A high-energy-storage flexible wood fiberboard, its preparation method and application

Abstract

This invention discloses a high-energy-storage flexible wood fiberboard, its preparation method, and its applications, belonging to the field of wood functional materials. It disperses a non-isocyanate polyurethane formed by the reaction of epoxidized soybean oil cyclic carbonate and soybean protein within polyacrylamide chains. The hydrogen bonding between the polyacrylamide chains and the non-isocyanate polyurethane transfers external stress and dissipates energy, thereby improving the adhesive's toughness. Simultaneously, a conductive material is introduced into the three-dimensional network structure formed by mixing porous wood fiber materials to prepare conductive composite wood fibers. A multi-dimensional, multi-scale hierarchical directional composite assembly technology of wood fiber materials and novel conductive adhesives is employed to achieve directional charge transfer from the polymer to the wood pores, giving the flexible wood fiberboard intrinsically high energy storage characteristics. This helps solve the problem of traditional furniture's single-carrier function and promotes the high-value utilization of wood materials.

Description

Technical Field

[0001] This invention belongs to the field of wood functional materials, specifically relating to a high-energy-storage flexible wood fiberboard, its preparation method, and its application. Background Technology

[0002] Wood is a sustainable, renewable, and biodegradable environmentally friendly material that exists in large quantities in nature. It is also widely used in building support, interior decoration, packaging, pulp and paper making, and biomass energy due to its advantages such as light weight, high strength, and easy processing.

[0003] Currently, wood materials are mainly processed into three types of engineered wood products (plywood, particleboard, and fiberboard). Due to their high raw material utilization rate, low production cost, and stable performance, engineered wood products are primarily used in the manufacture of traditional furniture such as bookcases, sofas, and door panels. However, this has also led to problems such as limited product functionality, low utilization rate of high-value products, and overcapacity in low-end production. Functionalization of wood materials, as an important means to improve wood quality and increase the added value of wood materials, can break through the limitations of wood materials in practical applications. In recent years, researchers have proposed a variety of functionalization methods for wood materials, mainly including: (i) using chemical and physical treatment methods to modify the structure of wood materials through component removal, pore modification, and high-temperature carbonization; (ii) utilizing the multi-scale hierarchical structure of wood materials, starting from the molecular perspective, to construct functionalized materials through self-assembly, directional arrangement, or aggregation.

[0004] Currently, the aforementioned research has made some progress, but two major drawbacks remain: Firstly, the modification of wood materials requires the consumption of large amounts of organic chemical reagents and energy, limiting the further large-scale utilization of functionalized wood materials; secondly, the methods for deconstructing and recombining wood materials at the molecular level are too complex and may cause them to lose some excellent intrinsic properties. Therefore, finding simple and green methods to achieve intrinsic functionalization of wood materials is of great significance for broadening the application range of wood materials, improving the quality of wood material products, and promoting the large-scale application of functionalized wood materials.

[0005] With the rapid development of IoT and AI technologies, smart homes, enabling human-computer interaction, are playing an increasingly important role in improving people's quality of life and health. Currently, smart homes are evolving towards greater intelligence and interconnectivity, using AI to intelligently sense, analyze, and adapt to user habits and needs, providing more personalized and intelligent home services. Furthermore, the interconnection between smart home devices will be more seamless and efficient, achieving higher levels of automation and collaboration through information and data sharing. However, the intelligence and interconnectivity of smart homes rely heavily on integrating intelligent systems capable of receiving, processing, and executing user requests into furniture, achieving the integrated nature of smart homes—something traditional furniture with only a single functional element cannot meet.

[0006] Therefore, there is an urgent need to enable furniture materials to have multi-functionality by endowing them with the inherent energy storage properties, so as to meet the development requirements of smart homes. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0009] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a high-energy-storage flexible wood fiberboard.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a high-energy-storage flexible wood fiberboard, comprising,

[0011] Epoxidized soybean oil was mixed with tetrabutylammonium bromide and reacted with carbon dioxide under heat and pressure to obtain epoxidized soybean oil cyclic carbonate.

[0012] Soy protein powder was mixed with distilled water to prepare a mixture, and then heated to obtain a soybean protein aqueous dispersion.

[0013] Epoxidized soybean oil-based cyclic carbonate was added to soybean protein aqueous dispersion, the pH was adjusted to 10, and the reaction was heated to obtain bio-based waterborne non-isocyanate polyurethane.

[0014] Acrylamide and lithium chloride were added to bio-based waterborne non-isocyanate polyurethane and dissolved completely to obtain non-isocyanate polyurethane-acrylamide prepolymer.

[0015] Conductive materials are incorporated into wood fibers and stirred thoroughly to ensure uniform dispersion, thereby obtaining a wood fiber mixture.

[0016] The non-isocyanate polyurethane-acrylamide prepolymer was uniformly sprayed onto the wood fiber mixture and stirred evenly to obtain glued wood fiber.

[0017] After spraying N,N'-methylenebisacrylamide and ammonium persulfate onto the glued wood fiber, it is pre-pressed in a mold and then hot-pressed on a flat vulcanizing machine to cure and crosslink, thus obtaining a high-energy-storage flexible wood fiberboard.

[0018] As a preferred embodiment of the preparation method of the present invention, wherein: the epoxidized soybean oil is mixed with tetrabutylammonium bromide, wherein the mass ratio of epoxidized soybean oil to tetrabutylammonium bromide is 1:0.01; and the mixture is heated and pressurized to react with carbon dioxide, wherein the heating temperature is 130°C and the pressure is 2.5 MPa.

[0019] As a preferred embodiment of the preparation method of the present invention, the following steps are taken: the soybean protein powder is mixed with distilled water to obtain a mixture, wherein the concentration of soybean protein in the mixture is 0.13-0.15 g / mL; the soybean protein aqueous dispersion is obtained by heating treatment, wherein the heating temperature is 90-95℃ and the heating and stirring time is 1.5-2 h.

[0020] As a preferred embodiment of the preparation method of the present invention, the epoxidized soybean oil-based cyclic carbonate is added to the soybean protein aqueous dispersion, wherein the mass ratio of the epoxidized soybean oil-based cyclic carbonate to the soybean protein aqueous dispersion is 1:3.3 to 1:3.5.

[0021] As a preferred embodiment of the preparation method described in this invention, the heating reaction yields a bio-based waterborne non-isocyanate polyurethane, wherein the heating temperature is 80–85°C and the reaction time is 0.5–1 h.

[0022] In a preferred embodiment of the preparation method described in this invention, acrylamide and lithium chloride are added to the bio-based waterborne non-isocyanate polyurethane, wherein the mass ratio of acrylamide to bio-based waterborne non-isocyanate polyurethane is 1:0.85 to 1:0.87, and the mass ratio of lithium chloride to bio-based waterborne non-isocyanate polyurethane is 1:75 to 1:77.

[0023] In a preferred embodiment of the preparation method described in this invention, the mass ratio of the conductive material to the wood fiber is 1:2.

[0024] The mass ratio of the non-isocyanate polyurethane-acrylamide prepolymer to wood fiber is 1:1.

[0025] In a preferred embodiment of the preparation method described in this invention, the amount of N,N'-methylenebisacrylamide added is 0.10-0.13% of the mass of acrylamide, and the amount of ammonium persulfate added is 4-5% of the mass of acrylamide.

[0026] The hot-pressing temperature is 60℃, the pressure is 0.4MPa, and the hot-pressing time is 3h.

[0027] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a high-energy-storage flexible wood fiberboard. The high-energy-storage flexible wood fiberboard obtained by this method has a specific capacitance of 31.57 mF, can withstand 40% of its own strain without breaking, and has a maximum tensile stress of 1.7 MPa.

[0028] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of high-energy-storage flexible wood fiberboard in smart furniture.

[0029] Beneficial effects of this invention:

[0030] (1) This invention provides a method for preparing a high-energy-storage flexible wood fiberboard and its application. First, a novel conductive adhesive is prepared. Non-isocyanate polyurethane formed by the reaction of epoxidized soybean oil cyclic carbonate and soybean protein is dispersed in the polyacrylamide macromolecular entanglement chain. The hydrogen bonding between the polyacrylamide entanglement chain and the non-isocyanate polyurethane is used to transfer external stress and dissipate energy, thereby improving the toughness of the adhesive. At the same time, conductive materials are introduced into the three-dimensional network structure formed by mixing porous wood fiber materials to prepare conductive composite wood fiber. The multi-dimensional-multi-scale hierarchical directional composite assembly technology of wood fiber materials and novel conductive adhesive is adopted to realize the directional transfer of charge from polymer to wood pores, so that the flexible wood fiberboard has the intrinsic high energy storage characteristics.

[0031] (2) This invention uses a novel adhesive with high electrical conductivity to prepare a high-energy-storage flexible wood fiberboard, which helps to solve the problem of the single carrier function of traditional furniture, provides a new idea for the realization of IoT-integrated smart and sustainable home, and helps to promote the high-value utilization of wood materials.

[0032] (3) The preparation process of this invention is simple, does not use organic solvents, has low energy consumption, is easy to mass-produce, and is conducive to industrial application and promotion. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0034] Figure 1 The image shows the microstructure of the non-isocyanate polyurethane-polyacrylamide conductive adhesive in Example 2 of the present invention; wherein, a is a transmission electron microscope image of the non-isocyanate polyurethane, and b is a scanning electron microscope image of the non-isocyanate polyurethane-polyacrylamide conductive adhesive.

[0035] Figure 2 This is a toughness diagram of the soybean protein-epoxidized soybean oil-based cyclic carbonate-polyacrylamide bio-based gel adhesive in the embodiments of the present invention; wherein, a is the stress-strain curve of the polymer gel, bd is the tear energy diagram of the bio-based gel adhesive, and e is a comparison diagram of Young's modulus, fracture stress, fracture strain and tear energy of bio-based gel adhesives in different embodiments.

[0036] Figure 3 The stress-strain curves of a single tensile-release cycle of the soybean protein-epoxidized soybean oil-based cyclic carbonate-polyacrylamide bio-based gel adhesive under different strains are shown in the embodiments of the present invention.

[0037] Figure 4 This is a graph showing the electrochemical performance of a high-energy-storage flexible wood fiberboard in an embodiment of the present invention.

[0038] Figure 5 The stress-strain curves of a single tensile-release cycle of a high-energy-storage flexible wood fiberboard under different strains in an embodiment of the present invention are shown.

[0039] Figure 6 This is an application diagram of the high-energy-storage flexible wood fiberboard in Embodiment 6 of the present invention.

[0040] Figure 7 The diagram shows a comparison of the mechanical properties of the soybean protein-epoxidized soybean oil-based cyclic carbonate-polyacrylamide bio-based gel adhesives prepared in Comparative Examples 1 and 2 of this invention with those in Example 2; wherein, a and b are tear energy diagrams of the bio-based gel adhesives, c is the stress-strain curve of a single tensile-release cycle under different strains, and d is a comparison of Young's modulus, fracture stress, fracture strain, and tear energy of the conductive adhesives of different examples.

[0041] Figure 8 The figures show the single-stretch-release cycle experiments of the flexible wood fiberboards prepared in Comparative Example 3 and Example 6 of this invention under different strains. Detailed Implementation

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0043] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0045] In this invention, the following reagents are used: soybean protein isolate: Maclean's reagent; epoxidized soybean oil: Aladdin's reagent; tetrabutylammonium bromide: Aladdin's reagent; acrylamide: Aladdin's reagent; ammonium persulfate: Sigma-Aldrich's reagent; N,N'-methylenebisacrylamide: Sigma-Aldrich's reagent; aniline: Maclean's reagent; hydrochloric acid: Nanjing Chemical Reagent; conductive activated carbon: Xianfeng Nano Reagent.

[0046] Example 1

[0047] This embodiment provides a method for preparing a non-isocyanate polyurethane-polyacrylamide conductive adhesive by polymerization, the main steps of which are:

[0048] (1) Add 1000g of epoxidized soybean oil and 10g of tetrabutylammonium bromide to a 2L high-pressure reactor, continuously introduce carbon dioxide to purge the air from the reactor, and maintain the pressure inside the reactor at 2.5MPa;

[0049] The reaction was stirred at 130℃ under carbon dioxide for 48 hours to obtain a golden yellow viscous epoxidized soybean oil cyclic carbonate.

[0050] (2) Disperse 20g of soy protein isolate powder in 150mL of deionized water and stir at room temperature for 0.5h to allow it to fully soak.

[0051] (3) Add 3g of epoxidized soybean oil-based cyclic carbonate to 10g of soybean protein isolate aqueous dispersion, and gradually add sodium hydroxide solution while stirring until pH=10;

[0052] The reaction was carried out at 85℃ for 1 hour to obtain a bio-based waterborne non-isocyanate polyurethane.

[0053] (4) Add 15g of acrylamide monomer and 0.17g of lithium chloride to the non-isocyanate polyurethane-acrylamide prepolymer cooled to room temperature, and stir at 55°C for 0.5h to fully dissolve it and form a non-isocyanate polyurethane-acrylamide prepolymer.

[0054] (5) Add 0.1 mmol N,N'-methylenebisacrylamide and 0.08 mmol ammonium persulfate dropwise to the non-isocyanate polyurethane-acrylamide prepolymer and stir at room temperature for 15 min to dissolve it completely.

[0055] (6) Pour the non-isocyanate polyurethane-acrylamide prepolymer into a square glass mold with a length of 12cm and a thickness of 0.2cm, and polymerize it at 35℃ for 3h to obtain non-isocyanate polyurethane-polyacrylamide conductive adhesive.

[0056] Example 2

[0057] This embodiment provides a method for preparing a non-isocyanate polyurethane-polyacrylamide conductive adhesive by polymerization, the main steps of which are:

[0058] (1) Add 1000g of epoxidized soybean oil and 10g of tetrabutylammonium bromide to a 2L high-pressure reactor, continuously introduce carbon dioxide to purge the air from the reactor, and maintain the pressure inside the reactor at 2.5MPa;

[0059] The reaction was stirred at 130℃ under carbon dioxide for 48 hours to obtain a golden yellow viscous epoxidized soybean oil cyclic carbonate.

[0060] (2) Disperse 20g of soy protein isolate powder in 150mL of deionized water and stir at room temperature for 0.5h to allow it to fully soak.

[0061] (3) Add 3g of epoxidized soybean oil-based cyclic carbonate to 10g of soybean protein isolate aqueous dispersion, and gradually add sodium hydroxide solution while stirring until pH=10;

[0062] The reaction was carried out at 85℃ for 1 hour to obtain a bio-based waterborne non-isocyanate polyurethane.

[0063] (4) Add 15g of acrylamide monomer and 0.51g of lithium chloride to the non-isocyanate polyurethane-acrylamide prepolymer cooled to room temperature, and stir at 55°C for 0.5h to fully dissolve it and form a non-isocyanate polyurethane-acrylamide prepolymer.

[0064] (5) Add 0.1 mmol N,N'-methylenebisacrylamide and 0.08 mmol ammonium persulfate dropwise to the non-isocyanate polyurethane-acrylamide prepolymer and stir at room temperature for 15 min to dissolve it completely.

[0065] (6) Pour the non-isocyanate polyurethane-acrylamide prepolymer into a square glass mold with a length of 12cm and a thickness of 0.2cm, and polymerize it at 35℃ for 3h to obtain non-isocyanate polyurethane-polyacrylamide conductive adhesive.

[0066] Example 3

[0067] This embodiment provides a method for preparing a non-isocyanate polyurethane-polyacrylamide conductive adhesive by polymerization, the main steps of which are:

[0068] (1) Add 1000g of epoxidized soybean oil and 10g of tetrabutylammonium bromide to a 2L high-pressure reactor, continuously introduce carbon dioxide to purge the air from the reactor, and maintain the pressure inside the reactor at 2.5MPa;

[0069] The reaction was stirred at 130℃ under carbon dioxide for 48 hours to obtain a golden yellow viscous epoxidized soybean oil cyclic carbonate.

[0070] (2) Disperse 20g of soy protein isolate powder in 150mL of deionized water and stir at room temperature for 0.5h to allow it to fully soak.

[0071] (3) Add 3g of epoxidized soybean oil-based cyclic carbonate to 10g of soybean protein isolate aqueous dispersion, and gradually add sodium hydroxide solution while stirring until pH=10;

[0072] The reaction was carried out at 85℃ for 1 hour to obtain a bio-based waterborne non-isocyanate polyurethane.

[0073] (4) Add 15g of acrylamide monomer and 0.85g of lithium chloride to the non-isocyanate polyurethane-acrylamide prepolymer cooled to room temperature, and stir at 55°C for 0.5h to fully dissolve it and form a non-isocyanate polyurethane-acrylamide prepolymer.

[0074] (5) Add 0.1 mmol N,N'-methylenebisacrylamide and 0.08 mmol ammonium persulfate dropwise to the non-isocyanate polyurethane-acrylamide prepolymer and stir at room temperature for 15 min to dissolve it completely.

[0075] (6) Pour the non-isocyanate polyurethane-acrylamide prepolymer into a square glass mold with a length of 12cm and a thickness of 0.2cm, and polymerize it at 35℃ for 3h to obtain non-isocyanate polyurethane-polyacrylamide conductive adhesive.

[0076] The microstructure of gel adhesives is as follows Figure 1As shown in the scanning electron microscope images, the adhesive exhibits a chain-entangled network structure. The spherical epoxidized soybean oil cyclic carbonate and soybean protein nanoparticles, forming a non-isocyanate polyurethane, are uniformly dispersed within the framework structure, acting as entanglement sites to achieve high chain entanglement of the polyacrylamide macromolecular chains. The non-isocyanate polyurethane clusters formed by the reaction of epoxidized soybean oil cyclic carbonate and soybean protein are spherical, while the polyacrylamide is the continuous phase, and the spherical aggregates of the non-isocyanate polyurethane are dispersed within this continuous phase.

[0077] Example 4

[0078] This embodiment provides a method for preparing a high-energy-storage flexible wood fiberboard, the main steps of which are:

[0079] (1) Mix and grind 0.8g activated carbon and 0.2g single-walled carbon nanotube powder for 0.5h, and stir with 2g wood fiber for 10min to make it evenly dispersed in the wood fiber;

[0080] (2) The 3g non-isocyanate polyurethane-acrylamide prepolymer prepared in Example 2 was evenly sprayed onto the wood fiber and mechanically stirred evenly to obtain glued wood fiber.

[0081] (3) Spray 0.1 mmol N,N'-methylenebisacrylamide and 0.027 mol ammonium persulfate solution onto the sizing wood fiber and stir for 5 min to fully impregnate it;

[0082] (4) The glued wood fiber is pre-pressed in a mold and then hot-pressed on a flat vulcanizing machine (60℃, pressure 0.4MPa, hot pressing time 3h) to cure and crosslink to obtain a high-energy flexible wood fiberboard.

[0083] Example 5

[0084] This embodiment provides a method for preparing a high-energy-storage flexible wood fiberboard, the main steps of which are:

[0085] (1) Add 0.365 mL of aniline to 15 mL of 1 M dilute hydrochloric acid and stir for 15 min to form an aniline emulsion;

[0086] (2) Dissolve 0.228g of ammonium persulfate in 5mL of 1M dilute hydrochloric acid and stir for 15min to form an ammonium persulfate solution;

[0087] (3) The aniline emulsion was slowly stirred and added to the ammonium persulfate solution under ice bath, and allowed to stand for polymerization for 6 hours to obtain a dark green liquid.

[0088] (4) Filter the dark green liquid and wash it with deionized water and anhydrous ethanol.

[0089] The filtered solid was dried at 60°C for 12 hours to obtain dark green polyaniline particles;

[0090] (5) Mix 0.5g activated carbon and 0.5g polyaniline and grind for 0.5h, then stir with 2g wood fiber for 10min to fully disperse it in the wood fiber;

[0091] (6) Spray the 3g non-isocyanate polyurethane-acrylamide prepolymer prepared in Example 2 evenly onto the wood fiber, and after mechanical stirring, obtain glued wood fiber.

[0092] (7) Spray 0.1 mmol N,N'-methylenebisacrylamide and 0.027 mol ammonium persulfate solution onto the sizing wood fiber and stir for 5 min to fully impregnate it;

[0093] (8) The glued wood fiber is pre-pressed in a mold and then hot-pressed on a flat vulcanizing machine (60°C, pressure 0.4MPa, hot pressing time 3h) to cure and crosslink to obtain a high-energy flexible wood fiberboard.

[0094] Example 6

[0095] This embodiment provides a method for preparing a high-energy-storage flexible wood fiberboard, the main steps of which are:

[0096] (1) Add 0.365 mL of aniline to 15 mL of 1 M dilute hydrochloric acid and stir for 15 min to form an aniline emulsion;

[0097] (2) Dissolve 0.228g of ammonium persulfate in 5mL of 1M dilute hydrochloric acid and stir for 15min to form an ammonium persulfate solution;

[0098] Dissolve 0.1g of activated carbon in ammonium persulfate solution and stir for 20 minutes to allow it to be fully impregnated.

[0099] (3) The aniline emulsion was slowly added to the ammonium persulfate solution under ice bath and stirred for 6 hours to obtain a dark green liquid.

[0100] (4) Filter the dark green liquid and wash it with deionized water and anhydrous ethanol.

[0101] The filtered solid was dried at 60°C for 12 hours to obtain dark red activated carbon in-situ polymerized polyaniline particles.

[0102] (5) Mix 1g of activated carbon in situ polymerized polyaniline particles and grind for 0.5h, then stir with 2g of wood fiber for 10min to fully disperse it in the wood fiber;

[0103] (6) Spray the 3g non-isocyanate polyurethane-acrylamide prepolymer prepared in Example 2 evenly onto the wood fiber, and after mechanical stirring, obtain glued wood fiber.

[0104] (7) Spray 0.1 mmol N,N'-methylenebisacrylamide and 0.027 mol ammonium persulfate solution onto the sizing wood fiber and stir for 5 min to fully impregnate it;

[0105] (8) The glued wood fiber is pre-pressed in a mold and then hot-pressed on a flat vulcanizing machine (60°C, pressure 0.4MPa, hot pressing time 3h) to cure and crosslink to obtain a high-energy flexible wood fiberboard.

[0106] Example 7

[0107] Mechanical property analysis of non-isocyanate polyurethane-polyacrylamide conductive adhesives:

[0108] The mechanical properties of non-isocyanate polyurethane-polyacrylamide conductive adhesives were evaluated by analyzing the tensile properties and fatigue strength of the samples.

[0109] The non-isocyanate polyurethane-polyacrylamide conductive adhesives prepared in Examples 1, 2, and 3 were cut into dumbbell-shaped unnotched samples (stretch length 20 mm, width 4 mm, thickness 2 mm) and notched samples (stretch length 20 mm, width 4 mm, thickness 2 mm, notch width = 2 mm). Then, uniaxial tensile tests and single-stretch-release cycle tests under different strains were performed on the samples in the vertical direction using an electronic universal testing machine with a load of 1 kN. Tensile-strain curves and energy dissipation diagrams were obtained, and the tear energy, tensile fracture stress, and fracture strain of the samples were obtained from these results.

[0110] Tensile tests were conducted at room temperature at a tensile rate of 50 mm / min.

[0111] Test results are as follows Figure 2 , 3 As shown in the figure. Comparing Examples 1, 2, and 3, it can be seen that with the increase of lithium chloride, the elongation at break increased from 379% to 466% and then decreased to 344%, while the tensile stress increased from 668 kPa to 1813 kPa and then decreased to 723 kPa. Further comparison of the Young's modulus and tear energy of Examples 1, 2, and 3 revealed that the gel adhesive prepared in Example 2 achieved 1.1 MPa and 17.31 kJ / m². -2 .

[0112] Meanwhile, the maximum stress that Example 2 could withstand under different strains in a single stretch-release cycle was much higher than that in Examples 1 and 3. This indicates that the introduction of an appropriate amount of salt ions can improve the toughness of the adhesive.

[0113] Example 8

[0114] Electrochemical performance testing of non-isocyanate polyurethane-polyacrylamide conductive adhesives:

[0115] Electromechanical properties of non-isocyanate polyurethane-polyacrylamide conductive adhesive were tested using an electrochemical workstation. The non-isocyanate polyurethane-polyacrylamide conductive adhesives prepared in Examples 1, 2, and 3 were cut into cuboid samples with a length of 10 mm, a width of 10 mm, and a thickness of 2 mm to prepare platinum sheet | conductive adhesive | platinum sheet capacitors. The ionic conductivity of the conductive adhesive was tested using electrochemical impedance spectroscopy.

[0116] As shown in Table 1, the non-isocyanate polyurethane-polyacrylamide conductive adhesives in Examples 1-3 demonstrate the improvement in electrochemical performance resulting from the introduction of lithium chloride.

[0117] Table 1

[0118] <![CDATA[Ionic conductivity / mScm -1 > Example 1 35.82 Example 2 38.67 Example 3 36.48

[0119] Example 9

[0120] Electrochemical performance analysis of high-energy-storage flexible wood fiberboard:

[0121] The electrochemical performance of high-energy-storage flexible wood fiberboard was evaluated by analyzing the constant current charge-discharge test of the samples.

[0122] The high-energy-storage flexible wood fiberboard was subjected to constant current charge-discharge tests using an electrochemical workstation under different current conditions of 0-1V voltage window and 0.0005-0.125mA. The high-energy-storage flexible wood fiberboards prepared in Examples 4, 5, and 6 were cut into cubes with a length of 2cm, a width of 2cm, and a thickness of 1.5mm. These cubes were then used to prepare single-walled carbon nanotube paper / wood fiberboard / single-walled carbon nanotube paper devices to test the electrochemical performance of the high-energy-storage flexible wood fiberboard.

[0123] like Figure 4 As shown, Example 6 can withstand a higher current density (0.05 mA cm⁻¹) compared to Examples 4 and 5. -2 At the same time, it has higher specific capacitance (31.57mF) and energy density (7.18mWh / m³). -2 The coulombic efficiency reached 92.90%. And when the current density increased from 0.05 mA / cm²... -2 Increased to 0.5mA cm -2 At that time, the specific capacitance of Example 6 could still be maintained at 18.67mF, and the coulombic efficiency was above 80%.

[0124] This indicates that wood fiberboard prepared by introducing activated carbon with in-situ polymerized polyaniline into wood fiber and using a multi-scale-multi-dimensional directional assembly strategy has excellent energy storage performance.

[0125] Example 10

[0126] Mechanical property analysis of high-energy-storage flexible wood fiberboard:

[0127] The mechanical properties of high-energy-storage flexible wood fiberboard were evaluated by analyzing single tensile-release cycle experiments of samples under different strains.

[0128] The high-energy-storage flexible wood fiberboard prepared in Example 6 was cut into rectangular samples (stretch length 50 mm, width 4 mm, thickness 1.5 mm). Then, a single tensile-release cycle test under different strains was performed on the samples in the vertical direction using an electronic universal testing machine with a load of 1 kN to obtain tensile-strain curves.

[0129] The results are as follows Figure 5 As shown, the high-energy-storage flexible fiberboard prepared in Example 6 can withstand 40% of its own strain without breaking, while the maximum tensile stress reaches 1.7 MPa, demonstrating a certain degree of flexibility.

[0130] Example 11

[0131] Applications of high-energy-storage flexible wood fiberboard:

[0132] The high-energy-storage flexible wood fiberboard prepared in Example 6 was cut into square samples (70 mm in length and 1.5 mm in thickness). Single-walled carbon nanotube paper was used as the current collector to prepare a single-walled carbon nanotube paper|wood fiberboard|single-walled carbon nanotube paper device. The high-energy-storage flexible wood fiberboard was charged for 30 min using an electrochemical workstation under a voltage window of 0-5V and a current of 2.5mA, and then the timer was powered.

[0133] The results are as follows Figure 6 As shown, the high-energy-storage flexible fiberboard can maintain the stable operation of the timer even after being folded, twisted, hammered, and sheared; this indicates that the prepared wood fiberboard not only has good energy storage performance but also excellent flexibility; at the same time, even under harsh conditions, the prepared high-energy-storage flexible wood fiberboard can still work normally and stably.

[0134] Comparative Example 1

[0135] This embodiment provides a method for preparing a non-isocyanate polyurethane-polyacrylamide conductive adhesive, the main steps of which are:

[0136] (1) Add 1000g of epoxidized soybean oil and 10g of tetrabutylammonium bromide to a 2L high-pressure reactor, continuously introduce carbon dioxide to purge the air from the reactor, and maintain the pressure inside the reactor at 2.5MPa;

[0137] The reaction was stirred at 130℃ under carbon dioxide for 48 hours to obtain a golden yellow viscous epoxidized soybean oil cyclic carbonate.

[0138] (2) Disperse 20g of soy protein isolate powder in 150mL of deionized water and stir at room temperature for 0.5h to allow it to fully soak.

[0139] (3) Add 3g of epoxidized soybean oil-based cyclic carbonate to 10g of soybean protein isolate aqueous dispersion, and gradually add sodium hydroxide solution while stirring until pH=10;

[0140] The reaction was carried out at 85℃ for 1 hour to obtain a bio-based waterborne non-isocyanate polyurethane.

[0141] (4) Add 15g of acrylamide monomer and 0.51g of lithium chloride to the non-isocyanate polyurethane-acrylamide prepolymer cooled to room temperature, and stir at 55°C for 0.5h to fully dissolve it and form a non-isocyanate polyurethane-acrylamide prepolymer.

[0142] (5) Add 0.1 mmol N,N'-methylenebisacrylamide and 0.12 mmol ammonium persulfate dropwise to the non-isocyanate polyurethane-acrylamide prepolymer and stir at room temperature for 15 minutes to dissolve it completely.

[0143] (6) Pour the non-isocyanate polyurethane-acrylamide prepolymer into a square glass mold with a length of 12cm and a thickness of 0.2cm, and polymerize it at 35℃ for 3h to obtain non-isocyanate polyurethane-polyacrylamide conductive adhesive.

[0144] Comparative Example 2

[0145] (1) Add 1000g of epoxidized soybean oil and 10g of tetrabutylammonium bromide to a 2L high-pressure reactor, continuously introduce carbon dioxide to purge the air from the reactor, and maintain the pressure inside the reactor at 2.5MPa;

[0146] The reaction was stirred at 130℃ under carbon dioxide for 48 hours to obtain a golden yellow viscous epoxidized soybean oil cyclic carbonate.

[0147] (2) Disperse 20g of soy protein isolate powder in 150mL of deionized water and stir at room temperature for 0.5h to allow it to fully soak.

[0148] (3) Add 3g of epoxidized soybean oil-based cyclic carbonate to 10g of soybean protein isolate aqueous dispersion, and gradually add sodium hydroxide solution while stirring until pH=10;

[0149] The reaction was carried out at 85℃ for 1 hour to obtain a bio-based waterborne non-isocyanate polyurethane.

[0150] (4) Add 15g of acrylamide monomer and 0.51g of lithium chloride to the non-isocyanate polyurethane-acrylamide prepolymer cooled to room temperature, and stir at 55°C for 0.5h to fully dissolve it and form a non-isocyanate polyurethane-acrylamide prepolymer.

[0151] (5) Add 0.1 mmol N,N'-methylenebisacrylamide and 0.04 mmol ammonium persulfate dropwise to the non-isocyanate polyurethane-acrylamide prepolymer and stir at room temperature for 15 min to dissolve it completely.

[0152] (6) Pour the non-isocyanate polyurethane-acrylamide prepolymer into a square glass mold with a length of 12cm and a thickness of 0.2cm, and polymerize it at 35℃ for 3h to obtain non-isocyanate polyurethane-polyacrylamide conductive adhesive.

[0153] The non-isocyanate polyurethane-polyacrylamide conductive adhesives prepared in Comparative Examples 1 and 2 were cut into unnotched samples (tensile length 20 mm, width 4 mm, thickness 2 mm) and notched samples (tensile length 20 mm, width 4 mm, thickness 2 mm, notch width 2 mm). Tensile fracture tests were then conducted on the unnotched and notched samples using an electronic universal testing machine with a load of 1 kN, obtaining tensile-displacement curves at a tensile rate of 50 mm / min. The coverage area was determined based on the unnotched tensile force and the displacement at which the notched crack began to propagate, and the tear energy was calculated.

[0154] Test results are as follows Figure 7 As shown in a, b, and d, comparative examples 1 and 2 with Example 2 show that when the mass ratio of ammonium persulfate to acrylamide is not properly controlled, the Young's modulus, fracture stress, and tear energy of the prepared conductive adhesive are significantly lower than those of Example 2, and the toughness difference is large.

[0155] The non-isocyanate polyurethane-polyacrylamide conductive adhesives prepared in Comparative Examples 1 and 2 were subjected to single-stretch-release cycle experiments under different strains, and the results were compared with those in Example 2. Figure 7 As shown in c. It can be seen that when the mass ratio of ammonium persulfate to acrylamide is not properly controlled, the maximum cyclic tensile stress of the prepared gel adhesive in a single stretch-release cycle under different strains decreases by 28.62% and 91.00% respectively compared with Example 2, demonstrating poor toughness.

[0156] Comparative Example 3

[0157] (1) Add 0.365 mL of aniline to 15 mL of 1 M dilute hydrochloric acid and stir for 15 min to form an aniline emulsion;

[0158] (2) Dissolve 0.228g of ammonium persulfate in 5mL of 1M dilute hydrochloric acid and stir for 15min to form an ammonium persulfate solution;

[0159] Dissolve 0.1g of activated carbon in ammonium persulfate solution and stir for 20 minutes to allow it to be fully impregnated.

[0160] (3) The aniline emulsion was slowly added to the ammonium persulfate solution under ice bath and stirred for 6 hours to obtain a dark green liquid.

[0161] (4) Filter the dark green liquid and wash it with deionized water and anhydrous ethanol.

[0162] The filtered solid was dried at 60°C for 12 hours to obtain dark red activated carbon in-situ polymerized polyaniline particles.

[0163] (5) Mix 1g of activated carbon in situ polymerized polyaniline particles and grind for 0.5h, then stir with 2g of wood fiber for 10min to fully disperse it in the wood fiber;

[0164] (6) Spray 3g of acrylamide prepolymer (add 15g of acrylamide to 8.82g of water and stir for 15min to fully dissolve it to obtain acrylamide prepolymer) evenly onto the wood fiber, and after mechanically stirring evenly, obtain glued wood fiber.

[0165] (7) Spray 0.1 mmol N,N'-methylenebisacrylamide and 0.027 mol ammonium persulfate solution onto the sizing wood fiber and stir for 5 min to fully impregnate it;

[0166] (8) The glued wood fiber is pre-pressed in a mold and then hot-pressed on a flat vulcanizing machine (60°C, pressure 0.4MPa, hot pressing time 3h) to cure and crosslink to obtain a flexible wood fiberboard.

[0167] The flexible wood fiberboard prepared in Comparative Example 3 was subjected to a single tensile-release cycle experiment under different strains, and the results were compared with those in Example 6. Figure 8 As shown, when the non-isocyanate polyurethane content is 0, the maximum cyclic tensile stress of the prepared flexible wood fiberboard under different strains in a single tensile-release cycle is reduced by 92.92% and the strain is reduced to 20% compared with Example 6, demonstrating poor toughness.

[0168] This invention provides a method for preparing a high-energy-storage flexible wood fiberboard and its application. First, a novel conductive adhesive is prepared. A non-isocyanate polyurethane formed by reacting epoxidized soybean oil cyclic carbonate with soybean protein is dispersed within a polyacrylamide macromolecular chain. The hydrogen bonding between the polyacrylamide chain and the non-isocyanate polyurethane transfers external stress and dissipates energy, thereby improving the adhesive's toughness. Simultaneously, a conductive material is introduced into the three-dimensional network structure formed by mixing porous wood fiber materials to prepare conductive composite wood fibers. A multi-dimensional, multi-scale hierarchical directional composite assembly technology of wood fiber materials and the novel conductive adhesive is employed to achieve directional charge transfer from the polymer to the wood pores, giving the flexible wood fiberboard its intrinsic high energy-storage characteristics. This invention, through a novel high-conductivity adhesive, prepares a high-energy-storage flexible wood fiberboard, which helps solve the problem of traditional furniture's single-carrier function, provides a new solution for realizing integrated smart and sustainable homes using the Internet of Things, and helps promote the high-value utilization of wood materials.

[0169] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing a high-energy-storage flexible wood fiberboard, characterized in that: include, Epoxidized soybean oil and tetrabutylammonium bromide are mixed and reacted with carbon dioxide under heat and pressure to obtain epoxidized soybean oil-based cyclic carbonate, wherein the mass ratio of epoxidized soybean oil to tetrabutylammonium bromide is 1:0.01; the heating and pressurizing reaction with carbon dioxide is carried out at a heating temperature of 130°C and a pressure of 2.5 MPa. Soy protein powder was mixed with distilled water to prepare a mixture, and then heated to obtain a soy protein aqueous dispersion. The concentration of soy protein in the mixture was 0.13~0.15 g / mL, the heating temperature was 90~95℃, and the heating and stirring time was 1.5~2h. Epoxidized soybean oil-based cyclic carbonate was added to a soybean protein aqueous dispersion, the pH was adjusted to 10, and the reaction was heated to obtain a bio-based waterborne non-isocyanate polyurethane. The mass ratio of epoxidized soybean oil-based cyclic carbonate to soybean protein aqueous dispersion was 1:3.3~1:3.

5. Acrylamide and lithium chloride were added to bio-based waterborne non-isocyanate polyurethane and dissolved completely to obtain non-isocyanate polyurethane-acrylamide prepolymer. The mass ratio of acrylamide to bio-based waterborne non-isocyanate polyurethane was 1:0.85 to 1:0.87, and the mass ratio of lithium chloride to bio-based waterborne non-isocyanate polyurethane was 1:75 to 1:

77. Conductive materials are incorporated into wood fibers and stirred thoroughly to ensure uniform dispersion, thereby obtaining a wood fiber mixture. The non-isocyanate polyurethane-acrylamide prepolymer was uniformly sprayed onto the wood fiber mixture and stirred evenly to obtain glued wood fiber. Will N,N' - Methylene bisacrylamide and ammonium persulfate are sprayed onto the glued wood fiber, pre-pressed in a mold, and then hot-pressed on a flat vulcanizing machine to cure and cross-link, thus obtaining a high-energy-storage flexible wood fiberboard.

2. The preparation method according to claim 1, characterized in that: The heating reaction yields a bio-based waterborne non-isocyanate polyurethane, wherein the heating temperature is 80-85°C and the reaction time is 0.5-1 h.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the conductive material to the wood fiber is 1:2; The mass ratio of the non-isocyanate polyurethane-acrylamide prepolymer to wood fiber is 1:

1.

4. The preparation method according to claim 1 or 3, characterized in that: The N,N' The amount of methylene bisacrylamide added is 0.10~0.13% of the mass of acrylamide, and the amount of ammonium persulfate added is 4~5% of the mass of acrylamide; The hot-pressing temperature is 60℃, the pressure is 0.4MPa, and the hot-pressing time is 3 hours.

5. The high-energy-storage flexible wood fiberboard prepared by any one of claims 1 to 4.

6. The application of the high-energy-storage flexible wood fiberboard as described in claim 5 in smart furniture.

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