A composite material with self-cleaning function and a preparation method and application thereof

Abstract

The application belongs to the technical field of functional polymer materials, and particularly relates to a composite material with self-cleaning function and a preparation method and application thereof. The composite material comprises the following raw materials in parts by weight: hydroxyl-terminated PDMS 55-70 parts, PTMEG 12-18 parts, cross-linking curing agent 5-7 parts, modified polydopamine 15-18 parts, and defoaming agent 0.2 part. The lotus-leaf-imitated structure formed between the modified polydopamine loaded with antibacterial active ingredients and the resin matrix has the characteristics of low surface tension, effectively reduces the adsorption and retention of water stains or dirt on the surface of the composite material, and plays a self-cleaning role. In addition, the components with antibacterial activity are loaded in the mesoporous polydopamine hollow structure, effectively reducing the volatilization loss, and the self-cleaning and antibacterial properties of the composite material are jointly given by the material properties and structural properties.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer materials technology, specifically relating to a self-cleaning composite material, its preparation method, and its application. Background Technology

[0002] Medical contact products and high-end cleaning and care equipment play a crucial role in modern clinical nursing and daily rehabilitation management. Especially in targeted care procedures such as hand cleaning, abdominal physiotherapy application, pressure ulcer prevention on the buttocks, and foot soaking, these contact products often face frequent immersion in warm water and prolonged contact with human sebum, sweat, dead skin cells, and various chemical detergents. Currently, most medical contact products on the market are made of polymer materials such as polypropylene (PP), ABS resin, conventional medical silicone, or traditional rubber. However, these traditional materials have poor aging resistance in complex humid and heat-prone environments and are prone to surface oxidation, hardening, whitening, and microscopic cracking. The tiny scratches and pores caused by material aging quickly absorb dirt and become a natural breeding ground for bacteria, fungi, and other microorganisms. In high-frequency, high-standard care scenarios such as hand, abdominal, buttock, and foot care, the complex contact environment necessitates extremely high standards of hygiene and sterility for the surface of the equipment. Traditional materials are prone to non-specific adsorption of proteins and lipids, making it difficult to thoroughly remove deep-seated dirt with regular washing or wiping. This not only severely restricts the cleaning effect of clinical or personal washing and care, but also easily produces stubborn odors and greatly increases the risk of infection.

[0003] Therefore, developing a safe, antibacterial, stain-resistant, and durable cleaning material has extremely broad application prospects and is a key technical problem that urgently needs to be solved in the field of personal cleaning appliances or high-end medical care materials. Summary of the Invention

[0004] To address the above issues, this invention provides a self-cleaning composite material, its preparation method, and its applications. By constructing a cross-linked network of low surface energy and highly flexible segments, the surface of low surface energy materials is enriched to build a durable anti-fouling barrier. Simultaneously, a surface-grafted modified mesoporous nanocarrier is introduced to deeply encapsulate and sustainably release antibacterial and antioxidant molecules, aiming to provide a functional composite material that combines high flexibility, self-cleaning, and antibacterial functions.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a composite material with self-cleaning function, the composite material comprising the following raw materials in parts by weight: 55-70 parts of hydroxyl-terminated PDMS (hydroxyl-terminated polydimethylsiloxane), 12-18 parts of PTMEG (polytetrahydrofuran ether diol), 5-7 parts of crosslinking curing agent, 15-18 parts of modified polydopamine, and 0.2 parts of defoaming agent.

[0006] Furthermore, the crosslinking curing agent is selected from any one of IPDI (isophorone diisocyanate), HDI (hexamethylene diisocyanate), and PDI (pentamethylene diisocyanate).

[0007] Furthermore, the defoaming agent is selected from any one of BYK-A 530, BYK-088 and DY-ET133 polyether modified silicone oil.

[0008] Furthermore, the modified polydopamine comprises the following raw materials: MPDA NPs (mesoporous polydopamine nanoparticles), 4-terpene alcohol, EGCG (epigallocatechin gallate), and KH-570 (γ-methacryloyloxypropyltrimethoxysilane), wherein the mass ratio of MPDA NPs, 4-terpene alcohol, EGCG, and KH-570 is 10:5:2.5:1.5.

[0009] Furthermore, the modified polydopamine is prepared as follows: S1: Dissolve 4-terpene alcohol and EGCG, add MPDA NPs, and disperse by ultrasonication in the dark for 20 min to fully wet the nanoparticles and obtain a mixture. Vacuum the mixture to a negative pressure state and maintain it for 30 min. Slowly release the vacuum to restore normal pressure. Repeat the above vacuuming-restoring normal pressure operation 3 times to use the pressure difference to press the active ingredients into the mesoporous space of the nanoparticles. Finally, remove the solvent by rotary evaporation to obtain active mesoporous particles. S2: Add KH-570 to a 90% (v / v) ethanol aqueous solution, adjust the pH to weakly acidic, stir at room temperature for 30 min to allow it to fully hydrolyze, and obtain a hydrolysate. The methoxy group of KH-570 hydrolyzes to generate silanol groups. Disperse the active mesoporous particles in the hydrolysate and stir in a water bath for 2 h. The silanol groups form strong hydrogen bonds with the hydroxyl groups on the surface of the active mesoporous particles. Under heating conditions, dehydration condensation occurs between the hydroxyl groups, so that KH-570 is covalently grafted onto the particle surface to obtain grafted mesoporous particles. S3: The grafted mesoporous particles were centrifuged at high speed, the precipitate was collected and washed with anhydrous ethanol, dried and pulverized to obtain modified polydopamine.

[0010] This invention also provides a method for preparing a composite material with self-cleaning function, the specific steps of which are as follows: Step 1: Heat PTMEG to a molten state and mix it with hydroxyl-terminated PDMS. Then add modified polydopamine and degassing agent to obtain a premix. Perform vacuum high-speed dispersion treatment on the premix for 20 min to make the modified polydopamine uniformly dispersed in the resin matrix. At the same time, use degassing agent and vacuum to remove water and micro bubbles in the system to obtain a dispersion. Step 2: Mix the dispersion and crosslinking curing agent under vacuum at 40-50℃ to obtain a mixed matrix; Step 3: Inject the mixed matrix into the mold, pre-cur at 50℃ for 1 h, then raise the temperature to 75-80℃ and hold for 3 h for deep curing. This allows the isocyanate groups in the crosslinking curing agent to undergo a three-dimensional crosslinking reaction with the hydroxyl groups of PDMS and PTMEG, as well as the active groups on the surface of the modified polydopamine. After cooling and demolding, a composite material with self-cleaning function is obtained.

[0011] The present invention also provides an application of a composite material with self-cleaning function, the composite material being used to manufacture medical care products or personal care products.

[0012] Furthermore, the composite material is used to prepare medical fumigation barrels, electrically heated foot baths, and hot compress therapy equipment.

[0013] The beneficial effects achieved by this invention are as follows: The self-cleaning composite material provided by this invention features hydroxyl-terminated PDMS with a compliant siloxane backbone and non-polar methyl side groups. This molecular structure results in low intrinsic surface tension, providing the chemical basis for the material's hydrophobic and oleophobic properties. PTMEG acts as a toughening and anti-aging agent, enhancing the composite material's service life and effectively preventing yellowing and brittleness. After being dispersed in the matrix, the modified polydopamine nanoparticles, on the one hand, act as rigid crosslinking nodes in the flexible polymer network of the resin, increasing the deformation stress of the composite material and significantly improving its tear strength and abrasion resistance without sacrificing the tensile elasticity of the matrix. On the other hand, some particles are distributed on the surface of the material interface, and their nanoscale particle size introduces a moderate micro-roughness into the originally smooth polyurethane / silicone resin surface, which is the structural basis for constructing a physical antifouling morphology. When proteins, sweat, or water-based stains come into contact with materials, their spreading and wetting on the surface are inhibited, and the adhesion between the dirt and the substrate is reduced, making it difficult for the stains to form a strong adsorption behavior. In addition, the rough surface and low surface tension formed by modified polydopamine at the micro level increase the contact angle of the droplets, making it less likely for water stains to remain, thus greatly reducing the growth rate of bacteria and other microorganisms.

[0014] Meanwhile, the mesoporous polydopamine exhibits a large number of catechol groups and amino groups distributed on its surface and within its pores. These polar groups not only endow it with excellent interfacial adhesion and free radical scavenging (antioxidant) capabilities, but also provide a high density of reactive sites for subsequent hydrogen bonding and silanization modification of KH-570 active molecules. Utilizing its mesoporous structure to load active ingredients with antibacterial and antioxidant activities significantly reduces the volatilization loss of 4-terpene alcohol and EGCG, providing long-lasting antibacterial properties to the functional composite material. The compatibility between the silane coupling agent-modified polydopamine and the resin matrix is ​​also improved. The composite material prepared in this invention achieves a self-cleaning effect through its material properties and lotus leaf-like structural morphology, making it difficult for dirt or water stains to remain. Attached Figure Description

[0015] Figure 1 The surface microstructure of the self-cleaning composite material prepared in Example 2; Figure 2 The contact angle of the self-cleaning composite materials prepared in Comparative Example 1 and Example 2 was investigated. Figure 3 The results of the antibacterial rate study of the self-cleaning composite materials prepared in Examples 1-5 and Comparative Examples 1-3; Figure 4 This is a schematic diagram of the structure of an electrically heated foot bath basin assembled using the self-cleaning composite material prepared in Example 2.

[0016] Figure 4 The components are: 1. Basin based on composite material; 2. Heating element; 3. Temperature sensor; 4. Electric massage rollers; 5. Bubble nozzle; 6. Infrared device; 7. Control panel; 8. Drain outlet. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0019] Unless otherwise specified, all methods used in the following examples are conventional. Unless otherwise specified, all materials used in the following examples are new materials purchased from the market. Among them, the hydroxyl-terminated PDMS used in the following examples and comparative examples has an average molecular weight of 5600 Da, a viscosity of 100 cPs, a hydroxyl value of 20 mg KOH / g, and a density of 0.98 g / mL; the PTMEG used has a molecular weight of 2000±50 Da, a hydroxyl value of 54.7-57.5 mg KOH / g, a viscosity of 1300 cps at 40℃, and a melting point of 29-31℃; the MPDANPs used are in lyophilized powder form with an average particle size of 300 nm and a pore size of 5-30 nm.

[0020] In the following examples, the modified polydopamine comprises the following raw materials in parts by weight: 100 parts MPDA NPs, 50 parts 4-terpene alcohol, 25 parts EGCG, and 15 parts KH-570; The modified polydopamine is prepared as follows: S1: Dissolve 50 parts of 4-terpene alcohol and 25 parts of EGCG in 500 parts of anhydrous ethanol, then add 100 parts of MPDA NPs. Disperse the mixture by ultrasonication at 40 kHz frequency and 200 W power for 20 min in the dark to obtain a mixture. Vacuum the mixture to a negative pressure (-0.08 MPa) and maintain it for 30 min. Slowly release the vacuum to restore normal pressure. Repeat the above vacuuming-restoring normal pressure operation 3 times. Finally, remove the solvent by rotary evaporation in a constant temperature water bath at 35℃ to obtain active mesoporous particles. S2: Take 15 parts of KH-570 and add them to 300 parts of 90% ethanol aqueous solution. Adjust the pH to 5.5 to make it weakly acidic. Stir at 300 rpm at room temperature for 30 min to allow it to be fully hydrolyzed and obtain hydrolysate. Disperse the active mesoporous particles in the hydrolysate and stir in a water bath at 40℃ and 400 rpm for 2 h to obtain grafted mesoporous particles. S3: The grafted mesoporous particles were centrifuged at 8000 rpm for 10 min, the precipitate was collected and washed with anhydrous ethanol, dried and pulverized to obtain modified polydopamine.

[0021] Example 1: This example provides a composite material with self-cleaning function. The composite material includes the following raw materials in parts by weight: 55 parts of hydroxyl-terminated PDMS, 18 parts of PTMEG, 5 parts of IPDI, 15 parts of modified polydopamine, and 0.2 parts of BYK-A 530.

[0022] This embodiment also provides a method for preparing a composite material with self-cleaning function, the specific steps of which are as follows: Step 1: Take 18 parts of PTMEG and heat it at 70℃ for 24 h until it reaches a molten state. Then mix it evenly with 55 parts of hydroxyl-terminated PDMS. Add 15 parts of modified polydopamine and 0.2 parts of BYK-A 530 to obtain a premix. Transfer the premix to a vacuum high-speed disperser for vacuum high-speed dispersion treatment for 20 min. The vacuum degree is -0.08 MPa and the dispersion disc speed is 1500 rpm to obtain a dispersion. Step 2: Mix the dispersion with 5 parts of IPDI under vacuum at 50°C for 10 min at 300 rpm to obtain the mixed matrix; Step 3: Inject the mixed matrix into the mold, pre-cur at 50℃ for 1 hour, then raise the temperature to 80℃ and hold for 3 hours for deep curing. After cooling and demolding, a composite material with self-cleaning function is obtained.

[0023] Example 2: This example provides a composite material with self-cleaning function. The composite material includes the following raw materials in parts by weight: 60 parts of hydroxyl-terminated PDMS, 16 parts of PTMEG, 6 parts of HDI, 16 parts of modified polydopamine, and 0.2 parts of BYK-088.

[0024] This embodiment also provides a method for preparing a composite material with self-cleaning function, the specific steps of which are as follows: Step 1: Take 16 parts of PTMEG and heat it at 70℃ for 24 h until it reaches a molten state. Then mix it evenly with 60 parts of hydroxyl-terminated PDMS. Add 16 parts of modified polydopamine and 0.2 parts of BYK-088 to obtain a premix. Transfer the premix to a vacuum high-speed disperser for vacuum high-speed dispersion treatment for 20 min. The vacuum degree is -0.08 MPa and the dispersion disc speed is 1500 rpm to obtain a dispersion. Step 2: Mix the dispersion with 6 parts of HDI under vacuum at 40°C for 10 min at 300 rpm to obtain a mixed matrix; Step 3: Inject the mixed matrix into the mold, pre-cur at 50℃ for 1 hour, then raise the temperature to 75℃ and hold for 3 hours for deep curing. After cooling and demolding, a composite material with self-cleaning function is obtained.

[0025] Example 3: This example provides a composite material with self-cleaning function. The composite material includes the following raw materials in parts by weight: 65 parts of hydroxyl-terminated PDMS, 14 parts of PTMEG, 7 parts of PDI, 18 parts of modified polydopamine, and 0.2 parts of DY-ET133 polyether modified silicone oil.

[0026] This embodiment also provides a method for preparing a composite material with self-cleaning function, the specific steps of which are as follows: Step 1: Take 14 parts of PTMEG and heat it at 70℃ for 24 h until it reaches a molten state. Then mix it evenly with 65 parts of hydroxyl-terminated PDMS. Add 18 parts of modified polydopamine and 0.2 parts of DY-ET133 polyether modified silicone oil to obtain a premix. Transfer the premix to a vacuum high-speed disperser for vacuum high-speed dispersion treatment for 20 min. The vacuum degree is -0.08 MPa and the dispersion disc speed is 1500 rpm to obtain a dispersion. Step 2: Mix the dispersion with 7 parts of PDI under vacuum at 45°C for 10 min at 300 rpm to obtain a mixed matrix; Step 3: Inject the mixed matrix into the mold, pre-cur at 50℃ for 1 hour, then raise the temperature to 70℃ and hold for 3 hours for deep curing. After cooling and demolding, a composite material with self-cleaning function is obtained.

[0027] Example 4: This example provides a composite material with self-cleaning function. The composite material includes the following raw materials in parts by weight: 64 parts of hydroxyl-terminated PDMS, 15 parts of PTMEG, 6 parts of PDI, 15 parts of modified polydopamine, and 0.2 parts of BYK-A 530.

[0028] This embodiment also provides a method for preparing a composite material with self-cleaning function, the specific steps of which are as follows: Step 1: Take 15 parts of PTMEG and heat it at 70℃ for 24 h until it reaches a molten state. Then mix it evenly with 64 parts of hydroxyl-terminated PDMS. Add 15 parts of modified polydopamine and 0.2 parts of BYK-A 530 to obtain a premix. Transfer the premix to a vacuum high-speed disperser for vacuum high-speed dispersion treatment for 20 min. The vacuum degree is -0.08 MPa and the dispersion disc speed is 1500 rpm to obtain a dispersion. Step 2: Mix the dispersion with 6 parts of PDI under vacuum at 45°C for 10 min at 300 rpm to obtain a mixed matrix; Step 3: Inject the mixed matrix into the mold, pre-cur at 50℃ for 1 hour, then raise the temperature to 70℃ and hold for 3 hours for deep curing. After cooling and demolding, a composite material with self-cleaning function is obtained.

[0029] Example 5: This example provides a composite material with self-cleaning function. The composite material includes the following raw materials in parts by weight: 58 parts of hydroxyl-terminated PDMS, 14 parts of PTMEG, 5 parts of HDI, 16 parts of modified polydopamine, and 0.2 parts of DY-ET133 polyether modified silicone oil.

[0030] This embodiment also provides a method for preparing a composite material with self-cleaning function, the specific steps of which are as follows: Step 1: Take 14 parts of PTMEG and heat it at 70℃ for 24 h until it reaches a molten state. Then mix it evenly with 58 parts of hydroxyl-terminated PDMS. Add 16 parts of modified polydopamine and 0.2 parts of DY-ET133 polyether modified silicone oil to obtain a premix. Transfer the premix to a vacuum high-speed disperser for vacuum high-speed dispersion treatment for 20 min. The vacuum degree is -0.08 MPa and the dispersion disc speed is 1500 rpm to obtain a dispersion. Step 2: Mix the dispersion with 5 parts of HDI under vacuum at 40°C for 10 min at 300 rpm to obtain a mixed matrix; Step 3: Inject the mixed matrix into the mold, pre-cur at 50℃ for 1 hour, then raise the temperature to 75℃ and hold for 3 hours for deep curing. After cooling and demolding, a composite material with self-cleaning function is obtained.

[0031] Example 6: This example provides an application of a composite material with self-cleaning function. The preparation method of the composite material is as shown in Example 2. The composite material is used to prepare an electrically heated foot bath: the composite material prepared in step 3 of Example 2 is molded in an electrically heated foot bath mold as a skeleton structure, i.e., the basin body 1 based on the composite material, and then combined and installed with the heating element 2, temperature sensor 3, electric massage roller 4, bubble nozzle 5, infrared device 6, control panel 7, and drain outlet 8 to obtain a foot bath with self-cleaning function. The structural diagram is shown below. Figure 4 As shown, the electric massage roller 4 is made of bio-based thermoplastic polyurethane elastomer (model B275), the bubble nozzle 5 and the internal water hose are made of food-grade high-temperature resistant silicone (good skin contact), the control panel 7 is made of acrylic material, the drain outlet 8 is integrally formed by casting the composite material of Example 2 into a mold, and the drain outlet 8 and the circuit are treated with insulating and sealing silicone to prevent wear and leakage. The heating element 2 is a water-electricity separation PTC die-cast aluminum tube heater with a rated power of 400 W. The infrared device 6 is a far-infrared physiotherapy lamp module (LED packaged) with an emission wavelength concentrated in 8-14 μm and a single module power of 3 W. The temperature sensor 3 is a high-precision NTC thermistor with a conventional resistance of 10 kΩ and a B value of 3950 K.

[0032] Comparative Example 1: The difference from Example 2 is that no modified polydopamine was added; the rest is the same as Example 2.

[0033] Comparative Example 2: As a blank process control group, the difference from Example 2 is that modified polydopamine was not used. 8.4 parts of MPDA NPs, 4.2 parts of 4-terpene alcohol, 2.1 parts of EGCG and 1.3 parts of KH-570 were mixed evenly to obtain a blend. The blend was used to replace modified polydopamine in the preparation of self-cleaning composite materials. The rest of the process was the same as in Example 2.

[0034] Comparative Example 3: The difference from Example 2 is that modified polydopamine was not used. 8.4 parts of MPDA NPs and 1.3 parts of KH-570 were used instead of modified polydopamine to prepare the self-cleaning composite material. The rest of the process was the same as in Example 2.

[0035] Morphological examination: The composite material prepared in Example 2 was fixed onto the sample plate using conductive adhesive. After gold deposition using a sputtering coating machine, the surface structure was examined under a scanning electron microscope. The results are shown in the figure. Figure 1 .

[0036] Surface wettability assessment: The surface hydrophobicity of the composite materials prepared in Example 2 and Comparative Example 1 was investigated at room temperature using a contact angle meter. A 5 μL drop of deionized water was added to the flat surface of the composite material sample using the pendant drop method. After the water droplet stabilized, the static water contact angle was measured. The results are shown in [Figure number missing]. Figure 2 .

[0037] Antibacterial activity test: The test was conducted using the film application method as per GB / T 31402-2015 "Test Method for Antibacterial Properties of Plastic Surfaces". Staphylococcus aureus and Trichophyton rubrum were selected as test microorganisms, and a concentration of 10... 5 CFU / mL bacterial suspensions were inoculated onto the surfaces of the composite materials prepared in Examples 1-5 and Comparative Examples 1-3, covered with a sterile film, and incubated at 37°C for 24 h. After washing, viable cell counts were performed on agar plates. The control group used conventional LB agar plates. The inhibition rate (%) was calculated as (number of colonies in the control group - number of colonies in the experimental group) / number of colonies in the control group × 100%. The results are shown in […]. Figure 3 .

[0038] Mechanical performance evaluation: In accordance with GB / T 528-2009 standard, the composite materials prepared in Examples 1-5 and Comparative Examples 1-3 were shaped into dumbbell-shaped specimens and tested using a universal testing machine at a tensile speed of 100 mm / min. The maximum tensile strength and elongation at break of the material were recorded. The results are shown in Table 1.

[0039] Stability Study: The self-cleaning composite material prepared in Example 2 was used to investigate the changes in mechanical strength and antibacterial properties under accelerated, mid-term, and long-term stability tests. The accelerated stability test conditions were: temperature 60℃, relative humidity 75%RH, 30 days, with sampling points at 0 and 30 days. The mid-term stability test conditions were: temperature 40℃, relative humidity 75%RH, 6 months, with sampling points at 0, 3, and 6 months. The long-term stability test conditions were: temperature 25℃, relative humidity 60%RH, 14 months, with sampling points at 0, 2, 6, 12, and 14 months. The mechanical properties of the composite material and its antibacterial properties against Staphylococcus aureus were recorded at the sampling points. The results are shown in Table 2.

[0040] Table 1 Mechanical properties of composite materials

[0041] Table 2 Stability Study of Composite Materials

[0042] Figure 1 The results showed that the surface of the composite material prepared in Example 2 had protrusions, and the micro-nano morphology formed by the modified polydopamine in its microstructure was beneficial to reducing the surface tension of water and exhibiting superhydrophobic properties.

[0043] Figure 2 The results showed that the water contact angle formed in Comparative Example 1 was 120.3°, and the water contact angle formed on the surface of the composite material prepared in Example 2 was 156.8°. This indicates that the modified polydopamine particles have a positive effect on the surface structure of the composite material that mimics the hydrophobic properties of lotus leaves, and water stains are not easily left behind, thus exhibiting self-cleaning properties.

[0044] Figure 3 The results showed that the composite materials prepared in Examples 1-5 all had good antibacterial activity and effectively prevented pathogenic microorganisms from remaining and growing on the material surface. Although Comparative Example 2 contained the same components as Example 2, its antibacterial ability was insufficient and its material formability was poor. Comparative Example 3 had good formability and its antibacterial ability was similar to that of Comparative Example 2, but both were significantly lower than those of the Example groups. This indicates that modified polydopamine and its loading process have a positive effect on improving the antibacterial ability of composite materials. Its good antibacterial properties cannot be achieved by simple blending. The self-cleaning composite material provided has great potential for medical and nursing applications.

[0045] Figure 4 The electric heating foot bath basin assembled from the composite material prepared in Example 2 has a frame that has greatly reduced material and energy loss in the production process, improved production efficiency, and also demonstrated its application value for medical care products with high requirements such as antibacterial properties and easy cleaning.

[0046] Table 1 shows that the composite materials prepared in Examples 1-5 have good tensile strength and elongation at break, which can improve the durability and weather resistance of materials or products and extend their service life. In Comparative Example 2, since the liquid form of 4-terpene alcohol and KH-570 were directly blended for the preparation of composite materials, their curing and molding properties were insufficient and their mechanical properties could not meet the product requirements. The composite material prepared in Comparative Example 3 can be molded, but its mechanical properties are similar to those in Comparative Example 1. Simply relying on KH-570 to improve the compatibility between polydopamine and PDMS and other matrices, its blending process has a low impact on the overall strength of the material. This indicates that the modified polydopamine process has a good effect on improving the overall tensile strength of composite materials and can meet the needs of daily household use or special needs of patients.

[0047] The results in Table 2 show that the composite material prepared in Example 2 can still maintain good mechanical properties and antibacterial activity under accelerated testing conditions of high temperature and high humidity. Its long-term stability over 14 months is good and can meet the requirements for long-term antibacterial effect.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0049] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A composite material with self-cleaning function, characterized in that, The composite material comprises the following raw materials in parts by weight: 55-70 parts of hydroxyl-terminated PDMS, 12-18 parts of PTMEG, 5-7 parts of crosslinking curing agent, 15-18 parts of modified polydopamine, and 0.2 parts of defoaming agent; The modified polydopamine comprises the following raw materials: MPDA NPs, 4-terpene alcohol, EGCG, and KH-570. The preparation method of the modified polydopamine is as follows: S1: Dissolve 4-terpene alcohol and EGCG, then add MPDA NPs to disperse them to obtain a mixture. Perform vacuum-restoration and rotary evaporation on the mixture to obtain active mesoporous particles. S2: Take KH-570 and hydrolyze it to obtain a hydrolysate. Disperse the active mesoporous particles in the hydrolysate, heat and stir to obtain grafted mesoporous particles. S3: The grafted mesoporous particles are centrifuged at high speed, the precipitate is collected, washed, dried and pulverized to obtain modified polydopamine.

2. The composite material with self-cleaning function according to claim 1, characterized in that, The mass ratio of MPDANPs, 4-terpene alcohol, EGCG and KH-570 is 10:5:2.5:1.

5.

3. A composite material with self-cleaning function according to claim 2, characterized in that, The crosslinking curing agent is selected from any one of IPDI, HDI and PDI.

4. A composite material with self-cleaning function according to claim 2, characterized in that, The defoaming agent is selected from any one of BYK-A 530, BYK-088 and DY-ET133 polyether modified silicone oil.

5. A method for preparing a composite material with self-cleaning function according to any one of claims 1-4, characterized in that, The specific steps are as follows: Step 1: Heat PTMEG to melt, mix with hydroxyl-terminated PDMS, then add modified polydopamine and defoaming agent to obtain a premixed solution. Disperse the premixed solution to obtain a dispersion. Step 2: Mix the dispersion with the crosslinking curing agent to obtain a mixed matrix; Step 3: Inject the mixed matrix into the mold, cure, cool and demold to obtain a composite material with self-cleaning function.

6. An application of a composite material with self-cleaning function according to any one of claims 1-4, characterized in that, The composite material is used to manufacture medical supplies or personal care products; The composite material is used to manufacture medical fumigation barrels, electrically heated foot baths, and hot compress therapy equipment.

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