A method for preparing a hydrophobic organic gel and an assembly composite thereof

Abstract

The application discloses a kind of hydrophobic organic gel and preparation method of its assembly composite, comprising: (1) monomer alkyl acrylate, crosslinking agent ethylene glycol acrylate and photo initiator are mixed, under the action of ultrasonic, mixed uniformly;(2) mixed solution is transferred to glass mould, is initiated polymerization under ultraviolet lamp, and hydrophobic organic gel is prepared;(3) organic gel is mixed with nonpolar solvent, mixed uniformly under magnetic stirring;(4) two-dimensional substrate or three-dimensional substrate cleaned is soaked in the mixed solution prepared above, and simple impregnation drying is carried out, thus obtaining multifunctional adsorbent with excellent hydrophobicity.The method uses photo-initiated polymerization, impregnation method is used to prepare hydrophobic organic gel assembly composite, with simple process easy to operate, controllable reaction condition, raw material source is extensive, low cost easy to degrade, excellent mechanical property, acid, alkali and salt resistance, durable and stable hydrophobicity, which can be applied in various occasions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrophobic organic gel and its assembled composite, and particularly relates to a preparation method of a hydrophobic organic gel and its assembled composite. BACKGROUND

[0002] Frequent offshore oil spill accidents and a large amount of oily wastewater generated in industry and life have caused serious resource waste and posed a major threat to the ecological system and human society. How to quickly and efficiently separate oil-water mixtures has become a difficult problem to be solved by the industry and academia. Compared with other separation technologies, adsorbents with special wettability are considered to be an ideal choice for efficient treatment of oily wastewater due to their simple and efficient characteristics. Existing separation materials mainly focus on the synergistic modification of the morphology and chemistry of ready-made substrates, such as the addition of fluorine-containing reagents and high-cost materials, which usually involves a complex multi-step manufacturing process and environmental pollution. Therefore, there is an urgent need to develop efficient new adsorbent materials using simple and environmentally friendly processes.

[0003] Organic gel is a kind of hydrophobic material composed of a three-dimensional (3D) polymer network infiltrated by a non-polar organic solvent, which can fix and adsorb a large amount of organic liquid or oil through a three-dimensional grid structure, and can realize the customization of various functions through molecular design and structure adjustment. Therefore, organic gel can be used as a novel potential adsorbent material to cope with the increasingly serious problem of oily wastewater pollution. However, existing gel adsorbents are unsatisfactory in terms of the type and speed of oil adsorption due to their inherent properties, and the recovery of adsorbed oil often requires additional energy input and special recovery devices. In addition, their preparation usually requires the use of toxic organic solvents, high temperatures, and toxic organic gel agents. There is also a lack of research on the expansion of organic gels with stable water-repellent ability, such as assembly with existing two-dimensional / three-dimensional substrate materials, which not only expands the application range of gels, but also is an important extension in hydrophobic modification and assembly. In view of the key problems of organic gel preparation, such as pollution, difficulty in recovering oil after adsorption, and lack of expansion research, the present application proposes to use alkyl acrylate as a monomer, ethylene glycol acrylate as a crosslinking agent, and ultraviolet light to initiate polymerization, successfully preparing a new type of hydrophobic gel adsorbent. Further assembly of organic gel with two-dimensional / three-dimensional substrate materials successfully constructs a multifunctional adsorbent with excellent hydrophobicity. The constructed organic gel and multifunctional adsorbent have good oil-water selectivity, excellent mechanical properties, and chemical stability, and have great practical application potential in the field of oil-water separation. More importantly, the proposed expansion assembly method is efficient and easy to operate, and is suitable for various two-dimensional / three-dimensional substrate materials, which provides key support for the construction of strong anti-icing coatings and anti-biofouling interfaces in the near future. SUMMARY

[0004] The application aims to provide a preparation method of a hydrophobic organic gel and an assembled composite thereof, and to solve the problems of difficult recycling, environmental harm, complicated operation and poor stability in the preparation of the organic gel by using photopolymerization and dip method to prepare the hydrophobic organic gel and the assembled composite thereof.

[0005] The technical scheme of the application is:

[0006] A preparation method of a hydrophobic organic gel and an assembled composite thereof, and the specific steps are as follows:

[0007] (1) Mix monomer alkyl acrylate, crosslinking agent ethylene glycol acrylate and photoinitiator, mix uniformly under the action of ultrasonic, and stand by;

[0008] (2) Transfer the mixed solution in step (1) to a mold, and perform photopolymerization under a UV lamp to prepare the hydrophobic organic gel;

[0009] (3) Mix the organic gel prepared in step (2) with a non-polar solvent, mix uniformly under magnetic stirring to obtain a mixed solution;

[0010] (4) Soak the cleaned two-dimensional substrate or three-dimensional substrate in the mixed solution in step (3), and perform simple dip drying to obtain a multifunctional adsorbent with excellent hydrophobicity.

[0011] Further, the monomer alkyl acrylate includes octadecyl methacrylate, dodecyl acrylate, tetradecyl acrylate and other alkyl esters; the crosslinking agent ethylene glycol acrylate includes polyethylene glycol diacrylate and ethylene glycol dimethacrylate; and the photoinitiator includes benzophenone, I2959 and I1173.

[0012] Further, step (1) specifically mixes one part of alkyl acrylate, 0.2-10 mol% of photoinitiator based on the molar fraction of monomer alkyl acrylate and a certain amount of ethylene glycol acrylate, mixes uniformly under the action of ultrasonic, and obtains a mixed solution.

[0013] Further, the molar fraction of ethylene glycol acrylate based on the monomer alkyl acrylate is 0.1-10 mol%.

[0014] Further, in step (2), the power of the UV lamp is 5-20 W, and the polymerization time is 30-180 min.

[0015] Further, in step (3), the non-polar solvent includes n-heptane and n-hexane, and the volume of the non-polar solvent is 5-100 mL.

[0016] Further, the concentration of the organic gel in the mixed solution obtained in step (3) is 1-9 mg / mL.

[0017] Further, the soaking time in step (4) is 1 min, and the drying temperature is 80 DEG C.

[0018] Further, the two-dimensional substrate in step (4) includes non-woven fabric, cotton fabric, metal mesh, etc., and the three-dimensional substrate includes melamine sponge and polyurethane sponge.

[0019] The present application has the following advantages:

[0020] (1) A new type of hydrophobic gel adsorbent is prepared by using ultraviolet light polymerization, the preparation process is simple, the operation is convenient, no toxic reagent is needed, the prepared organic gel has good water resistance and recyclability, and the problems of complex preparation process, long time consumption, environmental hazards and poor stability in many traditional methods are solved.

[0021] (2) The long-chain alkane monomer selected can endow the gel with good hydrophobicity, the presence of long-chain alkane is conducive to capturing small oil droplets, and the assembly with the substrate can also reduce the surface energy of the composite material and endow the composite material with good hydrophobicity. The high molecular crosslinking agent endows the gel with excellent flexibility, which is more conducive to the combination with the substrate and can quickly gel under the action of the photoinitiator.

[0022] (3) The organic gel is assembled with two-dimensional / three-dimensional substrate materials by a simple dipping method, so that the wettability of the substrate material is changed from hydrophilic to hydrophobic. The mechanism of inducing the change of wettability is that the surface roughness and low surface energy are the key factors to determine the hydrophobicity of the material. The deposition of organic gel clusters makes the skeleton surface of the substrate rough, and the long-chain alkyl of the organic gel greatly reduces the surface energy, so that the substrate surface has good hydrophobicity. This simple and efficient green gel modification is an important member of the hydrophobic modification method, and has a certain universality for substrates of different dimensions.

[0023] (4) The assembled composite material shows good physical and chemical stability, excellent mechanical properties, and stable binding force. The stability and corrosion resistance of the composite material are tested, the contact angle of the prepared hydrophobic sponge remains stable after ultrasonic treatment for 12 hours and continuous mechanical extrusion for 1000 times. The hydrophobic sponge is also soaked in strong acid, strong base and high salt solution, and the contact angle only decreases slightly after soaking for 24 hours, which has excellent acid and alkali resistance and stability. The non-woven fabric and commercial sponge are low in price, easy to modify, and have good physical and chemical properties, which solves the problems of high raw material cost, difficult modification and serious environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative labor.

[0025] Figure 1 Optical photo and water contact angle of the organic gel prepared for the embodiment 1 of the present application;

[0026] Figure 2 Changes of the mass and water contact angle of the organic gel prepared for the embodiment 1 of the present application after being soaked in water for 30 days;

[0027] Figure 3 SEM photo of the three-dimensional composite material prepared for the embodiment 1 of the present application;

[0028] Figure 4 SEM photo of the two-dimensional composite material prepared for the embodiment 1 of the present application;

[0029] Figure 5 Optical photo of the three-dimensional composite material prepared for the embodiment 1 of the present application and the water contact angle change trend chart of the composite material prepared by different gel concentrations;

[0030] Figure 6 The contact angle change trend chart of the surface of the three-dimensional composite material constructed by the gel after light-induced polymerization for 100 min in the embodiment 1 of the present application after being continuously mechanically extruded for 1000 times and ultrasonically treated for 12 hours;

[0031] Figure 7 The contact angle change trend chart of the surface of the three-dimensional composite material constructed by the gel after light-induced polymerization for 100 min in the embodiment 1 of the present application after being treated in acid, alkali and salt solutions for 24 hours;

[0032] Figure 8 Optical photo of the two-dimensional composite material prepared for the embodiment 1 of the present application. DETAILED DESCRIPTION

[0033] The present application provides a preparation method of a hydrophobic organic gel and an assembled composite thereof, comprising the following steps:

[0034] (1) Preparation of the organic gel

[0035] (2) Preparation of the assembled composite

[0036] In order to make the above-mentioned purpose, features and advantages of the present application more obvious and easy to understand, the following will further describe the present application in combination with the specific embodiments.

[0037] Step one: preparation of the organic gel

[0038] In one embodiment, the step can be performed as follows: using alkyl methacrylate, polyethylene glycol diacrylate and benzophenone as monomer, crosslinking agent and photoinitiator, respectively. First, 0.2-10 mol% of the photoinitiator is dissolved in one part of the monomer, and a uniform mixture is obtained after ultrasonic treatment at 30°C for 10 min. Then 0.1-10 mol% of the crosslinking agent is added to the above mixture, and ultrasonic treatment is performed for 30 min. The amount of crosslinking agent and initiator is the mole fraction of the monomer. Then they are transferred to a glass mold, and photopolymerization is performed under a 365 nm ultraviolet lamp (5-20 W) for 30-180 h. The gel is named according to the mole fraction of the added crosslinking agent.

[0039] Step two: preparation of the assembled composite

[0040] In one embodiment, the step can be performed as follows: first, cut 2-10 pieces of non-woven fabric and sponge according to the specifications of 4x4 cm and 2x2x1 cm, respectively, and place them in beakers and sequentially ultrasonic treat them in acetone, anhydrous ethanol, and ionized water for 30 min. After ultrasonic treatment, dry them in an oven at 60°C, and cool them for standby use. Add a certain amount of gel to n-heptane solvent, and magnetically stir for 12 h (500-1000 rpm). The gel concentration is 1-9 mg / mL, and the volume of n-heptane solvent is 5-100 mL. Then immerse the sponge or non-woven fabric in the gel mixture for 1 min, and finally dry them at 80°C.

[0041] Please refer to Figure 1 , Figure 1 The optical photograph and the contact angle of oil and water of the organic gel of the present application are shown in the figure. As shown, the water contact angle of the prepared organic gel is greater than 100°, and the oil contact angle is about 20°.

[0042] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions of the present application will be further described below with reference to the drawings and examples. However, the present application is not limited to the listed examples, and any known changes within the scope of the claimed rights of the present application should also be included.

[0043] First, the "one embodiment" or "embodiment" referred to herein means that a certain feature, structure or characteristic can be included in at least one implementation of the present application. The "in one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is separate or alternative to other embodiments.

[0044] Secondly, the present application is described in detail by using structural schematic diagram, and in the detailed description of the embodiments of the present application, the schematic diagram is partially enlarged without general proportion for the convenience of description, and the schematic diagram is only an example which should not limit the scope of protection of the present application. In addition, the three-dimensional space including length, width and depth should be contained in actual manufacture.

[0045] In addition, the letter abbreviations in the present application are all fixed abbreviations in the art, and part of the letter explanations are as follows: SEM image: electron scanning image; WCA: water contact angle; OCA: oil contact angle.

[0046] Example 1

[0047] The hydrophobic organic gel and the assembled composite thereof in the present embodiment are prepared according to the following steps:

[0048] Step one: preparation of the organic gel

[0049] Octadecyl methacrylate, polyethylene glycol diacrylate and benzophenone are used as monomer, crosslinking agent and photoinitiator respectively. First, 3.5 mol% of photoinitiator is dissolved in one part of monomer, and a uniform mixture is obtained after ultrasonic treatment at 30°C for 10 min. Then 0.5 mol%, 1.0 mol%, 1.5 mol%, 2.0 mol% and 2.5 mol% of crosslinking agent are added to the above mixture respectively, and ultrasonic treatment is carried out for 30 min. The amount of crosslinking agent and initiator is the molar fraction of monomer. Then they are transferred to a glass mold, and photopolymerization is carried out under a 365 nm ultraviolet lamp (5-20 W) for 30-180 h. According to the amount of crosslinking agent added, the gels are named as 0.5%, 1.0%, 1.5%, 2.0% and 2.5% respectively.

[0050] Step two: preparation of the assembled composite

[0051] First, 2-10 pieces of non-woven fabric and melamine are cut according to the specifications of 4×4 cm and 2×2×1 cm respectively, and are placed in beakers and sequentially treated by ultrasonic treatment for 30 min in acetone, anhydrous ethanol and ionized water. After ultrasonic treatment, they are placed in an oven at 60°C for drying, and are cooled for standby use. A certain amount of gel is added to n-heptane solvent, and magnetic stirring is carried out for 12 h (500-1000 rpm). The gel concentration is 1-9 mg / mL, and the volume of n-heptane solvent is 5-100 mL. Then the sponge or non-woven fabric is immersed in the gel mixture for 1 min, and is finally dried at 80°C.

[0052] The optical pictures of the hydrophobic organic gel and the assembled composite thereof prepared in the present embodiment can be seen in Figure 1 、 Figure 5 and Figure 8 .

[0053] Example 2

[0054] A hydrophobic organic gel and its assembled composite were prepared according to the following steps:

[0055] Step 1: Preparation of the organic gel

[0056] Octadecyl methacrylate, polyethylene glycol diacrylate and benzophenone were used as monomer, crosslinking agent and photoinitiator, respectively. First, 3.5 mol% of photoinitiator was dissolved in one part of monomer, and a homogeneous mixture was obtained after ultrasonic treatment at 30°C for 10 min. Then 1.0 mol%, 3.0 mol%, 5.0 mol%, 7.0 mol% and 9.0 mol% of crosslinking agent were added to the above mixture, respectively, and ultrasonic treatment was performed for 30 min. The amount of crosslinking agent and initiator was the molar fraction of monomer. Then they were transferred to a glass mold, and the polymerization was initiated by ultraviolet light (5-20 W) at 365 nm for 30-180 h.

[0057] Step 2: Preparation of the assembled composite

[0058] First, 2-10 pieces of cotton fabric and melamine sponge were cut according to the specifications of 4x4 cm and 2x2x1 cm, respectively, and placed in a beaker and sequentially treated with acetone, anhydrous ethanol, and ionized water for 30 min under ultrasonic treatment. After ultrasonic treatment, they were placed in an oven at 60°C for drying, and then cooled for standby use. A certain amount of gel was added to n-heptane solvent, and magnetic stirring was performed for 12 h (500-1000 rpm). The gel concentration was 1-9 mg / mL, and the volume of n-heptane solvent was 5-100 mL. Then the sponge or cotton fabric was immersed in the mixture for 1 min, and finally dried at 80°C.

[0059] Example 3

[0060] A hydrophobic organic gel and its assembled composite were prepared according to the following steps:

[0061] Step 1: Preparation of the organic gel

[0062] Step 1: Preparation of organic gel

[0063] Step 2: Preparation of assembled composite

[0064] Firstly, 2-10 pieces of cotton fabric and polyurethane sponge were cut into 4x4 cm and 2x2x1 cm, respectively, and placed in a beaker and sequentially treated with acetone, anhydrous ethanol, and ionized water under ultrasonication for 30 min. After ultrasonication, they were dried in an oven at 60 °C and cooled for standby use. A certain amount of gel was added to n-hexane solvent, and magnetic stirring was performed for 12 h (500-1000 rpm). The gel concentration was 1-9 mg / mL, and the volume of n-hexane solvent was 5-100 mL. Then, the sponge or cotton fabric was immersed in the mixed solution for 1 min, and finally dried at 80 °C.

[0065] Example 4

[0066] The present embodiment prepared a hydrophobic organic gel and its assembled composite according to the following steps:

[0067] Step 1: Preparation of organic gel

[0068] Step 1: Preparation of organic gel

[0069] Step 2: Preparation of assembled composite

[0070] Firstly, the non-woven fabric and melamine sponge were cut into 2-10 pieces with the size of 4x4 cm and 2x2x1 cm respectively, and were placed in beakers and sequentially treated with acetone, anhydrous ethanol, and ionized water under ultrasonic for 30 min. After the ultrasonic treatment, the sponge and non-woven fabric were dried in an oven at 60°C and cooled for standby. A certain amount of gel was added to n-heptane solvent, and magnetic stirring was performed for 12 h (500-1000 rpm). The gel concentration was 1-9 mg / mL, and the volume of n-heptane solvent was 5-100 mL. Then the sponge or non-woven fabric was immersed in the mixed solution for 1 min, and finally dried at 80°C.

[0071] Figure 2 The changes in mass and water contact angle of the organic gel prepared in Example 1 after water immersion for 30 days; as shown in FIG. 1, the volume, apparent morphology, and water contact angle of the gel remained stable after water immersion for 30 days. Figure 2

[0072] Figure 3 SEM images of the three-dimensional composite material (1.5 mol% crosslinking agent, gel concentration 5 mg / mL) prepared in Example 1, wherein a-c are SEM images of the three-dimensional sponge at different magnifications before assembly, and d-f are SEM images of the three-dimensional sponge at different magnifications after assembly; as shown in a-c, the skeleton of the three-dimensional sponge before assembly is smooth; as shown in d-f, obvious gel clusters can be observed after assembly.

[0073] Figure 4 SEM images of the two-dimensional composite material (1.5 mol% crosslinking agent, gel concentration 5 mg / mL) prepared in Example 1, wherein a-c are SEM images of the two-dimensional material at different magnifications before assembly, and d-f are SEM images of the two-dimensional material at different magnifications after assembly; as shown in a-c, the surface fibers of the two-dimensional material before assembly are independent of each other; as shown in d-f, the surface fibers after assembly are adhered to each other, and obvious gel clusters exist.

[0074] Figure 5 Optical photographs of the three-dimensional composite material (1.5 mol% crosslinking agent, gel concentration 5 mg / mL) prepared in Example 1 and a graph showing the change trend of the water contact angle of the composite material prepared at different gel concentrations (1.5 mol% crosslinking agent); as shown in FIG. 3, the three-dimensional composite material prepared exhibits excellent hydrophobicity both inside and outside, and the water contact angle is greater than 140°. Figure 5

[0075] In the above four examples, the organic gel and composite material prepared by ultraviolet induction and immersion method exhibit stable water-repellent ability. Please refer to Figure 6 ​​Figure 6 is a diagram showing the contact angle change trend of the surface of the three-dimensional composite material (1.5 mol% crosslinking agent) of the hydrophobic organic gel of the present application constructed at a concentration of 5 mg / mL after 100 min of photoinitiated polymerization, after 1000 continuous mechanical extrusions and 12 hours of ultrasonic treatment. As shown in Figure 6, the sample maintained good hydrophobicity after 1000 continuous extrusions and ultrasonic treatment. Figure 6 As shown in Figure 7, the contact angle of the surface of the sample remained stable after 24 hours of immersion in acid, alkali and salt solutions. Figure 7 As shown in Figure 7, the contact angle of the surface of the sample remained stable after 24 hours of immersion in acid, alkali and salt solutions.

[0076] In summary, the present application discloses a preparation method of a hydrophobic organic gel and an assembled composite. The method uses ultraviolet-induced monomer polymerization and immersion to construct a hydrophobic organic gel and an assembled composite material. The reaction conditions are mild, the process is simple and easy to operate, the physical and chemical stability is excellent, there is no environmental pollution, and it has great practical application potential in the field of oil-water separation. The proposed assembly method is efficient and easy to operate, and is suitable for various two-dimensional / three-dimensional substrate materials. This provides key support for the construction of strong anti-icing coatings and anti-biofouling interfaces in the near future.

[0077] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing a hydrophobic organogel assembly composite, characterized by, The method comprises the following steps: (1) mixing monomer octadecyl methacrylate, crosslinking agent polyethylene glycol diacrylate and photoinitiator benzophenone, mixing uniformly under ultrasonic action, and standing for use; (2) transferring the mixed solution in step (1) into a mold, and initiating polymerization under a UV lamp to obtain a hydrophobic organic gel; (3) mixing the organic gel prepared in step (2) with a non-polar solvent, mixing uniformly under magnetic stirring to obtain a mixed solution; (4) immersing a cleaned two-dimensional substrate or three-dimensional substrate in the mixed solution in step (3), and performing simple immersion and drying to obtain a multifunctional adsorbent with excellent hydrophobicity; Step (1) is specifically mixing one part of octadecyl methacrylate, 3.5 mol% of photoinitiator based on the molar fraction of monomer octadecyl methacrylate, and a certain amount of polyethylene glycol diacrylate, mixing uniformly under ultrasonic action to obtain a mixed solution; The molar fraction of polyethylene glycol diacrylate based on the monomer octadecyl methacrylate is 1.5 mol%; In step (2), the power of the UV lamp is 5-20 W, and the polymerization time is 30-180 min; In step (3), the non-polar solvent includes n-heptane and n-hexane, and the volume of the non-polar solvent is 5-100 mL; The concentration of the organic gel in the mixed solution obtained in step (3) is 5 mg / mL; In step (4), the immersion time is 1 min, and the drying temperature is 80℃; In step (4), the two-dimensional substrate includes non-woven fabric, cotton fabric and metal mesh; and the three-dimensional substrate includes melamine sponge and polyurethane sponge.

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