Biomass aerogel phase change plastic-wood composite material and preparation method thereof

Abstract

The invention discloses a biomass aerogel phase-change plastic-wood composite material which is formed by loading a biomass aerogel skeleton into a phase-change energy storage unit through vacuum and embedding the phase-change energy storage unit into a plastic matrix. The invention also discloses a preparation method of the biomass aerogel phase-change plastic-wood composite material. The preparation method comprises the following steps: (1) preparing a biomass aerogel skeleton; (2) preparing a core material of the phase change energy storage unit; (3) preparing a phase change energy storage unit; (4) preparing a plastic matrix; and (5) embedding the phase change energy storage unit into the plastic matrix to obtain the biomass aerogel phase change plastic-wood composite material. According to the biomass aerogel phase-change plastic-wood composite material and the preparation method thereof provided by the invention, biomass high-value utilization, phase-change energy storage and structural material design are subjected to cross-field fusion, the three industry pain points of functions, structures and environmental protection are solved, and the material with ultralow thermal conductivity, higher coating rate and higher bending strength is obtained; and the development and progress of the industry are promoted.

Description

Technical Field

[0001] The present application relates to the field of aerogel materials, and more specifically to a biomass aerogel phase-change plastic-wood composite material and a preparation method thereof. Background Art

[0002] With the advancement of global green building and carbon neutrality goals, the development of new building materials that are both energy-efficient and environmentally friendly has become an urgent need in the industry. Wood-plastic composites (WPC) are widely used in the construction industry due to their recyclability and weather resistance. However, traditional WPC materials have significant technical bottlenecks: (1) Insufficient thermal management performance. The thermal conductivity of traditional WPC is relatively high (usually >0.1W / m·K), which makes it difficult to meet the requirements of building envelope structures for thermal insulation performance, especially in tropical climates with high temperature and high humidity, which can easily lead to a surge in building cooling energy consumption; (2) Functional singleness defect. Existing materials lack active heat storage / release capabilities and cannot meet the needs of day and night temperature difference control. The external phase change material layer is prone to interface peeling and core material leakage (the leakage rate after recycling is >10%), which reduces system reliability; (3) Low-value utilization of biomass resources. The palm industry produces a large amount of waste (such as palm shells and palm fibers) every year. The current treatment methods are mainly incineration or landfill, which not only causes CO2 emissions but also fails to fully utilize its high cellulose content (about 60%-70%).

[0003] In recent years, researchers have attempted to use biomass resources to prepare aerogels and combine them with phase-change materials in the hope of obtaining composite materials with improved properties. Other researchers have also attempted to introduce aerogels and phase-change materials into WPC systems to enhance performance, but these innovations have largely remained within the linear thinking of "add aerogel → improve performance" or "add phase-change material → gain thermal storage."

[0004] There are still many challenges in breaking through the single function of plastic wood materials and creating a revolutionary green building material that integrates insulation, heat storage, structural bearing, and full bio-based recycling: (1) Aerogel composite technology. Although conventional silica aerogel has ultra-low thermal conductivity (<0.02W / m·K), it is brittle, expensive to produce, and has poor interface bonding with the plastic matrix, making it difficult to adapt to the mechanical requirements of building structures; (2) Phase change material encapsulation technology. The existing microencapsulation process (such as in-situ polymerization) has a low coverage rate (<90%) and insufficient thermal stability of the shell, which makes the phase change material easy to leak during high-temperature processing or long-term use; (3) Biomass component compatibility. The surface hydrophobicity of palm fiber is poorly compatible with the plastic matrix. Traditional coupling agents are difficult to achieve strong interface bonding, resulting in a decrease in the mechanical properties of the composite material (flexural strength <20MPa). Summary of the Invention

[0005] In view of the deficiencies of the prior art, the biomass aerogel phase change plastic-wood composite material and the preparation method thereof are provided, which combines high-value utilization of biomass, phase change energy storage and structural material design across fields, solves the triple industry pain points of "function, structure and environmental protection", obtains a material with ultra-low thermal conductivity, higher coating rate and higher bending strength, and promotes the development and progress of the industry.

[0006] A biomass aerogel phase change plastic-wood composite material, wherein a biomass aerogel skeleton is vacuum-loaded to become a phase change energy storage unit, and the phase change energy storage unit is embedded in a plastic matrix to form the biomass aerogel phase change plastic-wood composite material, the thermal conductivity of the biomass aerogel phase change plastic-wood composite material is less than 0.033 W / m·K, and the bending strength is greater than 28 MPa.

[0007] Further, the biomass aerogel skeleton is a three-dimensional hierarchical porous aerogel prepared from nanocellulose extracted from palm shells through freeze-induced assembly and supercritical drying, the porosity of the three-dimensional hierarchical porous aerogel is greater than 97%, and the specific surface area is 750-1100 m 2 / g.

[0008] The phase change energy storage unit is a core-shell type microcapsule, the core material of the core-shell type microcapsule is a eutectic system of palm oil derivative fatty acid and lauric acid-stearic acid loaded on the biomass aerogel skeleton, and the shell layer is a silicon dioxide-titanium dioxide hybrid material; wherein the coating rate of the shell layer to the core material is greater than 95%, and the phase change latent heat is greater than or equal to 190 J / g.

[0009] The plastic matrix is composed of biodegradable plastic and surface-modified palm fiber powder through a reactive extrusion-molding process, wherein the palm fiber powder accounts for 30%-50% of the mass of the matrix; and the biodegradable plastic is at least one of polylactic acid, polyhydroxybutyrate and polybutylene adipate terephthalate.

[0010] A preparation method of a biomass aerogel phase change plastic-wood composite material, comprising the following steps:

[0011] (1) preparing a biomass aerogel skeleton;

[0012] (2) preparing a core material of a phase change energy storage unit;

[0013] (3) preparing a phase change energy storage unit;

[0014] (4) preparing a plastic matrix;

[0015] (5) embedding the phase change energy storage unit in the plastic matrix to obtain the biomass aerogel phase change plastic-wood composite material.

[0016] The specific preparation method of the biomass aerogel skeleton in step (1) is as follows:

[0017] (11) crushing the palm shells and soaking them in 8-10 wt% NaOH solution at 80-90° C. for 3-5 hours to remove lignin and obtain a primary cellulose mixture;

[0018] (12) subjecting the primary cellulose mixture to ultrasonic stripping at 40-60 kHz for 1-3 hours to obtain a nanocellulose suspension with a diameter of 20-50 nm, and assembling the nanocellulose suspension into a gel by freeze-induction;

[0019] Freeze induction is the process of nanocellulose (NC) suspension assembling to form a gel. In essence, it is the process of driving the self-assembly of nanocellulose to form a three-dimensional network structure through the synergistic effect of the phase change (freezing) of water in the frozen nanocellulose suspension and the intermolecular forces of nanocellulose. When the nanocellulose suspension is cooled below the freezing point, the water molecules in the system preferentially crystallize to form ice crystals. The high concentration of nanocellulose molecules are cross-linked through various forces such as hydrogen bonds, van der Waals forces, or electrostatics to form a preliminary three-dimensional network. This process does not require additional chemical cross-linking agents. It is a green and controllable gel preparation method. It is one of the current methods for preparing gels and will not be described in detail here.

[0020] (13) The gel was treated with a CO2 supercritical drying process at a temperature of 30-32 °C and a pressure of 7-8 MPa for 48-60 h to obtain an aerogel with a porosity of >97%, i.e., a biomass aerogel skeleton.

[0021] The preparation method of the core material described in step (2) is:

[0022] (21) preparing a mixture of palm oil hydrolyzed fatty acids with a C16-C18 content of >80% and lauric acid-stearic acid in a mass ratio of 1:1 to 7:3;

[0023] (22) A core material with a leakage rate of <2% was obtained after 200 thermal cycles within the controllable phase transition temperature range of 20–38 °C.

[0024] The preparation method of the phase change energy storage unit in step (3) is:

[0025] (31) The molten core material was used as the aqueous phase and a 1–3 wt % Span 80 toluene solution was used as the oil phase at a temperature of 55–65 °C to form a W / O emulsion using microfluidic emulsification technology, with a microchannel diameter ranging from 150 to 250 μm;

[0026] (32) The biomass aerogel skeleton was immersed in W / O emulsion and immersed under a vacuum condition of -0.1 MPa for 3–5 h to obtain an aerogel-loaded shape-stabilized phase change composite material;

[0027] (33) adding the aerogel-loaded shaped phase change composite material to a mixed solution of ethyl orthosilicate and tetrabutyl titanate and stirring to mix uniformly, then adding hydrochloric acid while stirring to adjust the pH value to 2-4, and obtaining a solid-liquid mixture after the reaction is complete;

[0028] (34) drying the solid-liquid mixture in a vacuum oven to obtain core-shell microcapsules, i.e., phase change energy storage units;

[0029] The silicon dioxide-titanium dioxide shell layer of the phase-change energy storage unit has a thickness of 0.5-1.2 μm and a coverage rate greater than 95%.

[0030] The preparation method of the plastic substrate described in step (4) is:

[0031] (41) premixing modified palm fiber powder with a particle size of 80-120 mesh and a bio-based compatibilizer in an internal mixer at a temperature of 160-180° C. for 10-20 minutes to obtain a premix;

[0032] The bio-based compatibilizer is prepared by mixing a polycondensate of palm oil epoxy resin and hexamethylenediamine in a molar ratio of 1:1-1:1.2;

[0033] (42) mixing the premix with the biodegradable plastic in a mass ratio of 3:7 to 1:1, and reactively extruding the mixture through a screw extruder at a temperature gradient of 160-190°C to obtain an extrudate;

[0034] The screw speed is 100-150 rpm, and the residence time of the premix in the screw extruder is 2-3 minutes;

[0035] (43) The extrudate is pelletized to obtain a plastic matrix.

[0036] The method for embedding the phase change energy storage unit into the plastic matrix in step (5) is:

[0037] (51) The phase change energy storage unit and the plastic matrix were mixed in a mass ratio of 3:7 and reactively extruded through a screw extruder at a temperature gradient of 150–190 °C to obtain a primary composite material;

[0038] Among them, the temperature range of the feed section of the screw extruder is 150-170℃, the temperature range of the melt mixing section of the screw extruder is 170-190℃, and the temperature range of the head section of the screw extruder is 160-180℃;

[0039] (52) The composite material was placed into a mold at a temperature of 170-200 °C and a pressure of 10-20 MPa and maintained under pressure for 8-12 minutes to obtain a biomass aerogel phase change plastic-wood composite material profile.

[0040] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0041] This invention integrates high-value utilization of biomass, phase change energy storage, and structural material design across fields, solving the three industry pain points of "function, structure, and environmental protection", and obtaining materials with ultra-low thermal conductivity, higher coverage, and higher bending strength, thus promoting the development and progress of the industry.

[0042] Some additional features of the present application may be described in the following description. Some additional features of the present application will be apparent to those skilled in the art from an inspection of the following description and accompanying drawings, or from a thorough understanding of the production or operation of the embodiments. The features disclosed in this application may be realized and achieved through the practice or use of the various methods, means, and combinations of the specific embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The exemplary embodiments of the present application and their descriptions are used to explain the present application and do not constitute a limitation of the present application. In each figure, the same reference numerals represent the same components.

[0044] Figure 1 It is a step diagram of the present invention. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0046] It should be noted that, if the description and claims of the present application and the above-mentioned drawings relate to the terms "first", "second", etc., they are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein. In addition, if the terms "including" and "having" and any of their variations are involved, it is intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] In this application, when terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inside," "outside," "center," "vertical," "horizontal," "transverse," and "longitudinal" are used, the orientations or positional relationships they indicate are based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0048] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0049] Furthermore, in this application, the terms "installed," "disposed," "provided with," "connected," "connected," and "socketed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0050] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] Example 1

[0052] A biomass aerogel phase-change plastic-wood composite material is formed by converting a biomass aerogel skeleton into a phase-change energy storage unit through vacuum loading, and then embedding the phase-change energy storage unit into a plastic matrix. The thermal conductivity is less than 0.033W / m·K and the flexural strength is greater than 28MPa.

[0053] The biomass aerogel skeleton is a three-dimensional hierarchical porous aerogel prepared by freeze-induced assembly and supercritical drying of nanocellulose extracted from palm shells. Its porosity is greater than 97% and its specific surface area is 750-1100m 2 / g;

[0054] The phase change energy storage unit is a core-shell microcapsule, the core material of which is a biomass aerogel skeleton loaded with a eutectic system of palm oil derivative fatty acids and lauric acid-stearic acid, and the shell layer is a silica-titanium dioxide hybrid material; wherein the shell layer has a coverage rate of more than 95% on the core material, and the phase change latent heat is ≥190 J / g;

[0055] The plastic matrix is ​​compounded by biodegradable plastic and surface-modified palm fiber powder through a reactive extrusion-compression molding process, wherein the palm fiber powder accounts for 30%-50% of the matrix mass; and the biodegradable plastic is polylactic acid.

[0056] Example 2

[0057] The difference between this embodiment and embodiment 1 is that the biodegradable plastic is composed of polyhydroxybutyrate and polybutylene terephthalate-adipate in a mass ratio of 1:1.

[0058] Example 3

[0059] like Figure 1 As shown, a method for preparing a biomass aerogel phase change plastic-wood composite material comprises the following steps:

[0060] (1) preparing a biomass aerogel skeleton;

[0061] The specific preparation method of biomass aerogel skeleton is:

[0062] (11) crushing the palm shell and soaking it in 8 wt % NaOH solution at 80 °C for 5 h to remove lignin and obtain a primary cellulose mixture;

[0063] (12) The primary cellulose mixture was subjected to ultrasonic stripping at 40 kHz for 3 hours to obtain a nanocellulose suspension with a diameter of 20 nm, and the nanocellulose suspension was assembled into a gel by freeze-induction;

[0064] (13) The gel was treated with a CO2 supercritical drying process at a temperature of 30 °C and a pressure of 8 MPa for 60 h to obtain an aerogel with a porosity of >97%, namely, a biomass aerogel skeleton.

[0065] (2) preparing a core material for a phase change energy storage unit;

[0066] The preparation method of the core material is:

[0067] (21) preparing a mixture of palm oil hydrolyzed fatty acids with a C16-C18 content of >80% and lauric acid-stearic acid in a mass ratio of 1:1;

[0068] (22) A core material with a leakage rate of <2% was obtained after 200 thermal cycles within the controllable phase transition temperature range of 20–38 °C.

[0069] (3) preparing a phase change energy storage unit;

[0070] The preparation method of the phase change energy storage unit is as follows:

[0071] (31) The molten core material was used as the aqueous phase and a 1 wt % Span 80 toluene solution was used as the oil phase at 55 °C to form a W / O emulsion using microfluidic emulsification technology, with a microchannel diameter ranging from 150 to 250 μm;

[0072] (32) The biomass aerogel skeleton was immersed in W / O emulsion and immersed under a vacuum condition of −0.1 MPa for 3 h to obtain an aerogel-loaded shape-stabilized phase change composite material;

[0073] (33) adding the aerogel-loaded shaped phase change composite material to a mixed solution of ethyl orthosilicate and tetrabutyl titanate and stirring to mix uniformly, then adding hydrochloric acid while stirring to adjust the pH value to 2, and obtaining a solid-liquid mixture after the reaction is complete;

[0074] (34) drying the solid-liquid mixture in a vacuum oven to obtain core-shell microcapsules, i.e., phase change energy storage units;

[0075] The silicon dioxide-titanium dioxide shell layer of the phase-change energy storage unit has a thickness of 0.5-1.2 μm and a coverage rate greater than 95%.

[0076] (4) preparing a plastic matrix;

[0077] The preparation method of the plastic matrix is ​​as follows:

[0078] (41) Modified palm fiber powder with a particle size of 80 mesh and a bio-based compatibilizer were premixed in an internal mixer at a temperature of 180 °C for 10 min to obtain a premix;

[0079] The bio-based compatibilizer is prepared by mixing a polycondensate of palm oil epoxy resin and hexamethylenediamine in a molar ratio of 1:1-1:1.2;

[0080] (42) The premix and the biodegradable plastic were mixed in a mass ratio of 3:7, and the mixture was reactively extruded through a screw extruder at a temperature gradient of 160-190 °C to obtain an extrudate;

[0081] The screw speed is 100 rpm, and the residence time of the premix in the screw extruder is 2-3 minutes;

[0082] (43) The extrudate is pelletized to obtain a plastic matrix.

[0083] (5) embedding the phase change energy storage unit into the plastic matrix to obtain a biomass aerogel phase change plastic-wood composite material;

[0084] The method of embedding the phase change energy storage unit into the plastic matrix is:

[0085] (51) The phase change energy storage unit is mixed with the plastic matrix at a mass ratio of 3:7, and is reacted and extruded through a screw extruder at a temperature gradient of 150-190℃ to obtain a primary composite material;

[0086] The temperature range of the feeding section of the screw extruder is 150℃, the temperature range of the melting mixing section of the screw extruder is 170℃, and the temperature range of the head section of the screw extruder is 160℃.

[0087] (52) The composite material is loaded into a mold at a temperature of 170℃ and a pressure of 20MPa, and is kept for 12 minutes to obtain a biomass aerogel phase change plastic-wood composite material profile.

[0088] Example 4

[0089] The difference between this embodiment and Example 3 is that,

[0090] In step (11), the crushed palm shell is soaked in a 9wt% NaOH solution at 85℃ for 4 hours.

[0091] In step (12), the primary cellulose mixture is subjected to ultrasonic stripping at 50kHz for 2 hours to obtain a nanocellulose suspension with a diameter of 35nm.

[0092] In step (13), the gel is treated by CO2 supercritical drying process at a temperature of 31℃ and a pressure of 7.5MPa for 55 hours.

[0093] In step (21), the mixture is composed of palm oil hydrolyzed fatty acids and lauric acid-stearic acid compounded at a mass ratio of 7:5.

[0094] In step (31), the temperature condition is controlled at 60℃, and a 2wt% Span 80 toluene solution is used as the oil phase.

[0095] In step (32), the soaking time is 4 hours.

[0096] In step (33), the pH value is adjusted to 3 by hydrochloric acid.

[0097] In step (41), the particle size of the modified palm fiber powder is 100 mesh, and the modified palm fiber powder and the bio-based compatibilizer are premixed in an internal mixer at a temperature of 170℃ for 15 minutes.

[0098] In step (42), the premix and the biodegradable plastic are mixed at a mass ratio of 3:5, and the screw speed is 130rpm.

[0099] In step (51), the temperature range of the feeding section of the screw extruder is 160℃, the temperature range of the melting mixing section of the screw extruder is 180℃, and the temperature range of the head section of the screw extruder is 170℃.

[0100] In step (52), the composite material profile is maintained in the mold at a temperature of 185° C. and a pressure of 15 MPa for 10 minutes.

[0101] Example 5

[0102] The difference between this embodiment and embodiment 3 is that:

[0103] In step (11), the crushed palm shells were soaked in a 10 wt% NaOH solution at 90° C. for 3 hours.

[0104] In step (12), the primary cellulose mixture is subjected to ultrasonic stripping at 60 kHz for 1 hour to obtain a nanocellulose suspension with a diameter of 50 nm.

[0105] In step (13), the gel is dried using a CO2 supercritical drying process at a temperature of 32°C and a pressure of 7 MPa for 48 hours.

[0106] The mixture in step (21) is prepared by compounding palm oil hydrolyzed fatty acids and lauric acid-stearic acid in a mass ratio of 7:3.

[0107] In step (31), the temperature condition is controlled at 65° C., and a 3 wt % Span 80 toluene solution is used as the oil phase.

[0108] The immersion time in step (32) is 5 hours.

[0109] In step (33), the pH value is adjusted to 4 by hydrochloric acid.

[0110] In step (41), the particle size of the modified palm fiber powder is 120 mesh, and the modified palm fiber powder and the bio-based compatibilizer are premixed in an internal mixer at a temperature of 160° C. for 20 minutes.

[0111] In step (42), the premix and the biodegradable plastic are mixed in a mass ratio of 1:1, and the screw speed is 150 rpm.

[0112] In step (51), the temperature range of the feed section of the screw extruder is 170°C, the temperature range of the melt mixing section of the screw extruder is 190°C, and the temperature range of the head section of the screw extruder is 180°C.

[0113] In step (52), the composite material profile is kept in the mold at a temperature of 200° C. and a pressure of 10 MPa for 8 minutes.

[0114] It should be noted that all features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any manner.

[0115] In addition, the above specific embodiments are exemplary, and those skilled in the art can think of various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range of the present application and fall within the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are illustrative and do not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents.

Claims

1. A biomass aerogel phase change plastic-wood composite material, characterized in that: The biomass aerogel skeleton is vacuum loaded to become a phase change energy storage unit, and the phase change energy storage unit is embedded in a plastic matrix. Its thermal conductivity is less than 0.033W / m·K and its bending strength is greater than 28MPa.

2. The biomass aerogel phase change plastic-wood composite material according to claim 1, characterized in that: The biomass aerogel skeleton is a three-dimensional hierarchical porous aerogel prepared by freeze-induced assembly and supercritical drying of nanocellulose extracted from palm shells. Its porosity is greater than 97% and its specific surface area is 750-1100m 2 / g; The phase change energy storage unit is a core-shell microcapsule, the core material of which is a biomass aerogel skeleton loaded with a eutectic system of palm oil derivative fatty acids and lauric acid-stearic acid, and the shell layer is a silica-titanium dioxide hybrid material; wherein the shell layer has a coverage rate of more than 95% on the core material, and the phase change latent heat is ≥190 J / g; The plastic matrix is ​​compounded by biodegradable plastic and surface-modified palm fiber powder through a reactive extrusion-compression molding process, wherein the palm fiber powder accounts for 30%-50% of the matrix mass; the biodegradable plastic is at least one of polylactic acid, polyhydroxybutyrate, and polybutylene terephthalate-adipate.

3. A method for preparing a biomass aerogel phase change plastic-wood composite material according to claim 1 or 2, characterized in that: The following steps are involved: (1) preparing a biomass aerogel skeleton; (2) preparing the core material of the phase change energy storage unit; (3) preparing a phase change energy storage unit; (4) preparing a plastic matrix; (5) The phase change energy storage unit is embedded in the plastic matrix to obtain a biomass aerogel phase change plastic-wood composite material.

4. The method for preparing a biomass aerogel phase change plastic-wood composite material according to claim 3, characterized in that: The specific preparation method of the biomass aerogel skeleton described in step (1) is: (11) crushing the palm shells and soaking them in 8-10 wt% NaOH solution at 80-90° C. for 3-5 hours to remove lignin and obtain a primary cellulose mixture; (12) subjecting the primary cellulose mixture to ultrasonic stripping at 40-60 kHz for 1-3 hours to obtain a nanocellulose suspension with a diameter of 20-50 nm, and assembling the nanocellulose suspension into a gel by freeze-induction; (13) The gel was treated with a CO2 supercritical drying process at a temperature of 30-32 °C and a pressure of 7-8 MPa for 48-60 h to obtain an aerogel with a porosity of >97%, i.e., a biomass aerogel skeleton.

5. The method for preparing a biomass aerogel phase change plastic-wood composite material according to claim 4, characterized in that: The preparation method of the core material described in step (2) is: (21) preparing a mixture of palm oil hydrolyzed fatty acids with a C16-C18 content of >80% and lauric acid-stearic acid in a mass ratio of 1:1 to 7:3; (22) A core material with a leakage rate of <2% was obtained after 200 thermal cycles within the controllable phase transition temperature range of 20–38 °C.

6. The method for preparing a biomass aerogel phase change plastic-wood composite material according to claim 5, characterized in that: The preparation method of the phase change energy storage unit in step (3) is: (31) The molten core material was used as the aqueous phase and a 1–3 wt % Span 80 toluene solution was used as the oil phase at a temperature of 55–65 °C to form a W / O emulsion using microfluidic emulsification technology, with a microchannel diameter ranging from 150 to 250 μm; (32) The biomass aerogel skeleton was immersed in W / O emulsion and immersed under a vacuum condition of -0.1 MPa for 3–5 h to obtain an aerogel-loaded shape-stabilized phase change composite material; (33) adding the aerogel-loaded shaped phase change composite material to a mixed solution of ethyl orthosilicate and tetrabutyl titanate and stirring to mix uniformly, then adding hydrochloric acid while stirring to adjust the pH value to 2-4, and obtaining a solid-liquid mixture after the reaction is complete; (34) drying the solid-liquid mixture in a vacuum oven to obtain core-shell microcapsules, i.e., phase change energy storage units; The silicon dioxide-titanium dioxide shell layer of the phase-change energy storage unit has a thickness of 0.5-1.2 μm and a coverage rate greater than 95%.

7. The method for preparing a biomass aerogel phase change plastic-wood composite material according to claim 6, characterized in that: The preparation method of the plastic substrate described in step (4) is: (41) premixing modified palm fiber powder with a particle size of 80-120 mesh and a bio-based compatibilizer in an internal mixer at a temperature of 160-180° C. for 10-20 minutes to obtain a premix; The bio-based compatibilizer is prepared by mixing a polycondensate of palm oil epoxy resin and hexamethylenediamine in a molar ratio of 1:1-1:1.2; (42) mixing the premix with the biodegradable plastic in a mass ratio of 3:7 to 1:1, and reactively extruding the mixture through a screw extruder at a temperature gradient of 160-190°C to obtain an extrudate; The screw speed is 100-150 rpm, and the residence time of the premix in the screw extruder is 2-3 minutes; (43) The extrudate is pelletized to obtain a plastic matrix.

8. The method for preparing a biomass aerogel phase change plastic-wood composite material according to claim 7, characterized in that: The method for embedding the phase change energy storage unit into the plastic matrix in step (5) is: (51) The phase change energy storage unit and the plastic matrix were mixed in a mass ratio of 3:7 and reactively extruded through a screw extruder at a temperature gradient of 150–190 °C to obtain a primary composite material; Among them, the temperature range of the feed section of the screw extruder is 150-170℃, the temperature range of the melt mixing section of the screw extruder is 170-190℃, and the temperature range of the head section of the screw extruder is 160-180℃; (52) The composite material was placed into a mold at a temperature of 170-190 °C and a pressure of 10-20 MPa and maintained under pressure for 8-12 minutes to obtain a biomass aerogel phase change plastic-wood composite material profile.

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