High-performance shell-imitated structure wood and preparation method thereof

Abstract

The application discloses high-performance shell-imitated structure wood and a preparation method thereof, and belongs to the technical field of structural wood preparation. In order to develop a structural wood with simple preparation method and excellent performance, the poplar veneer is immersed into a mixed solution of lithium hydroxide and dimethyl sulfoxide according to a material-liquid ratio, is swelled at 50-55 DEG C for 36-40h, and then is added into maleic anhydride to be esterified and modified at room temperature for 3-4h; then, the modified poplar veneer is neutralized by being soaked in a sodium hydroxide aqueous solution for 3-4h after multiple rinsing, is rinsed to be neutral, and is freeze-dried, so that the modified poplar veneer is obtained; an ammonium dihydrogen phosphate and magnesium chloride mixed aqueous solution is configured, the modified poplar veneer is vacuum-impregnated in the mixed aqueous solution for 3-4h, and then is transferred into a sodium silicate solution with a certain concentration to be vacuum-impregnated for 3-4h, so that a mineralized poplar veneer is obtained; and the shell-imitated structure single-layer poplar is prepared by densifying the mineralized poplar veneer to obtain the shell-imitated structure poplar.

Description

Technical Field

[0001] The invention belongs to the technical field of structural wood preparation, and in particular relates to high-performance shell-like structural wood and a preparation method thereof. Background Art

[0002] Currently, natural wood resources are insufficient for direct utilization. Consequently, the development of fast-growing timber, which grows quickly, matures early, and has a short rotation period, has attracted widespread attention. However, due to its loose texture, low density, and high porosity, its mechanical and mechanical strength are unsatisfactory, severely limiting its application. There is an urgent need to develop efficient technologies for the physical or chemical modification of fast-growing timber.

[0003] The invention patent with patent number CN112171830B and invention name "A high-strength wood and its preparation method" discloses the technical solution as "The high-strength wood is a dense microstructure formed by the tightly arranged wood cell units. The wood cell units are solid structures composed of nanocellulose fibers and lignin. The lignin content ranges from 0% to 90%. The preparation method of the present invention is: first, through the process of removing lignin, a wood with partially removed lignin is obtained; then the wood fibers are treated with a chemical solution, and finally the sample is washed with water to remove chemical residues, and high-strength wood is obtained after drying. The high-strength wood has greatly improved density and mechanics. The preparation method has the characteristics of wide range of raw materials, simple preparation steps, low cost, etc., which greatly expands the application range of wood." However, this method requires delignification of the wood through harsh chemical treatment (sodium hydroxide / sodium sulfite treatment). Summary of the Invention

[0004] The problem to be solved by the present invention is to develop a structural wood with a simple preparation method and excellent performance, and propose a high-performance shell-like structural wood and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A method for preparing high-performance shell-like structural timber comprises the following steps:

[0007] S1. Modification of Poplar Veneer: First, the poplar veneer is immersed in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allowed to swell at 50-55°C for 36-40 hours. The poplar veneer is then esterified by adding maleic anhydride and maintaining it at room temperature for 3-4 hours.

[0008] The poplar veneer is then removed from the maleic anhydride, rinsed with an ethanol solution multiple times, and then immersed in a sodium hydroxide aqueous solution for 3-4 hours for neutralization reaction, and then rinsed with distilled water until neutral, and then freeze-dried to obtain a modified poplar veneer;

[0009] S2. Mineralization of poplar veneer: A mixed aqueous solution of ammonium dihydrogen phosphate and magnesium chloride at a certain concentration was configured, and the modified poplar veneer obtained in step S1 was placed in the mixed aqueous solution and vacuum impregnated for 3-4h, and then transferred to a certain concentration of sodium silicate solution and vacuum impregnated for 3-4h to obtain a mineralized poplar veneer;

[0010] S3. Preparation of a single-layer poplar wood with a shell-like structure: The mineralized poplar wood veneer obtained in step S2 is densified to obtain a shell-like poplar wood.

[0011] Furthermore, for the preparation of the shell-like structure multi-layer poplar: a layer of adhesive is coated on the surface of the shell-like structure poplar veneer obtained in step S3, and the veneers coated with adhesive are stacked layer by layer with the fiber directions of the two adjacent layers of veneers perpendicular to each other, and hot pressed to obtain the shell-like structure multi-layer poplar.

[0012] Furthermore, in step S1, the material-liquid ratio of the poplar veneer to the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g: 100-120 mL;

[0013] In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 2-4 mg / mL;

[0014] The mass ratio of the poplar veneer to maleic anhydride is 1:3-5.

[0015] Furthermore, in step S1, the number of ethanol rinses is 3-5 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa and -50°C, and the freeze-drying time is 12-48 hours.

[0016] Furthermore, in step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 30-35 wt%, the concentration of magnesium chloride in the mixed aqueous solution is 15-20 wt%; and the concentration of the sodium silicate solution is 10-50 wt%.

[0017] Furthermore, in step S3, the densification treatment conditions are 10-100 MPa and 60-120° C. for 6-8 hours.

[0018] Furthermore, the adhesive coated on the surface during the preparation of the multi-layer poplar wood with imitation shell structure is one of starch adhesive, soybean protein adhesive, isocyanate adhesive, epoxy resin adhesive, polyurethane adhesive, and polyvinyl acetate adhesive.

[0019] Furthermore, the hot pressing treatment conditions for the preparation of the shell-like multi-layer poplar wood are 10-100 MPa, 60-120° C. and hot pressing for 6-8 hours.

[0020] A method for preparing high-performance imitation shell structural timber prepares high-performance imitation shell structural timber, wherein the flame retardant performance of the high-performance imitation shell structural timber meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard.

[0021] Beneficial effects of the present invention:

[0022] The present invention discloses a method for preparing high-performance shell-like structural wood, which comprises pre-treating poplar veneers with lithium hydroxide / dimethyl sulfoxide solution to increase the intercellular spaces between the wood, then performing an esterification reaction to enhance electrostatic repulsion and further increase the intercellular spaces between the wood, thereby enhancing the penetration of inorganic salt-modified precursors, and simultaneously introducing sites for in-situ mineralization of inorganic salts. Finally, a high-performance shell-like structural wood is obtained through in-situ inorganic salt mineralization combined with a densification process, which can be used as structural wood in the fields of construction, furniture, interior decoration, etc.

[0023] The present invention discloses a method for preparing high-performance shell-like structural wood. By combining cell swelling technology with the electrostatic repulsion introduced by esterification, the intercellular spaces between wood cells are increased to enhance the penetration of inorganic salt-modified precursors. At the same time, sites for in-situ mineralization of inorganic salts are introduced, and further in-situ inorganic salt mineralization and densification are performed to ultimately obtain high-performance shell-like structural wood. This method does not require delignification treatment and avoids the use of highly toxic chemicals such as formaldehyde, while achieving high performance such as flame retardancy. The tensile strength of the shell-like structural wood obtained by this method is 2-3 times higher than that of the original poplar veneer, and the compressive strength is increased by 1.5-2 times. At the same time, the flame retardant performance meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard. In addition, the obtained shell-like structural poplars can be bonded together with adhesives to obtain multi-layer shell-like structural poplars. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic flow chart of a method for preparing high-performance shell-like structural timber according to the present invention;

[0025] Figure 2 These are photos of samples at various stages of the preparation process of the present invention;

[0026] Figure 3 This is a SEM image of the cross section of the poplar wood in the present invention;

[0027] Figure 4 This is an SEM image of the cross section of the modified poplar wood of the present invention. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the specific embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the specific embodiments of the present invention described and illustrated in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0029] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected specific embodiments of the present invention. All other specific embodiments obtained by those skilled in the art based on the specific embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] In order to further understand the content, features and effects of the present invention, the following specific embodiments are given as examples, and the attached Figure 1 -Attached Figure 4 The detailed instructions are as follows:

[0031] Example 1:

[0032] A method for preparing high-performance shell-like structural timber comprises the following steps:

[0033] S1. Modification of Poplar Veneer: First, the poplar veneer was immersed in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allowed to swell at 50°C for 36 hours. The poplar veneer was then esterified by adding maleic anhydride and maintaining it at room temperature for 3 hours.

[0034] The poplar veneer is then removed from the maleic anhydride, rinsed with an ethanol solution multiple times, and then immersed in a sodium hydroxide aqueous solution for 3 hours for neutralization reaction. The poplar veneer is then rinsed with distilled water until neutrality is achieved, and then freeze-dried to obtain a modified poplar veneer.

[0035] Furthermore, in step S1, the material-liquid ratio of the poplar veneer and the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g:100 mL;

[0036] In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 2 mg / mL;

[0037] The mass ratio of the poplar veneer to maleic anhydride is 1:3.

[0038] Furthermore, in step S1, the number of ethanol rinses is 3 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa, -50°C, and the freeze-drying time is 24 hours.

[0039] S2. Mineralization of poplar veneer: A mixed aqueous solution of ammonium dihydrogen phosphate and magnesium chloride at a certain concentration was prepared, and the modified poplar veneer obtained in step S1 was placed in the mixed aqueous solution and vacuum impregnated for 3 hours, and then transferred to a certain concentration of sodium silicate solution and vacuum impregnated for 3 hours to obtain a mineralized poplar veneer;

[0040] Furthermore, in step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 30 wt%, the concentration of magnesium chloride in the mixed aqueous solution is 15 wt%; and the concentration of the sodium silicate solution is 20 wt%.

[0041] S3. Preparation of a single-layer poplar shell structure: The mineralized poplar veneer obtained in step S2 was densified to obtain a poplar shell structure;

[0042] Furthermore, in step S3, the densification treatment conditions are 10 MPa and 80° C. for 6 h;

[0043] The high-performance imitation shell structural timber prepared by the preparation method of the high-performance imitation shell structural timber described in this embodiment is characterized in that the flame retardant performance of the high-performance imitation shell structural timber meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard.

[0044] A high-performance shell-like structural timber prepared in this embodiment, such as Figure 2 As shown, from Figure 2 It can be seen that through the cell swelling process, in-situ mineralization technology, and densification process, a brown-yellow and relatively uniform shell-like structural wood can be obtained; SEM images are compared. Figure 3 and Figure 4 As shown in the figure, a looser wood structure can be obtained through chemical swelling pretreatment, and the cell swelling process can open the dense cell structure of poplar wood, which facilitates the subsequent penetration of modifiers and in-situ mineralization.

[0045] The performance test of a high-performance shell-like structural timber prepared in this embodiment is shown in Table 1:

[0046] Table 1:

[0047]

[0048] The flame retardant standard is GB / T11785 "Classification of Fire Performance of Artificial Boards". As can be seen from Table 1, the tensile strength of the obtained imitation shell structural wood is 2-3 times higher than that of the original poplar veneer, and the compressive strength is increased by 1.5-2 times. At the same time, the flame retardant performance meets the Class B requirements specified in GB / T11785 "Classification of Fire Performance of Artificial Boards".

[0049] Example 2:

[0050] A method for preparing high-performance shell-like structural timber comprises the following steps:

[0051] S1. Modification of Poplar Veneer: First, the poplar veneer was immersed in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allowed to swell at 55°C for 40 hours. The poplar veneer was then esterified by adding maleic anhydride and maintaining it at room temperature for 4 hours.

[0052] The poplar veneer is then removed from the maleic anhydride, rinsed with an ethanol solution multiple times, and then immersed in a sodium hydroxide aqueous solution for 4 hours for neutralization reaction. The poplar veneer is then rinsed with distilled water until neutrality is achieved, and then freeze-dried to obtain a modified poplar veneer.

[0053] Furthermore, in step S1, the material-liquid ratio of the poplar veneer to the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g:120 mL;

[0054] In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 4 mg / mL;

[0055] The mass ratio of the poplar veneer to maleic anhydride is 1:5.

[0056] Furthermore, the number of ethanol rinses in step S1 is 5 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa, -50°C, and the freeze-drying time is 12 hours.

[0057] S2. Mineralization of poplar veneer: A mixed aqueous solution of ammonium dihydrogen phosphate and magnesium chloride at a certain concentration was prepared, and the modified poplar veneer obtained in step S1 was placed in the mixed aqueous solution and vacuum impregnated for 4 hours, and then transferred to a certain concentration of sodium silicate solution and vacuum impregnated for 4 hours to obtain a mineralized poplar veneer;

[0058] Furthermore, in step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 35 wt%, the concentration of magnesium chloride in the mixed aqueous solution is 20 wt%, and the concentration of the sodium silicate solution is 50 wt%.

[0059] S3. Preparation of a single-layer poplar shell structure: The mineralized poplar veneer obtained in step S2 was densified to obtain a poplar shell structure;

[0060] Furthermore, in step S3, the densification treatment conditions are 100 MPa and 120° C. for 8 h;

[0061] S4. Preparation of multilayer poplar imitation shell structure: A layer of adhesive is applied to the surface of the poplar veneer obtained in step S3, and the fiber directions of two adjacent veneers are perpendicular to each other and the veneers are stacked with adhesive, and hot pressed to obtain a multilayer poplar imitation shell structure;

[0062] Furthermore, the adhesive applied to the surface in step S4 is a soy protein adhesive;

[0063] Furthermore, in step S4, the hot pressing treatment conditions are 50 MPa and 60° C. for 6 hours.

[0064] The high-performance imitation shell structural timber prepared by the preparation method of the high-performance imitation shell structural timber described in this embodiment is characterized in that the flame retardant performance of the high-performance imitation shell structural timber meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard.

[0065] Example 3:

[0066] A method for preparing high-performance shell-like structural timber comprises the following steps:

[0067] S1. Modification of Poplar Veneer: First, the poplar veneer was immersed in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allowed to swell at 55°C for 36 hours. The poplar veneer was then esterified by adding maleic anhydride and maintaining it at room temperature for 4 hours.

[0068] The poplar veneer is then removed from the maleic anhydride, rinsed with an ethanol solution multiple times, and then immersed in a sodium hydroxide aqueous solution for 4 hours for neutralization reaction. The poplar veneer is then rinsed with distilled water until neutrality is achieved, and then freeze-dried to obtain a modified poplar veneer.

[0069] Furthermore, in step S1, the material-liquid ratio of the poplar veneer to the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g:110 mL;

[0070] In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 3 mg / mL;

[0071] The mass ratio of the poplar veneer to maleic anhydride is 1:4.

[0072] Furthermore, the number of ethanol rinses in step S1 is 4 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa, -50°C, and the freeze-drying time is 48 hours.

[0073] S2. Mineralization of poplar veneer: A mixed aqueous solution of ammonium dihydrogen phosphate and magnesium chloride at a certain concentration was prepared, and the modified poplar veneer obtained in step S1 was placed in the mixed aqueous solution and vacuum impregnated for 3 hours, and then transferred to a certain concentration of sodium silicate solution and vacuum impregnated for 3 hours to obtain a mineralized poplar veneer;

[0074] Furthermore, in step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 32 wt%, the concentration of magnesium chloride in the mixed aqueous solution is 16 wt%; and the concentration of the sodium silicate solution is 25 wt%.

[0075] S3. Preparation of a single-layer poplar shell structure: The mineralized poplar veneer obtained in step S2 was densified to obtain a poplar shell structure;

[0076] Furthermore, in step S3, the densification treatment conditions are 20 MPa and 60-120° C. for 7 h;

[0077] The high-performance imitation shell structural timber prepared by the preparation method of the high-performance imitation shell structural timber described in this embodiment is characterized in that the flame retardant performance of the high-performance imitation shell structural timber meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard.

[0078] Example 4:

[0079] A method for preparing high-performance shell-like structural timber comprises the following steps:

[0080] S1. Modification of Poplar Veneer: First, the poplar veneer was immersed in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allowed to swell at 50°C for 36 hours. The poplar veneer was then esterified by adding maleic anhydride and maintaining it at room temperature for 3-4 hours.

[0081] The poplar veneer is then removed from the maleic anhydride, rinsed multiple times with an ethanol solution, and then immersed in a sodium hydroxide aqueous solution for 3.5 hours for neutralization reaction. The poplar veneer is then rinsed with distilled water until neutrality is achieved, and then freeze-dried to obtain a modified poplar veneer.

[0082] Furthermore, in step S1, the material-liquid ratio of the poplar veneer and the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g:100 mL;

[0083] In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 3 mg / mL;

[0084] The mass ratio of the poplar veneer to maleic anhydride is 1:3.5.

[0085] Furthermore, the number of ethanol rinses in step S1 is 5 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa and -50°C, and the freeze-drying time is 12-48 hours.

[0086] S2. Mineralization of poplar veneer: A mixed aqueous solution of ammonium dihydrogen phosphate and magnesium chloride at a certain concentration was prepared, and the modified poplar veneer obtained in step S1 was placed in the mixed aqueous solution and vacuum impregnated for 3 hours, and then transferred to a certain concentration of sodium silicate solution and vacuum impregnated for 3 hours to obtain a mineralized poplar veneer;

[0087] Furthermore, in step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 33 wt%, the concentration of magnesium chloride in the mixed aqueous solution is 17 wt%, and the concentration of the sodium silicate solution is 30 wt%.

[0088] S3. Preparation of a single-layer poplar shell structure: The mineralized poplar veneer obtained in step S2 was densified to obtain a poplar shell structure;

[0089] Furthermore, in step S3, the densification treatment conditions are 50 MPa and 100° C. for 6 h;

[0090] S4. Preparation of multilayer poplar imitation shell structure: A layer of adhesive is applied to the surface of the poplar veneer obtained in step S3, and the fiber directions of two adjacent veneers are perpendicular to each other and the veneers are stacked with adhesive, and hot pressed to obtain a multilayer poplar imitation shell structure;

[0091] Furthermore, the adhesive applied to the surface in step S4 is an isocyanate adhesive;

[0092] Furthermore, in step S4, the hot pressing treatment conditions are 20 MPa and 120° C. for 6 hours.

[0093] The high-performance imitation shell structural timber prepared by the preparation method of the high-performance imitation shell structural timber described in this embodiment is characterized in that the flame retardant performance of the high-performance imitation shell structural timber meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard.

[0094] Example 5:

[0095] A method for preparing high-performance shell-like structural timber comprises the following steps:

[0096] S1. Modification of Poplar Veneer: First, the poplar veneer was immersed in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allowed to swell at 50°C for 39 hours. The poplar veneer was then esterified by adding maleic anhydride and maintaining the mixture at room temperature for 3 hours.

[0097] The poplar veneer is then removed from the maleic anhydride, rinsed with an ethanol solution multiple times, and then immersed in a sodium hydroxide aqueous solution for 3 hours for neutralization reaction. The poplar veneer is then rinsed with distilled water until neutrality is achieved, and then freeze-dried to obtain a modified poplar veneer.

[0098] Furthermore, in step S1, the material-liquid ratio of the poplar veneer to the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g:120 mL;

[0099] In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 4 mg / mL;

[0100] The mass ratio of the poplar veneer to maleic anhydride is 1:3.

[0101] Furthermore, the number of ethanol rinses in step S1 is 4 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa, -50°C, and the freeze-drying time is 48 hours.

[0102] S2. Mineralization of poplar veneer: A mixed aqueous solution of ammonium dihydrogen phosphate and magnesium chloride at a certain concentration was prepared, and the modified poplar veneer obtained in step S1 was placed in the mixed aqueous solution and vacuum impregnated for 3 hours, and then transferred to a certain concentration of sodium silicate solution and vacuum impregnated for 3 hours to obtain a mineralized poplar veneer;

[0103] Furthermore, in step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 30 wt%, the concentration of magnesium chloride in the mixed aqueous solution is 15 wt%; and the concentration of the sodium silicate solution is 40 wt%.

[0104] S3. Preparation of a single-layer poplar shell structure: The mineralized poplar veneer obtained in step S2 was densified to obtain a poplar shell structure;

[0105] Furthermore, in step S3, the densification treatment conditions are 30 MPa and 90° C. for 8 h;

[0106] S4. Preparation of multilayer poplar imitation shell structure: A layer of adhesive is applied to the surface of the poplar veneer obtained in step S3, and the fiber directions of two adjacent veneers are perpendicular to each other and the veneers are stacked with adhesive, and hot pressed to obtain a multilayer poplar imitation shell structure;

[0107] Furthermore, the adhesive applied to the surface in step S4 is a polyvinyl acetate adhesive;

[0108] Furthermore, in step S4, the hot pressing treatment conditions are 10 MPa and 60° C. for 8 hours.

[0109] The high-performance imitation shell structural timber prepared by the preparation method of the high-performance imitation shell structural timber described in this embodiment is characterized in that the flame retardant performance of the high-performance imitation shell structural timber meets the Class B requirements specified in the GB / T11785 "Classification of Fire Performance of Artificial Panels" standard.

[0110] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0111] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of these combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A method for preparing high-performance shell-like structural timber, characterized in that: The steps include: S1. Poplar veneer modification: First, immerse the poplar veneer in a mixture of lithium hydroxide and dimethyl sulfoxide (DMSO) according to the material-liquid ratio and allow it to swell at 50-55°C for 36-40 hours. Then, esterification modification is performed by adding maleic anhydride to the veneer and maintaining it at room temperature for 3-4 hours. The poplar veneer is then removed from the maleic anhydride, rinsed with an ethanol solution multiple times, and then immersed in a sodium hydroxide aqueous solution for 3-4 hours for neutralization reaction, and then rinsed with distilled water until neutral, and then freeze-dried to obtain a modified poplar veneer; S2 poplar veneer mineralization: configure a certain concentration of ammonium dihydrogen phosphate and magnesium chloride mixed aqueous solution, the modified poplar veneer obtained in step S1 is placed in the mixed aqueous solution for vacuum impregnation 3-4h, and then transferred to a certain concentration of sodium silicate solution vacuum impregnation 3-4h to obtain a mineralized poplar veneer; In step S2, the concentration of ammonium dihydrogen phosphate in the mixed aqueous solution is 30-35wt%, the concentration of magnesium chloride in the mixed aqueous solution is 15-20wt%; the concentration of the sodium silicate solution is 10-50wt%; S3 imitation shell structure single layer poplar preparation: The mineralized poplar veneer obtained in step S2 was densified to obtain imitation shell structure poplar; The densification treatment conditions in step S3 are 10-100 MPa and 60-120°C for 6-8 hours.

2. The method for preparing high-performance shell-like structural timber according to claim 1, characterized in that: For the preparation of multi-layer poplar wood with imitation shell structure: a layer of adhesive is coated on the surface of the poplar wood veneer with imitation shell structure obtained in step S3, and the veneers coated with adhesive are stacked layer by layer in the form of fiber directions of two adjacent layers of veneers perpendicular to each other, and hot pressed to obtain the multi-layer poplar wood with imitation shell structure.

3. The method for preparing high-performance shell-like structural timber according to claim 2, characterized in that: In step S1, the material-liquid ratio of the poplar veneer to the mixed solution of lithium hydroxide and dimethyl sulfoxide is 1 g: 100-120 mL; In the mixed solution of lithium hydroxide and dimethyl sulfoxide, the concentration of lithium hydroxide is 2-4 mg / mL; The mass ratio of the poplar veneer to maleic anhydride is 1:3-5.

4. The method for preparing high-performance shell-like structural timber according to claim 3, characterized in that: In step S1, the number of ethanol rinses is 3-5 times, the pH of the sodium hydroxide aqueous solution is 10, the freeze-drying conditions are 1 Pa, -50 ºC, and the freeze-drying time is 12-48 h.

5. The method for preparing high-performance shell-like structural timber according to claim 4, characterized in that: The adhesive coated on the surface during the preparation of the multi-layer poplar wood with imitation shell structure is one of starch adhesive, soybean protein adhesive, isocyanate adhesive, epoxy resin adhesive, polyurethane adhesive and polyvinyl acetate adhesive.

6. The method for preparing high-performance shell-like structural timber according to claim 5, characterized in that: For the preparation of multi-layer poplar wood with imitation shell structure, the hot pressing treatment conditions are 10-100MPa and 60-120ºC for 6-8h.

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