Biomass nanoparticle-based self-charging nonwoven fabric, method for preparing same, and use thereof

Abstract

The present application relates to the technical field of functional non-woven fabric, in particular to a self-charging non-woven fabric based on biomass nanoparticles, a preparation method and application thereof, comprising polyacrylonitrile nanofibers and superfine fibers; 50-200nm wool particles are compounded in the polyacrylonitrile nanofibers. The superfine fiber is a fiber with a skin-core structure, the skin layer is a low-melting-point fiber, and active carbon particles are compounded; the polyacrylonitrile nanofiber and the superfine fiber are fused and bonded through heating treatment. The present application solves the problems of low static electricity durability and easy failure of traditional melt-blown non-manufacturing materials in actual use, realizes the self-charging function under the condition of air blowing, and greatly improves the durability of the electrostatic non-woven fabric.

Description

Technical Field

[0001] This invention relates to the field of functional nonwoven fabric technology, and in particular to a self-charging nonwoven fabric based on biomass nanoparticles, its preparation method, and its application. Background Technology

[0002] With the deepening of industrialization, fine particulate matter has become one of the most important air pollutants, posing a serious threat to human health. Therefore, how to effectively prevent industrial particulate matter from entering the atmosphere and how to prevent atmospheric particulate matter from being absorbed by the human body are urgent problems to be solved. Traditional protective filter materials mainly rely on physical interception, inertial impaction, Brownian diffusion and other mechanical actions to capture fine particulate matter. While achieving high efficiency in filtering fine particulate pollutants, they also have high pressure resistance, poor air permeability and comfort, and a short service life.

[0003] The trapping force of electret filter materials mainly consists of the Coulomb force and inductive force exerted by charged fibers on microparticles (charged or uncharged particles). Electrostatically enhanced fiber filtration achieves efficiency improvement and resistance reduction by pre-charging or applying an external electric field; however, if the external electric field is removed, the fibers retain their charge for a very short time, or the residual charge decays rapidly. Electret filter materials can store space charge for a relatively long period. CN105231523A discloses a high-efficiency protective mask with a triboelectric nanogenerator as the filter layer. This invention performs surface nano-modification on traditional mask filter materials and adds another nano-aluminum-modified copper mesh as the friction layer electrode, which can generate a static voltage of 300-400V, improving electrostatic filtration performance. Metal electrode materials such as copper mesh have poor flexibility and are prone to cracking and breakage during continuous bending; furthermore, the friction material obtained through surface nano-modification has poor wear resistance, which directly affects the filtration stability and service life of the mask material. Patent CN11249638A discloses a high-efficiency protective mask based on an all-fiber electret generator and its preparation method. Its filter layer comprises a silicone film, a conductive fabric, an electret fiber membrane, and a non-woven fabric, stacked sequentially. The conductive fabric and the electret fiber membrane have different electronegativity, and can generate a static voltage of 200-1000V driven by autonomous breathing. It has high filtration efficiency, low piezoresistive resistance, and good flexibility and breathability. However, its complex structure and the fact that exhalation and inhalation alone cannot effectively drive significant contact and separation between the two membrane layers result in poor static charge generation and stability.

[0004] In view of this, it is necessary to provide a self-charging nonwoven fabric based on biomass nanoparticles, its preparation method and application, in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a self-charging nonwoven fabric based on biomass nanoparticles, its preparation method, and its application. This invention solves the problems of low electrostatic durability and easy failure of traditional meltblown nonwoven materials in actual use, and realizes the self-charging function under airflow purging conditions, which greatly improves the durability of electrostatic nonwoven fabrics.

[0006] To achieve the above objectives, the present invention provides a self-charging nonwoven fabric based on biomass nanoparticles, comprising polyacrylonitrile nanofibers and ultrafine fibers; wherein the polyacrylonitrile nanofibers are composite with wool particles of 50-200 nm.

[0007] Furthermore, the wool particles have a multi-sized microporous structure with a porosity of 5-50%.

[0008] Furthermore, the amount of wool particles added is 1-20% of the mass of the polyacrylonitrile nanofibers.

[0009] Furthermore, the mass ratio of polyacrylonitrile nanofibers to ultrafine fibers is 1:(0.1-1);

[0010] And / or, the diameter of the polyacrylonitrile nanofibers is 100-800 nm, and the diameter of the ultrafine fibers is 1-10 μm.

[0011] Furthermore, the ultrafine fiber is a fiber with a core-sheath structure, and the sheath is a low-melting-point fiber, and is composite with activated carbon particles; through heat treatment, the polyacrylonitrile nanofibers and ultrafine fibers are melt-bonded.

[0012] Furthermore, the amount of activated carbon particles added is 1-20% of the mass of the low-melting-point fiber;

[0013] The low-melting-point fiber is a polyester fiber or a polyamide fiber with a melting point of 80-120℃;

[0014] The core layer diameter of the fiber with the core-sheath structure is 1-10 μm, and the core layer material is polyester or polypropylene.

[0015] Secondly, the present invention provides a method for preparing a self-charging nonwoven fabric based on biomass nanoparticles as described in any one of the above claims, comprising the following steps:

[0016] S1. Wool particles are added to a polyacrylonitrile solution and spun to obtain polyacrylonitrile fibers;

[0017] S2. Core-sheath fibers are obtained by coaxial spinning, wherein the sheath layer of the core-sheath fibers is a low-melting-point fiber and is compounded with activated carbon particles.

[0018] S3. The polyacrylonitrile fiber and the core-sheath fiber are combined to obtain a nonwoven fabric by hot pressing, and then water electret is performed to obtain the self-charging nonwoven fabric.

[0019] Furthermore, the composite method of the polyacrylonitrile fiber and the core-sheath fiber includes: simultaneously spinning and depositing the polyacrylonitrile fiber and the core-sheath fiber to achieve composite;

[0020] Alternatively, one type of fiber can be spun and deposited first, and then another type of fiber can be deposited on its surface. Further, step S2 includes: using polypropylene as the core layer and activated carbon particles and low-melting-point polyester as the sheath layer, and obtaining a core-sheath fiber by coaxial spinning.

[0021] Thirdly, the present invention provides an application of the above-described self-charging nonwoven fabric based on biomass nanoparticles, wherein the self-charging nonwoven fabric is used in the preparation of air filter materials.

[0022] The beneficial effects of this invention are as follows:

[0023] The self-charging nonwoven fabric based on biomass nanoparticles provided by this invention uses 50-200nm wool particles combined with PAN nanofibers. The PAN composite nonwoven fabric, rich in nano-wool particles, can achieve high electrostatic performance under water electret conditions. Simultaneously, during use, the PAN composite nanofibers vibrate under the influence of airflow vortices, causing the nano-wool particles to momentarily contact and separate from the surrounding composite fibers, resulting in a large accumulation of charge. This gives the product excellent dust particle interception efficiency and self-charging characteristics. Furthermore, the gradient lamination structure of the nanofibers and ultrafine fibers in the PAN / nano-wool particle composite nonwoven fabric endows it with extremely high dust-holding capacity. Attached Figure Description

[0024] Figure 1 This is a physical image of wool micro / nanoparticles;

[0025] Figure 2 These are TEM images of wool micro / nanoparticles. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] This invention provides a self-charging nonwoven fabric based on biomass nanoparticles, comprising polyacrylonitrile nanofibers and ultrafine fibers; wherein the polyacrylonitrile (PAN) nanofibers are composite with wool particles of 50-200 nm.

[0028] Wool in nature is a high-quality biomass polypeptide material that is abundant and renewable. It has unique physicochemical properties. Studies have found that the amphoteric molecular properties and hydrophilic properties of wool give it good water electret properties. At the same time, the instantaneous contact and separation between the α-helical polypeptide structure of wool and polymer materials such as PAN will generate a large amount of electrostatic charge. After nano-modification, the water electret and contact electrification properties can be greatly improved.

[0029] Therefore, this invention uses 50-200nm wool particles combined with PAN nanofibers. The PAN composite nonwoven fabric rich in nanofibers can achieve high electrostatic performance under water electret conditions. Simultaneously, during use, the PAN composite nanofibers vibrate under the influence of airflow vortices, causing the nanofibers to momentarily contact and separate from the surrounding composite fibers, resulting in a large accumulation of charge. This gives the product excellent dust particle interception efficiency and self-charging characteristics. Furthermore, the gradient lamination structure of the nanofibers and ultrafine fibers in the PAN / nanofoo particle composite nonwoven fabric endows it with extremely high dust-holding capacity.

[0030] like Figure 1 and 2 As shown, wool particles aggregate together in a macroscopic state, while in a microscopic state, the particle size is between 50-200nm, and the morphology is a uniform spherical shape.

[0031] Preferably, the wool particles have a multi-sized microporous structure with a porosity of 5-50%. Utilizing the high hydrophilicity and hydrothermal reaction properties of the wool micro / nanoparticles, a method of flash expansion of the wool fiber micro / nanoparticles using high-pressure steam can be employed, achieving a volume expansion rate of 80% and a specific surface area of ​​20 m². 2 / g not only increases the number of microporous structures in wool micro-nanoparticles, but also enables the construction of multi-size microporous structures.

[0032] The amount of wool particles added is 1-20% of the mass of the polyacrylonitrile nanofibers, preferably 5-15%. If the amount of wool particles added is too small, it will not be conducive to the instantaneous contact and separation of the nanowool particles with the surrounding composite fibers to generate charges. If the amount added is too large, it will affect the spinning performance and strength of the PAN nanofibers.

[0033] The mass ratio of polyacrylonitrile nanofibers to ultrafine fibers is 1:(0.1-1), preferably 1:(0.5-1; the polyacrylonitrile nanofibers and ultrafine fibers form a gradient laminated structure, which can improve the dust holding capacity and strength of the self-charging nonwoven fabric, thereby improving its service life.

[0034] And / or, the diameter of the polyacrylonitrile nanofibers is 100-800 nm, for example 150, 200, 300, 500, 600 nm; the diameter of the ultrafine fibers is 1-10 μm, for example 2, 3, 5, 6, 8 μm.

[0035] Preferably, the microfiber is a fiber with a core-sheath structure, and the sheath is a low-melting-point fiber, composited with activated carbon particles. Through heat treatment, the polyacrylonitrile nanofibers and microfibers are fused together. This operation, through the fusion bonding of the sheath, significantly improves the bonding strength between the polyacrylonitrile nanofibers and microfibers, as well as the load-bearing capacity of the activated carbon particles, thereby improving the stability of the self-charging nonwoven fabric. The adsorption effect of the activated carbon particles further enhances the filtration and adsorption properties, and can adsorb and intercept a certain amount of wool nanoparticles, preventing their loss, thus improving the durability of the self-charging performance.

[0036] The amount of activated carbon particles added is 1-20% of the mass of the low melting point fiber, preferably 3-12%; the particle size of the activated carbon particles is 10-200μm, preferably 10-100μm, and the pore size is 1nm-10μm, preferably 10nm-1μm.

[0037] The low-melting-point fiber is a polyester fiber or a polyamide fiber with a melting point of 80-120℃.

[0038] The core layer diameter of the fiber with the core-sheath structure is 1-10 μm, and the core layer material is polyester or polypropylene.

[0039] Secondly, the present invention provides a method for preparing a self-charging nonwoven fabric based on biomass nanoparticles as described in any one of the above claims, comprising the following steps:

[0040] S1. Wool particles are added to a polyacrylonitrile solution and spun to obtain polyacrylonitrile fibers;

[0041] S2. Core-sheath fibers are obtained by coaxial spinning, wherein the sheath layer of the core-sheath fibers is a low-melting-point fiber and is compounded with activated carbon particles.

[0042] S3. The polyacrylonitrile fiber and the core-sheath fiber are combined to obtain a nonwoven fabric, which is then hot-pressed and followed by water electret treatment to obtain the self-charging nonwoven fabric. During the hot-pressing process, activated carbon particles are released. The hot-pressing temperature is higher than the melting point of the low-melting-point fiber. The water pressure of the high-pressure water pump is adjusted to 2MPa, and pure water is delivered to the fan-shaped nozzle through the high-pressure water pump. The fan-shaped nozzle performs hydroentangling through the nonwoven fabric, and the pure water generates an electric charge through friction with the nonwoven fabric, thus obtaining the self-charging nonwoven fabric.

[0043] The composite method of the polyacrylonitrile fiber and the core-sheath fiber includes: simultaneously spinning and depositing the polyacrylonitrile fiber and the core-sheath fiber to achieve composite;

[0044] Alternatively, one type of fiber can be spun and deposited first, and then another type of fiber can be deposited on its surface.

[0045] Preferably, step S2 includes: using polypropylene as the core layer and activated carbon particles and low-melting-point polyester as the sheath layer, and obtaining core-sheath fiber by coaxial spinning.

[0046] Thirdly, the present invention provides an application of the above-described self-charging nonwoven fabric based on biomass nanoparticles, wherein the self-charging nonwoven fabric is used in the preparation of air filter materials.

[0047] Example 1

[0048] A self-charging nonwoven fabric based on biomass nanoparticles comprises 300nm polyacrylonitrile nanofibers and ultrafine fibers; the PAN nanofibers are composited with 50-200nm wool particles. The ultrafine fibers are core-sheath fibers, with the sheath being polyester composited with activated carbon particles and the core being 2μm polyacrylonitrile fibers. The preparation method includes the following steps:

[0049] S1. Wool particles are added to a polyacrylonitrile solution and spun to obtain polyacrylonitrile fibers; the amount of wool particles added is 10% of the mass of the polyacrylonitrile nanofibers.

[0050] S2. Sheath-core fiber is obtained by coaxial spinning with polypropylene as the core layer and activated carbon particles and low-melting-point polyester as the sheath layer; the amount of activated carbon particles added is 8% of the mass of low-melting-point polyester.

[0051] S3. The polyacrylonitrile fibers and the core-sheath fibers are combined to obtain a nonwoven fabric, which is then hot-pressed to obtain a self-charging nonwoven fabric. The mass ratio of polyacrylonitrile nanofibers to ultrafine fibers is 1:0.8.

[0052] Example 2

[0053] A self-charging nonwoven fabric based on biomass nanoparticles differs from Example 1 in that the wool particles have a multi-sized microporous structure with a porosity of 30%.

[0054] Example 3

[0055] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that the amount of wool particles added is 15% of the mass of polyacrylonitrile nanofibers.

[0056] Example 4

[0057] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that the amount of wool particles added is 5% of the mass of polyacrylonitrile nanofibers.

[0058] Example 5

[0059] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that the amount of activated carbon particles added is 3% of the mass of low-melting-point polyester.

[0060] Example 6

[0061] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that the amount of activated carbon particles added is 1% of the mass of low-melting-point polyester.

[0062] Comparative Example 1

[0063] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that it does not contain microfibers.

[0064] Comparative Example 2

[0065] A self-charging nonwoven fabric based on biomass nanoparticles differs from Example 1 in that the microfiber skin does not contain activated carbon particles.

[0066] Comparative Example 3

[0067] A self-charging nonwoven fabric based on biomass nanoparticles differs from Example 1 in that it is not subjected to hot pressing treatment.

[0068] Comparative Example 4

[0069] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that it does not contain wool particles.

[0070] Comparative Example 5

[0071] A self-charging nonwoven fabric based on biomass nanoparticles, which differs from Example 1 in that the wool particles have a particle size of 500 nm.

[0072] Comparative Example 6

[0073] A self-charging nonwoven fabric based on biomass nanoparticles differs from Example 1 in that its preparation method includes the following steps:

[0074] S1. Wool particles are added to a polyacrylonitrile solution and spun to obtain polyacrylonitrile fibers; the amount of wool particles added is 10% of the mass of the polyacrylonitrile nanofibers.

[0075] S2. Prepare polypropylene fiber, activated carbon particles, and low-melting-point polyester composite fiber respectively. The amount of activated carbon particles added is 8% of the mass of low-melting-point polyester.

[0076] S3. Polyacrylonitrile fibers, polypropylene fibers, activated carbon particles, and low-melting-point polyester composite fibers are combined to obtain a nonwoven fabric, which is then hot-pressed to obtain a self-charging nonwoven fabric. The content of each component is the same as in Example 1.

[0077] The filtration performance was tested according to GB / 14295-2008 "Air Filters", with a rated air volume of 1000m³ / h. 3 / h, the weight of the self-charging nonwoven fabric is 200g / m² 2 The average filtration efficiency, initial resistance, and dust holding capacity when the final resistance reaches twice the initial resistance were tested.

[0078] Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-6

[0079] Sample ≥0.5μm filtration efficiency (%) Initial resistance (Pa) <![CDATA[Dust holding capacity (g / m 2 )]]> Example 1 99.93 18.5 135 Example 2 99.95 18.2 140 Example 3 99.96 19 145 Example 4 98.99 18 130 Example 5 99.91 18.3 131 Example 6 99.85 18.1 126 Comparative Example 1 98.10 18 92 Comparative Example 2 99.16 18.8 122 Comparative Example 3 98.80 18.3 120 Comparative Example 4 97.55 18 130 Comparative Example 5 98.20 19.5 125 Comparative Example 6 98.50 22.5 105

[0080] As shown in Table 1, the self-charging nonwoven fabric of this invention exhibits extremely high filtration efficiency, relatively high dust holding capacity, and low resistance, indicating a reasonable structural design. When the wool particle size increases to 500 nm, the filtration efficiency and dust holding capacity decrease, while the resistance increases. This indicates that excessively large particle size is not conducive to the generation of triboelectric static electricity, thus reducing the adsorption of particulate matter. The increased resistance may be due to poor adsorption and dispersion of particulate matter, leading to severe clogging. When the wool particles contain pores, the filtration efficiency and dust holding capacity further improve. Without ultrafine fibers, the filtration efficiency and dust holding capacity decrease significantly, indicating that the composite of ultrafine fibers can synergistically improve filtration performance. If activated carbon is not present, the filtration efficiency and dust holding capacity also decrease, indicating that activated carbon can synergistically regulate the adsorption of particulate matter. Without hot-pressing treatment, the filtration effect also deteriorates, indicating that hot-pressing melts and bonds the outer layer, improving the stability of the nonwoven fabric structure and thus improving the uniformity of particulate adsorption.

[0081] If ultrafine fibers with a core-sheath fiber structure are not used for bonding, the filtration effect will also be reduced. This is because the resulting composite nonwoven fabric cannot form a better gradient bonding structure as the core-sheath fiber sheath layer is melt-bonded, and the gradient uniformity is also reduced.

[0082] In summary, this invention utilizes a dot-contact composite nonwoven fabric filled with wool nanoparticles to solve the problems of low electrostatic durability and easy failure of traditional meltblown nonwoven materials in actual use. It achieves self-charging function under airflow purging conditions, greatly improving the durability of electrostatic nonwoven fabrics.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a self-charging nonwoven fabric based on biomass nanoparticles, characterized by, The self-charging non-woven fabric comprises polyacrylonitrile nanofibers and superfine fibers, and the preparation method comprises the following steps: S1, adding wool particles into a polyacrylonitrile solution to obtain polyacrylonitrile nanofibers through spinning; S2, obtaining a sheath-core fiber through coaxial spinning, wherein the sheath layer of the sheath-core fiber is a low-melting-point fiber, and the sheath-core fiber is compounded with activated carbon particles, i.e., a superfine fiber is obtained; S3, compounding the polyacrylonitrile nanofiber and the sheath-core fiber to obtain a non-woven fabric through hot pressing, and then performing water electret treatment to obtain the self-charging non-woven fabric; The compounding mode of the polyacrylonitrile nanofiber and the sheath-core fiber comprises: simultaneously spinning and depositing the polyacrylonitrile nanofiber and the sheath-core fiber to realize compounding; or, spinning and depositing one kind of fiber first, and then depositing the other kind of fiber on the surface of the one kind of fiber; Step S2 comprises: taking polypropylene as a core layer, and taking activated carbon particles and low-melting-point polyester as sheath layers, and obtaining a sheath-core fiber through coaxial spinning.

2. A self-charging nonwoven fabric based on biomass nanoparticles, characterized by, The polyacrylonitrile nanofiber is compounded with 50-200 nm wool particles through the preparation method of claim 1.

3. The self-charging nonwoven fabric based on biomass nanoparticle according to claim 2, characterized by, The wool particles have a multi-size micropore structure, and the porosity is 5-50%.

4. The self-charging nonwoven fabric based on biomass nanoparticle according to claim 2, wherein The addition amount of the wool particles is 1-20% of the mass of the polyacrylonitrile nanofiber.

5. The self-charging nonwoven fabric based on biomass nanoparticle according to claim 2, wherein The mass ratio of the polyacrylonitrile nanofiber to the superfine fiber is 1:(0.1-1); and / or, the diameter of the polyacrylonitrile nanofiber is 100-800 nm, and the diameter of the superfine fiber is 1-10 μm.

6. The self-charging nonwoven fabric based on biomass nanoparticle according to claim 2, wherein The polyacrylonitrile nanofiber and the superfine fiber are fused and bonded through heating treatment.

7. The self-charging nonwoven fabric based on biomass nanoparticle according to claim 6, characterized by, The addition amount of the activated carbon particles is 1-20% of the mass of the low-melting-point fiber; the low-melting-point fiber is a polyester fiber with a melting point of 80-120°C; and the diameter of the core layer of the sheath-core fiber is 1-10 μm.

8. Use of the self-charging nonwoven fabric based on biomass nanoparticle according to any one of claims 2 to 7, characterized in that, The self-charging non-woven fabric is used for preparing an air filtration material.

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