Non-woven fabric composite material and preparation method thereof

Abstract

The invention discloses a non-woven fabric composite material and a preparation method thereof, and belongs to the technical field of non-woven fabrics. Wood pulp cellulose and epoxy chloropropane are mixed, stirred and reacted to obtain epoxidized cellulose; mixing epoxidized cellulose, aniline and ammonium persulfate, stirring and reacting to obtain polyaniline cellulose; a silane coupling agent KH-570 and polyaniline cellulose are mixed, stirred and reacted to obtain modified cellulose; mixing the modified cellulose and the modified polysiloxane, and sequentially performing stirring and ultrasonic treatment to obtain fiber slurry; the fiber slurry is sequentially subjected to spunlace treatment and drying to obtain the non-woven fabric composite material. The modified cellulose is modified to construct a rigid conductive framework, so that the problem of conductivity and interface adaptation of the traditional cellulose is solved; the modified polysiloxane overcomes defects through a flexible chain, a disulfide bond and interface modification, and solves the problem that the conductive stability is influenced by repeated deformation in the prior art.

Description

Technical Field

[0001] This invention relates to the field of nonwoven fabric technology, specifically to a nonwoven composite material and its preparation method. Background Technology

[0002] With the rapid development of flexible electronics, smart sensing, and wearable devices, there is an urgent need for nonwoven fabric-based composite materials that combine high conductivity, excellent flexibility, and long-term stability. However, existing conductive nonwoven fabrics often suffer from poor conductivity due to the lack of a strong chemical bond between the conductive components and the fiber matrix, as well as the lack of an effective stress buffering mechanism. This leads to easy breakage of the conductive network and interfacial delamination, resulting in a significant decrease in conductivity and making it difficult to meet the requirements for conductivity stability in practical applications.

[0003] Patent CN108004681A discloses a conductive nonwoven fabric and its preparation method. The conductive nonwoven fabric is prepared by blending polypropylene fibers, seaweed fibers, and components such as nano-copper and silane coupling agents. While this improves the conductivity and mechanical properties of the material to some extent, the conductive filler mainly relies on physical mixing or weak interactions to disperse in the matrix, failing to form a covalent bond structure with the fiber skeleton. Therefore, during repeated deformation, conductive particles are prone to migration, aggregation, and even detachment, leading to unstable conductive pathways and a significant increase in resistance after long-term use. Furthermore, this system lacks a dynamically reversible chemical bond design, making it unable to achieve stress release and local damage repair, and thus unable to cope with mechanical fatigue problems under complex working conditions. These problems indicate that existing conductive nonwoven composite materials suffer from defects such as weak anchoring of conductive components, weak interfacial bonding, and a lack of dynamic stress buffering and self-healing mechanisms, making it difficult to simultaneously achieve high conductivity, high flexibility, and long-term service stability.

[0004] Therefore, providing a solution to the technical problem of poor electrical conductivity stability of nonwoven composite materials after repeated bending or stretching in the prior art has become an important issue that urgently needs to be addressed in this field. Summary of the Invention

[0005] This invention provides a nonwoven composite material and its preparation method. Modified cellulose is used to construct a rigid conductive framework, solving the problems of conductivity and interface compatibility in traditional cellulose fabrics. Modified polysiloxane, with its flexible chains, dynamic disulfide bonds, and interface modification to compensate for defects, addresses the problem of repeated deformation affecting conductivity stability in existing technologies. Specifically, the technical solution of this invention includes the following: A method for preparing a nonwoven composite material, the method comprising the following steps: Wood pulp cellulose and epichlorohydrin were mixed and stirred at a weight ratio of 20:3~4 to obtain epoxidized cellulose; Epoxidized cellulose, aniline, and ammonium persulfate were mixed and stirred in a weight ratio of 14~16:4.2~4.8:2.4~2.6 to obtain polyanilined cellulose; Modified cellulose was obtained by mixing and stirring silane coupling agent KH-570 and polyanilined cellulose at a weight ratio of 1.8~2.2:10; Modified cellulose and modified polysiloxane are mixed at a weight ratio of 70~80:20~30 and then stirred and ultrasonicated to obtain a fiber slurry. The nonwoven composite material is obtained by sequentially hydroentangling and drying the fiber slurry.

[0006] Furthermore, the conditions for the mixing and stirring reaction of wood pulp cellulose and epichlorohydrin include a reaction pH of 10-11, a reaction temperature of 75-85°C, and a reaction time of 2-4 hours; the hydroxyl groups in wood pulp cellulose react with the chlorine atoms in epichlorohydrin to introduce epoxy groups on the surface of wood pulp cellulose, providing sites for subsequent grafting reactions.

[0007] Furthermore, the conditions for the mixed stirring reaction of epoxidized cellulose, aniline and ammonium persulfate include a reaction pH of 1-2, a reaction temperature of 0-5℃ and a reaction time of 24-26h; the amino group in aniline reacts with the epoxy group in epoxidized cellulose to graft aniline onto epoxidized cellulose, and ammonium persulfate acts as an oxidant to initiate the oxidative polymerization of aniline monomers to form polyaniline, thus obtaining polyanilined cellulose.

[0008] Furthermore, the conditions for the mixing and stirring reaction of the silane coupling agent KH-570 and polyanilined cellulose include a reaction pH of 3-4, a reaction temperature of 75-85℃, and a reaction time of 4-6h.

[0009] Furthermore, the preparation method of the modified polysiloxane includes the following steps: Hydroxyl-terminated polydimethylsiloxane, 3,3'-dithiodipropionic acid and p-toluenesulfonic acid were mixed and stirred under reflux at a weight ratio of 10:1~1.5:0.05~0.08 to obtain a disulfide-bonded siloxane. Copper sulfate and sodium thiosulfate were mixed and stirred to obtain a reaction solution. A disulfide bond-containing siloxane was added and stirred to react to obtain a copper sulfide-containing siloxane. Modified siloxane is obtained by mixing and stirring silane coupling agent KH-550, acetic acid and copper sulfide-containing siloxane in a weight ratio of 0.2~0.4:0.01~0.02:10.

[0010] Furthermore, the conditions for mixing and refluxing the hydroxyl-terminated polydimethylsiloxane, 3,3'-dithiodipropionic acid, and p-toluenesulfonic acid include a reflux temperature of 110-120°C and a reflux time of 4-6 h; the hydroxyl-terminated polydimethylsiloxane and 3,3'-dithiodipropionic acid undergo an esterification reaction under the catalysis of p-toluenesulfonic acid to obtain a disulfide-bonded siloxane.

[0011] Furthermore, the weight ratio of copper sulfate, sodium thiosulfate, and disulfide-containing siloxane is 0.25~0.5:0.25~0.5:10.

[0012] Furthermore, the conditions for mixing and stirring the copper sulfate and sodium thiosulfate include a stirring speed of 200 r / min and a stirring time of 10-15 min.

[0013] Furthermore, the conditions for adding disulfide-bonded siloxanes and mixing and stirring the reaction include a reaction temperature of 75-85℃ and a reaction time of 2-4h; copper sulfate and sodium thiosulfate react under acidic conditions to generate copper sulfide, and the anchoring of copper sulfide and siloxane is achieved through the coordination of carboxyl groups with copper ions to obtain copper sulfide-containing siloxanes.

[0014] Furthermore, the conditions for the reaction of the silane coupling agent KH-550, acetic acid, and copper sulfide-containing siloxane include a reaction temperature of 75-85°C and a reaction time of 4-6 hours.

[0015] Furthermore, the conditions for mixing the modified cellulose and the modified polysiloxane include a mixing speed of 300 r / min and a mixing time of 1 to 2 h.

[0016] Furthermore, the conditions for the ultrasound include an ultrasound power of 300W and an ultrasound time of 25-35 minutes.

[0017] Furthermore, the conditions for the hydroentangling treatment include a high-pressure water jet of 80-120 bar.

[0018] Furthermore, the drying conditions include drying at 60~70℃ for 1.5~2.5h, followed by vacuum drying at 90~100℃ for 2~4h.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, active epoxy groups are introduced through epoxidation modification to provide stable anchoring points for subsequent functional grafting; polyaniline conjugated structure is introduced through aniline grafting and oxidative polymerization to endow the material with antibacterial and conductive functions; the surface functional groups are regulated by silane coupling agent modification to optimize the interfacial interaction with hydrophobic components; although modified cellulose has conductive rigid skeleton characteristics, it inherits the rigid nature of native cellulose, which is not flexible enough and is prone to brittleness under stress; and its surface polarity characteristics have significant interfacial tension with hydrophobic polysiloxane, resulting in poor mechanical toughness of single modified cellulose-based materials, and phase separation is easy to occur when mixed with flexible components, making it difficult to form a structurally stable composite system. Modified polysiloxanes introduce carboxyl groups and dynamic disulfide bonds simultaneously through esterification, achieving coordination anchoring of copper sulfide and endowing the material with dynamic repair potential. Its good flexibility can effectively alleviate stress concentration in modified cellulose and improve the overall toughness of the material. After interfacial functional modification, the surface-active groups of modified polysiloxanes can form covalent bonds with the active sites of modified cellulose, significantly reducing interfacial tension and solving the core problem of poor compatibility between the two, thus achieving the organic connection between rigid and flexible components.

[0020] (2) In this invention, modified cellulose serves as a rigid conductive framework, providing structural support and the main conductive channel; modified polysiloxane serves as a flexible functional matrix, endowing the material with flexibility and self-healing ability. The copper sulfide loaded on it and the polyaniline on the cellulose surface form a synergistic conductive network. The covalent bonding at the interface allows the two to fuse tightly. The photothermal effect of copper sulfide and the dynamic disulfide bond work together to drive the local repair of the conductive network, achieving synergistic optimization of mechanical and conductive properties, solving the problem of poor conductive stability after repeated deformation, and enabling the nonwoven composite material to achieve self-healing through near-infrared light triggering. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0023] Wood pulp cellulose, degree of polymerization 750, product of Shandong Hailong Co., Ltd.

[0024] Preparation Example 1 The preparation method of modified polysiloxane includes the following steps: 10 parts by weight of hydroxyl-terminated polydimethylsiloxane (viscosity 40 mpa·s), 1 part by weight of 3,3'-dithiodipropionic acid and 0.05 parts by weight of p-toluenesulfonic acid were dispersed in 100 parts by weight of toluene. The mixture was heated to 110 °C and stirred under reflux at 150 r / min for 4 h. After the reaction was completed, the mixture was cooled to 80 °C and distilled under reduced pressure for 2 h. The mixture was then washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 10 h to obtain a disulfide-bonded siloxane. 0.25 parts by weight of copper sulfate were dispersed in 50 parts by weight of a mixed solvent (V 无水甲醇 V 去离子水 =4:1) deionized water, stirred at 200 r / min for 20 min, then 0.25 parts by weight of sodium thiosulfate were added and stirred for another 10 min. The pH was adjusted to 2 with 1 mol / L citric acid solution to obtain the reaction solution. 10 parts by weight of disulfide bond-containing siloxane were added and the temperature was raised to 75℃ and stirred at 200 r / min for 2 h. After the reaction was completed, the temperature was lowered to 25℃ and the precipitate was collected by centrifugation at 5000 r / min for 15 min. After washing three times with deionized water, the precipitate was dried under vacuum at 60℃ for 10 h to obtain copper sulfide-containing siloxane. 0.2 parts by weight of silane coupling agent KH-550 dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, 0.01 parts by weight of acetic acid was added, and the mixture was stirred at 100 r / min for 15 min. Then, 10 parts by weight of copper sulfide-containing siloxane were added, and the mixture was heated to 75 °C and stirred for 4 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain the modified polysiloxane.

[0025] Preparation Example 2 The preparation method of modified polysiloxane includes the following steps: 10 parts by weight of hydroxyl-terminated polydimethylsiloxane (viscosity 40 mpa·s), 1.1 parts by weight of 3,3'-dithiodipropionic acid and 0.055 parts by weight of p-toluenesulfonic acid were dispersed in 100 parts by weight of toluene. The mixture was heated to 112 °C and refluxed at 150 r / min for 4.5 h. After the reaction was completed, the mixture was cooled to 80 °C and distilled under reduced pressure for 2 h. The mixture was then washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 10 h to obtain a disulfide-bonded siloxane. 0.3 parts by weight of copper sulfate were dispersed in 50 parts by weight of a mixed solvent (V 无水甲醇 V 去离子水=4:1) deionized water, stirred at 200 r / min for 20 min, then 0.3 parts by weight of sodium thiosulfate were added and stirred for another 10 min. The pH was adjusted to 2.2 with 1 mol / L citric acid solution to obtain the reaction solution. 10 parts by weight of disulfide bond-containing siloxane were added and the temperature was raised to 77℃ and stirred at 200 r / min for 2.5 h. After the reaction was completed, the temperature was lowered to 25℃ and the precipitate was collected by centrifugation at 5000 r / min for 15 min. After washing three times with deionized water, the precipitate was dried under vacuum at 60℃ for 10 h to obtain copper sulfide-containing siloxane. 0.25 parts by weight of silane coupling agent KH-550 dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, 0.012 parts by weight of acetic acid were added, and the mixture was stirred at 100 r / min for 15 min. Then, 10 parts by weight of copper sulfide-containing siloxane were added, and the mixture was heated to 77 °C and stirred for 4.5 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain the modified polysiloxane.

[0026] Preparation Example 3 The preparation method of modified polysiloxane includes the following steps: 10 parts by weight of hydroxyl-terminated polydimethylsiloxane (viscosity 40 mpa·s), 1.2 parts by weight of 3,3'-dithiodipropionic acid and 0.06 parts by weight of p-toluenesulfonic acid were dispersed in 100 parts by weight of toluene. The mixture was heated to 115 °C and refluxed at 150 r / min for 5 h. After the reaction was completed, the mixture was cooled to 80 °C and distilled under reduced pressure for 2 h. The mixture was then washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 10 h to obtain a disulfide-bonded siloxane. 0.3 parts by weight of copper sulfate were dispersed in 50 parts by weight of a mixed solvent (V 无水甲醇 V 去离子水 =4:1) deionized water, stirred at 200 r / min for 20 min, then 0.3 parts by weight of sodium thiosulfate were added and stirred for another 10 min. The pH was adjusted to 2.5 with 1 mol / L citric acid solution to obtain the reaction solution. 10 parts by weight of disulfide bond-containing siloxane were added and the temperature was raised to 80℃ and stirred at 200 r / min for 3 h. After the reaction was completed, the temperature was lowered to 25℃ and the precipitate was collected by centrifugation at 5000 r / min for 15 min. After washing three times with deionized water, the precipitate was dried under vacuum at 60℃ for 10 h to obtain copper sulfide-containing siloxane. 0.3 parts by weight of silane coupling agent KH-550 dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水In a mixture of 4:1, 0.015 parts by weight of acetic acid were added, and the mixture was stirred at 100 r / min for 15 min. Then, 10 parts by weight of copper sulfide-containing siloxane were added, and the mixture was heated to 80 °C and stirred for 5 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain the modified polysiloxane.

[0027] Preparation Example 4 The preparation method of modified polysiloxane includes the following steps: 10 parts by weight of hydroxyl-terminated polydimethylsiloxane (viscosity 40 mpa·s), 1.4 parts by weight of 3,3'-dithiodipropionic acid and 0.07 parts by weight of p-toluenesulfonic acid were dispersed in 100 parts by weight of toluene. The mixture was heated to 117 °C and refluxed at 150 r / min for 5.5 h. After the reaction was completed, the mixture was cooled to 80 °C and distilled under reduced pressure for 2 h. The mixture was then washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 10 h to obtain a disulfide-bonded siloxane. 0.4 parts by weight of copper sulfate were dispersed in 50 parts by weight of a mixed solvent (V 无水甲醇 V 去离子水 =4:1) deionized water, stirred at 200 r / min for 20 min, then 0.4 parts by weight of sodium thiosulfate were added and stirred for another 10 min. The pH was adjusted to 2.8 with 1 mol / L citric acid solution to obtain the reaction solution. 10 parts by weight of disulfide bond-containing siloxane were added and the temperature was raised to 82℃ and stirred at 200 r / min for 3.5 h. After the reaction was completed, the temperature was lowered to 25℃ and the precipitate was collected by centrifugation at 5000 r / min for 15 min. After washing three times with deionized water, the precipitate was dried under vacuum at 60℃ for 10 h to obtain copper sulfide-containing siloxane. 0.3 parts by weight of silane coupling agent KH-550 dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, 0.018 parts by weight of acetic acid were added, and the mixture was stirred at 100 r / min for 15 min. Then, 10 parts by weight of copper sulfide-containing siloxane were added, and the mixture was heated to 82 °C and stirred for 5.5 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain the modified polysiloxane.

[0028] Preparation Example 5 The preparation method of modified polysiloxane includes the following steps: 10 parts by weight of hydroxyl-terminated polydimethylsiloxane (viscosity 40 mpa·s), 1.5 parts by weight of 3,3'-dithiodipropionic acid and 0.08 parts by weight of p-toluenesulfonic acid were dispersed in 100 parts by weight of toluene. The mixture was heated to 120 °C and refluxed at 150 r / min for 6 h. After the reaction was completed, the mixture was cooled to 80 °C and distilled under reduced pressure for 2 h. The mixture was then washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 10 h to obtain a disulfide-bonded siloxane. 0.5 parts by weight of copper sulfate are dispersed in 50 parts by weight of a mixed solvent (V 无水甲醇 V 去离子水 =4:1) deionized water, stirred at 200 r / min for 20 min, then 0.5 parts by weight of sodium thiosulfate were added and stirred for another 10 min. The pH was adjusted to 3 with 1 mol / L citric acid solution to obtain the reaction solution. 10 parts by weight of disulfide bond-containing siloxane were added and the temperature was raised to 85℃ and stirred at 200 r / min for 4 h. After the reaction was completed, the temperature was lowered to 25℃ and the precipitate was collected by centrifugation at 5000 r / min for 15 min. After washing three times with deionized water, the precipitate was dried under vacuum at 60℃ for 10 h to obtain copper sulfide-containing siloxane. 0.4 parts by weight of silane coupling agent KH-550 dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, 0.02 parts by weight of acetic acid were added, and the mixture was stirred at 100 r / min for 15 min. Then, 10 parts by weight of copper sulfide-containing siloxane were added, and the mixture was heated to 85 °C and stirred for 6 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain the modified polysiloxane.

[0029] Preparation Example 6 The preparation method of modified polysiloxane includes the following steps: In Preparation Example 5, 1.5 parts by weight of 3,3'-dithiodipropionic acid was replaced with 1.5 parts by weight of succinic acid, and all other operations were the same as in Preparation Example 5.

[0030] Preparation Example 7 The preparation method of modified polysiloxane includes the following steps: Remove copper sulfate and sodium thiosulfate from Preparation Example 5, replace 10 parts by weight of copper sulfide-containing siloxane with 10 parts by weight of disulfide-containing siloxane, and keep other operations consistent with Preparation Example 5.

[0031] Example 1 A method for preparing a nonwoven composite material includes the following steps: 20 parts by weight of wood pulp cellulose were dispersed in 200 parts by weight of 85% ethanol solution. The mixture was stirred at 300 r / min for 5 min at 25 °C. The pH was adjusted to 10 with 20 wt% sodium hydroxide solution. The temperature was raised to 75 °C and stirring was continued for 30 min. 3 parts by weight of epichlorohydrin were added and the mixture was stirred for 2 h. After the reaction was completed, the pH was adjusted to 7.0. The solid was collected by filtration, washed three times with 85% ethanol solution, and dried under vacuum at 50 °C for 10 h to obtain epoxidized cellulose. 14 parts by weight of epoxidized cellulose were dispersed in 200 parts by weight of 85% ethanol solution, 4.2 parts by weight of aniline were added, and the mixture was stirred at 300 r / min for 2 h. The mixture was then cooled to 0 °C and the pH was adjusted to 1 with 50% hydrochloric acid solution. 2.4 parts by weight of ammonium persulfate were added, and the mixture was stirred and reacted under a nitrogen atmosphere for 24 h. After the reaction was completed, the mixture was washed three times with deionized water and dried under vacuum at 60 °C for 12 h to obtain polyanilined cellulose. 1.8 parts by weight of silane coupling agent KH-570 were dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, the mixture was stirred at 100 rpm for 15 min, the pH was adjusted to 3, 10 parts by weight of polyaniline cellulose were added, and the mixture was stirred at 300 rpm for 60 min. The temperature was then raised to 75°C and the reaction was continued for 4 h. After the reaction was completed, the mixture was cooled to 25°C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60°C for 12 h to obtain modified cellulose. 70 parts by weight of modified cellulose and 20 parts by weight of modified polysiloxane prepared in Example 1 were dispersed in 500 parts by weight of deionized water, ultrasonically treated with 300W power for 25 min, and then stirred and mixed at 300r / min speed for 1 h. After the mixing was completed, the slurry was filtered with a 100-mesh filter to obtain fiber slurry. The fiber slurry is evenly spread onto the conveyor belt using a carding machine to form a loose fiber web, with a basis weight controlled at 50 g / m². 2 With a thickness of 200μm, the hydroentangling machine is turned on, and a high-pressure water jet of 100 bar is used to vertically impact the fiber web. The free water is then adsorbed by a vacuum water-absorbing roller, increasing the solid content to 65% to obtain a shaped nonwoven fabric. The shaped nonwoven fabric is dried at 65℃ for 2 hours, then heated to 100℃ for vacuum drying for 3 hours, and then cooled to 25℃ to obtain a nonwoven composite material.

[0032] Example 2 A method for preparing a nonwoven composite material includes the following steps: 20 parts by weight of wood pulp cellulose were dispersed in 200 parts by weight of 85% ethanol solution. The mixture was stirred at 300 r / min for 5 min at 25 °C. The pH was adjusted to 10.2 with 20 wt% sodium hydroxide solution. The temperature was raised to 77 °C and stirring was continued for 35 min. 3.2 parts by weight of epichlorohydrin were added and the mixture was stirred for 2.5 h. After the reaction was completed, the pH was adjusted to 7.0. The solid was collected by filtration, washed three times with 85% ethanol solution, and dried under vacuum at 50 °C for 10 h to obtain epoxidized cellulose. 14.5 parts by weight of epoxidized cellulose were dispersed in 200 parts by weight of 85% ethanol solution, 4.3 parts by weight of aniline were added, and the mixture was stirred at 300 r / min for 2.2 h. The mixture was then cooled to 1 °C and the pH was adjusted to 1.2 with 50% hydrochloric acid solution. 2.45 parts by weight of ammonium persulfate were added, and the mixture was stirred and reacted under a nitrogen atmosphere for 24.5 h. After the reaction was completed, the mixture was washed three times with deionized water and dried under vacuum at 60 °C for 12 h to obtain polyanilined cellulose. 1.9 parts by weight of silane coupling agent KH-570 were dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, the mixture was stirred at 100 rpm for 15 min, the pH was adjusted to 3.2, 10 parts by weight of polyaniline cellulose were added, and the mixture was stirred at 300 rpm for 65 min. The temperature was then raised to 77°C and the reaction was continued for 4.5 h. After the reaction was completed, the mixture was cooled to 25°C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60°C for 12 h to obtain modified cellulose. 72 parts by weight of modified cellulose and 21 parts by weight of modified polysiloxane prepared in Example 2 were dispersed in 500 parts by weight of deionized water, ultrasonically treated with 300W power for 27 min, and then stirred and mixed at 300r / min speed for 1.2 h. After the mixing was completed, the slurry was filtered with a 100-mesh filter to obtain fiber slurry. The fiber slurry is evenly spread onto the conveyor belt using a carding machine to form a loose fiber web, with a basis weight controlled at 50 g / m². 2 With a thickness of 200μm, the hydroentangling machine is turned on, and a high-pressure water jet of 100 bar is used to vertically impact the fiber web. The free water is then adsorbed by a vacuum water-absorbing roller, increasing the solid content to 65% to obtain a shaped nonwoven fabric. The shaped nonwoven fabric is dried at 65℃ for 2 hours, then heated to 100℃ for vacuum drying for 3 hours, and then cooled to 25℃ to obtain a nonwoven composite material.

[0033] Example 3 A method for preparing a nonwoven composite material includes the following steps: 20 parts by weight of wood pulp cellulose were dispersed in 200 parts by weight of 85% ethanol solution. The mixture was stirred at 300 r / min for 5 min at 25 °C. The pH was adjusted to 10.5 with 20 wt% sodium hydroxide solution. The temperature was raised to 80 °C and stirring was continued for 40 min. 3.5 parts by weight of epichlorohydrin were added and the mixture was stirred for 3 h. After the reaction was completed, the pH was adjusted to 7.0. The solid was collected by filtration, washed three times with 85% ethanol solution, and dried under vacuum at 50 °C for 10 h to obtain epoxidized cellulose. 15 parts by weight of epoxidized cellulose were dispersed in 200 parts by weight of 85% ethanol solution, 4.5 parts by weight of aniline were added, and the mixture was stirred at 300 r / min for 2.5 h. The mixture was then cooled to 2 °C and the pH was adjusted to 1.5 with 50% hydrochloric acid solution. 2.5 parts by weight of ammonium persulfate were added, and the mixture was stirred and reacted under a nitrogen atmosphere for 25 h. After the reaction was completed, the mixture was washed three times with deionized water and dried under vacuum at 60 °C for 12 h to obtain polyanilined cellulose. 2.0 parts by weight of silane coupling agent KH-570 were dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, the mixture was stirred at 100 rpm for 15 min, the pH was adjusted to 3.5, 10 parts by weight of polyaniline cellulose were added, and the mixture was stirred at 300 rpm for 70 min. The temperature was then raised to 80 °C and the reaction was continued for 5 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain modified cellulose. 75 parts by weight of modified cellulose and 205 parts by weight of modified polysiloxane prepared in Example 3 were dispersed in 500 parts by weight of deionized water, ultrasonically treated with 300W power for 30 min, and then stirred and mixed at 300 r / min for 1.5 h. After the mixing was completed, the slurry was filtered through a 100 mesh filter to obtain fiber slurry. The fiber slurry is evenly spread onto the conveyor belt using a carding machine to form a loose fiber web, with a basis weight controlled at 50 g / m². 2 With a thickness of 200μm, the hydroentangling machine is turned on, and a high-pressure water jet of 100 bar is used to vertically impact the fiber web. The free water is then adsorbed by a vacuum water-absorbing roller, increasing the solid content to 65% to obtain a shaped nonwoven fabric. The shaped nonwoven fabric is dried at 65℃ for 2 hours, then heated to 100℃ for vacuum drying for 3 hours, and then cooled to 25℃ to obtain a nonwoven composite material.

[0034] Example 4 A method for preparing a nonwoven composite material includes the following steps: 20 parts by weight of wood pulp cellulose were dispersed in 200 parts by weight of 85% ethanol solution. The mixture was stirred at 300 r / min for 5 min at 25 °C. The pH was adjusted to 10.7 with 20 wt% sodium hydroxide solution. The temperature was raised to 82 °C and stirring was continued for 50 min. 3.7 parts by weight of epichlorohydrin were added and the mixture was stirred for 3.5 h. After the reaction was completed, the pH was adjusted to 7.0. The solid was collected by filtration, washed three times with 85% ethanol solution, and dried under vacuum at 50 °C for 10 h to obtain epoxidized cellulose. 15.5 parts by weight of epoxidized cellulose were dispersed in 200 parts by weight of 85% ethanol solution, 4.6 parts by weight of aniline were added, and the mixture was stirred at 300 r / min for 2.7 h. The mixture was then cooled to 4 °C and the pH was adjusted to 1.7 with 50% hydrochloric acid solution. 2.55 parts by weight of ammonium persulfate were added, and the mixture was stirred and reacted under a nitrogen atmosphere for 25.5 h. After the reaction was completed, the mixture was washed three times with deionized water and dried under vacuum at 60 °C for 12 h to obtain polyanilined cellulose. 2.1 parts by weight of silane coupling agent KH-570 are dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, the mixture was stirred at 100 rpm for 15 min, the pH was adjusted to 3.7, 10 parts by weight of polyaniline cellulose were added, and the mixture was stirred at 300 rpm for 75 min. The temperature was then raised to 82°C and the reaction was continued for 5.5 h. After the reaction was completed, the mixture was cooled to 25°C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60°C for 12 h to obtain modified cellulose. 78 parts by weight of modified cellulose and 28 parts by weight of modified polysiloxane prepared in Example 4 were dispersed in 500 parts by weight of deionized water, ultrasonically treated with 300W power for 32 min, and then stirred and mixed at 300r / min speed for 1.8 h. After the mixing was completed, the slurry was filtered with a 100-mesh filter to obtain fiber slurry. The fiber slurry is evenly spread onto the conveyor belt using a carding machine to form a loose fiber web, with a basis weight controlled at 50 g / m². 2 With a thickness of 200μm, the hydroentangling machine is turned on, and a high-pressure water jet of 100 bar is used to vertically impact the fiber web. The free water is then adsorbed by a vacuum water-absorbing roller, increasing the solid content to 65% to obtain a shaped nonwoven fabric. The shaped nonwoven fabric is dried at 65℃ for 2 hours, then heated to 100℃ for vacuum drying for 3 hours, and then cooled to 25℃ to obtain a nonwoven composite material.

[0035] Example 5 A method for preparing a nonwoven composite material includes the following steps: 20 parts by weight of wood pulp cellulose were dispersed in 200 parts by weight of 85% ethanol solution. The mixture was stirred at 300 r / min for 5 min at 25 °C. The pH was adjusted to 11 with 20 wt% sodium hydroxide solution. The temperature was raised to 85 °C and stirring was continued for 60 min. 4 parts by weight of epichlorohydrin were added and the mixture was stirred for 4 h. After the reaction was completed, the pH was adjusted to 7.0. The solid was collected by filtration, washed three times with 85% ethanol solution, and dried under vacuum at 50 °C for 10 h to obtain epoxidized cellulose. 16 parts by weight of epoxidized cellulose were dispersed in 200 parts by weight of 85% ethanol solution, 4.8 parts by weight of aniline were added, and the mixture was stirred at 300 r / min for 3 h. The mixture was then cooled to 5 °C and the pH was adjusted to 2 with 50% hydrochloric acid solution. 2.6 parts by weight of ammonium persulfate were added, and the mixture was stirred and reacted under a nitrogen atmosphere for 26 h. After the reaction was completed, the mixture was washed three times with deionized water and dried under vacuum at 60 °C for 12 h to obtain polyanilined cellulose. 2.2 parts by weight of silane coupling agent KH-570 were dispersed in 100 parts by weight of mixed solvent (V 无水乙醇 V 去离子水 In a mixture of 4:1, the mixture was stirred at 100 r / min for 15 min, the pH was adjusted to 4, 10 parts by weight of polyaniline cellulose were added, and the mixture was stirred at 300 r / min for 80 min. The temperature was then raised to 85 °C and the reaction was continued for 6 h. After the reaction was completed, the mixture was cooled to 25 °C, the solid was collected by filtration, washed three times with anhydrous ethanol, and then dried under vacuum at 60 °C for 12 h to obtain modified cellulose. 80 parts by weight of modified cellulose and 30 parts by weight of the modified polysiloxane prepared in Example 5 were dispersed in 500 parts by weight of deionized water, ultrasonically treated with 300W power for 35 min, and then stirred and mixed at 300r / min speed for 2 h. After the mixing was completed, the slurry was filtered with a 100-mesh filter to obtain fiber slurry. The fiber slurry is evenly spread onto the conveyor belt using a carding machine to form a loose fiber web, with a basis weight controlled at 50 g / m². 2 With a thickness of 200μm, the hydroentangling machine is turned on, and a high-pressure water jet of 100 bar is used to vertically impact the fiber web. The free water is then adsorbed by a vacuum water-absorbing roller, increasing the solid content to 65% to obtain a shaped nonwoven fabric. The shaped nonwoven fabric is dried at 65℃ for 2 hours, then heated to 100℃ for vacuum drying for 3 hours, and then cooled to 25℃ to obtain a nonwoven composite material.

[0036] Comparative Example 1 A method for preparing a nonwoven composite material includes the following steps: The epichlorohydrin in Example 5 was removed, and 16 parts by weight of epoxidized cellulose was replaced with 16 parts by weight of wood pulp cellulose. Other operations were the same as in Example 5.

[0037] Comparative Example 2 A method for preparing a nonwoven composite material includes the following steps: In Example 5, aniline was replaced with N-methylaniline, and all other operations remained the same as in Example 5.

[0038] Comparative Example 3 A method for preparing a nonwoven composite material includes the following steps: The modified polysiloxane prepared in Example 5 was replaced with the modified polysiloxane prepared in Example 6, and all other operations were the same as in Example 5.

[0039] Comparative Example 4 A method for preparing a nonwoven composite material includes the following steps: The modified polysiloxane prepared in Example 5 was replaced with the modified polysiloxane prepared in Example 7, and all other operations were the same as in Example 5.

[0040] Comparative Example 5 A method for preparing a nonwoven composite material includes the following steps: The modified polysiloxane prepared in Example 5 was used to replace the copper sulfide-containing siloxane in Example 5, and the silane coupling agent KH-570 in Example 5 was removed. All other operations were the same as in Example 5.

[0041] Performance testing The properties of the nonwoven composite materials obtained in Examples 1-5 and Comparative Examples 1-5 were tested using the following methods: Conductivity test: The non-woven composite material was cut into 50mm×50mm square samples and tested using a 4200A-SCS parameter analyzer. The electrode clips were attached to both ends of the non-woven sample, and the resistance value was observed after the instrument was turned on. The corresponding resistivity was obtained after the value stabilized. Mechanical property testing: The nonwoven composite material was cut into strips of 100mm×20mm, and the tensile strength and elongation at break of the samples were tested using a universal testing machine. Self-healing performance test: Non-woven composite material was cut into strips of 100mm × 20mm. The initial resistivity (ρ0) was tested. Using the bending fixture of a universal testing machine, the sample was bent 180° 300 times, with a bending radius of 10mm and a bending frequency of 1 Hz. The damaged area coincided with the test area. The bent sample was fixed on the tensile fixture and subjected to 100 cycles of 20% tensile rate at a rate of 5mm / min. Tension-recovery constituted one cycle, with a recovery time of 10s per cycle. The resistivity (ρ1) of the damaged sample was tested. The damaged sample was fixed on the test stage and subjected to 0.5W / cm² tensile test. 2The test area was irradiated with an 808nm laser for 10 minutes, then cooled to 25℃ and left to stand for 60 minutes. The resistivity (ρ2) of the repaired sample was then measured, and the self-repair efficiency η was calculated as η = [(ρ1-ρ2) / (ρ1-ρ0)] × 100%. The test results are shown in Table 1.

[0042] Table 1. Performance Test Results

[0043] (1) As can be seen from the test results in Table 1, the nonwoven composite materials prepared in Examples 1 to 5 of the present invention have good performance, while the nonwoven composite materials prepared in Comparative Examples 1 to 5 have different degrees of performance reduction. (2) The reason for the decrease in Comparative Example 1 may be that the wood pulp cellulose was not treated with epichlorohydrin, and stable epoxy active sites could not be formed on the surface, making it difficult for aniline and cellulose to establish a strong covalent bond grafting effect. Polyaniline can only be attached to the fiber surface through physical adsorption. This non-chemical bonded bonding form lacks structural stability. Under the action of external force, the conductive components are easy to fall off from the fiber matrix or agglomerate, directly destroying the continuity of the conductive network. At the same time, the insufficient interfacial bonding strength makes it easy for the fiber and conductive components to slip under stress. The mechanical structure is loose and cannot effectively transfer stress, which leads to a decrease in conductivity, mechanical properties and self-healing efficiency. (3) The reason for the decrease in Comparative Example 2 may be that after replacing aniline with N-methylaniline, the steric hindrance effect of N-methyl may hinder the oxidative polymerization reaction of aniline monomers, and it is impossible to form a continuous and complete polyaniline conjugated conductive structure. Only isolated molecular fragments or incomplete polymer chains can be formed. The breakage of the conjugated system makes it difficult for charge to be effectively transported, and the conductivity of the material deteriorates. The discontinuous conductive network is more prone to irreversible breakage during deformation, and the conductive path cannot be restored through self-repair mechanism after breakage. Even if the mechanical structure is partially maintained, the conductive function is difficult to restore, which ultimately leads to defects in conductivity stability and self-repair efficiency. (4) The reason for the decrease in Comparative Example 3 may be that after replacing 3,3'-dithiodipropionic acid with succinic acid in equal amounts, the modified polysiloxane molecular chain lacked the dynamic reversible disulfide bond structure, and only the coordination effect of the carboxyl group was retained. The loss of dynamic bonds caused the material to lose its core repair mechanism. After damage, it could not restore its structure and conductivity through chemical bond recombination. In addition, the stress buffering effect between rigid cellulose and flexible polysiloxane was weakened, and the material's toughness was insufficient, which further aggravated the deterioration of mechanical properties and conductivity stability. (5) The reason for the decrease in Comparative Example 4 may be that the reaction step with copper sulfate / sodium thiosulfate was omitted in the preparation process of modified polysiloxane, resulting in the lack of copper sulfide component in the material. On the one hand, the synergistic conductive network formed between copper sulfide and polyaniline cannot be constructed. Relying solely on the single conductive channel of polyaniline, the integrity and stability of the conductive network are insufficient, making it susceptible to breakage due to external forces. On the other hand, the photothermal effect of copper sulfide disappears, making it impossible to accelerate molecular motion and dynamic bond recombination through laser irradiation during the self-repair process, resulting in a significant decrease in the repair rate of disulfide bonds and a significant decrease in self-repair efficiency. At the same time, the lack of coordination and anchoring effect of copper sulfide also affects the interfacial coordination between polysiloxane and cellulose to some extent, indirectly weakening the conductive stability. (6) The reason for the decrease in the proportion may be that the cellulose grafted with polyaniline was not modified by KH-570, and the polysiloxane introduced with copper sulfide was not modified by KH-550, which resulted in the surface functional groups of the two core components being unable to form effective covalent bonds. There is a significant interfacial tension between the polar surface of the modified cellulose and the hydrophobic polysiloxane, which easily leads to phase separation during the mixing process, causing the conductive network to be broken into isolated regions and unable to form continuous conductive channels; at the same time, the lack of covalent bond connection at the interface makes it easy for rigid cellulose and flexible polysiloxane to peel off under stress, resulting in stress concentration, loose mechanical structure, and inability to cooperate in bearing external forces, thus causing a decrease in conductivity, mechanical properties, conductivity stability and self-healing efficiency.

[0044] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for producing a nonwoven fabric composite material, characterized by comprising the steps of: The preparation method comprises the following steps: ​ wood pulp cellulose and epichlorohydrin are mixed and stirred to react to obtain epoxidized cellulose; epoxidized cellulose, aniline and ammonium persulfate are mixed and stirred to react to obtain polyaniline cellulose; silane coupling agent KH-570 and polyaniline cellulose are mixed and stirred to react to obtain modified cellulose; modified cellulose and modified polysiloxane are mixed and stirred and then ultrasonic treated to obtain fiber slurry; the fiber slurry is treated by water jet and dried to obtain the non-woven fabric composite material.

2. The method for preparing a nonwoven composite material as described in claim 1, characterized in that, The mixing and stirring reaction of the wood pulp cellulose and epichlorohydrin is carried out under the conditions of reaction pH 10-11, reaction temperature 75-85℃ and reaction time 2-4h.

3. The method for preparing a nonwoven composite material as described in claim 1, characterized in that, The mixing and stirring reaction of the epoxidized cellulose, aniline and ammonium persulfate is carried out under the conditions of reaction pH 1-2, reaction temperature 0-5℃ and reaction time 24-26h.

4. The method for preparing a nonwoven composite material as described in claim 1, characterized in that, The preparation method of the modified polysiloxane comprises the following steps: hydroxyl-terminated polydimethylsiloxane, 3,3'-dithiodipropionic acid and p-toluenesulfonic acid are mixed and stirred to reflux to obtain disulfide bond-containing siloxane; copper sulfate and sodium thiosulfate are mixed and stirred to obtain a reaction solution, and the disulfide bond-containing siloxane is added and mixed and stirred to react to obtain copper sulfide-containing siloxane; silane coupling agent KH-550, acetic acid and the copper sulfide-containing siloxane are mixed and stirred to react to obtain modified siloxane.

5. The method for preparing a nonwoven composite material as described in claim 4, characterized in that, The mixing and stirring reflux of the hydroxyl-terminated polydimethylsiloxane, 3,3'-dithiodipropionic acid and p-toluenesulfonic acid is carried out under the conditions of reflux temperature 110-120℃ and reflux time 4-6h.

6. The method for preparing a nonwoven composite material as described in claim 4, characterized in that, The weight ratio of the copper sulfate, the sodium thiosulfate and the disulfide bond-containing siloxane is 0.25-0.5:0.25-0.5:10; and the mixing and stirring of the copper sulfate and the sodium thiosulfate is carried out under the conditions of stirring speed 200r / min and stirring time 10-15min.

7. The method for preparing a nonwoven composite material as described in claim 4, characterized in that, The mixing and stirring reaction of the disulfide bond-containing siloxane is carried out under the conditions of reaction temperature 75-85℃ and reaction time 2-4h.

8. The method for preparing a nonwoven composite material as described in claim 1, characterized in that, The mixing of the modified cellulose and the modified polysiloxane is carried out under the conditions of mixing speed 300r / min and mixing time 1-2h.

9. The method for preparing a nonwoven composite material as described in claim 1, characterized in that, The water jet treatment is carried out under the condition of high-pressure water jet 80-120bar; and the drying is carried out under the conditions of drying at 60-70℃ for 1.5-2.5h and then vacuum drying at 90-100℃ for 2-4h.

10. A nonwoven composite material, characterized by, The non-woven fabric composite material is prepared by the preparation method of any one of claims 1-9.

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