Core-shell structure photo-thermal phase change fiber material and preparation method thereof

Abstract

The invention discloses a photo-thermal phase change fiber material with a core-shell structure and a preparation method of the photo-thermal phase change fiber material. The method comprises the following steps: performing coaxial electrostatic spinning on a shell layer spinning solution and a core layer spinning solution to obtain core-shell structure nanofibers; soaking the core-shell structure nanofiber in the hydrophobic modification solution; and heating and drying the soaked fibers to obtain the photo-thermal phase change fiber material with the core-shell structure. The material can enhance adsorption of marine leaked crude oil through solar heating, can cope with complex weather conditions through heat storage of the phase change material, and has the advantages of simple preparation method, strong crude oil adsorption performance, environmental protection, harmlessness and the like.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a core-shell structure photothermal phase change fiber material and a preparation method thereof. Background Art

[0002] Frequent crude oil spills at sea have had a huge impact on the marine ecological environment and coastal economy. Various advanced porous absorbents with hydrophobic and oleophilic channels have strong oil absorption capacity and recyclable properties, and are therefore considered to be the key technology for the adsorption of heavy oil at sea. These absorbents include natural materials (such as cellulose, cotton) and polymers (such as commercial sponges and various gels). However, these absorbents are mainly suitable for the recovery of low-viscosity oils and cannot effectively adsorb high-viscosity crude oils. Studies have shown that when the temperature rises, the viscosity of crude oil drops sharply. Therefore, researchers have given traditional porous adsorbents a heating function to improve their crude oil adsorption efficiency.

[0003] Collecting solar energy and converting it into heat is a low-cost and simple method, but solar energy is greatly affected by weather, time and location. Phase change material is a common heat storage material that can convert heat energy into chemical energy in the form of phase change latent heat and store it in the material, and then release the heat when the temperature drops. Adding phase change material to solar heating adsorption material can make the material have better environmental adaptability, and it is expected to maintain the heating and oil absorption state in complex environments. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a core-shell structure photothermal phase change fiber material and a preparation method thereof, so as to solve the problem that the existing photothermal porous adsorption materials are difficult to adapt to the complexity of the environment.

[0005] To achieve the above objectives, an embodiment of the present invention provides a core-shell structured photothermal phase change fiber material, the fiber material comprising:

[0006] Fiber matrix;

[0007] Phase change materials in a fiber matrix;

[0008] A hydrophobic layer of organic material outside the fiber matrix.

[0009] Another aspect of the present invention provides a method for preparing a core-shell structure photothermal phase change fiber material, the method comprising:

[0010] a. Prepare the shell layer spinning solution and the core layer spinning solution respectively,

[0011] b. Spinning the spinning solution into fiber material,

[0012] c. Prepare hydrophobic modification solution.

[0013] d. Soaking the spun fiber in a hydrophobic modification solution,

[0014] e. Heat and dry the soaked solution.

[0015] In one embodiment of the present invention, the shell spinning solution in step a is prepared by adding N,N-dimethylacetamide as solvent, surfactant, polyacrylonitrile (average molecular weight 250,000), and hydroxylated multi-walled carbon nanotubes.

[0016] In one embodiment of the present invention, the core layer spinning solution in step a is prepared by adding N,N-dimethylacetamide as solvent, surfactant, polyacrylonitrile (average molecular weight 250,000), and polyethylene glycol (average molecular weight 10,000); wherein the concentration of polyethylene glycol is greater than 0.45 g / mL.

[0017] In one embodiment of the present invention, the fiber in step b is prepared by coaxial electrospinning, wherein the shell feed rate is 0.9-2.0 mL / h, the shell feed rate is 0.1-0.6 mL / h, and the applied voltage is 14 kV-18 kV.

[0018] In one embodiment of the present invention, the hydrophobic modified solution in step c is prepared by adding a hydrophobic modified material including polydimethylsiloxane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and ferrosoferric oxide nanoparticles (average particle size 20 nm) to the solvent n-hexane.

[0019] In one embodiment of the present invention, the soaking time in step d is 12 hours.

[0020] In one embodiment of the present invention, the heating drying in step e is carried out at 60° C. to 100° C. for 12-24 hours.

[0021] The embodiments of the present invention have the following advantages:

[0022] The present invention utilizes coaxial electrospinning to completely encapsulate the phase change material in the fiber, completely avoiding leakage of the phase change material during the phase change process. At the same time, the material has the advantages of high porosity, high adsorption efficiency, good photothermal performance, and continuous heating performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 These are the SEM and TEM photos of the fiber material before modification provided in Example 1 of the present invention.

[0024] Figure 2 This is a SEM photograph of the modified fiber material provided in Example 1 of the present invention and its element distribution.

[0025] Figure 3 These are photos of the oil and water contact angles of the fiber material before and after modification provided in Example 1 of the present invention.

[0026] Figure 4 The absorbance of the fiber material before and after modification provided in Example 2 of the present invention.

[0027] Figure 5 The DSC curves of the fiber material before and after modification provided in Example 2 of the present invention.

[0028] Figure 6 The temperature change curves of the photothermal test of the fiber material before and after modification provided in Example 2 of the present invention.

[0029] Figure 7 This is a temperature change curve of the photothermal cycle test of the modified fiber material provided in Example 2 of the present invention.

[0030] Figure 8 This is the static oil absorption-deoiling curve of the modified fiber material provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0031] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0032] Example 1

[0033] First, polyethylene glycol and fs-3100 surfactant were added to N,N-dimethylacetamide to prepare a core spinning solution with a PEG content of 45%, and polyacrylonitrile, hydroxylated multi-walled carbon nanotubes, and fs-3100 surfactant were added to N,N-dimethylacetamide to prepare a shell spinning solution with a PAN content of 14% and a CNTs content of 1.4%. The spinning solution was placed on a magnetic stirring heating table and stirred until it was uniform and stable. Coaxial electrospinning was performed at a feed rate of 0.5 ml / h for the core spinning solution and 1.2 ml / h for the shell spinning solution to spin a phase change fiber material with uniform fiber size. The fiber material was placed in a 60°C oven and dried for 3 hours to remove excess organic solution. Weigh 0.15g of polydimethylsiloxane, 0.5g of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and 0.015g of curing agent, dissolve in n-hexane to prepare 15mL of hydrophobic modification solution, and add 0.02g of Fe3O4 nanoparticles. The dried fiber material is completely immersed in the hydrophobic modification solution, shaken on a circular shaker for 6 hours, then taken out after standing for 6 hours, and dried at 60°C for 12 hours. The method for preparing this fiber material is coaxial electrospinning. The prepared fiber encapsulates a phase change material. The performance of the materials before and after modification was tested. The scanning electron microscope photos and transmission electron microscope photos of the fiber material before modification are shown in the following figure. Figure 1As shown, it shows that the prepared fiber encapsulates the phase change material therein; the scanning electron microscope photo and element distribution of the modified fiber material are shown in Figure 2 As shown in Figure 2, it shows that a hydrophobic layer is formed on the fiber surface; the oil and water contact angles of the fiber material before and after modification are shown in Figure 2. Figure 3 shown.

[0034] Example 2

[0035] The unmodified and modified fiber materials in the above Example 1 were subjected to absorbance test, DSC test and photothermal test, and the modified fiber material was subjected to photothermal cycle test. Figure 4 As shown; the DSC curves of unmodified and modified fiber materials are as shown Figure 5 As shown; the unmodified and modified fiber materials were placed under a simulated light source, and the photothermal test results were as follows Figure 6 The modified fiber material was placed in a simulated light source for a photothermal cycle test. The test results are shown in Figure 7 The photothermal conversion efficiency of the modified material can reach 95%, the phase change enthalpy value can reach 77.12 J / g, and it can reach 82°C in 400 seconds under the intensity of one sun. After 10 photothermal cycles, the properties remain basically unchanged.

[0036] Example 3

[0037] The modified fiber material in the above Example 1 was subjected to a static cycle oil absorption-oil removal test and a dynamic oil absorption test. The static oil absorption-oil removal test results of the modified fiber material are as follows: Figure 8 As shown, after 10 adsorption-desorption cycles, the adsorption amount only decreased by 12%; the modified fiber material was placed on a simulated ocean oil surface, the fiber material and the collector were connected by a tube, and the crude oil was collected using a peristaltic pump. 4.16g was collected in 25 minutes under simulated light conditions, and only 0.71g was collected in 25 minutes without simulated light conditions, indicating that illumination can accelerate the crude oil collection rate; the shell spinning solution in the above-mentioned embodiment 1 was used for electrospinning alone, and the subsequent modification steps were the same as in embodiment 1 to obtain a fiber material loaded with phase change material. Tests were carried out under conditions of light changes simulating light sources. After loading the phase change material, 1.91g could be collected in 45 minutes, and only 1.49g was collected after 45 minutes without the phase change material, indicating that the addition of the phase change material can accelerate the crude oil adsorption rate when the external environment changes, improve the adsorption material's ability to resist environmental changes, and the crude oil collection rate can be increased by 24.99% after adding the phase change material.

[0038] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A core-shell structure photothermal phase change fiber material, the core-shell structure photothermal phase change fiber comprising: a fiber matrix; a phase change material in the fiber matrix; and a hydrophobic layer organic material coated outside the fiber matrix, wherein the phase change material is encapsulated inside a single fiber, and the selected phase change material is polyethylene glycol (average molecular weight 10000); the hydrophobic layer organic material is coated on the outer layer of a single fiber, and the selected hydrophobic layer organic material is polydimethylsiloxane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and ferrosoferric oxide nanoparticles (average particle size 20nm); the selected material for the fiber matrix is ​​polyacrylonitrile (average molecular weight 250000).

2. A method for preparing a core-shell structured photothermal phase change fiber material, the method comprising: a. respectively preparing a shell spinning solution and a core spinning solution, b. spinning the spinning solution into a fiber material, c. preparing a hydrophobic modification solution, d. soaking the spun fiber in the hydrophobic modification solution, and e. heating and drying the soaked solution.

3. The preparation method according to claim 2, wherein the shell spinning solution in step a is prepared by adding N,N-dimethylacetamide as solvent, surfactant, polyacrylonitrile (average molecular weight 250,000), and hydroxylated multi-walled carbon nanotubes.

4. The preparation method according to claim 2, wherein the core layer spinning solution in step a is prepared by adding N,N-dimethylacetamide as solvent, surfactant, polyacrylonitrile (average molecular weight 250,000), and polyethylene glycol (average molecular weight 10,000); wherein the concentration of polyethylene glycol is greater than 0.45 g / mL.

5. The preparation method according to claim 2, wherein the fiber in step b is prepared by coaxial electrospinning, wherein the shell feed rate is 0.9-2.0 mL / h, the shell feed rate is 0.1-0.6 mL / h, and the applied voltage is 14 kV-18 kV.

6. The preparation method according to claim 2, wherein the hydrophobic modified solution in step c is prepared by adding a hydrophobic modified material including polydimethylsiloxane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and ferrosoferric oxide nanoparticles (average particle size 20 nm) to a solvent of n-hexane.

7. The preparation method according to claim 2, wherein the soaking time in step d is 12 hours.

8. The preparation method according to claim 2, wherein the heating and drying in step e is carried out at 60°C to 100°C for 12-24 hours.

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