Preparation method of high-load nanoparticle functional non-woven material

Abstract

The invention discloses a preparation method of a high-load nanoparticle functional non-woven material. The preparation method comprises the following steps: firstly, carrying out simple pretreatment on the non-woven material by using an alkaline solution, and combining inorganic nanoparticles with the non-woven material in a chemical bond manner by using a hydrophilic organic monomer containing unsaturated double bonds under the action of irradiation, so as to prepare the functional non-woven material. The non-woven material has more contact sites with the nano-particles in an alkalization mode, the nano-particles with the ultra-small size are connected in a chemical bond mode, pores among fibers cannot be blocked, the wearability such as breathability, hand feeling and appearance of the non-woven material is reserved to the maximum extent, the problem that a traditional nano-particle loading material is prone to falling off is solved, and the service life of the non-woven material is prolonged. The material has high load rate and high durability, the antibacterial performance of the nanoparticles can be fully exerted, and the preparation process is simple, easy to implement and environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of functional non-woven materials, and particularly relates to a preparation method for the stable combination of nanoparticles and inert fibers. Background Art

[0002] Nanomaterials refer to materials in which at least one dimension is in the nanoscale (1-100 nm) in three-dimensional space or materials composed of them as basic units, and have many unique properties different from traditional materials. At present, non-woven materials loaded with nanoparticles mainly load nanoparticles on the materials by means of physical adsorption, coating, blending, etc., and each has its own drawbacks: Patent No. 111468072A uses a method of blending polyacrylonitrile and ZIF-8 to coat nanoparticles into fibers, but the aggregation of nanoparticles will affect the spinnability of the materials, reduce the mechanical properties of the materials, and cannot be applied to natural fibers, with great limitations; Patent CN111926562A uses polydopamine to bond nanoparticles, with a high loading rate, but uses a large amount of chemical aids for bonding, which will affect the service performance of the materials such as the surface and handle, and cause serious environmental pollution. The binder will also gradually fail during use, resulting in the shedding of nanoparticles; Patent CN109680495A uses a method of radiation grafting and ring-opening polymerization to react modified nanoparticles with a substrate grafted with functional groups and graft them onto the substrate by chemical bonds, improving the durability of the materials. However, modifying both the substrate and the nanoparticles at the same time has a high cost, complex operation, and cumbersome steps, making it difficult to achieve large-scale production.

[0003] At present, functional materials with non-woven fabrics as the substrate loaded with nanoparticles are still difficult to be applied in practice. The main reasons are: (1) The low loading amount results in nanoparticles being unable to play a role. (2) The chemical reagents used to bond nanoparticles are prone to cause environmental pollution and will gradually fail. (3) Nanoparticles are prone to fall off during actual use, and the loading stability is poor. How to avoid these problems is still the key to the research and development of multifunctional and high-value-added non-woven materials. Summary of the Invention

[0004] The technical problem actually to be solved by the present invention is to overcome the problems of low nanoparticle loading rate and poor durability in the prior art, and provides a preparation method for a functional non-woven material with high-loading nanoparticles. The present invention greatly improves the nanoparticle loading rate and durability of non-woven materials, and at the same time maximally retains the various properties of the raw materials. The preparation process is simple, easy to implement, green and environmentally friendly. The specific preparation method includes the following steps:

[0005] 1. Ultrasonically clean the non-woven material in a cleaning solution and vacuum dry it to remove excess impurities;

[0006] 2. Alkalize and etch the non-woven material with an alkaline solution to provide more contact sites between the non-woven fibers and the inorganic nanoparticles;

[0007] 3. Prepare a grafting solution by mixing inorganic nanoparticles and a linking monomer containing a carbon-carbon double bond, and uniformly disperse the nanoparticles in an organic solvent;

[0008] 4. The linking monomer containing a carbon-carbon double bond undergoes a graft polymerization reaction under the action of radiation, and a graft reaction occurs with the inorganic nanoparticles and the non-woven material;

[0009] 5. Wash with deionized water and dry to obtain the functional non-woven material.

[0010] Among them, the non-woven material in step 1 includes one of polypropylene meltblown cloth and polyester needled cloth.

[0011] Among them, the cleaning solvent in step 1 can be one of methanol, ethanol, acetone, or deionized water, the ultrasonic power is 100w - 3000w, and the time is 5min - 30min.

[0012] Among them, the alkaline solution in step 2 can be one of sodium hydroxide or potassium hydroxide, the concentration is 0.1mol / L - 0.5mol / L, the ultrasonic power is 100w - 3000w, and the alkalization time is 5min - 60min.

[0013] Among them, the chemical structure of the linking monomer in step 3 is a self-polymerizable monomer containing a carbon-carbon double bond (C=C) in the monomer molecule, such as one of 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.

[0014] Among them, the inorganic nanoparticles in step 3 are any one of nano-TiO2, nano-ZnO, nano-SiO2, nano-CuO, and nano-ZIF-8, and the particle size of the inorganic nanoparticles is between 1 - 200nm; the organic solvent can be one or several of methanol, ethanol, or deionized water.

[0015] Among them, the environment for uniformly dispersing the inorganic nanoparticles in the organic solvent in step 3 is an ultrasonic environment, the ultrasonic time is 5 - 30min, and the ultrasonic power is 100w - 3000w.

[0016] Among them, the radiation source in step 4 is an electron beam, which generates active free radicals on the non-woven material through irradiation, and the irradiation dose is 5 - 200kGy.

[0017] Among them, the application method of the grafting liquid in step 4 is atomized spraying (spraying time is 3 - 10s) and ultrasonic impregnation (1 - 15min), and the best method is atomized spraying.

[0018] Among them, the liquid-carrying rate of the non-woven material in step 4 is controlled to be 100%-300% of its own mass.

[0019] Among them, the weight ratio of the inorganic nanoparticles to the substrate in step 4 is controlled to be 0.05% - 15%.

[0020] Among them, the irradiation environment in step 4 is an oxygen-free environment. The oxygen-free condition can be achieved by conventional technical means in the art. For example, an inert gas can be introduced into the material to discharge the oxygen therein (the inert gas refers to a gas that does not react with the material, not limited to the conventionally referred rare gases, for example, it can be nitrogen). The oxygen-free condition can also be achieved by vacuum packaging into a sealed bag to create an oxygen-free environment. In a preferred embodiment of the present invention, the oxygen-free condition is achieved by introducing nitrogen for 5 - 20 minutes.

[0021] Advantages of the present invention:

[0022] In the present invention, the non-woven fabric substrate is pretreated by alkalization to etch the surface of the non-woven material fibers, so that the nanoparticles and the substrate have larger contact sites, thereby increasing the loading amount of the nanoparticles.

[0023] The present invention utilizes irradiation to initiate graft polymerization reaction. The long chains at both ends of the self-polymerizing monomer are respectively connected to the non-woven material and the nanoparticles, so that the inorganic nanoparticles are combined with the substrate in the form of covalent bonds, with firm loading, solving the problem that the nanoparticles are easily detached during actual use, making the material have excellent durability. After ultrasonic treatment in an ultrasonic environment of up to 3000w for 1h, the loading of the surface nanoparticles does not change significantly and the mass loss is extremely small.

[0024] The three-dimensional structure of the non-woven material in the present invention does not change. The nanoparticles only cover the fiber surface and do not block the pores between the fibers. Compared with the method of loading nanoparticles using adhesives, less chemical reagents are used and it is more environmentally friendly, and the impact on the performance of the material such as air permeability and hand feeling is smaller.

[0025] In the present invention, the grafting solution is applied to the non-woven fabric by atomized spraying, which reduces the waste of the grafting solution during actual operation and also avoids the contamination of the grafting solution by impurities on the surface of the non-woven material; compared with the dipping method in other inventions, the inorganic nanoparticles are more evenly distributed, less used, and more easily and evenly attached to the fiber surface;

[0026] The introduction of hydrophilic monomers in the present invention can improve the hydrophilicity of the material. Adjusting the liquid-carrying rate of the material can be precisely controlled. It can be sprayed on one side or both sides according to actual use requirements to prepare one-way functional materials; under the condition of not affecting the original performance of the raw material, the contact angle can be reduced by up to 24° compared with the raw material. Description of the Drawings

[0027] Figure 1 It is a scanning electron microscope image (SEM) of polypropylene fiber modified and loaded with nanoparticles (ZIF-8);

[0028] Figure 2 (a) and (b) are respectively schematic diagrams of the antibacterial zones of polypropylene fibers irradiated and grafted with ZIF-8 against Escherichia coli and Staphylococcus aureus;

[0029] Figure 3 (a) and (b) are respectively schematic diagrams of the contact angles of polypropylene fibers before and after irradiation and grafting with ZIF-8.

[0030] Figure 4 It is an XRD schematic diagram of polypropylene fiber modified and grafted with ZIF-8 nanoparticles. Detailed Embodiments

[0031] The following further details the preparation method of a high-load nanoparticle functional nonwoven material provided by the present invention in combination with specific embodiments. It should be understood that the specific examples are only used to explain and introduce the present invention and cannot limit the application scope of the present invention. Any modifications and changes made to the present invention without departing from the purpose and scope of the present invention fall within the protection scope of the present invention.

[0032] As shown in the schemes of Examples 1-3:

[0033] Example 1:

[0034] Step 1: Take a pure polypropylene melt-blown fabric sample, cut the polypropylene nonwoven fabric into squares with a size of 10 cm × 10 cm, then put the cut polypropylene nonwoven fabric into a methanol solution, and perform ultrasonic cleaning for 10 minutes at an ultrasonic power of 600 w. Finally, wash the sample three times with deionized water and then put it into a conventional oven at 65 °C for 7 hours to dry and remove excess impurities.

[0035] Step 2: Place the polypropylene nonwoven fabric in a 0.2 mol / L NaOH solution and perform alkalization in an ultrasonic environment with an ultrasonic power of 1200 w for 10 min;

[0036] Step 3: Prepare a grafting solution by mixing 75.8 wt% water, 22.7 wt% 2-hydroxyethyl methacrylate, and 1.5 wt% ZIF-8 nanoparticles, place it in an ultrasonic environment to make the nanoparticles uniformly dispersed in the solution with an ultrasonic power of 1000 w and an ultrasonic time of 5 min, and then pass nitrogen through the above system at room temperature for 15 min to remove oxygen in the system.

[0037] Step 4: Using the spray coating method, evenly distribute the grafting solution on the polypropylene nonwoven fabric. The spraying time is 5 s to make the material surface evenly moisture-permeable. Under the anaerobic environment protected by nitrogen, irradiate using an electron accelerator with an irradiation dose of 25 kGy to initiate the graft polymerization reaction.

[0038] Step 5: Wash the reacted polypropylene nonwoven fabric 3 times with ethanol and deionized water respectively to remove the excess monomers, and dry it in a conventional oven at 60 °C for 6 h.

[0039] Example 2:

[0040] Step 1: Cut the polypropylene nonwoven fabric into squares with a size of 10 cm × 10 cm. Then put the cut polypropylene nonwoven fabric into an ethanol solution and perform ultrasonic cleaning at an ultrasonic power of 800 w for 25 minutes. Finally, wash the sample 3 times with deionized water and then dry it in a conventional oven at 70 °C for 6 hours to remove the excess impurities.

[0041] Step 2: Place the polypropylene nonwoven fabric in a 0.3 mol / L NaOH solution and perform alkalization in an ultrasonic environment with an ultrasonic power of 1000 w for 15 min;

[0042] Step 3: Prepare a grafting solution by mixing 78.44 wt% ethanol, 19.6 wt% 2-hydroxyethyl acrylate, and 1.96 wt% ZnO nanoparticles. Place it in an ultrasonic environment to make the nanoparticles evenly dispersed in the solution. The ultrasonic power is 1000 w and the ultrasonic time is 5 min. Then purge the above system with nitrogen at room temperature for 15 min to remove the oxygen in the system.

[0043] Step 4: Using the spray coating method, evenly distribute the grafting solution on the polypropylene nonwoven fabric. The spraying time is 10 s to make the material surface evenly moisture-permeable. Seal the polypropylene nonwoven fabric in a sealed bag and store it under vacuum. Under an anaerobic environment, irradiate using an electron accelerator with an irradiation dose of 30 kGy to initiate the graft polymerization reaction.

[0044] Step 5: Wash the reacted polypropylene nonwoven fabric 3 times with ethanol and deionized water respectively to remove the excess monomers, and dry it in a conventional oven at 55 °C for 7 h.

[0045] Example 3:

[0046] Step 1: Take a pure polyester needle-punched fabric sample. Cut the polyester nonwoven fabric into squares with a size of 10 cm × 10 cm. Then put the cut polyester nonwoven fabric into a methanol solution and perform pretreatment at an ultrasonic power of 1200 w for 20 minutes. Finally, wash the sample 3 times with deionized water and then dry it in a conventional oven at 70 °C for 6 hours to remove the excess impurities.

[0047] Step 2: Place the polyester fabric in a 0.5 mol / L NaOH solution and subject it to alkalization in an ultrasonic environment with an ultrasonic power of 1500 w for 12 min.

[0048] Step 3: Prepare a grafting solution by mixing 69.6 wt% methanol, 26.1 wt% 2-hydroxyethyl acrylate, and 4.3 wt% TiO2 nanoparticles. Place the grafting solution in an ultrasonic environment to uniformly disperse ZIF-8 in the solution with an ultrasonic power of 800 w for 5 min. Then, purge the system with nitrogen for 12 min at room temperature to remove oxygen in the system.

[0049] Step 4: Immerse the polyester nonwoven fabric in the grafting solution and promote the uniform distribution of the grafting solution on the nonwoven fabric in an ultrasonic environment with an ultrasonic power of 1000 w for 4 min. Under an anaerobic environment protected by nitrogen, irradiate it using an electron accelerator with an irradiation dose of 100 kGy to initiate the graft polymerization reaction.

[0050] Step 5: Wash the reacted polyester nonwoven fabric 3 times with ethanol and deionized water respectively to remove excess monomers, and dry it in a conventional oven at 65 °C for 5 h.

[0051] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention in any other form. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change, and improvement made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a high-load nanoparticle-functional nonwoven material, characterized in that The steps are as follows: 1) Ultrasonically clean the non-woven material in a cleaning solution and vacuum dry it to remove excess impurities; 2) Alkaline etch the non-woven material with an alkaline solution to provide more contact sites between the non-woven fibers and the inorganic nanoparticles; 3) Prepare a grafting solution by mixing inorganic nanoparticles with a linking monomer containing a carbon-carbon double bond and uniformly disperse the nanoparticles in an organic solvent; 4) The linking monomer containing a carbon-carbon double bond undergoes a graft polymerization reaction under the action of radiation and undergoes a graft reaction with the inorganic nanoparticles and the non-woven material; 5) Wash with deionized water and dry to obtain the functional non-woven material.

2. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that The non-woven material in step 1) includes one of polypropylene meltblown cloth and polyester needle punched cloth.

3. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The cleaning solvent in step 1) can be one of methanol, ethanol, acetone or deionized water, the ultrasonic power is 100w - 3000w, and the time is 5min - 30min.

4. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The alkaline solution in step 2) can be one of sodium hydroxide or potassium hydroxide, the concentration is 0.1mol / L - 0.5mol / L, the ultrasonic power is 100w - 3000w, and the alkalization time is 5min - 60min.

5. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, wherein The chemical structure of the linking monomer in step 3) is a self-polymerizable monomer containing a carbon-carbon double bond (C=C) in the monomer molecule, such as one of hydroxyethyl acrylate and hydroxyethyl methacrylate.

6. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The inorganic nanoparticles in step 3) are any one of nano-TiO2, nano-ZnO, nano-SiO2, nano-CuO, nano-ZIF-8, the particle size of the inorganic nanoparticles is between 1 - 200nm, and the solvent can be one or more of methanol, ethanol or deionized water.

7. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The environment for uniformly dispersing the inorganic nanoparticles in the organic solvent in step 3) is an ultrasonic environment, the ultrasonic time is 5 - 30min, and the ultrasonic power is 100w - 3000w.

8. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The radiation source in step 4) is an electron beam, which generates active free radicals on the non-woven material through irradiation, and the irradiation dose is 5 - 200kGy.

9. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The application method of the grafting liquid in step 4) is atomized spraying (spraying time is 3 - 10s) and ultrasonic impregnation (1 - 15min), and the best method is atomized spraying.

10. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, wherein, The liquid-carrying rate of the non-woven material in step 4) is controlled within 100% - 300% of its own mass.

11. The preparation method according to claim 1, wherein, The weight ratio of the inorganic nanoparticles to the substrate in step 4) is controlled within 0.05% - 15%.

12. The preparation method of a high-load nanoparticle-functional nonwoven material according to claim 1, characterized in that, The irradiation environment in step 4) is an anaerobic environment. The anaerobic condition can be achieved by conventional technical means in the art. For example, an inert gas can be introduced into the material to expel the oxygen therein (the inert gas refers to a gas that does not react with the material, not limited to the conventionally referred noble gases, for example, it can be nitrogen); the anaerobic condition can also be achieved by vacuum packaging into a sealed bag to create an anaerobic environment. In a preferred embodiment of the present invention, the anaerobic condition is achieved by introducing nitrogen for 5 - 20min.

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