Flame-retardant hydrophobic lipophilic polyurethane sponge composite material with photothermal effect and preparation method thereof
By modifying polyurethane sponge with lignin/porous corn starch/SiO2 and combining it with WS2 and PDMS modification, a flame-retardant, hydrophobic and oleophilic composite material with photothermal effect is formed. This solves the problems of poor hydrophilicity, flammability and environmental adaptability of polyurethane sponge materials in oil-water separation, and achieves improved high-efficiency adsorption and flame-retardant performance.
Patent Information
- Application Number
- CN202511953384.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-02-24
AI Technical Summary
Existing polyurethane foam materials suffer from problems such as hydrophilicity, oleophilicity, flammability, and poor environmental adaptability in oil-water separation, making it difficult to meet the oil-water separation requirements in complex environments.
By modifying polyurethane sponge with lignin/porous corn starch/SiO2 and combining it with WS2 and PDMS, a flame-retardant, hydrophobic and oleophilic composite material with photothermal effect is formed. The pore structure and surface energy are regulated to enhance hydrophobicity, flame retardancy and adsorption.
It enables the sponge to rapidly heat up under light to reduce oil viscosity and increase adsorption rate, possessing efficient adsorption and regeneration capabilities, while also exhibiting excellent flame retardant properties, making it suitable for oil-water separation in complex environments.
Smart Images
Figure CN121554820A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of oil-water separation technology, specifically relating to a flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect and its preparation method. Background Technology
[0002] With the continuous development of industrialization, oil spills at sea occur frequently due to factors such as oil extraction and transportation, natural disasters, human error, and illegal discharge. These spills not only cause severe damage to ecosystems but also have a profound impact on human health and economic activities. Therefore, researching more efficient oil-water separation technologies and related products is an important area of research.
[0003] Commonly used oil-water separation materials mainly include membrane materials, aerogels, carbon-based materials, and polyurethane foam. Among them, polyurethane (PU) foam is widely used in the research of adsorbent oil-water separation materials due to its advantages such as light weight, porous structure, good compressibility, and low cost. However, the original PU foam itself is hydrophilic and oleophilic, flammable, has a short service life, and poor environmental adaptability, making it difficult to meet the oil-water separation requirements in complex environments.
[0004] To overcome these shortcomings, researchers have attempted to modify PU foams through surface modification or the introduction of functional nanomaterials to improve their hydrophobic and oleophilic properties. Furthermore, some studies have begun to focus on the photothermal response of materials, using carbon-based materials for modification. While this enhances the photothermal effect, it does not significantly improve flame retardant properties. Therefore, developing a polyurethane foam that combines superhydrophobicity and oleophilicity, high flame retardancy, and excellent photothermal effects is of significant practical importance. Summary of the Invention
[0005] This invention aims to provide a flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect and its preparation method. This composite material combines superhydrophobicity and oleophilicity, high-efficiency flame retardancy, and excellent photothermal effect, possessing significant practical application value. The invention first provides a method for preparing a flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect, comprising the following steps: adding tungsten disulfide (WS2) powder, polydimethylsiloxane (PDMS), and a curing agent to an ethyl acetate solution, and ultrasonically dispersing them uniformly to obtain a PDMS / WS2 solution. A polyurethane sponge synergistically modified with lignin / porous corn starch / SiO2 is completely immersed in the dispersed PDMS / WS2 solution, shaken in a 25°C water bath (180 rpm) for 50 minutes, repeatedly washed and extruded, and dried to obtain a WS2-SiO2@PDMS sponge.
[0006] In the PDMS / WS2 solution, the mass ratio of WS2 powder, PDMS and curing agent is 0.1-0.4:1:0.1; the concentration of PDMS is 25 mg / mL.
[0007] Furthermore, the curing agent is ethyl silicate.
[0008] The particle size of the WS2 powder is 60-80 mesh.
[0009] Specifically, the method for preparing the tungsten disulfide powder includes the following steps: Add tungsten disulfide powder and grinding balls to the grinder in a ratio of 1:10 to 1:20. Set the grinding parameters, including a rotation speed of 400 rpm, and grind for 2 hours. To prevent oxidation during grinding, add an inert gas (such as nitrogen or argon) to the sealed container. After grinding, remove the ground tungsten disulfide powder and use a filter to remove larger particles.
[0010] The impregnation process involves shaking the sponge in a water bath at 25-30°C for 50-60 minutes with a stirring speed of 180-200 rpm, repeatedly absorbing and extruding the sponge to ensure full absorption.
[0011] The drying and curing process involves drying in an oven at 180°C for 2 hours.
[0012] The preparation method of the modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge includes the following steps: Mixing modified lignin, porous corn starch, dimethylsiloxane, green tea polyphenol extract, hydroxypropyl methylcellulose, fumed hydrophobic silica, organotin catalyst, and water uniformly to obtain a modifier solution. Immersing a pretreated blank polyurethane sponge in the modifier solution until fully absorbed, removing it, and drying it, yields the modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge.
[0013] The pretreated blank polyurethane sponge was prepared by the following method: The polyurethane sponge was cut into 1cm × 1cm × 1cm cubes, continuously washed with an ethanol solution for 30 minutes, and then dried in an oven at 60°C to obtain the pretreated blank polyurethane sponge. Preferably, the pore density of the polyurethane sponge was 40 PPI-60 PPI.
[0014] Optionally, the preparation method of the above-mentioned modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge further includes repeated impregnation and drying steps multiple times, so that the obtained modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge is 5-8 times heavier than the pretreated blank polyurethane sponge.
[0015] In the modified solution, the mass ratio of modified lignin, porous corn starch, dimethylsiloxane, green tea polyphenol extract, hydroxypropyl methylcellulose, fumed hydrophobic silica, organotin catalyst and water is 0.5:2:0.92:1:1:6:0.8:20.
[0016] The green tea polyphenol extract includes one or more of tea polyphenols, dopamine, and eugenol.
[0017] Furthermore, the method for preparing the modified lignin includes the following steps: The dried lignin was placed in a beaker, deionized water was added, and then pyridine was added. The mixture was stirred thoroughly at 120°C to ensure that the lignin was dissolved evenly. Then, glacial acetic acid was added, and the mixture was stirred at a constant temperature for 12 hours. After the reaction was completed, the reaction solution was continuously added dropwise to cold water. After standing and precipitation, the precipitate was collected. The precipitate was dried under vacuum at 50°C to obtain the modified lignin. The ratio of lignin, deionized water, pyridine and glacial acetic acid was 10g:50mL:0.4mL:1mL.
[0018] Furthermore, the method for preparing the porous corn starch includes the following steps: Corn starch, organotin catalyst, Na2HPO4 aqueous solution, and Tris buffer solution (pH=6) were uniformly dispersed by ultrasonication at 50°C to obtain an acidic mixture. Then, deionized water was added to the acidic mixture at a volume ratio of 1:3. After standing and separating into layers, the supernatant was removed, and the lower precipitate was collected and dried at 50°C. After pulverization and sieving, porous corn starch with an average particle size of 150 mesh was obtained. The mass concentration of Na2HPO4 aqueous solution was 49.5%, and the volume ratio of corn starch to catalyst, Na2HPO4 aqueous solution, and Tris buffer solution (pH=6) was 25 g: 1 mL: 8 mL: 40 mL.
[0019] The present invention further provides a flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect prepared by the above preparation method.
[0020] This invention also provides the above-mentioned flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect for oil-water separation in complex environments such as marine oil spill recovery, flammable chemical leaks, and oily wastewater treatment.
[0021] This invention first prepares a polyurethane sponge synergistically modified with lignin / porous corn starch / SiO2. The polyurethane sponge itself has a three-dimensional porous framework. After synergistic modification with lignin / porous corn starch / SiO2, the pore structure and surface energy are further regulated. Then, it is further modified with WS2 and PDMS, which further improves the comprehensive properties of the composite material, such as hydrophobicity, flame retardancy and adsorption.
[0022] As a semiconductor material, WS2 exhibits broad-spectrum absorption characteristics in the visible-near-infrared band, efficiently converting light energy into heat energy, causing the sponge to heat up rapidly under light irradiation. This photothermal heating reduces the viscosity of high-viscosity oils, increasing their adsorption rate. Simultaneously, after adsorption saturation, light heating can desorb the adsorbed oil, achieving sponge regeneration and oil recovery, reducing energy consumption and operating costs. Furthermore, the two-dimensional structure of WS2 promotes char layer formation at high temperatures, slowing heat release and smoke diffusion. Combined with the inorganic flame-retardant material SiO2, which forms a heat-insulating and oxygen-barrier silicon barrier during combustion, it further enhances the material's flame-retardant properties.
[0023] PDMS, as a low surface energy elastomer encapsulating the framework, not only helps increase the modification amount of WS2 but also endows the sponge with excellent hydrophobic and oleophilic properties. WS2 nanosheets and SiO2 particles together construct the micro-nano level roughness of the surface. PDMS provides low surface energy chemical modification, significantly increasing the water contact angle of the sponge surface (typically >150°), achieving superhydrophobicity; at the same time, it gives it high adsorption capacity and adsorption rate for various oils and organic solvents. The PDMS cross-linked network enhances the mechanical toughness of the sponge, maintaining structural stability during multiple oil absorption-desorption cycles, preventing collapse, and allowing for reuse. PDMS decomposes upon heating to generate silica char residue, further isolating flames and improving the fire safety of the sponge.
[0024] The flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect prepared by this invention has outstanding application potential in complex environments such as marine oil spill recovery, flammable chemical leaks, and oily wastewater treatment. Attached Figure Description
[0025] Figure 1 This is a flowchart illustrating the preparation process of a flame-retardant, hydrophobic, and oleophilic polyurethane sponge with photothermal effect according to the present invention.
[0026] Figure 2 The graphs show the relationship between the water contact angle and the number of cycles, and the relationship between the oil absorption capacity and the number of cycles for the flame-retardant, hydrophobic, and oleophilic polyurethane sponge with photothermal effect obtained in Example 3.
[0027] Figure 3 The image shows the EDS test results of the flame-retardant, hydrophobic, and oleophilic polyurethane foam with photothermal effect obtained in Example 3.
[0028] Figure 4 The images show combustion test diagrams of the polyurethane foams obtained in Examples 1-3 and Comparative Example 1.
[0029] Figure 5 The image shows an experimental diagram of the photothermal effect of the flame-retardant, hydrophobic, and oleophilic polyurethane sponge with photothermal effect obtained in Example 3. Detailed Implementation
[0030] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.
[0031] The ethyl acetate, dibutyltin dilaurate, fumed hydrophobic silica, and tungsten disulfide used in this invention were of analytical grade and purchased from Shanghai Aladdin Chemical Reagent Co., Ltd. Dichloromethane, ethanol, and Tris buffer (C4H2O) were also used. 11 NO3 (mass concentration 24.4%), analytical grade, purchased from Shanghai Boer Chemical Reagent Co., Ltd. Soybean oil purchased from Jinshan Dongluhua Soybean Oil Co., Ltd. Diesel fuel purchased from China Petroleum & Chemical Corporation (Sinopec). All other raw materials and reagents unless otherwise specified are conventional and common.
[0032] The polyurethane foam used in this invention was purchased from Chengdu Zhuoleng Technology Co., Ltd., China, with a pore density of 50 PPI. In use, the polyurethane foam was cut into 1cm × 1cm × 1cm cubes, continuously washed with an ethanol solution for 30 minutes, and then dried in an oven at 60°C to obtain pretreated blank polyurethane foam.
[0033] The modified lignin used in this invention is prepared according to the following steps: Place 10g of dried lignin in a beaker, add 50mL of deionized water, then add 0.4mL of pyridine, and stir thoroughly at 120℃ to dissolve the lignin evenly. Then add 1mL of glacial acetic acid and stir at a constant temperature for 12h. After the reaction is complete, continuously add the reaction solution to cold water, allow it to stand and precipitate, collect the precipitate, and vacuum dry the precipitate at 50℃ to obtain modified lignin.
[0034] The porous corn starch used in this invention is prepared according to the following steps: 25g of corn starch, 1mL of dibutyltin dilaurate, 8mL of 49.5% Na2HPO4 aqueous solution, and 40mL of Tris buffer solution with pH=6 were placed in a constant temperature ultrasonic dispersion at 50℃ to obtain an acidic mixture. Then, 3 times the volume of deionized water was added to the acidic mixture. After standing and separating into layers, the supernatant was removed, the lower precipitate was collected and dried at 50℃, and then pulverized and passed through a 150-mesh sieve to obtain porous corn starch.
[0035] The performance testing methods used in the following embodiments of the present invention are as follows: Oil adsorption capacity test: The oil absorption capacity and recycling performance of the prepared modified hydrophobic and oleophilic sponge were tested. The modified sponge was weighed W0, placed in oil, and soaked for 5 minutes. After soaking, it was removed and weighed again until no more oil droplets fell from the sponge. The oil absorption capacity (C) of the sponge was calculated using the following formula: C=(W1-W0) / W0 Oil absorption capacity test: In each cycle, the weight of the saturated sponge and the sponge after full compression were recorded to investigate the performance of repeated use.
[0036] Example 1
[0037] A method for preparing a modified lignin / porous corn starch polyurethane sponge, the specific preparation method is as follows: (1) Dissolve 0.5g of modified lignin and 2g of porous corn starch in 20mL of water and stir and mix evenly at 70℃. Add 0.92g of dimethylsilane, 1g of green tea polyphenol extract, 1g of hydroxypropyl methylcellulose, 6g of SiO2 with an average particle size of 0.4μm and 0.8g of dibutyltin dilaurate, and stir and mix evenly at 70℃ to obtain an impregnation solution.
[0038] (2) The pretreated blank polyurethane sponge is immersed in the immersion solution obtained in step (1) at an immersion temperature of 45°C for 30 minutes. After immersion, the polyurethane sponge is removed and vacuum dried at 65°C.
[0039] (3) Repeat step (2) multiple times to obtain modified lignin / porous corn starch sponge, which is about 7 times heavier than blank polyurethane sponge.
[0040] Example 2
[0041] A method for preparing a polyurethane sponge synergistically modified with lignin / porous corn starch and SiO2, the specific preparation method is as follows: (1)-(3) Same as Example 1.
[0042] (4) 30 mL of halloysite nanotubes (HNTs) aqueous dispersion (6 μg / mL) was added to 40 mL of ethyl acetate and mixed and stirred at 70 °C to obtain a mixed solution. The ethyl acetate mixed solution formed by HNTs was uniformly coated on the surface of the sponge obtained in step (4) with a coating thickness of 0.2 mm.
[0043] Example 3
[0044] A method for preparing a flame-retardant, hydrophobic, and oleophilic polyurethane foam with photothermal effect is described below: (1)-(3) Same as Example 1.
[0045] (4) Add 0.1g WS2 powder and 1.0g PDMS with 0.1g ethyl silicate (TEOS) curing agent to 40mL ethyl acetate solution. Sonicate at 40kHz for 10min at 25℃ to ensure good dispersion. Completely immerse the sponge in the dispersed PDMS / WS2 solution and shake in a 25℃ water bath for 50min. Repeatedly wash and extrude the modified sponge. Dry in an oven at 180℃ for 2 hours to obtain the final prepared sponge.
[0046] The method for preparing the tungsten disulfide powder includes the following steps: Tungsten disulfide powder and grinding balls were loaded into the grinder at a ratio of 1:10. The grinding parameters were set, with the rotation speed set to 400 rpm, and grinding was carried out for 2 hours. To prevent oxidation during the grinding process, inert gas (nitrogen) was added to the sealed container. After grinding, the ground tungsten disulfide powder was removed and larger particles were removed using a 60-mesh filter.
[0047] Example 4
[0048] The difference from Example 3 is that in step (4) it is 0.2g WS2.
[0049] Example 5
[0050] The difference from Example 3 is that in step (4) it is 0.3g WS2.
[0051] Example 6
[0052] The difference from Example 3 is that in step (4) it is 0.4g WS2.
[0053] Comparative Example 1
[0054] The polyurethane foam was cut into 1cm×1cm×1cm cubes, washed continuously with ethanol solution for 30 minutes, and then dried in an oven at 60℃ to obtain pretreated blank polyurethane foam.
[0055] The experimental test results of the obtained hydrophobic and oleophilic polyurethane sponge are shown in Table 1 below.
[0056] Table 1. Experimental test results of hydrophobic and oleophilic polyurethane foam
[0057] Figure 2 The graphs show the relationship between the water contact angle and the number of cycles, and the relationship between the oil absorption capacity and the number of cycles for the flame-retardant, hydrophobic, and oleophilic polyurethane sponge with photothermal effect obtained in Example 3. As can be seen from the graphs, the WS was used repeatedly in the experiment... 2-The SiO2@PDMS polyurethane sponge was subjected to 20 cycles, and the average contact angle after five cycles was used as the result. The results showed that the oil absorption capacity steadily decreased from over 24 g / g initially to about 18 g / g by the 20th cycle; while the water contact angle remained at 130°-150° throughout the 20+ cycles, with little change, indicating good hydrophobic properties.
[0058] Figure 3 The images show SEM and EDS spectra of the flame-retardant, hydrophobic, and oleophilic polyurethane sponge with photothermal effect obtained in Example 3 at different magnifications. As can be seen from the figures, the original sponge skeleton was smooth, but wrinkles appeared after covering it with the PDMS layer. The introduction of hydrophobic SiO2 increased the skeleton roughness and improved the hydrophobic properties. The sponge has an open-cell frame structure, with a large amount of material adhering and fixing to the protrusions of the skeleton, altering the wettability of the original sponge. This is one of the physical reasons for the increased water contact angle.
[0059] Figure 4 The figures show the combustion test results of the polyurethane foams obtained in Examples 1-3 and Comparative Example 1. As can be seen from the figures, the materials in Examples 1 and 2 produced a flame after ignition, but the flame subsequently weakened and extinguished to varying degrees. In Example 3, after the flame was ignited, it disappeared, leaving only residual smoke, and the material remained relatively intact, demonstrating outstanding flame-retardant performance.
[0060] Figure 5 The figure shows the photothermal effect of the flame-retardant, hydrophobic, and oleophilic polyurethane sponge with photothermal effect obtained in Example 3. As can be seen from the figure, it takes 636 seconds for the modified sponge to completely adsorb crude oil without light, but only 152 seconds with light, saving 484 seconds compared to the no-light condition. The adsorption rate is significantly improved, and the adsorption effect is better with light.
[0061] Multiple tests and analyses showed that the WS2-SiO2@PDMS polyurethane sponge obtained in Example 3 was the best-performing modified polyurethane sponge.
[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect, characterized in that, Includes the following steps: Tungsten disulfide powder, polydimethylsiloxane, and curing agent were added to an ethyl acetate solution and ultrasonically dispersed to obtain a PDMS / WS2 solution. The modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge was completely impregnated in the PDMS / WS2 solution for full absorption. After drying and curing, WS2-SiO2@PDMS sponge was obtained.
2. The method for preparing the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect according to claim 1, characterized in that, In the PDMS / WS2 solution, the mass ratio of tungsten disulfide powder, polydimethylsiloxane, and curing agent is 0.1-0.4:1:0.
1.
3. The method for preparing the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect according to claim 1, characterized in that, The concentration of polydimethylsiloxane in the PDMS / WS2 solution is 25 mg / mL.
4. The method for preparing the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect according to claim 1, characterized in that, The curing agent is ethyl silicate.
5. The method for preparing the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect according to claim 1, characterized in that, The tungsten disulfide powder has a particle size of 60-80 mesh.
6. The method for preparing the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect according to claim 1, characterized in that, The impregnation process involves shaking in a water bath at 25-30°C for 50-60 minutes, followed by repeated absorption and extrusion.
7. The method for preparing the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect according to claim 1, characterized in that, The modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge is prepared by the following method: Modified lignin, porous corn starch, dimethylsiloxane, green tea polyphenol extract, hydroxypropyl methylcellulose, fumed hydrophobic silica, organotin catalyst, and water are mixed evenly to obtain a modifier solution; a pretreated blank polyurethane sponge is immersed in the modifier solution for full absorption, removed, and dried to obtain the modified lignin / porous corn starch / SiO2 synergistic modified polyurethane sponge; the mass ratio of modified lignin, porous corn starch, dimethylsiloxane, green tea polyphenol extract, hydroxypropyl methylcellulose, fumed hydrophobic silica, organotin catalyst, and water in the modifier solution is 0.5:2:0.92:1:1:6:0.8:
20.
8. The flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect prepared by the method according to any one of claims 1-7.
9. The application of the flame-retardant, hydrophobic, and oleophilic polyurethane sponge composite material with photothermal effect as described in claim 8 in marine oil spill recovery, flammable chemical leaks, and oily wastewater treatment.