabric. Figure 3

(4) Use an optical contact angle measuring instrument (OCA50) to test the water contact angle (WCA) on the surface of the modified fabric, control the syringe to drop 8 μL of water on the surface of the test sample, take pictures of the droplets, and measure their corresponding contact angles. The average value of the tests was taken as the test result. The results are shown in Figure 4-5.

As shown in Figure 4-5, the left is the friction resistance test process. A 100g weight is used to drive the modified fabric to rub 40cm on the table for one friction. It can be seen from Figure 5 that the contact angle of AL/FeⅢ@cotton fabric increases with the number of frictions increases first and then decreases. Because the fabric fiber breaks at the initial stage of friction, the fine fibers are exposed on the surface, increasing the surface roughness, and the contact angle value increases; further rubbing the exposed fine fibers is worn away from the fabric, and the contact angle decreases. When rubbing 200 times, the maximum contact angle is 137.6°, and the contact angle is still 126° after rubbing 500 times. The contact angle of AL/FeⅡ@cotton fabric decreased gradually with the increase of rubbing times, but it still had 138.4° after 500 rubbing times. Therefore, the fabric has good friction resistance and still has good hydrophobicity after rubbing 500 times.

Oil-Water Separation Experiment

As shown in Figures 6-7, (1) Preparation of oil-water mixture: In the oil-water separation experiment, 30ml of deionized water and 30ml of oil dyed with Oil Red O were mixed in equal volume. In this experiment, toluene, carbon tetrachloride, methylene chloride, chloroform, n-hexane, and petroleum ether were selected as experimental oils for hydrophobic fabrics.

(2) Oil-water separation: In order to remove chloroform, dichloromethane, and carbon tetrachloride, which are denser than water, gravity is used as the driving force to carry out oil-water separation. Pour the oil-water mixture onto the fabric for oil-water separation; in order to remove toluene, n-hexane, and petroleum ether which are less dense than water, use a peristaltic pump for oil-water separation.

(3) calculate its separation efficiency, the calculation formula of separation efficiency η is as shown in (1) below. Repeat the above operation 30 times to test the reusability of the fabricated fabric.

M ₀ : water quality before separation;

M ₁ : mass of water after separation.

The modified AL/FeⅢ@cotton fabric and AL/FeⅡ@cotton fabric can be separated from oil and water (as shown in Figure 6). For staining, deionized water was used for staining with blue dye. As shown in Figure 7, the red oil and blue deionized water are separated by the peristaltic pump and gravity, and the oil-water separation efficiency of AL/FeⅢ@cotton fabric and AL/FeⅡ@cotton fabric is above 95%. The separation efficiency of AL/FeⅢ@cotton fabric for n-hexane can reach 99%. Therefore, the hydrophobic light oil fabric obtained by the modification method can be used for oil-water separation.

The above are only preferred embodiments of the present invention; however, the protection scope of the present invention is not limited thereto. Anyone familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention and its improved concept to make equivalent replacements or changes shall fall within the scope of protection of the present invention.

Claims (10)

1. a preparation method of hydrophobic fabric, it is characterized in that, utilize the group contained in the alkali lignin to react with metal ion, form hydrogen bond connection with the hydroxyl on fabric then, increase the roughness of fabric surface, surface modification obtains Hydrophobic fabric. 2. the preparation method of a kind of hydrophobic fabric according to claim 1, is characterized in that, described group comprises hydroxyl, carboxyl and methoxy. 3. the preparation method of a kind of hydrophobic fabric according to claim 1, is characterized in that, specifically comprises the steps: 1) uniformly mixing the alkali lignin aqueous solution and the metal ion aqueous solution to obtain a co-solution system of the two; 2) placing the fabric in the co-solvent system in step 1), followed by impregnation, removal, and drying to obtain a hydrophobic fabric; The fabric is preferably a pretreated fabric, and the pretreatment steps are as follows: The fabric is washed with deionized water, ethanol and deionized water in sequence, and dried. 4. the preparation method of a kind of hydrophobic fabric according to claim 1, is characterized in that, metal ion is a kind of in Fe ²⁺ and Fe ³⁺ . 5. the preparation method of a kind of hydrophobic fabric according to claim 4 is characterized in that, Fe ²⁺ comes from ferrous sulfate heptahydrate, Fe ³⁺ comes from ferric chloride. 6. the preparation method of a kind of hydrophobic fabric according to claim 5 is characterized in that, the mass concentration of described alkali lignin is 2g/L; Described ferrous sulfate heptahydrate and described ferric chloride solution mass concentration Both are 3g/L. 7. The preparation method of a kind of hydrophobic fabric according to claim 3, characterized in that, in step 2), the dipping temperature is 50°C, the time is 24h, and the fabric is turned over every 4h; In step 2), the drying temperature is 50°C. 8. according to the preparation method of a kind of hydrophobic fabric described in any one in claim 1-7, it is characterized in that, described fabric is a kind of in 100% pure cotton, polyester-cotton a and polyester-cotton b; The polyester-cotton a is 35% cotton+65% polyester fiber, and the polyester-cotton b is 20% cotton+80% polyester fiber. 9. A hydrophobic fabric, characterized in that it is prepared by the method for preparing a hydrophobic fabric according to any one of claims 1-8. 10. The application of the hydrophobic fabric according to claim 9 in oil-water separation.

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