Enhanced strength engineering structural materials and methods of making and using same

Abstract

An engineered structure may include a first laminate having a plurality of layers of constituent plant material. The plurality of constituent plant material layers may include one or more first layers and one or more second layers. Each layer of plant material may be adhered to an adjacent layer of plant material via glue. Each first layer may be a dense layer of plant material having a density greater than or equal to 1.15 g / cm3 and having a first mechanical strength. Each second layer may be a layer of plant material having a density less than 1.15 g / cm3 and having a second mechanical strength less than the first mechanical strength. For example, the plant material of each layer can be wood or bamboo.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 399,795, filed on August 22, 2022, entitled “Strength-Enhanced Engineered Structural Materials, and Methods for Fabrication and Use Thereof,” the entire contents of which are hereby incorporated herein by reference.

[0003] Statement Regarding Federally Funded Research

[0004] This invention was made with government support under the Advanced Research Projects Agency-Energy (ARPA-E) of the U.S. Department of Energy (DOE) under Award DEAR0001025. The U.S. Government has certain rights in this invention. Technical Field

[0005] The present disclosure relates generally to engineered structural materials, and more particularly to strength-reinforced structures employing plant materials (e.g., wood, bamboo, etc.), such as, but not limited to, cross-laminated timber (CLT), glue-laminated timber (glulam), laminated veneer lumber (LVL), oriented strand board (OSB), and / or oriented structural straw board (OSSB). Background Art

[0006] Engineered wood is attractive for replacing CO2-intensive building materials (e.g., concrete, steel, ceramics, etc.) with the goal of achieving carbon-negative buildings. However, the performance (e.g., stiffness) of engineered wood must be further improved to expand its use. Cross-laminated timber (CLT) is the latest engineered wood product (commonly known as aggregate wood) that can replace concrete in buildings at a fraction of the weight and carbon footprint. While CLTs are generally strong enough, they lack the stiffness to match the span of reinforced concrete slabs, requiring thicker floor systems and more densely packed columns than their concrete counterparts, which in turn increases construction costs.

[0007] Embodiments of the disclosed subject matter may address one or more of the above-mentioned problems and disadvantages, as well as others. Summary of the invention

[0008] Embodiments of the disclosed subject matter system provide an engineering structural material with enhanced mechanical strength. In some embodiments, the engineering structural material includes multiple plant material layers (e.g., including one or more plant material sheets), which are glued, adhered, bonded or otherwise coupled together to form a laminate. At least one plant material layer within the laminate can be a dense plant material layer (e.g., including one or more dense plant material sheets), for example, the dense plant material layer is compressed to collapse the cavities of its natural cellulose-based microstructure so as to have a strength of at least 1.15 g / cm 3 In some embodiments, the densified plant material layer can be formed from a lignin-damaged material (e.g., an in-situ lignin-modified plant material or a partially delignified plant material). In some embodiments, the densified plant material layer can enhance the overall structure, thereby allowing other plant material layers to have lower strength, allowing the laminate to be used in more demanding applications, and / or allowing the laminate to have a smaller cross-section.

[0009] In one or more embodiments, the engineering structure may include a first laminate. The first laminate may include a plurality of constituent plant material layers. The plurality of constituent plant material layers may include one or more first layers and one or more second layers. Each plant material layer may be adhered to an adjacent plant material layer via corresponding one or more adhesives. Each first plant material layer may have a density greater than or equal to 1.15 g / cm 3 and a dense plant material layer with a mechanical strength greater than or equal to the first value. Each second plant material layer may be a layer with a density less than 1.15 g / cm 3 And the plant material layer has a mechanical strength less than the first value.

[0010] In one or more embodiments, the engineering structural material may include one or more laminated structures. Each laminated structure may have a plurality of constituent plant material layers. Each plant material layer may be coupled to an adjacent plant material layer via one or more corresponding adhesives. At least one of the plurality of constituent plant material layers may have a density greater than or equal to 1.15 g / cm 3 layer of dense plant material.

[0011] In one or more embodiments, a method may include providing one or more first layers. Each first layer may include a density greater than or equal to 1.15 g / cm 3 The method may further include providing one or more second layers. Each second layer may include a plant material having a density less than 1.15 g / cm 3 and a plant material having a mechanical strength less than a first value. The method may further include coupling the one or more first layers to the one or more second layers via corresponding one or more glues to form a laminate.

[0012] Any of the various innovations of the present disclosure may be used in combination or alone. This disclosure is provided to introduce in simplified form a selection of concepts that will be further described in the detailed description below. This disclosure is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The foregoing and other purposes, features, and advantages of the disclosed technology will become more clearly understood based on the following detailed description made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments will be described below with reference to the accompanying drawings, which are not necessarily drawn to scale. Where applicable, some elements may be simplified or otherwise not shown to help illustrate and describe essential features. In all the accompanying drawings, the same reference numerals represent the same elements.

[0014] Figures 1A-1G is a simplified schematic diagram of various enhanced strength engineered structures formed from one or more plant materials in accordance with one or more embodiments of the disclosed subject matter.

[0015] Figure 2A-2B is a partial isometric view of a strength-enhanced cross-laminated timber (CLT) structure according to one or more embodiments of the disclosed subject matter.

[0016] Figures 3A-3D is a partial isometric view of various enhanced strength glued laminated timber (glulam) structures according to one or more embodiments of the disclosed subject matter.

[0017] Figures 4A-4D is a partial isometric view of various strength-enhanced laminated veneer lumber (LVL) structures according to one or more embodiments of the disclosed subject matter.

[0018] Figures 5A-5E Various enhanced strength I-beam structures are shown in accordance with one or more embodiments of the disclosed subject matter.

[0019] Figure 6 is a simplified process flow diagram for fabricating an engineered structure of enhanced strength using one or more plant materials, according to one or more embodiments of the disclosed subject matter. DETAILED DESCRIPTION

[0020] General

[0021] For the purpose of this specification, certain aspects, advantages and novel features of embodiments of the present disclosure are described herein. The disclosed methods and systems should not be interpreted as limiting in any way. On the contrary, the present disclosure relates to all novel and non-obvious features and aspects of the various disclosed embodiments, whether they exist alone or in a variety of combinations and sub-combinations. The methods and systems are not limited to any particular aspect or feature or combination thereof, nor do the disclosed embodiments require the presence of any one or more specific advantages or the resolution of specific problems. The technology from any embodiment or example may be combined with the technology described in any one or more of the other embodiments or examples. In view of the many possible embodiments to which the principles of the disclosed technology can be applied, it should be recognized that the illustrated embodiments are exemplary only and should not be considered to limit the scope of the disclosed technology.

[0022] Although the operations of some disclosed methods are described in a particular order for ease of presentation, it should be understood that this description encompasses rearrangement unless the specific language set forth below requires a specific order. For example, in some cases, the operations described in sequence may be rearranged or performed simultaneously. In addition, for simplicity, the accompanying drawings may not show the various ways in which the disclosed methods can be used in conjunction with other methods. In addition, the specification sometimes uses terms such as "providing" or "implementing" to describe the disclosed methods. These terms are high-level abstractions of the actual operations performed. The actual operations corresponding to these terms may vary depending on the specific implementation, and are easily discernible by those skilled in the art.

[0023] Unless otherwise stated, the disclosure of the numerical range should be understood to refer to each discrete point within the range, including endpoints. Unless otherwise stated, all numbers used in this patent specification or claims to represent the number of components, molecular weight, percentage, temperature, time, etc. should be understood to be slightly modified by the term "about". Therefore, unless otherwise implicitly or explicitly indicated, or unless the context is properly understood by those skilled in the art to have a more explicit structure, the numerical parameters set forth are approximate values, which may depend on the desired properties sought and / or the detection limits under standard test conditions / methods, as known to those skilled in the art. When the embodiment is directly and clearly distinguished from the prior art discussed, unless the words "about", "substantially" or "roughly" are used, the embodiment numbers are not approximate values. Whenever "substantially", "roughly", "about" or similar language is explicitly used in conjunction with a specific value, unless otherwise explicitly stated, it is intended to indicate a change of up to and including ±10% of the value.

[0024] Directional and other relative references may be used to facilitate discussion of the drawings and principles herein, but are not intended to be limiting. For example, certain terms such as "inside," "outside," "upper," "lower," "top," "bottom," "inside," "outside," "left," "right," "front," "rear," "back," and the like may be used. Where applicable, such terms are used to provide some clarity when describing relative relationships, particularly with respect to the illustrated embodiments. However, such terms are not intended to imply absolute relationships, positions, and / or orientations. For example, a "top" portion of an object may become a "bottom" portion simply by flipping the object. However, it is still the same part, and the object remains unchanged.

[0025] As used herein, "including" means "comprising," and the singular forms "a," "an," or "the" include plural references unless the context clearly indicates otherwise. The term "or" refers to a single element or a combination of two or more elements of the alternative elements, unless the context clearly indicates otherwise.

[0026] Although there are alternatives to the various components, parameters, operating conditions, etc. described herein, this does not mean that those alternatives are necessarily equivalent and / or perform equally well. Unless otherwise indicated, it is not intended to list alternatives in a preferred order. Unless otherwise indicated, any group defined below may be substituted or unsubstituted.

[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the disclosure belongs. Although methods and materials similar or equivalent to the methods and materials described herein can be used to implement or test the disclosure, applicable methods and materials are described below. Materials, methods and examples are illustrative only and are not intended to be restrictive. According to the following detailed description and the appended claims, the features of the current disclosed subject matter will be readily understood.

[0028] Terminology Overview

[0029] The following content is provided to facilitate description of various aspects of the disclosed subject matter and to guide those skilled in the art to practice the disclosed subject matter.

[0030] Plant material: A part of any eukaryotic organism of the plant kingdom in its natural state when growing (e.g., a piece or part obtained by mechanical means or other means of cutting). In some embodiments, the plant material includes wood (e.g., hardwood or softwood), bamboo (e.g., any of the subfamily Bambusoideae, such as, but not limited to, Phyllostachys pubescens, Phyllostachys chinensis, Phyllostachys sibiricum, Phyllostachys glabra, and Phyllostachys nigromaculata), reed (e.g., any of the common reed (Phragmites australis), giant reed (Phragmites spp.), Burmese reed (Phragmites spp.), reed canary grass (Phragmites australis), reed sweet grass (Phragmites australis), small reed (Phragmites spp.), paper reed (Cyperus rotundus), black sedge (Phragmites spp.), reed mace (Typha spp.), cloak thatch (Phyllostachys roxburghii), and cap reed (Phragmites spp.)) or grass (e.g., a species selected from the order or family Poaceae). For example, the natural wood can be any type of hardwood (e.g., with a natural lignin content in the range of 18-25% by weight (wt%)) or softwood (e.g., with a natural lignin content in the range of 25-35 wt%), such as, but not limited to, basswood, oak, poplar, ash, alder, poplar, fir, beech, birch, cherry, walnut, coconut palm, elm, hickory, maple, oak, rosewood, plum, walnut, willow, boxwood, bald cypress, cedar, cypress, Douglas fir, fir, hemlock, larch, pine, redwood, spruce, tamarisk, juniper, and yew. Alternatively, in some embodiments, the plant material can be a fiber plant of any type consisting of lignin, hemicellulose, and cellulose. For example, the plant material may be bagasse (e.g. formed from the residue of processing of sugar cane or sorghum stalks) or wheat straw (e.g. formed from the residue of processing of cereal plants such as rice, wheat, millet or corn) .

[0031] Engineered structure or engineered structural material: A structure formed from multiple sheets or layers of natural or modified plant materials joined together using glue or other adhesives to form a structure with improved strength and / or durability. Examples of such structures / materials include, but are not limited to, cross-laminated timber (CLT), glue-laminated timber (glulam), laminated veneer lumber (LVL), oriented strand board (OSB), and / or oriented structural straw board (OSSB).

[0032] Lignin-damaged plant material: Plant material that has been modified by one or more chemical treatments to (a) modify the native lignin therein in situ, (b) partially remove the native lignin therein (i.e., partial delignification), or (c) completely remove the native lignin therein (i.e., complete delignification). In some embodiments, the lignin-damaged plant material can substantially retain the native microstructure of the native plant material formed by the cellulose-based cell wall.

[0033] Partial delignification: Removing some (e.g., at least 1%) but not all (e.g., less than or equal to 90%) of the natural lignin (e.g., on a weight percentage basis) from a naturally occurring plant material. In some embodiments, partial delignification can be performed by subjecting the natural plant material to one or more chemical treatments. In some embodiments, the lignin content after partial delignification can be in the range of 0.9-23.8 wt % for hardwoods, or in the range of 1.25-33.25 wt % for softwoods. The lignin content in plant materials before and after partial delignification can be assessed using techniques known in the art, for example, Laboratory Analytical Procedure (LAP) TP-510-42618 (August 3, 2012 edition) for "Determination of Structural Carbohydrates and Lignin in Biomass" published by the National Renewable Energy Laboratory (NREL) and ASTM E1758-01 (2020) for "Standard Test Method for Determination of Carbohydrates in Biomass by High Performance Liquid Chromatography" published by the American Society for Testing and Materials, both of which are incorporated herein by reference. In some embodiments, the partial delignification process may be as described, for example, in U.S. Publication No. 2020 / 0223091, published on July 16, 2020, entitled “Strong and Tough Structural Wood Materials, and Methods for Fabricating and Use Thereof,” and U.S. Patent No. 2022 / 0412002, published on December 29, 2022, entitled “Bamboo Structures, and Methods for Fabrication and Use Thereof,” which delignification processes and densification processes are incorporated herein by reference.

[0034] Complete delignification: removing substantially all (e.g., 90-100%) of the natural lignin from naturally occurring plant materials. In some embodiments, full delignification can be performed by subjecting natural plant materials to one or more chemical treatments. The same or similar techniques as described above for partial delignification can be used to assess the lignin content in plant materials before and after full delignification. In some embodiments, the full delignification method can be, for example, as described in U.S. Publication No. 20200238565 entitled “Delignified Wood Materials, and Methods for Fabricating and Use Thereof” published on July 30, 2020, and these delignification processes are incorporated herein by reference.

[0035] Lignin modification: In situ modification of one or more properties of native lignin in naturally occurring plant material without removing the modified lignin from the plant material. In some embodiments, the lignin content of the plant material before and after the in situ modification can be substantially the same, for example, such that the in situ modified plant material retains at least 95% of the native lignin content (e.g., no more than 1% or no more than 0.5% of the native lignin content is removed). In some embodiments, the plant material can be modified (e.g., by contacting with OH -The plant material is modified in situ by a chemical reaction to depolymerize lignin, wherein the depolymerized lignin is retained within the plant material microstructure. The lignin content in the plant material before and after lignin modification can be assessed using techniques known in the art, such as Laboratory Analytical Procedure (LAP) TP-510-42618 for "Determination of Structural Carbohydrates and Lignin in Biomass" (August 3, 2012 edition) published by the National Renewable Energy Laboratory (NREL), ASTM E1758-01 (2020) for "Standard Test Method for Determination of Carbohydrates in Biomass by High Performance Liquid Chromatography" published by the American Society for Testing and Materials and / or the Technical Association of the Pulp and Paper Industry (TAPPI), Standard T 222-om-83 in "Standard Test Method for Acid-Insoluble Lignin in Wood", all of which are incorporated herein by reference. In some embodiments, the lignin modification method can be, for example, as described in International Publication No. WO 2023 / 028356, published on March 2, 2023, entitled “Waste-free Processing for Lignin Modification of Fibrous Plant Materials, and Lignin-modified Fibrous Plant Materials,” and these lignin modification processes are incorporated herein by reference.

[0036] Densified plant material or densified wood: Plant material (e.g., wood) that has been compressed to a reduced thickness. In some embodiments, the thickness has been reduced by at least three times. In some embodiments, the density of the densified plant material (e.g., wood) may be greater than the density of the natural plant material, e.g., at least 1.15 g / cm 3 , for example at least 1.2 g / cm 3 , or even at least 1.3 g / cm 3 (e.g., 1.4-1.5 g / cm 3). For example, the dense plant material can be formed as described in the following documents, which are not limited to U.S. Patent No. 11,130,256 entitled "Strong and Tough Structural Wood Materials, and Methods for Fabricating and Use Thereof" issued on September 28, 2021 and International Publication No. WO 2021 / 108576 entitled "Bamboo Structures, and Methods for Fabrication and Use Thereof" published on June 3, 2021, each of which is incorporated herein by reference.

[0037] Non-densified plant material or non-densified wood: Plant material (e.g., wood) that substantially retains its natural density. In some embodiments, the density of the non-densified plant material (e.g., wood) may be, for example, less than 1.15 g / cm 3 , for example, less than or equal to 1.0 g / cm 3 , or even less than or equal to 0.9g / cm 3 (e.g., 0.1-0.9 g / cm 3 ). In some embodiments, the cavities of the cellulose-based microstructures of the non-densified plant material may remain substantially open, at least prior to inclusion within an engineered structure.

[0038] Longitudinal growth direction: The direction in which a plant grows from its roots or from its trunk, with the cellulose fibers that form the plant's cell walls generally aligned with the longitudinal growth direction. In some cases, the longitudinal growth direction may be generally vertical or correspond to the direction of its transpiration water flow. This is in contrast to the radial direction, which extends outward from the central portion of the plant and may be generally horizontal.

[0039] introduce

[0040] Disclosed herein is an engineering structural material formed by one or more plant materials. In some embodiments, for example, compared with existing engineering structural materials (for example, formed only by natural or non-dense wood), the engineering structural material can have enhanced mechanical strength. Due to the enhanced strength (for example, rigidity, tensile strength, compressive strength, etc.), the engineering structural material can be made into a smaller cross-section (for example, compared with existing engineering structural materials) for specific applications (for example, requiring a specific strength grade). Alternatively, in some embodiments, due to the enhanced strength, the engineering structural material with the same cross-section can be used in (for example, compared with existing engineering structural materials) more demanding applications by spanning a longer distance. Alternatively or in addition, in some embodiments, by including an appropriate number and / or arrangement of dense plant material layers in the engineering structural material, the size and / or strength of the engineering structural material can be customized for a specific application.

[0041] In some embodiments, the engineered structural material comprises a laminate structure having a plurality of constituent plant material layers bonded, adhered, or otherwise coupled to one another via glue, wherein at least one of the layers is a dense plant material layer, e.g., having a density of at least 1.15 g / cm 3 (e.g., ≥1.2 g / cm 3 or ≥1.3 g / cm 3 , for example, at 1.4-1.5 g / cm 3 In some embodiments, one, some or all of the other layers of the laminate structure may be a non-densified plant material layer, for example, having a density of less than 1.15 g / cm 3 (e.g., ≤1.0 g / cm 3 or ≤0.9g / cm 3 , for example, between 0.1 and 0.9 g / cm 3 In some embodiments, the non-densified plant material layer may be formed from natural plant material (e.g., without compression). Alternatively or additionally, in some embodiments, one, some, or all of the other layers of the laminate structure may be a plant material layer that has been densified (e.g., before inclusion in the laminate or after inclusion in the laminate), but to a lesser degree than the densified plant material layer, e.g., such that the densified density remains less than 1.15 g / cm 3. In the following description, references to non-densified plant material layers are intended to include such less densified plant material layers. In some embodiments, the mechanical strength of a densified plant material layer may be greater than the mechanical strength of other (e.g., non-densified or less densified) plant material layers. For example, the strength of each densified plant material layer may be at least 100 MPa (e.g., 100-600 MPa), while the strength of each non-densified plant material layer may be less than 100 MPa (e.g., 15-65 MPa).

[0042] The laminate structure may have any number of layers of plant material. For example, Figure 1A A laminated structure 100 is shown having a pair of plant material layers, particularly a dense plant material layer 102 coupled to a non-dense plant material layer 106 via an intermediate glue layer 104. For example, the glue layer 104 may include any type of adhesive, such as, but not limited to, epoxy resins, polyurethane adhesives, polyvinyl acetate-isocyanate adhesives, resorcinol formaldehyde resin adhesives, phenolic resins, and / or sodium carboxymethyl cellulose (CMC). Alternatively or additionally, in some embodiments, one, some, or all of the plant material layers making up the laminated structure may be formed from a plurality of plant material sheets.

[0043] In some embodiments, at least one of the densified plant material layers may be arranged at a location within the laminate structure that will be subjected to stress exceeding a predetermined threshold and / or maximum stress. In some embodiments, the densified plant material layer may be used as the outermost layer of the laminate structure in a cross-sectional view, e.g. Figure 1B As shown. Figure 1B In the example shown, the laminate structure 110 has three plant material layers - a pair of dense plant material layers 102a, 102b, which are connected to opposite sides of a centrally arranged non-densified plant material layer 106 via respective intermediate glue layers 104a, 104b. Alternatively or additionally, the dense plant material layers can be arranged at any position within the laminate structure. For example, Figure 1C As shown, in cross-sectional view, the densified plant material layer can be used as an inner or center layer of a laminate structure. Figure 1C In the example shown, the laminate structure 120 has three layers of plant material - a pair of non-densified plant material layers 106a, 106b coupled to a centrally disposed densified plant material layer 102 via respective intermediate glue layers 104a, 104b.

[0044] although Figures 1A-1C A single layer of dense plant material or a single layer of non-densified plant material is shown, but embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, multiple layers of dense plant material and multiple layers of non-densified plant material may be arranged together in a single laminate structure. For example, Figure 1DA laminated structure 130 is shown having more than three layers of plant material. In the example shown, the laminated structure 130 has a stack 132 of three non-densified plant material layers 106a-106c coupled together via intermediate glue layers 108a, 108b (which may have the same formulation as the glue layers 104a, 104b or a different formulation). Other numbers of layers in the stack 132 are possible, such as 3, 5, or 7 layers for a CLT structure or 12-15 layers for a LVL structure, according to one or more contemplated embodiments. Similar to Figure 1B The laminate structure 130 has a pair of dense plant material layers 102a, 102b, which are connected to a centrally arranged stack 132 via corresponding intermediate glue layers 104a, 104b. In some embodiments, the stack 132 can be a conventional engineering structure (e.g., CLT, glued wood, LVL, OSB, etc.), and the pair of dense plant material layers 102a, 102b can be used to enhance or strengthen the strength of the stack 132.

[0045] exist Figures 1A-1D In examples of, the lateral side surfaces of the non-dense plant material layer may be exposed. However, in some embodiments, the dense plant material layer may also be disposed on one, some, or all of these exposed surfaces, for example, to contain, incorporate, or otherwise enclose the non-dense plant material layer within a surrounding structure formed by the dense plant material layer. In some embodiments, disposing a dense plant material layer to surround the non-dense plant material layer may form a column or beam with improved aesthetics (e.g., a more desirable appearance due to the dense layer compared to the non-dense layer), improved durability (e.g., due to the greater fire resistance and / or weather resistance of the dense layer compared to the non-dense layer), and / or improved installation flexibility (e.g., providing enhanced strength regardless of orientation). For example, Figure 1E A laminate structure 140 is shown in which a stack 132 consisting of a non-densified plant material layer 106a is covered on its left and right sides by a densified plant material layer 102c, 102d and a corresponding glue layer 142a, 142b (which may have the same or different formulation and / or thickness as the glue layer 108a, 108b and / or the glue layer 104a, 104b). Figure 1D In such a manner, the top and bottom sides of the stack 132 of the laminate structure 140 are covered by the densified plant material layers 102a, 102b, thereby enclosing the stack 132 within a circumferential surrounding wall formed by the densified plant material layers 102a-102d.

[0046] although Figure 1D-1EThe non-densified plant material layers are shown arranged in the stack along the thickness direction of the laminated structure, but the embodiments of the disclosed subject matter are not limited thereto. Instead, in some embodiments, the non-densified plant material layers may be stacked relative to the width and / or length direction of the laminated structure. For example, Figure 1F A laminate structure 150 is shown having a transverse stack 152 consisting of three non-densified plant material layers 106a-106c arranged in the width direction and coupled together via intermediate layers 108a, 108b (which may have the same or different formulation and / or thickness as the glue layers 104a, 104b). Figure 1F As shown, the height of each non-densified plant material layer 106a-106c can be greater than its width. In another example, Figure 1G A laminate structure 160 is shown having a transverse stack of three non-densified plant material layers 162a-162c arranged in a width direction and coupled together via intermediate glue layers 164a, 164b (which may have the same or different formulation and / or thickness as the glue layers 104a, 104b). Figure 1G As shown, each non-densified plant material layer 162a-162c may be less tall than it is wide. Other sizes and / or numbers of layers of the transverse stack are possible in accordance with one or more contemplated embodiments.

[0047] Similar to Figure 1B and Figure 1D In the configuration of the laminated structures 150 and 160, a pair of dense plant material layers 102a, 102b are connected to the centrally arranged transverse stack via corresponding intermediate glue layers 104a, 104b. In some embodiments, the transverse stack can be a conventional engineering structure (e.g., CLT, glulam, LVL, OSB, etc.), and the pair of dense plant material layers 102a, 102b can be used to enhance or strengthen the strength of the transverse stack.

[0048] although Figures 1A-1G A laminate structure having at least one non-densified plant material layer is shown, but embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, each layer of the laminate structure may be a dense plant material layer (e.g., each layer having a density greater than or equal to 1.15 g / cm 3 In such embodiments, the individual dense plant material layers may be coupled to each other via an intermediate glue layer (e.g., similar to glue layer 104) or in other ways (e.g., without any glue and / or by relying on hydrogen bonding between faces and surfaces of the dense plant material layers).

[0049] although Figures 1A-1GOne or two dense plant material layers are shown, but embodiments of the disclosed subject matter are not limited in this regard. Rather, in some embodiments, more than two dense plant material layers may be included in a laminate structure. For example, in some embodiments, the dense plant material layers may constitute 5-50% of the laminate structure (e.g., based on number of layers and / or by thickness and / or by weight), while the remaining 50-95% may constitute non-densified plant material layers. Alternatively, in some embodiments, the dense plant material layers may constitute a majority (e.g., 50%) of the laminate structure, with the remainder being formed by non-densified plant material layers. Although Figures 1A-1G The densified plant material layer is shown at a particular location (e.g., top, bottom, or middle) of the laminate structure, but embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, the densified plant material layer can be located at any location within the laminate structure, for example, thereby replacing Figures 1A-1G Any of the non-densified wood layers shown in .

[0050] although Figures 1A-1G A single plant material sheet in each layer is shown, but embodiments of the disclosed subject matter are not limited thereto. In contrast, in some embodiments, multiple plant material sheets may be joined together at adjacent edges (e.g., via mechanical joining techniques, such as finger joints and / or adhesives) to form a corresponding layer, for example, to expand the width and / or length of the layer. In some embodiments, the plant material of each layer of the laminated structure may come from the same plant or at least from the same species. Alternatively, in some embodiments, the plant material of at least one of the multiple layers in the laminated structure may come from a species different from the species of at least one other layer. Alternatively or in addition, in some embodiments, each of the dense plant material layers may be formed by the same species, and / or each of the non-dense plant material layers may be formed by the same species (which may be the same or different from the dense plant material layer).

[0051] In some embodiments, the plant material layers may be arranged in a laminated structure so that their orientation (e.g., based on their respective longitudinal growth directions) is substantially aligned or parallel. Alternatively, in some embodiments, at least one of the plant material layers may be arranged in a laminated structure so that its orientation is substantially orthogonal to or at least intersects with the orientation of at least another of the plant material layers. Alternatively or additionally, in some embodiments, each of the dense plant material layers may have an orientation that is substantially aligned. Alternatively or additionally, each of the non-dense plant material layers may have an orientation that is substantially aligned, intersecting, or substantially orthogonal (which may be the same or different from the orientation of the dense plant material layers). Alternatively or additionally, in some embodiments, one, some, or all of the plant material layers may have a random orientation (e.g., without considering the orientation of other plant material layers).

[0052] Although the following section focuses primarily on engineering structural materials formed from wood, embodiments of the disclosed subject matter are not limited thereto. Rather, the teachings of the present disclosure can be easily extended to other plant materials (eg, bamboo, straw, etc.).

[0053] Examples of Engineered Timber Structures

[0054] Figure 2A A strength-enhanced cross-laminated timber (CLT) structure 200 having a laminated structure is shown, wherein a stack 202 is located between outer layers of dense wood panels 204a, 204b (e.g., having a thickness t1 or t2 of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm), such as 3 / 8 inch (9.35 mm)). In some embodiments, the stack 202 can be a conventional CLT structure, for example, having three (or five or seven) layers of wood boards. For example, in a cross-section perpendicular to the corresponding longitudinal growth direction, each wood board of the stack 202 can have a thickness of 5 / 8 inch to 2 inches (15.88 mm to 50.8 mm) and / or a width of 2.4 inches to 9.5 inches (60.96 mm to 241.3 mm). In some embodiments, the length L of the strength-enhanced CLT structure 200 can be at least 6 feet (1.83 m), for example, about 8 feet (2.43 m). Alternatively or additionally, in some embodiments, the width W of the enhanced strength CLT structure 200 can be at least 1 foot (0.30 m), for example, about 2 feet (0.61 m). Alternatively or additionally, in some embodiments, the height H of the enhanced strength CLT structure 200 can be at least 6 inches (15.2 cm), for example, about 8 inches (20.3 cm). Other dimensions are possible according to one or more contemplated embodiments. In some embodiments, the planks in each layer can be connected together via connection means such as finger joints and / or structural adhesives.

[0055] The stack 202 may be formed by stacking wood planks that are staggered at 90 degree angles and glued in place. For example, the outermost wood planks 208a, 208b may have orientations 210a, 210b that are substantially aligned with each other, and the center wood plank 212 may have an orientation 214 that is orthogonal to the orientations 210a, 210b. In the example shown, the densified wood panels 204a, 204b may have orientations 206a, 206b that are substantially aligned with each other and aligned with the orientation 214 of the center wood panel 212. Alternatively, in some embodiments, the orientation 206a, 206b of one or both of the densified wood panels 204a, 204b may be substantially aligned with the orientations 210a, 210b of the outer wood panels 208a, 208b, or may not be aligned with any of the orientations 210a, 210b, 214 of the stack 202. In some embodiments, in addition to providing the top and bottom layers 204a, 204b of densified wood, additional lateral layers 204c, 204d of densified wood (e.g., having orientations 206d that are substantially aligned with each other and with the orientation 214 of the central plank 212) may be provided to surround the stack 202 (e.g., in a circumferential direction), e.g., as Figure 2B 200 and / or CLT structure 220. In some embodiments, by using densified wood as the top and bottom tension layers, the in-plane bending stiffness of stack 202 can be improved (e.g., doubled), and / or the spanning capability of stack 202 can be enhanced. Strengthened CLT (e.g., CLT structure 200 and / or CLT structure 220) can be used in a variety of applications (e.g., but not limited to floors, walls, and roofs), for example, to replace reinforced concrete in residential and commercial buildings.

[0056] Figure 3AA strength-enhanced glued laminated timber (glulam) structure 300 is shown having a laminated structure in which a transverse array 302 of timber layers 308 is located between outer layers of dense timber panels 304a, 304b (e.g., 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm) thick). In some embodiments, the array 302 can be a conventional glulam structure. For example, each timber panel of the array 302 can have a thickness of 1 inch to 6 inches (2.5 cm to 15.2 cm) and / or a width of 2 inches to 12 inches (5.1 cm to 30.5 cm) in a cross-section perpendicular to the respective longitudinal growth directions. Other dimensions are possible according to one or more contemplated embodiments. In some embodiments, the timber segments in each layer can be connected together via connection means such as finger joints and / or structural adhesives. The array 302 may be formed by arranging individual wood layers 308 (and / or their constituent segments) in a substantially aligned orientation 310 (e.g., substantially parallel wood fibers) and gluing them together. In some embodiments, in addition to providing densified wood as the top layer 304a and the bottom layer 304b, additional densified wood may be provided as lateral layers 304c, 304d to surround the stack 302 (e.g., in a circumferential direction), such as Figure 3D The glulam structure 350 is shown in FIG. Figure 3A and Figure 3D In the example shown, the densified wood panels 304a-304d may have orientations 306a-306d that are substantially aligned with each other and with the orientation 310 of the wood layer 308. Alternatively, in some embodiments, the orientations 306a-306d of one, some, or all of the densified wood panels 304a-304d may be substantially orthogonal to, or at least intersect, the orientation 310 of the wood layer 308.

[0057] Figure 3B Another enhanced strength glulam structure 320 is shown that employs a vertical array 322 of wood layers 328 (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)) between outer layers of dense wood panels 324a, 324b. Figure 3B30.5 cm). In the example shown, the dense wood panels 324a, 324b may have an orientation 326a, 326b that is substantially aligned with each other and with the orientation 330 of the wood layer 328. Alternatively, in some embodiments, the orientation 326a, 326b of one or both of the densified wood panels 324a, 324b may be substantially orthogonal to, or at least intersect, the orientation 330 of the wood layer 328.

[0058] Figure 3C Another strength-enhanced glued wood structure 340 is shown with a vertical array 322 of wood layers 328 between outer layers 324a, 324b of dense wood segments. The top layer 324a may be formed by a plurality of dense wood segments 342a-342c, and the bottom layer 324b may be formed by a plurality of dense wood segments 344a-344c. Similarly, each wood layer 328 of the vertical array 322 may be formed by a plurality of wood segments 346a-346d (which may be offset from each other along the length direction L and / or the width direction W). In some embodiments, the wood segments in each layer 324a, 324b, 328 may be connected together via a connection method such as finger joints and / or structural adhesives. In some embodiments, the use of multiple wood segments in each layer may allow the glued wood structure 340 to be formed in any length without any restrictions. In the illustrated example, each top densified wood segment 342a-342c may be substantially aligned with a corresponding one of the bottom densified wood segments 344a-344c (e.g., along the length direction L and / or the width direction W). Alternatively, in some embodiments, the top densified wood segments and the bottom densified wood segments may be offset relative to each other (e.g., in a manner similar to the wood segments 346a-346d that make up the wood layer 328 of the array 322), for example, to further enhance mechanical rigidity.

[0059] Figure 4AA strength-enhanced laminated veneer lumber (LVL) structure 400 having a laminated structure is shown, wherein a stack 402 of wood veneers 408 is located between outer layers of dense wood panels 404a, 404b (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)). Alternatively, in some embodiments, one or more dense wood panels may be provided as part of the stack 402, for example, in place of one or more of the dense wood panels 404a, 404b or in addition to one or more of the dense wood panels 404a, 404b. In some embodiments, the stack 402 can be a conventional LVL structure. For example, in a cross-section perpendicular to the corresponding longitudinal growth direction, each wood veneer 408 of the stack 402 can have a thickness of 2.5-4.8 mm. Other dimensions are also possible according to one or more contemplated embodiments. The LVL stack 402 may be manufactured, for example, by gluing together veneers (e.g., while pressing) from rotational peeling (e.g., using a rotary cutter). The veneers may be assembled along their longitudinal directions (e.g., with substantially aligned orientations 410). In the illustrated example, the dense wood panels 404a, 404b may have orientations 406a, 406b that are substantially aligned with each other and with the orientation 410 of the wood veneer 408. Alternatively, in some embodiments, the orientation 406a, 406b of one or both of the dense wood panels 404a, 404b may be substantially orthogonal to or at least intersect with the orientation 410 of the wood veneer 408. In some embodiments, the load 412 may be applied substantially parallel to the width direction of the strength-enhanced LVL structure 400 and / or substantially perpendicular to the direction along which the veneers 408 are stacked (e.g., the height direction of the stack 402).

[0060] Figure 4B Another LVL structure 420 of strength enhancement is shown, which adopts a stack 422 consisting of a wood veneer 408 between the outer layers 404a, 404b consisting of dense wood segments. The top layer 404a can be formed by a plurality of dense wood segments 424a-424c, and the bottom layer 404b can be formed by a plurality of dense wood segments 444a-444c. In some embodiments, the wood segments in each layer 404a, 404b can be connected together via a connection method such as finger joints and / or structural adhesives. In the example shown, each top dense wood segment 424a-424c can be substantially aligned with a corresponding one (e.g., along the length direction L and / or the width direction W) in the bottom dense wood segment 444a-444c. Alternatively, in some embodiments, the top dense wood segment and the bottom dense wood segment can be offset relative to each other, for example, to further enhance mechanical rigidity.

[0061] Figure 4CAnother enhanced strength LVL structure 430 having a laminated structure is shown, wherein a stack 432 of wood veneers 408 is located between outer layers of dense wood panels 404a, 404b (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)). Figure 4C In the example shown, the densified wood panels 404a, 404b are arranged on opposite sides of the stack 432 in a direction substantially perpendicular to the direction in which the wood veneers 408 are stacked. Figure 4A 400, the stack 432 can be a conventional LVL structure, for example, each wood veneer 408 of the stack 432 has a thickness of 2.5-4.8 mm in a cross section perpendicular to the longitudinal growth direction 410; however, other dimensions are possible according to one or more contemplated embodiments. The LVL stack 432 can be manufactured, for example, by gluing together veneers from rotary peeling (e.g., while pressing). The veneers can be assembled along their longitudinal direction (e.g., with a substantially aligned orientation 410).

[0062] In some embodiments, in addition to providing the top layer 404a and the bottom layer 404b of the densified wood, additional densified wood may be provided as lateral layers 404c, 404d to surround the stack 432 (e.g., in a circumferential direction), such as Figure 4D 40. In the example shown, the densified wood panels 404a-404d may have orientations 406a-406d that are substantially aligned with each other and parallel to the orientation 410 of the wood veneer 408. Alternatively, in some embodiments, the orientation 406a-406d of one or both of the densified wood panels 404a-404d may be substantially orthogonal to, or at least intersecting with, the orientation 410 of the wood veneer 408. In some embodiments, the load 434 may be applied substantially parallel to the width direction of the strength-enhanced LVL structure 430 or 450 and / or substantially perpendicular to the direction along which the veneers 408 are stacked (e.g., the height direction of the stack 432). Figure 4C-4D In the example shown, the load 434 may be applied substantially perpendicular to the exposed surfaces of the densified wood panels 404a, 404b.

[0063] In some embodiments, LVL structure 400, LVL structure 420, LVL structure 430, and / or LVL structure 440 may be used as part of another engineered structure, for example, instead of Figure 3A One or two outermost layers 304a, 304b of the glued laminated timber structure 300 are replaced by Figure 3B One or two outermost layers 324a, 324b of the glued laminated timber structure 320 in place of Figure 3COne or two outermost layers 324a, 324b of the glued laminated timber structure 340 in place of Figure 3D One, some or all of the outermost layers 304a-304d of the glue laminated timber structure 350.

[0064] In some embodiments, LVL structure 400, LVL structure 420, LVL structure 430, and / or LVL structure 440 may be used as part of a flange of an I-beam. Figure 5A A cross section of an I-beam 500 is shown that uses strength-enhanced LVL for flanges 502a, 502b. In the example shown, the top flange 502a has a LVL stack 504a disposed between a pair of dense wood layers 506a, 508a, and the bottom flange 502b has a LVL stack 504b disposed between a pair of dense wood layers 506b, 508b. A web 512 may be inserted into corresponding grooves 510a, 510b in the flanges 502a, 502b and glued thereto (the glue may have the same formulation as the glue layers forming the flanges or a different formulation). For example, the web may be formed of plywood, LVL, oriented strand board (OSB), or other engineered wood structures. After assembly, the I-beam 500 may be end trimmed and heat cured, or left at room temperature to reach an approximately balanced moisture content.

[0065] Figure 5B Another I-beam 520 is shown using LVL for the flanges. Figure 5A , the web 512 is coupled to the corresponding grooves 510a, 510b and extends between the top flange 502a and the bottom flange 502b. Figure 5A In contrast, the flanges use only the densified wood as the outermost layer of the flanges. In the example shown, the top flange 522a has a LVL stack 524a and a densified wood layer 506a at the end of the LVL stack 524a opposite the web 512, and the bottom flange 522b has a LVL stack 524b and a densified wood layer 506b at the end of the LVL stack 524b opposite the web 512.

[0066] In some embodiments, the flanges of the I-beams may be formed from solid wood for strength enhancement rather than LVL. For example, Figure 5CAnother I-beam 540 is shown that uses reinforced solid wood for flanges 542a, 542b (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)). In the example shown, the top flange 542a has a solid wood panel 544a and a dense wood layer 546a glued to the end of the wood panel 544a opposite the web 552, and the bottom flange 542b has a solid wood panel 544b and a dense wood layer 546b glued to the end of the wood panel 544b. The web 552 can be inserted into corresponding grooves 550a, 550b in the solid wood panels 544a, 544b and glued thereto (the glue can have the same formulation as the glue forming the glue layer of the flanges or a different formulation). For example, the web 552 can be formed from plywood, LVL, oriented strand board (OSB), or other engineered wood structure. After assembly, the I-beam 540 may be end trimmed and heat cured, or left at room temperature to reach an approximate equilibrium moisture content.

[0067] although Figure 5C The strength enhancement achieved via a single layer of densified wood for each flange of the I-beam is shown, but embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, multiple layers of densified wood may be combined with solid wood in each flange. For example, Figure 5D A cross section of another I-beam 560 is shown. Figure 5A The web 512 is coupled to the corresponding grooves 510a, 510b and extends between the top flange 502a and the bottom flange 502b. Figure 5C In contrast, the top flange 562a has a solid wood panel 564a disposed between and glued to a pair of dense wood layers 506a, 508a, and the bottom flange 562b has a solid wood panel 564b disposed between and glued to a pair of dense wood layers 506b, 508b.

[0068] Although the use of densified wood is limited to Figures 5A-5D The flanges of the I-beams in the webs may be used, but embodiments of the disclosed subject matter are not limited thereto. Instead, in some embodiments, the densified wood may be used as part of the web, for example to allow for an open structure of the web. For example, Figure 5EA side view of another I-beam 580 is shown having a grid 584 extending between a top flange 582a and a bottom flange 582b. In the example shown, densified wood may be used to form the grid 584, or as part of an engineered wood structure used to form the grid 584. For example, the grid 584 may take the form of a truss or other open structure that is otherwise capable of supporting the loads to which the I-beam 580 is subjected. Although Figure 2A-5E The above description focuses on the use of wood, but the embodiments of the disclosed subject matter are not limited thereto. Instead, any or all of the above wood components may be replaced by other plant materials according to one or more contemplated embodiments.

[0069] Manufacturing method

[0070] Figure 6 Aspects of a method 600 for manufacturing an engineering structure using one or more plant material sheets are shown. Method 600 may start at process frame 602, where one or more natural plant material sheets may be provided. In some embodiments, the provision of process frame 602 may include cutting, removing or otherwise separating a sheet of material from a parent plant (e.g., a tree, a bamboo stem, etc.). In some embodiments, cutting may form the natural plant material into a substantially flat planar structure, wherein the direction of the cellulose fibers extends parallel to the plane of the structure (e.g., longitudinal cutting or rotary cutting) or perpendicular to the plane of the structure (e.g., radial cutting). Alternatively, in some embodiments, preparation may include pre-treating the natural plant material sheet, e.g., cleaning to remove any undesirable material or contaminant in preparation for subsequent processing, forming the natural plant material into a specific shape in preparation for subsequent processing (e.g., cutting into strips), or any combination of the foregoing. For example, in some embodiments, cutting can form the plant material piece into any one-dimensional structure (e.g., an elongated structure in which both the thickness and width are at least one order of magnitude less than its length), a two-dimensional structure (e.g., a substantially flat planar structure in which the thickness is at least one order of magnitude less than its length and width), or a three-dimensional structure (e.g., a block in which the thickness, width, and length are within an order of magnitude of each other). In some embodiments, providing of process box 602 can include assembling multiple plant material pieces into a single layer. Alternatively, in some embodiments, assembling multiple plant material pieces into a single layer can occur after processing, for example, after the optional pre-compression modification of process box 617 but before compression of process box 618, or after compression of process box 618 but before coupling of process box 626.

[0071] Method 600 may proceed to decision block 604, where a determination is made as to whether the plant material should be subjected to a lignin-compromising treatment. In some embodiments, lignin damage may be undesirable, for example, particularly where a lower degree of densification of the plant material is desired. In such embodiments, method 600 may proceed directly from decision block 604 to optional process block 617. Alternatively, if in situ lignin modification is desired at decision block 604, method 600 may proceed to process block 606, where the plant material piece may be infiltrated with one or more chemical solutions to modify the lignin therein. For example, in some embodiments, the infiltration may be performed by soaking the plant material piece in a solution containing one or more chemicals under vacuum. In some embodiments, the chemical solution may contain at least one OH-containing - ions or otherwise capable of generating OH in solution - Chemical components of ions. In some embodiments, one, some or all of the chemicals in the solution may be alkaline. In some embodiments, the chemical solution includes p-toluenesulfonic acid, NaOH, LiOH, KOH, Na2O, or any combination thereof. Exemplary combinations of chemical substances may include, but are not limited to, p-toluenesulfonic acid, NaOH, NaOH+Na2SO3 / Na2SO4, NaOH+Na2S, NaHSO3+SO2+H2O, NaHSO3+Na2SO3, NaOH+Na2SO3, NaOH / NaH2O3+AQ, NaOH / Na2S+AQ, NaOH+Na2SO3+AQ, Na2SO3+NaOH+CH3OH+AQ, NaHSO3+SO2+AQ, NaOH+Na2Sx, wherein AQ is anthraquinone, any of the foregoing chemical substances in the case of using LiOH or KOH instead of NaOH, or any combination of the foregoing chemical substances. In some embodiments, chemical infiltration may be performed without heating, for example, at room temperature (20-30° C., for example, about 22-23° C.). In some embodiments, the chemical solution is not agitated to avoid damaging the natural cellulose-based microstructure of the plant material pieces.

[0072] For example, in some embodiments, the wood can be immersed in a chemical solution (e.g., 2-5% NaOH) in a container. The container can then be placed in a vacuum box and placed in a vacuum state. In this way, the air in the wood can be extracted and a negative pressure can be formed. When the vacuum pump is turned off, the negative pressure inside the wood can draw the solution into the wood through the natural channels therein (e.g., the cavity defined by the longitudinal cells). This process can be repeated more than once (e.g., 3 times) so that the channels inside the wood can be filled with the chemical solution (e.g., about 2 hours). After this process, the moisture content can increase from about 10.2% (e.g., for natural wood) to about 70% or more.

[0073] Method 600 may proceed to process block 608, wherein the modification may be activated by subjecting the infiltrated plant material sheet to an elevated temperature (e.g., greater than 80° C. (e.g., 80-180° C., such as 120-160° C.)), thereby producing a softened plant material sheet (e.g., softened compared to a native plant material sheet). In some embodiments, the heating of process block 608 may be accomplished via steam heating, e.g., via steam generated in a closed reactor, via a steam flow in a flow-through reactor, and / or via steam from a superheated steam generator. Alternatively or additionally, in some embodiments, the heating of process block 608 may be accomplished via dry heating, e.g., via conduction and / or radiation of thermal energy from one or more heating elements, without using steam alone. In some embodiments, during process block 608, the infiltrated plant material sheet may be subjected to an elevated temperature for a first period of time, e.g., 1-5 hours (e.g., depending on the size of the plant material sheet, with thicker sheets requiring longer heating times). In some embodiments, after the first period of time, any steam generated by heating the infiltrated plant material sheet can be released, for example, by opening a pressure release device (e.g., a safety valve) of the reactor. For example, in some embodiments, the pressure release can effectively remove about 50% of the moisture in the modified plant material sheet. For example, in some embodiments, the moisture content of the now softened plant material sheet can be in the range of 30-50wt% (inclusive).

[0074] Method 600 can proceed from process box 608 to process box 610, wherein the plant material pieces can be selectively dried to reduce the moisture content of these plant material pieces, for example, without removing too much moisture so that the plant material pieces lose their softening properties (for example, so that the moisture content is greater than or equal to about 8-10wt%). In some embodiments, the optional drying of process box 610 can effectively reduce the moisture content of the plant material pieces from greater than 30wt% (for example, 30-50wt%) to, for example, within the range of 10-20wt% (for example, about 15wt%). Although moisture can be removed from the softened plant material pieces by heating of process box 608 and / or drying of process box 610 (for example, via evaporation), the removed moisture may be substantially free of residual salts and / or chemicals from in-situ lignin modification. In contrast, in some embodiments, the chemicals may be substantially consumed by modification, and residual salts may be retained in the microstructure of the softened plant material pieces.

[0075] If delignification is desired at decision box 604 instead, method 600 may proceed to process box 612, wherein, one or more chemical treatments may be performed to the plant material piece to remove at least some lignin therefrom, for example, by immersing one or more plant material pieces (or one or more parts thereof) in a chemical solution associated with the treatment to remove. In some embodiments, each chemical treatment or only some chemical treatments may be performed under vacuum, so as to facilitate the solution associated with the treatment to fully penetrate the cell wall and cavity of the plant material piece. Alternatively, in some embodiments, the chemical treatment may be performed under ambient pressure conditions or high pressure conditions (e.g., about 6-8 bar). In some embodiments, each chemical treatment or some chemical treatments may be performed at any temperature between ambient temperature (e.g., about 23°C) and a high temperature (e.g., about 70-160°C) at which the solution associated with the chemical treatment boils. In some embodiments, the solution is not stirred to minimize the amount of damage to the natural cellulose-based microstructure of the plant material piece.

[0076] In certain embodiments, soaking time can be in the range of 0.1 to 96 hours (including end values), for example, 1-12 hours (including end values). The amount of time immersed in the solution can be a function of the amount of lignin to be removed, the type of plant material, the size of the plant material sheet, solution temperature, treatment pressure and / or stirring. For example, a lesser amount of lignin removal, a smaller plant material sheet size (for example, cross-sectional thickness), a higher solution temperature, a higher treatment pressure and stirring can be associated with a shorter soaking time, while a larger amount of lignin removal, a larger plant material sheet size, a lower solution temperature, a lower treatment pressure and no stirring can be associated with a longer soaking time.

[0077] In some embodiments, each chemical treatment or at least one chemical treatment of process box 612 may include injecting, permeating or otherwise exposing the plant material piece to one or more first chemical solutions at a first temperature. In some embodiments, the first chemical solution may be an alkaline solution, and the first temperature may be less than 100°C. For example, the first temperature may be in the range of 5-95°C (including end values), such as room temperature (e.g., about 23°C). Alternatively or additionally, one or more chemical treatments of process box 612 may include partially or completely immersing the plant material piece in a second chemical solution at a second temperature greater than the first temperature. Alternatively or additionally, at least one chemical treatment may include injecting, permeating or otherwise exposing the plant material to a second chemical solution at a second temperature. In some embodiments, the second chemical solution may be an alkaline solution, and the second temperature may be greater than 100°C. For example, the second temperature may be in the range of 120-180°C, such as 160°C. For example, the temperature of the chemical solution may be increased to 50-180°C and continued for 0.1 to 10 hours to remove 5-95% of lignin and hemicellulose from the plant material piece. In some embodiments, the second chemical solution can be a solution identical to the first chemical solution. In this case, the first chemical solution can be heated from a first temperature to a second temperature while retaining the plant material piece therein. Alternatively, in some embodiments, the composition of the second chemical solution can be identical to that of the first chemical solution, for example, by providing a new batch of solutions for use as the second chemical solution (e.g., by removing the plant material piece from the first chemical solution and immersing it in the second chemical solution, or by draining the first chemical solution and replacing it with a new second chemical solution). Alternatively, in some embodiments, the composition of the second chemical solution can be different from that of the first chemical solution.

[0078] In some embodiments, the chemical treatment solution may include sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), sodium sulfite (Na2SO3), sodium sulfide (Na2S), Na n S (where n is an integer), urea (CH4N2O), sodium bisulfite (NaHSO3), sulfur dioxide (SO2), anthraquinone (AQ) (C 14H8O2), methanol (CH3OH), ethanol (C2H5OH), butanol (C4H9OH), formic acid (CH2O2), hydrogen peroxide (H2O2), acetic acid (CH3COOH), butyric acid (C4H8O2), peroxyformic acid (CH2O3), peracetic acid (C2H4O3), ammonia (NH3), toluenesulfonic acid (p-TsOH), sodium hypochlorite (NaClO), sodium chlorite (NaClO2), chlorine dioxide (ClO2), chlorine (Cl2), or any combination thereof. Exemplary combinations of chemicals for chemical treatment may include, but are not limited to, NaOH+Na2SO3, NaOH+Na2S, NaOH+urea, NaHSO3+SO2+H2O, NaHSO3+Na2SO3, NaOH+Na2SO3, NaOH+AQ, NaOH+Na2S+AQ, NaHSO3+SO2+H2O+AQ, NaOH+Na2SO3+AQ, NaHSO3+AQ, NaHSO3+Na2SO3+AQ, Na2SO3+AQ, NaOH+Na2S+Na n S (wherein n is an integer), Na2SO3+NaOH+CH3OH+AQ, C2H5OH+NaOH, CH3OH+HCOOH, NH3+H2O, and NaClO2+acetic acid. For example, the first chemical solution and the second chemical solution can be ≤2wt% NaOH and Na2SO3 (e.g., formed by adding H2SO3 acid to NaOH).

[0079] The chemical treatment may continue (or may be repeated with subsequent solutions) until the desired reduction in the lignin content in the plant material piece is achieved. In some embodiments, the lignin content may be reduced to between 0.1% (the lignin content is 0.1% of the original lignin content in the natural plant material) and 99% (the lignin content is 99% of the original lignin content in the natural plant material). In some embodiments, the chemical treatment reduces both the lignin content and the hemicellulose content, for example, to the same or lower extent than the reduction in the lignin content. In some embodiments, when the plant material piece is hardwood, the lignin content after the chemical treatment of process box 612 may be at least 10 wt% (e.g., in the range of 10-15 wt% (including the end values)). In some embodiments, when the plant material piece is softwood, the lignin content after the chemical treatment of process box 612 may be at least 12.5 wt% (e.g., 12.5-17.5 wt% (including the end values)). In some embodiments, when the plant material piece is bamboo, the lignin content after the chemical treatment at process block 612 may be at least 13 wt % (eg, 13-18 wt %, inclusive).

[0080] Method 600 can proceed from process box 612 to process box 614, wherein rinsing can be performed. For example, rinsing can be used to remove residual chemicals or particles produced by chemical treatment. For example, the delignified plant material piece can be partially or completely immersed in one or more rinsing solutions. The rinsing solution can be a solvent, such as but not limited to deionized (DI) water, alcohol (e.g., ethanol, methanol, isopropanol, etc.) or any combination thereof. For example, the rinsing solution can be formed by equal volumes of water and ethanol. In some embodiments, rinsing can be performed without stirring, for example to avoid damaging the microstructure. In some embodiments, for each iteration, a fresh mixture rinsing solution can be used to repeatedly rinse multiple times (e.g., at least 3 times), or until a substantially neutral pH value of the chemically treated plant material piece is measured.

[0081] Method 600 may proceed to optional process frame 616, wherein the chemically treated plant material piece may be dried, for example, so that the moisture content therein is less than 15wt% (e.g., 8-12wt%). The drying of process frame 610 or process frame 616 may include any of a conductive heating process, a convection heating process, and / or a radiant heating process, including but not limited to an air drying process, a vacuum assisted drying process, an oven drying process, a freeze drying process, a critical point drying process, a microwave drying process, or any combination thereof. For example, an air drying process may include allowing the treated plant material piece to dry naturally in static or moving air, which air may be at any temperature, such as room temperature (e.g., 23°C) or a high temperature (e.g., greater than 23°C). For example, a vacuum assisted drying process may include, for example, decompressing the treated plant material piece in a vacuum chamber or a vacuum oven, for example, less than 1 bar. For example, an oven drying process may include heating the treated plant material piece at an elevated temperature (e.g., greater than 23°C) such as 70°C or higher using an oven, hot plate or other conductive heating device, convection heating device or radiant heating device. For example, a freeze drying process may include reducing the temperature of the treated plant material piece to below the freezing point of a fluid therein (e.g., less than 0°C) and then reducing the pressure to allow the frozen fluid therein to sublime (e.g., less than a few millibars). For example, a critical point drying process may include immersing the treated plant material piece in a fluid (e.g., liquid carbon dioxide) to increase the temperature and pressure of the plant material piece to above the critical point of the fluid (e.g., 7.39 MPa, 31.1°C for carbon dioxide) and then gradually releasing the pressure to remove the now gaseous fluid. For example, a microwave drying process may include using a microwave oven or other microwave generating device to cause dielectric heating within the treated plant material piece by exposing it to electromagnetic radiation having a frequency in the microwave range (e.g., 300 MHz to 300 GHz), such as a frequency of about 915 MHz or about 2.45 GHz.

[0082] After optional process box 610 or optional process box 616, or if lignin damage treatment is not required at decision box 604, method 600 may proceed to process box 617, wherein one or more internal modifications may be optionally performed to the treated plant material piece before pressing. Although the term "interior" is used to refer to the modification of process box 617, it is conceivable that in some embodiments, the modification may be applied to the external features and internal features of the treated plant material piece, and in other embodiments, the modification may be applied to the internal features or external features of the treated plant material piece, without otherwise affecting other features. In some embodiments, the internal modification may include forming, depositing or otherwise providing non-natural particles on the surface of the treated plant material piece. Such a surface may include at least an inner surface, such as a cell wall lining the cavity, but may also include the outer surface of the treated plant material piece. The non-natural particles incorporated into the surface of the treated plant material sheet can impart certain advantageous properties to the final structure, such as hydrophobicity, weather resistance, corrosion resistance (e.g., salt water resistance), and / or flame retardancy, among other properties. For example, in some embodiments, hydrophobic nanoparticles (e.g., SiO2 nanoparticles) can be formed on the surface of the treated plant material sheet.

[0083] Alternatively or additionally, in some embodiments, the internal modification may include performing another chemical treatment that changes the surface chemistry of the treated plant material piece. For example, in some embodiments, the other chemical treatment may provide weathering or corrosion resistance and may include at least one of the following: copper dimethyldithiocarbamate (CDDC), quaternary ammonium copper (ACQ), chromium copper arsenate (CCA), ammonia soluble alkylamine copper (ACZA), copper naphthenate, acid copper chromate, copper citrate, copper azole, 8-hydroxyquinolinate copper, pentachlorophenol, zinc naphthenate, copper naphthenate, creosote oil, titanium dioxide, propiconazole, tebuconazole, cyproconazole, boric acid, borax, organic iodide (IPBC) and Na2B8O 13 ·4H2O.

[0084] Alternatively or additionally, in some embodiments, the internal modification of process block 617 may include infiltrating the treated plant material sheet with one or more polymers (or polymer precursors). For example, the treated plant material sheet may be immersed in a polymer solution under vacuum to form a mixed material. The polymer may be any type of polymer that is capable of penetrating into the pores of the treated plant material sheet, for example, a synthetic polymer, a natural polymer, a thermosetting polymer, or a thermoplastic polymer. For example, in some embodiments, the polymer can be epoxy resin, polyvinyl alcohol (PVA), polyethylene glycol (PEO), polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polypropylene terephthalate (PTT), polyacrylonitrile (PAN), polycaprolactam (PA6), poly(m-phenylene isophthalamide) (PMIA), poly(p-phenylene terephthalamide) (PPTA), polyurethane (PU), polycarbonate (PC), polypropylene (PP), high-density polyethylene (HDPE), polystyrene (PS), polycaprolactone (PCL), polybutylene succinate (PBS), polybutylene terephthalate adipate (PBAT), polybutylene succinate-adipate copolymer (PBSA), polyhydroxybutyrate (PHB), poly(3-hydroxybutyric acid-CO-3-hydroxyvaleric acid) (PHBV), polyglycolic acid (PGA), polypyrrole (PPy), poly Thiophene (PTh), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), polyisophthalamide (MXD6), polyethylene (PE), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polyimide (PI), polyethylene imine (PEI), polylactic acid (PLA), octadecyltrichlorosilane (OTS), polyoctahedral silsesquioxane (POSS), p-methylstyrene (PMS), polydimethylsiloxane (PDMS), polyethylene naphthalate (PEN), a graft copolymer of acrylonitrile-butadiene-styrene-methyl methacrylate (ABSM), dodecyltrimethoxysilane (DTMS), rosin, chitin, chitosan, protamine, vegetable oil, lignin, hemicellulose, carboxymethyl cellulose, cellulose acetate, starch, agar, or any combination thereof.

[0085] Method 600 may proceed to process frame 618, wherein the treated plant material sheet is pressed in a direction intersecting with its longitudinal direction. In some embodiments, pressing may be performed in a direction substantially perpendicular to the longitudinal direction, while in other embodiments, pressing may have a force component perpendicular to the longitudinal direction. In either case, pressing may effectively reduce the thickness of the treated plant material sheet, thereby increasing its density and causing the natural cavity (e.g., the lumen in the conduit, each fiber, thin-walled cells, etc.), voids and / or gaps (at least partially) to collapse in the cross section of the treated plant material sheet. In some embodiments, pressing may be performed along a single direction (e.g., along the radial direction R), such as to reduce the thickness of the treated plant material sheet (e.g., compared to the plant material sheet before pressing, the size is reduced by at least 5:2). Alternatively or additionally, in some embodiments, the treated plant material sheet may be pressed simultaneously in two directions (e.g., along the radial direction R and a second direction perpendicular to both the radial direction R and the longitudinal direction L), such as to reduce the cross-sectional area of ​​the plant material sheet (e.g., to produce a densified rectangular rod). Alternatively or additionally, in some embodiments, the treated plant material sheets may be pressed sequentially in different directions (eg, first along the radial direction R and then along a second direction perpendicular to the radial direction R and the longitudinal direction L).

[0086] In certain embodiments, can carry out this pressing when the plant material sheet is not carried out any prior drying or when retaining at least some water or other fluid in the plant material sheet. Pressing can effectively remove at least some water or other fluid from the plant material sheet thus, and its size is reduced and density is increased. In certain embodiments, independent drying process can be combined with pressing process. For example, can initially press the plant material sheet to cause densification and remove at least some water or fluid therefrom, then carry out drying process (for example, air drying) to remove remaining water or fluid. Alternatively, in certain embodiments, can initially dry the plant material sheet to remove at least some water or fluid therefrom (for example, carry out initial drying in humidity chamber, carry out air drying at room temperature subsequently, make the moisture content of the plant material sheet approach but keep greater than 15wt%, for example, 10wt%), then press to cause densification (and potentially further remove water or other fluid, for example, moisture content is less than 10wt%, for example 3-8wt%).

[0087] In some embodiments, pressing can promote hydrogen bonding between cellulose-based fibers of the cell walls of the plant material sheet, thereby improving the mechanical properties of the plant material sheet. In addition, any particles or materials formed on the surface of the plant material sheet or within the plant material sheet (e.g., via optional modification of process block 617) can be retained after pressing, wherein the particles / materials on the inner surface are embedded in the collapsed cavity and tangled cell walls.

[0088] The pressure and time of pressing can be factors of the size of the plant material sheet before pressing, the desired size of the plant material sheet after pressing, the moisture or fluid content (if any) in the plant material sheet, the temperature at which pressing is performed, the relative humidity, the properties of the material (e.g., the infiltrated polymer) from the internal modification (if any), and / or other factors. For example, the plant material sheet can be kept under pressure for a period of 1 minute up to several hours (e.g., 1-180 minutes (including end values)). In some embodiments, the plant material sheet can be kept under pressure for 3-72 hours (including end values). In some embodiments, pressing can be performed at a pressure between 0.5MPa and 20MPa (including end values, such as 5MPa). In some embodiments, pressing can be performed without heating (e.g., cold pressing), while in other embodiments, pressing can be performed with heating (e.g., hot pressing). For example, pressing can be performed at a temperature of 20°C to 160°C (e.g., greater than or equal to 100°C). In some embodiments, pressing can effectively cause the cavity of the natural cellulose-based microstructure of the plant material to collapse completely and / or can result in a density of at least 1.15g / cm 3 (e.g., ≥1.2 g / cm 3 or ≥1.3 g / cm 3 , for example, at 1.4-1.5 g / cm 3 within the range of ).

[0089] Method 600 may proceed to process box 620, wherein the now densified plant material piece may be optionally subjected to external modification. Although the term "external" is used to refer to the optional modification of process box 620, it is contemplated that in some embodiments, the modification may be applied to both internal and external features of the dense plant material piece, while in other embodiments, the modification may be applied to either the internal or external features of the dense plant material piece without affecting other features. In some embodiments, the external modification may include forming, depositing or otherwise arranging a coating on one or more outer surfaces of the dense plant material piece. The coating may impart certain advantageous properties to the dense plant material piece, such as, but not limited to, hydrophobicity, weatherability, corrosion resistance (e.g., salt water resistance) and / or flame retardancy. For example, the coating may include an oil-based coating, a hydrophobic coating, a polymer coating and / or a refractory coating. In some embodiments, the refractory coating may include nanoparticles (e.g., boron nitride nanoparticles). Alternatively or additionally, in some embodiments, the coating for the densified plant material sheet may include boron nitride (BN), montmorillonite clay, hydrotalcite, silica (SiO2), sodium silicate, calcium carbonate (CaCO3), aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), magnesium carbonate (MgCO3), aluminum sulfate, iron sulfate, zinc borate, boric acid, borax, triphenyl phosphate (TPP), melamine, polyurethane, ammonium polyphosphate, phosphate esters, phosphites, ammonium phosphate, ammonium sulfate, phosphonates, diammonium phosphate (DAP), diammonium phosphate, monoammonium phosphate (MAP), guanyl urea phosphate (GUP), dihydrogen guanidine phosphate, antimony pentoxide, or any combination of the foregoing.

[0090] Method 600 may proceed to process box 622, wherein the dense plant material piece may be selectively machined, cut and / or otherwise physically manipulated for final use. Machining processes may include, but are not limited to, cutting (e.g., sawing), drilling, wood turning, tapping, boring, carving, routing, sanding, grinding and rolling. Manipulation processes may include, but are not limited to, bending, molding and other forming techniques. In some embodiments, manipulation may include assembling a plurality of treated plant material pieces into a single layer. For example, in some embodiments, treated plant material strands may be mixed with waterproof resin and interlaced to form a mat, which may then be heated and / or pressurized to bond the strands to the resin.

[0091] Method 600 may proceed to process block 624, where one or more non-densified plant material sheets may be provided. In some embodiments, the arrangement of process block 624 may be similar to the arrangement of process block 602. For example, the plant material of the non-densified sheet may be the same type of plant material as the plant material used in process block 602 or a different type of plant material. In some embodiments, the density of the non-densified plant material sheet may be less than 1.15 g / cm 3 (e.g., ≤1.0 g / cm 3 or ≤0.9g / cm 3 , for example, between 0.1 and 0.9 g / cm 3 In some embodiments, the process block 624 may include, for example, machining, cutting, or otherwise physically manipulating to form layers of appropriate dimensions for the desired configuration of the engineered structure. For example, the number of non-densified plant material sheets (or non-densified plant material layers) may be greater than the number of dense plant material sheets (or dense plant material layers), for example, at least twice.

[0092] Method 600 may proceed to process box 626, where the non-dense plant material sheets and the dense plant material sheets may be connected together (e.g., via a glue or other adhesive layer) to form an engineered structure. In some embodiments, process box 626 may include layering, aligning, or otherwise positioning the non-dense plant material sheets and the dense plant material sheets relative to each other. In some embodiments, the non-dense plant material sheets and / or the dense plant material sheets may be connected together using epoxy resins, polyurethane adhesives, polyvinyl acetate-isocyanate adhesives, resorcinol formaldehyde resin adhesives, phenolic resins, and / or sodium carboxymethyl cellulose (CMC). In some embodiments, the connection of the non-dense plant material sheets and the dense plant material sheets may form a laminated structure or a portion thereof, for example, Figures 1A-5E Any of the engineering structures shown in .

[0093] Method 600 may proceed to process block 628, wherein the engineered structure formed by the compact plant material sheet and the non-compact plant material sheet may be used for a particular application. For example, the engineered structure may be suitable for use as a structural material (e.g., a load-bearing component or a non-load-bearing component). Those skilled in the art will readily appreciate that, based on the teachings of the present disclosure, the engineered structures disclosed herein may be readily adapted for use in a variety of applications.

[0094] Although blocks 602-628 of method 600 have been described as being performed once, in some embodiments, a particular process block may be repeated multiple times before proceeding to the next decision block or process block. Furthermore, although blocks 602-628 of method 600 have been shown and described separately, in some embodiments, the process blocks may be combined together and performed together (simultaneously or sequentially). Furthermore, although Figure 6A specific order of blocks 602-628 is shown, but embodiments of the disclosed subject matter are not limited thereto. Indeed, in some embodiments, the blocks may appear in an order different from that shown or may appear simultaneously with other blocks. In some embodiments, method 600 may include Figure 6 Alternatively or additionally, in some embodiments, method 600 may only include: Figure 6 Some of boxes 602-628.

[0095] Additional Examples of the Disclosed Technology

[0096] In view of the above embodiments of the disclosed subject matter, the present application discloses additional examples in the clauses listed below. It should be noted that a single feature of a clause or more than one feature of a clause adopted in combination and optionally, combined with one or more features of one or more other clauses are additional examples that also fall within the scope of the disclosure of the present application.

[0097] Clause 1. An engineering structure comprising:

[0098] a first laminate comprising a plurality of constituent plant material layers, the plurality of constituent plant material layers comprising one or more first layers and one or more second layers, each plant material layer being adhered to an adjacent plant material layer via a respective one or more adhesives,

[0099] Wherein, each first plant material layer has a density greater than or equal to 1.15 g / cm 3 and a layer of dense plant material having a mechanical strength greater than or equal to a first value, and

[0100] Each second plant material layer has a density of less than 1.15 g / cm 3 And the plant material layer has a mechanical strength less than the first value.

[0101] Clause 2. An engineering structure as described in any clause or example herein (particularly clause 1), wherein the plant material forming one, some or all of the constituent layers in the first laminate is wood or bamboo.

[0102] Clause 3. An engineering structure as described in any clause or example herein (particularly any of clauses 1-2), wherein the densified plant material forming one, some or all of the one or more first layers is densified wood or densified bamboo.

[0103] Clause 4. An engineering structure as described in any clause or example herein (particularly any of clauses 1-3), wherein the plant material forming one, some or all of the one or more second layers is natural wood or natural bamboo.

[0104] Clause 5. An engineering structure as described in any clause or example herein (particularly any of clauses 1-4), wherein the plant material forming one, some or all of the one or more first layers is the same plant material as one, some or all of the plant material forming one or more second layers.

[0105] Clause 6. An engineering structure as described in any clause or example herein (particularly any of clauses 1-5), wherein the plant material forming one, some or all of the one or more first layers is a plant material different from the plant material forming one, some or all of the one or more second layers.

[0106] Clause 7. An engineering structure as described in any clause or example herein (in particular any of clauses 1 to 6), wherein:

[0107] (a1) one, some or all of the one or more first layers have a density greater than or equal to 1.2 g / cm 3 ;

[0108] (a2) one, some or all of the one or more second layers have a density less than or equal to 1.0 g / cm 3 ;or

[0109] Both (a1) and (a2).

[0110] Clause 8. An engineering structure as described in any clause or example herein (in particular any of clauses 1 to 7), wherein:

[0111] (a3) one, some or all of the one or more first layers have a density greater than or equal to 1.3 g / cm 3 ;

[0112] (a4) one, some or all of the one or more second layers have a density less than or equal to 0.9 g / cm 3 ;or

[0113] Both (a3) ​​and (a4).

[0114] Item 9. An engineered structure as described in any item or example herein (particularly any of items 1-8), wherein one, some or all of the one or more second layers comprise one or more pieces of non-densified plant material that retain the natural microstructure of the cellulose-based cavities of the plant material.

[0115] Clause 10. An engineered structure as described in any clause or example herein (particularly any of clauses 1-9), wherein one, some or all of the one or more first layers comprise one or more sheets of dense plant material, the cellulose-based cavities of the natural microstructure of the plant material being substantially collapsed.

[0116] Clause 11. An engineered structure as described in any clause or example herein, in particular any of clauses 1-10, wherein one, some or all of the one or more first layers comprise lignin-damaged plant material.

[0117] Item 12. An engineered structure as described in any item or example herein (particularly item 11), wherein the lignin-damaged plant material contains modified lignin therein, and the macromolecular chains of the modified lignin are shorter than the macromolecular chains of the natural lignin in the natural plant material.

[0118] Item 13. An engineered structure as described in any item or example herein (particularly item 12), wherein the content of the modified lignin in one, some or all of the one or more first layers is at least 90% of the content of the natural lignin in the natural plant material on a weight percentage basis.

[0119] Clause 14. An engineered structure as described in any clause or example herein (particularly any of clauses 12-13), wherein the content of the modified lignin in one, some or all of the one or more first layers is at least 20% on a weight basis.

[0120] Item 15. An engineered structure as described in any item or example herein (particularly any of items 12-14), wherein one, some or all of the one or more first layers comprise salts of alkaline chemicals fixed within the cellulose-based microstructure of the lignin-damaged plant material.

[0121] Clause 16. An engineered structure as described in any clause or example herein (particularly clause 15), wherein the salt is substantially pH neutral.

[0122] Clause 17. An engineered structure as described in any clause or example herein (particularly clause 11), wherein the lignin-damaged plant material comprises at least partially delignified wood.

[0123] Clause 18. An engineered structure as described in any clause or example herein (particularly clause 17), wherein the lignin content of the at least partially delignified plant material is between 5% and 95%, inclusive, of the lignin content of the natural plant material.

[0124] Clause 19. An engineering structure as described in any clause or example herein (in particular any of clauses 17-18), wherein:

[0125] The plant material is hardwood or bamboo and the lignin content of the at least partially delignified plant material is between 0.9% and 23.8%, inclusive, on a weight percentage basis; or

[0126] The plant material is softwood and the at least partially delignified plant material has a lignin content of between 1.25% and 33.25% on a weight percent basis, inclusive.

[0127] Clause 20. An engineered structure as described in any clause or example herein (particularly any of clauses 17-19), wherein the at least partially delignified plant material has a lignin content of at least 10% on a weight basis.

[0128] Clause 21. An engineering structure as described in any clause or example herein (in particular any of clauses 1 to 20), wherein:

[0129] (a5) each first layer consists essentially of dense plant material;

[0130] (a6) each second layer consists essentially of non-densified wood; or

[0131] Both (a5) and (a6).

[0132] Clause 22. An engineering structure as described in any clause or example herein (particularly any of clauses 1-21), wherein the corresponding one or more adhesives include epoxy resin, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, sodium carboxymethyl cellulose (CMC) or any combination of the foregoing.

[0133] Clause 23. An engineering structure as described in any clause or example herein (in particular any of clauses 1 to 22), wherein:

[0134] one, some or all of the one or more first layers are formed from the same wood species as one, some or all of the one or more second layers; or

[0135] One, some or all of the one or more first layers are formed from a different wood species to the wood species from which one, some or all of the one or more second layers are formed.

[0136] Clause 24. An engineering structure as described in any clause or example herein (in particular any of clauses 1-23), wherein one, some or all of the one or more first layers are arranged within the first laminate at corresponding positions where the first laminate is subjected to the highest stress.

[0137] Clause 25. An engineering structure as described in any clause or example herein (particularly any of clauses 1-24), wherein one, some or all of the one or more first layers are arranged as respective outermost layers of the first laminate.

[0138] Clause 26. An engineering structure as described in any clause or example herein (particularly any of clauses 1-25), wherein the one or more first layers surround the one or more second layers in a cross-sectional view.

[0139] Clause 27. An engineering structure as described in any clause or example herein, in particular any of clauses 1-26, wherein the one or more first layers completely surround the one or more second layers on all sides.

[0140] Clause 28. An engineering structure as described in any clause or example herein (in particular any of clauses 1 to 27), wherein:

[0141] the second layer comprises a stack of panels of plant material arranged such that adjacent panels of plant material have an orthogonal orientation, and

[0142] The stack of panels of plant material is arranged between a pair of the first layers so as to form a reinforced cross-laminated timber (CLT) structure.

[0143] Clause 29. An engineering structure as described in any clause or example herein (in particular any of clauses 1-28), wherein the first laminate comprises a plurality of second layers and a pair of first layers, each second layer comprising one or more segments of plant material, the second layers being arranged into a stack such that adjacent second layers have a parallel orientation, the stack being arranged between the pair of first layers to form a reinforced glued laminate (glulam) structure.

[0144] Clause 30. An engineering structure as described in any clause or example herein (in particular any of clauses 1-28), wherein the first laminate comprises a plurality of second layers and a pair of first layers, each second layer comprising one or more plant material veneers, the second layers being arranged into a stack such that adjacent second layers have a parallel orientation, the stack being arranged between the pair of first layers to form a reinforced laminated veneer lumber (LVL) structure.

[0145] Clause 31. An engineering structure as described in any clause or example herein (particularly any of clauses 1 to 30), wherein the engineering structure further comprises:

[0146] a second laminate comprising a second plurality of constituent plant material layers, the second plurality of constituent plant material layers comprising one or more third layers and one or more fourth layers, each plant material layer being adhered to an adjacent plant material layer via a respective one or more glues; and

[0147] a web extending between the first laminate and the second laminate,

[0148] Among them, each third layer has a density greater than or equal to 1.15g / cm 3 and a dense plant material layer having a mechanical strength greater than or equal to a second value,

[0149] Each fourth layer has a density less than 1.15g / cm 3 and the mechanical strength of the plant material layer is less than the second value,

[0150] The web forms an I-beam with the first laminate and the second laminate, and

[0151] The first laminate and the second laminate form a first flange and a second flange of the I-beam, respectively.

[0152] Clause 32. An engineered structure as described in any clause or example herein (particularly clause 31), wherein the web comprises one or more sheets of non-densified plant material that retain the natural microstructure of the cellulose-based cavities of the plant material.

[0153] Clause 33. An engineered structure as described in any clause or example herein (particularly any of clauses 31-32), wherein the web comprises one or more sheets of dense plant material, the cellulose-based cavities of the natural microstructure of the plant material being substantially collapsed.

[0154] Clause 34. An engineering structure as described in any clause or example herein (particularly any of clauses 31-33), wherein the plant material forming one, some or all of the constituent layers in the second laminate is wood or bamboo.

[0155] Clause 35. An engineering structure as described in any clause or example herein (in particular any of clauses 31-34), wherein:

[0156] (a7) the plant material forming one, some or all of the one or more third layers is densified wood or densified bamboo;

[0157] (a8) the plant material forming one, some or all of the one or more fourth layers is natural wood or natural bamboo; or

[0158] Both (a7) and (a8).

[0159] Clause 36. An engineering structure as described in any clause or example herein (in particular any of clauses 31-35), wherein one of the one or more first layers forms an exposed side of the first flange opposite to the web, and / or one of the one or more third layers forms an exposed side of the second flange opposite to the web.

[0160] Clause 37. An engineering structure as described in any clause or example herein (in particular any of clauses 31-35), wherein:

[0161] (a9) one of the one or more second layers forms an exposed side of the first flange opposite the web, and one of the one or more first layers is arranged within the first flange between the exposed side of the first flange and the web;

[0162] (a10) one of the one or more fourth layers forms an exposed side of the second flange opposite the web, and one of the one or more third layers is arranged within the second flange between the exposed side of the second flange and the web; or

[0163] Both (a9) and (b10).

[0164] Clause 38. An engineering structure as described in any clause or example herein (particularly any of clauses 31-37), wherein the first value, the second value, or both are 100 MPa.

[0165] Clause 39. An engineering structure as described in any clause or example herein (particularly any of clauses 31-37), wherein the mechanical strength of each first layer, the mechanical strength of each third layer, or both are within the range of 100-600 MPa and inclusive.

[0166] Clause 40. An engineering structure as described in any clause or example herein, in particular any of clauses 1-39, wherein the first value is about 100 MPa, or the first value is within the range of 100-600 MPa and including the end values.

[0167] Clause 41. An engineering structure as described in any clause or example herein (particularly any of clauses 1-40), wherein the first laminate has a first cross-sectional area and the mechanical strength of the first laminate is greater than the mechanical strength of a laminate structure having the first cross-sectional area and formed only using the one or more second layers and the one or more adhesives.

[0168] Clause 42. An engineering structure as described in any clause or example of the present invention (particularly any of clauses 1-40), wherein the first laminate has a first cross-sectional area and mechanical strength, and the first cross-sectional area is smaller than the cross-sectional area of ​​a laminate structure having the same mechanical strength and formed only using the one or more second layers and the one or more adhesives.

[0169] Clause 43. An engineering structural material comprising:

[0170] One or more laminate structures, each laminate structure having a plurality of constituent plant material layers, each plant material layer being coupled to adjacent plant material layers via corresponding one or more adhesives, at least one of the plurality of constituent plant material layers being of density greater than or equal to 1.15 g / cm 3 layer of dense plant material.

[0171] Clause 44. An engineering structural material as described in any clause or example herein (particularly Clause 43), wherein the densified plant material layer is densified wood or densified bamboo.

[0172] Clause 45. An engineering structural material as described in any clause or example herein (especially any of clauses 43-44), wherein the dense plant material layer has a density greater than or equal to 1.2 g / cm 3 density.

[0173] Clause 46. An engineering structural material as described in any clause or example herein (especially any of clauses 43-45), wherein the dense plant material layer has a density greater than or equal to 1.3 g / cm 3 density.

[0174] Clause 47. An engineering structural material as described in any clause or example herein (particularly any of clauses 43-46), wherein the layer of dense plant material comprises one or more pieces of dense wood or dense bamboo, the cellulose-based cavities of the natural microstructure of the wood or bamboo being substantially collapsed.

[0175] Clause 48. An engineered structural material as described in any clause or example herein (particularly any of clauses 43-47), wherein the densified plant material layer comprises at least partially delignified plant material or lignin-modified plant material.

[0176] Clause 49. An engineering structural material as described in any clause or example herein (particularly any of clauses 43-48), wherein the one or more adhesives comprise epoxy resin, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination thereof.

[0177] Clause 50. An engineering structural material as described in any clause or example herein (in particular any of clauses 43-49), wherein the one or more laminated structures are formed as part of a cross-laminated timber (CLT) structure, a glue-laminated timber (glulam) structure, a laminated veneer lumber (LVL) structure, an oriented strand board (OSB) structure or an I-beam structure.

[0178] Clause 51. An engineering structural material as described in any clause or example herein (particularly any of clauses 43-50), wherein each of the plurality of constituent plant material layers has a density of less than 1.15 g / cm 3 Layer of non-compacted plant material or density at least 1.15 g / cm 3 layer of dense plant material.

[0179] Clause 52. An engineering structural material as described in any clause or example herein (particularly any of clauses 43-50), wherein each of the plurality of constituent plant material layers has a density of less than 1.15 g / cm 3 Natural plant material layer or density at least 1.15g / cm 3 layer of dense plant material.

[0180] Clause 53. A method comprising:

[0181] One or more first layers are provided, each first layer comprising a density greater than or equal to 1.15 g / cm 3 and a dense plant material having a mechanical strength greater than or equal to a first value;

[0182] One or more second layers are provided, each second layer comprising a density less than 1.15 g / cm 3 and the plant material has a mechanical strength less than the first value; and

[0183] The one or more first layers are coupled to the one or more second layers via respective one or more glues so as to form a laminate.

[0184] Clause 54. A method as described in any clause or example herein (particularly clause 53), wherein:

[0185] (b1) one, some or all of the plant materials of the one or more first layers comprise densified wood or densified bamboo;

[0186] (b2) one, some or all of the plant materials of the one or more second layers comprise non-densified wood or non-densified bamboo; or

[0187] Both (b1) and (b2).

[0188] Clause 55. A method as described in any clause or example herein (particularly any of clauses 53-54), wherein:

[0189] (b3) one, some or all of the plant materials of the one or more first layers comprise densified wood or densified bamboo;

[0190] (b4) one, some or all of the plant materials of the one or more second layers comprise natural wood or natural bamboo; or

[0191] Both (b3) and (b4).

[0192] Clause 56. A method as described in any clause or example herein (particularly any of clauses 53-55), wherein:

[0193] The density of one, some or all of the one or more first layers is greater than or equal to 1.2 g / cm 3 ;

[0194] The density of one, some or all of the one or more first layers is greater than or equal to 1.3 g / cm 3 ;

[0195] The density of one, some or all of the one or more second layers is less than or equal to 1.0 g / cm 3 ;

[0196] The density of one, some or all of the one or more second layers is less than or equal to 0.9 g / cm 3 ;or

[0197] Any combination of the foregoing.

[0198] Clause 57. A method as described in any clause or example herein (particularly any of clauses 53-56), wherein providing the one or more first layers comprises:

[0199] chemically treating one or more pieces of natural plant material having native lignin therein so as to damage the native lignin, thereby forming one or more pieces of lignin-damaged plant material; and

[0200] compressing said one or more pieces of lignin-damaged plant material to form said one or more first layers of said densified plant material,

[0201] Wherein, the density of the densified plant material after the compression is greater than the density of the natural plant material before the chemical treatment.

[0202] Clause 58. A method as described in any clause or example herein (particularly Clause 57), wherein the compressing is performed in a direction intersecting the longitudinal growth direction of the one or more pieces of lignin-damaged plant material.

[0203] Clause 59. A method as described in any clause or example herein (particularly any of clauses 57-58), wherein the compressing comprises pressing the one or more pieces of lignin-damaged plant material at a pressure of at least 1 MPa.

[0204] Clause 60. A method as described in any clause or example herein (particularly any of clauses 57-59), wherein the compressing comprises pressing the one or more pieces of lignin-damaged plant material at a pressure in the range of 5-20 MPa (inclusive).

[0205] Clause 61. A method as described in any clause or example herein (particularly any of clauses 57-60), wherein the compressing comprises pressing the one or more pieces of lignin-damaged plant material while being subjected to a temperature of at least 50°C.

[0206] Clause 62. A method as described in any clause or example herein (particularly clauses 57-61), wherein the compressing comprises pressing the one or more pieces of lignin-damaged plant material while being subjected to a temperature in the range of 80-180°C (inclusive).

[0207] Clause 63. A method as described in any clause or example herein (particularly any of clauses 57-62), wherein, after the subjecting, the one or more pieces of lignin-damaged plant material contain modified lignin, and the macromolecular chains of the modified lignin are shorter than the macromolecular chains of the natural lignin in the piece of natural plant material.

[0208] Clause 64. A method as described in any clause or example herein (particularly clause 63), wherein performing the chemical treatment comprises:

[0209] infiltrating the one or more pieces of natural plant material with one or more chemical solutions; and

[0210] Subsequent to said infiltrating, said one or more pieces of natural plant material having said one or more chemical solutions therein are subjected to a first temperature of at least 80° C. for a first time to form said one or more pieces of lignin-damaged plant material.

[0211] Item 65. A method as described in any item or example herein (especially item 64), wherein the one or more chemical solutions contain p-toluenesulfonic acid, NaOH, NaOH+Na2SO3 / Na2SO4, NaOH+Na2S, NaHSO3+SO2+H2O, NaHSO3+Na2SO3, NaOH+Na2SO3, NaOH / NaH2O3+AQ, NaOH / Na2S+AQ, NaOH+Na2SO3+AQ, Na2SO3+NaOH+CH3OH+AQ, NaHSO3+SO2+AQ, NaOH+Na2Sx, wherein AQ is anthraquinone, any one of the foregoing or any combination of the foregoing when NaOH is replaced by LiOH or KOH.

[0212] Clause 66. A method as described in any clause or example herein (particularly any of clauses 64-65), wherein:

[0213] The first temperature is within the range of 120-160°C and inclusive; and / or

[0214] The first time is in the range of 1-5 hours, inclusive.

[0215] Clause 67. A method as described in any clause or example herein (particularly any of clauses 64-66), wherein at least 90% of the one or more chemical solutions infiltrated into the one or more pieces of natural plant material is consumed by subjecting the one or more chemical solutions to the first temperature for the first time.

[0216] Clause 68. A method as described in any clause or example herein (particularly any of clauses 64-67), wherein subjecting the first temperature for the first time comprises heating the one or more pieces of natural plant material having the one or more chemical solutions therein using steam.

[0217] Clause 69. A method as described in any clause or example herein (particularly according to any of clauses 64-68), wherein after being subjected to the first temperature for the first time:

[0218] (b5) the content of modified lignin in the one or more pieces of lignin-damaged plant materials is at least 90% of the content of the natural lignin in the one or more pieces of natural plant materials on a weight basis;

[0219] (b6) the content of modified lignin in the one or more pieces of lignin-damaged plant material is at least 20% on a weight basis; or

[0220] Both (b5) and (b6).

[0221] Item 70. A method as described in any item or example herein (in particular any of items 64-69), wherein, after being subjected to the first temperature and for the first time, a salt of an alkaline chemical is fixed within the cellulose-based microstructure of the one or more pieces of lignin-damaged plant material.

[0222] Clause 71. A method as described in any clause or example herein (particularly clause 70), wherein the salt is substantially pH neutral.

[0223] Clause 72. A method as described in any clause or example herein (particularly any of clauses 70-71), wherein the salt is formed by reacting the one or more chemical solutions with acidic degradation products of natural hemicellulose in the one or more natural plant materials produced by the one or more chemical solutions.

[0224] Clause 73. A method as described in any clause or example herein (particularly any of clauses 57-62), wherein, after said chemical treatment, said one or more pieces of lignin-damaged plant material are at least partially delignified.

[0225] Item 74. A method as described in any item or example herein (particularly item 73), wherein the chemical treatment comprises partially or completely immersing the one or more natural plant materials in one or more chemical solutions at a second temperature and for a second time so as to remove at least some lignin from the one or more natural plant materials.

[0226] Clause 75. A method as described in any clause or example herein (particularly clause 74), wherein the one or more chemical solutions include an alkaline solution.

[0227] Clause 76. A method as described in any clause or example herein (particularly any of clauses 74-75), wherein the one or more chemical solutions comprise sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), sodium sulfite (Na2SO3), sodium sulfate (Na2SO4), sodium sulfide (Na2S), Na n S (where n is an integer), urea (CH4N2O), sodium bisulfite (NaHSO3), NaH2O3, sulfur dioxide (SO2), anthraquinone (C 14H8O2), methanol (CH3OH), ethanol (C2H5OH), butanol (C4H9OH), formic acid (CH2O2), hydrogen peroxide (H2O2), acetic acid (CH3COOH), butyric acid (C4H8O2), peroxyformic acid (CH2O3), peracetic acid (C2H4O3), ammonia (NH3), toluenesulfonic acid (p-TsOH), sodium hypochlorite (NaClO), sodium chlorite (NaClO2), chlorine dioxide (ClO2), chlorine (ClO2), water (H2O), or any combination of the foregoing.

[0228] Clause 77. A method as described in any clause or example herein (particularly according to any of clauses 74-76), wherein the one or more chemical solutions comprise a boiling mixture of NaOH and Na2SO3.

[0229] Clause 78. A method as described in any clause or example herein (particularly any of clauses 74-77), wherein:

[0230] (b7) the second temperature is in the range of 100-160° C. and including the end values;

[0231] (b8) the second time is in the range of 0.1 to 96 hours, inclusive; or

[0232] Both (b7) and (b8).

[0233] Clause 79. A method as described in any clause or example herein (particularly any of clauses 74-78), wherein the lignin content of the one or more pieces of lignin-damaged plant material is between 5% and 95%, inclusive, of the lignin content of the natural plant material.

[0234] Clause 80. A method as described in any clause or example herein (particularly any of clauses 74-79), wherein:

[0235] The natural plant material is hardwood or bamboo, and the lignin-damaged plant material has a lignin content between 0.9 wt % and 23.8 wt %, inclusive; or

[0236] The natural plant material is softwood, and the lignin-damaged plant material has a lignin content of between 1.25 wt% and 33.25 wt%, inclusive.

[0237] Clause 81. A method as described in any clause or example herein (particularly any of clauses 74-80), wherein the lignin-damaged plant material has a lignin content of at least 10 wt%.

[0238] Clause 82. A method as described in any clause or example herein (particularly any of clauses 53-81), wherein:

[0239] (b9) each first layer consists essentially of dense plant material;

[0240] (b10) each second layer consists essentially of non-densified or natural plant material; or

[0241] Both (b9) and (b10).

[0242] Clause 83. A method as described in any clause or example of the present invention (especially any of clauses 53-82), wherein the corresponding one or more glues include epoxy resin, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, sodium carboxymethyl cellulose (CMC) or any combination of the foregoing.

[0243] Clause 84. A method as described in any clause or example herein (particularly any of clauses 53-83), wherein the first layer and the second layer are connected in the form of a reinforced cross-laminated timber structure, a reinforced glue-laminated structure, a reinforced laminated veneer structure, an oriented strand board structure, an I-beam structure, or part of any of the foregoing.

[0244] Clause 85. A method as described in any clause or example herein (particularly any of clauses 53-84), wherein one, some or all of the one or more second layers comprise non-densified plant material.

[0245] in conclusion

[0246] For example, this article is about Figure 1A-6 and any features shown or described in clauses 1-85 may be used in conjunction with any of the features described herein, for example with respect to Figure 1A-6 and any other features shown or described in clauses 1-85 to provide materials, systems, devices, structures, methods, and embodiments not otherwise shown or specifically described herein. All features described herein are independent of each other and, unless structurally impossible, may be used in combination with any other features described herein. In view of the many possible embodiments to which the principles of the disclosed technology can be applied, it should be recognized that the illustrated embodiments are merely examples and should not be taken as limiting the scope of the disclosed technology. Instead, the scope is defined by the appended claims. We therefore claim protection for all that falls within the scope and spirit of these claims.

Claims

1. An engineering structure comprising: a first laminate comprising a plurality of constituent plant material layers, the plurality of constituent plant material layers comprising one or more first layers and one or more second layers, each plant material layer being adhered to an adjacent plant material layer via a respective one or more adhesives, Wherein, each first plant material layer has a density greater than or equal to 1.15 g / cm 3 and a layer of dense plant material having a mechanical strength greater than or equal to a first value, and Each second plant material layer has a density of less than 1.15 g / cm 3 And the plant material layer has a mechanical strength less than the first value.

2. The engineering structure according to claim 1, wherein: The plant material forming one, some or all of the constituent layers in the first laminate is wood or bamboo.

3. The engineering structure according to claim 1, wherein: The densified plant material forming one, some or all of the one or more first layers is densified wood or densified bamboo.

4. The engineering structure according to claim 1, wherein: The plant material forming one, some or all of the one or more second layers is natural wood or natural bamboo.

5. The engineering structure according to claim 1, wherein: The plant material forming one, some or all of the one or more first layers is the same plant material as the plant material forming one, some or all of the one or more second layers.

6. The engineering structure according to claim 1, wherein: The plant material forming one, some or all of the one or more first layers is a different plant material to the plant material forming one, some or all of the one or more second layers.

7. The engineering structure of claim 1, wherein: (a1) the density of one, some or all of the one or more first layers is greater than or equal to 1.2 g / cm 3 ; (a2) the density of one, some or all of the one or more second layers is less than or equal to 1.0 g / cm 3 ;or Both (a1) and (a2).

8. The engineering structure of claim 1, wherein: (a3) the density of one, some or all of the one or more first layers is greater than or equal to 1.3 g / cm 3 ; (a4) one, some or all of the one or more second layers have a density less than or equal to 0.9 g / cm 3 ;or Both (a3) ​​and (a4).

9. The engineering structure according to claim 1, wherein: One, some or all of the one or more second layers comprise one or more sheets of non-densified plant material that retain the natural microstructure of the cellulose-based cavities of the plant material.

10. The engineering structure according to claim 1, wherein: One, some or all of the one or more first layers comprise one or more sheets of densified plant material, the cellulose-based cavities of the natural microstructure of which are substantially collapsed.

11. The engineering structure of claim 1, wherein: One, some or all of the one or more first layers comprise lignin-damaged plant material.

12. The engineering structure according to claim 11, wherein: The lignin-damaged plant material contains modified lignin therein, and the macromolecular chains of the modified lignin are shorter than those of the natural lignin in the natural plant material.

13. The engineering structure of claim 12, wherein: The content of the modified lignin in one, some or all of the one or more first layers is at least 90% of the content of the natural lignin in the natural plant material on a weight basis.

14. The engineering structure of claim 12, wherein: The content of the modified lignin in the one, some or all of the one or more first layers is at least 20% on a weight percentage basis.

15. The engineered structure of claim 12, wherein: Said one, some or all of said one or more first layers comprise a salt of an alkaline chemical immobilized within the cellulose-based microstructure of said lignin-damaged plant material.

16. The engineering structure of claim 15, wherein: The salt is substantially pH neutral.

17. The engineering structure of claim 11, wherein: The lignin-damaged plant material comprises at least partially delignified wood.

18. The engineering structure of claim 17, wherein: The at least partially delignified plant material has a lignin content of between 5% and 95% of the lignin content of the native plant material, inclusive.

19. The engineering structure of claim 17, wherein: The plant material is hardwood or bamboo and the lignin content of the at least partially delignified plant material is between 0.9% and 23.8% on a weight percent basis, inclusive; or The plant material is softwood and the at least partially delignified plant material has a lignin content of between 1.25% and 33.25% on a weight percent basis, inclusive.

20. The engineering structure of claim 17, wherein: The at least partially delignified plant material has a lignin content of at least 10% on a weight basis.

21. The engineering structure of claim 1, wherein: (a5) each first layer consists essentially of dense plant material; (a6) each second layer consists essentially of non-densified wood; or Both (a5) and (a6).

22. The engineering structure of claim 1, wherein: The corresponding one or more glues include epoxy resin, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, sodium carboxymethyl cellulose (CMC) or any combination thereof.

23. The engineering structure of claim 1, wherein: one, some or all of the one or more first layers are formed from the same wood species as one, some or all of the one or more second layers; or One, some or all of the one or more first layers are formed from a different wood species to the wood species from which one, some or all of the one or more second layers are formed.

24. The engineering structure of claim 1, wherein: One, some or all of the one or more first layers are arranged within the first laminate at respective locations of the first laminate which are subject to highest stresses.

25. The engineering structure of claim 1, wherein: One, some or all of the one or more first layers are arranged as respective outermost layers of the first laminate.

26. The engineering structure of claim 1, wherein: The one or more first layers surround the one or more second layers in a cross-sectional view.

27. The engineering structure of claim 1, wherein: The one or more first layers completely surround the one or more second layers on all sides.

28. The engineering structure of claim 1, wherein: the second layer comprises a stack of panels of plant material arranged such that adjacent panels of plant material have an orthogonal orientation, and The stack of panels of plant material is arranged between a pair of the first layers so as to form a reinforced cross-laminated timber (CLT) structure.

29. The engineering structure of claim 1, wherein: The first laminate comprises a plurality of second layers and a pair of first layers, each second layer comprising one or more plant material segments, the second layers being arranged into a stack such that adjacent second layers have a parallel orientation, the stack being arranged between the pair of first layers to form a reinforced glued laminate (glulam) structure.

30. The engineering structure of claim 1, wherein: The first laminate comprises a plurality of second layers and a pair of first layers, each second layer comprising one or more plant material veneers, the second layers being arranged into a stack such that adjacent second layers have a parallel orientation, the stack being arranged between the pair of first layers to form a reinforced laminated veneer lumber (LVL) structure.

31. The engineering structure of claim 1, wherein: The engineering structure also includes: a second laminate comprising a second plurality of constituent plant material layers, the second plurality of constituent plant material layers comprising one or more third layers and one or more fourth layers, each plant material layer being adhered to an adjacent plant material layer via a respective one or more glues; and a web extending between the first laminate and the second laminate, Among them, each third layer has a density greater than or equal to 1.15g / cm 3 and a dense plant material layer having a mechanical strength greater than or equal to a second value, Each fourth layer has a density less than 1.15g / cm 3 and the mechanical strength of the plant material layer is less than the second value, The web forms an I-beam with the first laminate and the second laminate, and The first laminate and the second laminate form a first flange and a second flange of the I-beam, respectively.

32. The engineering structure of claim 31, wherein: The web comprises one or more sheets of non-densified plant material that retain the natural microstructure of the cellulose-based cavities of the plant material.

33. The engineering structure of claim 31, wherein: The web comprises one or more sheets of densified plant material, the cellulose-based cavities of the plant material's natural microstructure being substantially collapsed.

34. The engineering structure of claim 31, wherein: The plant material forming one, some or all of the constituent layers in the second laminate is wood or bamboo.

35. The engineering structure of claim 31, wherein: (a7) the plant material forming one, some or all of the one or more third layers is densified wood or densified bamboo; (a8) the plant material forming one, some or all of the one or more fourth layers is natural wood or natural bamboo; or Both (a7) and (a8).

36. The engineering structure of claim 31, wherein: One of the one or more first layers forms an exposed side of the first flange opposite the web, and / or one of the one or more third layers forms an exposed side of the second flange opposite the web.

37. The engineering structure of claim 31, wherein: (a9) one of the one or more second layers forms an exposed side of the first flange opposite the web, and one of the one or more first layers is arranged within the first flange between the exposed side of the first flange and the web; (a10) one of the one or more fourth layers forms an exposed side of the second flange opposite the web, and one of the one or more third layers is arranged within the second flange between the exposed side of the second flange and the web; or Both (a9) and (b10).

38. The engineering structure of claim 31, wherein: The first value, the second value, or both are 100 MPa.

39. The engineering structure of claim 31, wherein: The mechanical strength of each first layer, the mechanical strength of each third layer, or both are in the range of 100-600 MPa, inclusive.

40. The engineering structure of claim 1, wherein: The first value is 100 MPa.

41. The engineering structure of claim 1, wherein: The first laminate has a first cross-sectional area, and the mechanical strength of the first laminate is greater than the mechanical strength of a laminate structure having the first cross-sectional area and formed using only the one or more second layers and the one or more glues.

42. The engineering structure of claim 1, wherein: The first laminate has a first cross-sectional area and a mechanical strength, and the first cross-sectional area is smaller than a cross-sectional area of ​​a laminate structure having the same mechanical strength and formed using only the one or more second layers and the one or more glues.

43. An engineering structural material, comprising: One or more laminate structures, each laminate structure having a plurality of constituent plant material layers, each plant material layer being coupled to adjacent plant material layers via corresponding one or more adhesives, at least one of the plurality of constituent plant material layers being of density greater than or equal to 1.15 g / cm 3 layer of dense plant material.

44. The engineering structural material according to claim 43, wherein: The densified plant material layer is densified wood or densified bamboo.

45. The engineering structural material according to claim 43, wherein: The dense plant material layer has a thickness greater than or equal to 1.2 g / cm 3 density.

46. ​​The engineering structural material according to claim 43, wherein: The dense plant material layer has a thickness greater than or equal to 1.3 g / cm 3 density.

47. The engineering structural material according to claim 43, wherein: The densified plant material layer comprises one or more sheets of densified wood or densified bamboo, the cellulose-based cavities of the natural microstructure of the wood or bamboo being substantially collapsed.

48. The engineering structural material according to claim 43, wherein: The densified plant material layer comprises at least partially delignified plant material or lignin modified plant material.

49. The engineering structural material according to claim 43, wherein: The one or more glues include epoxy resin, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination thereof.

50. The engineering structural material of claim 43, wherein: The one or more laminate structures are formed as part of a cross laminated timber (CLT) structure, a glue laminated timber (glulam) structure, a laminated veneer lumber (LVL) structure, an oriented strand board (OSB) structure or an I-beam structure.

51. The engineering structural material of claim 43, wherein: Each of the plurality of constituent plant material layers has a density of less than 1.15 g / cm 3 A layer of non-densified plant material or a density of at least 1.15 g / cm 3 layer of dense plant material.

52. The engineering structural material of claim 43, wherein: Each of the plurality of constituent plant material layers has a density of less than 1.15 g / cm 3 A layer of natural plant material or a density of at least 1.15 g / cm 3 layer of dense plant material.

53. A method comprising: One or more first layers are provided, each first layer comprising a density greater than or equal to 1.15 g / cm 3 and a dense plant material having a mechanical strength greater than or equal to a first value; One or more second layers are provided, each second layer comprising a density less than 1.15 g / cm 3 and the plant material has a mechanical strength less than the first value; and The one or more first layers are coupled to the one or more second layers via respective one or more glues so as to form a laminate.

54. The method of claim 53, wherein: (b1) one, some or all of the plant materials of the one or more first layers comprise densified wood or densified bamboo; (b2) one, some or all of the plant materials of the one or more second layers comprise non-densified wood or non-densified bamboo; or Both (b1) and (b2).

55. The method of claim 53, wherein: (b3) one, some or all of the plant materials of the one or more first layers comprise densified wood or densified bamboo; (b4) one, some or all of the plant materials of the one or more second layers comprise natural wood or natural bamboo; or Both (b3) and (b4).

56. The method of claim 53, wherein: The density of one, some or all of the one or more first layers is greater than or equal to 1.2 g / cm 3 ; The density of one, some or all of the one or more first layers is greater than or equal to 1.3 g / cm 3 ; The density of one, some or all of the one or more second layers is less than or equal to 1.0 g / cm 3 ; The density of one, some or all of the one or more second layers is less than or equal to 0.9 g / cm 3 ;or Any combination of the foregoing.

57. The method of claim 53, wherein: Providing the one or more first layers comprises: chemically treating one or more pieces of natural plant material having native lignin therein so as to damage the native lignin, thereby forming one or more pieces of lignin-damaged plant material; and compressing said one or more pieces of lignin-damaged plant material to form said one or more first layers of said densified plant material, Wherein, the density of the densified plant material after the compression is greater than the density of the natural plant material before the chemical treatment.

58. The method of claim 57, wherein: The compressing is performed in a direction intersecting a longitudinal growth direction of the one or more pieces of lignin-damaged plant material.

59. The method of claim 57, wherein: The compressing comprises pressing the one or more pieces of lignin-damaged plant material at a pressure of at least 1 MPa.

60. The method of claim 57, wherein: The compressing comprises pressing the one or more pieces of lignin-damaged plant material at a pressure within the range of 5-20 MPa, inclusive.

61. The method of claim 57, wherein: The compressing comprises pressing the one or more pieces of lignin-damaged plant material while being subjected to a temperature of at least 50°C.

62. The method of claim 57, wherein: The compressing comprises pressing the one or more pieces of lignin-damaged plant material while being subjected to a temperature in the range of 80-180°C.

63. The method of claim 57, wherein: After the subjecting, the one or more pieces of lignin-damaged plant materials have modified lignin, and the macromolecular chains of the modified lignin are shorter than the macromolecular chains of the natural lignin in the piece of natural plant material.

64. The method of claim 63, wherein: Carrying out the chemical treatment comprises: infiltrating the one or more pieces of natural plant material with one or more chemical solutions; and Subsequent to said infiltrating, said one or more pieces of natural plant material having said one or more chemical solutions therein are subjected to a first temperature of at least 80° C. for a first time to form said one or more pieces of lignin-damaged plant material.

65. The method of claim 64, wherein: The one or more chemical solutions include p-toluenesulfonic acid, NaOH, NaOH+Na2SO3 / Na2SO4, NaOH+Na2S, NaHSO3+SO2+H2O, NaHSO3+Na2SO3, NaOH+Na2SO3, NaOH / NaH2O3+AQ, NaOH / Na2S+AQ, NaOH+Na2SO3+AQ, Na2SO3+NaOH+CH3OH+AQ, NaHSO3+SO2+AQ, NaOH+Na2Sx, wherein AQ is anthraquinone, any one of the foregoing or any combination of the foregoing when LiOH or KOH is used instead of NaOH.

66. The method of claim 64, wherein: The first temperature is within the range of 120-160°C and inclusive; and / or The first time is in the range of 1-5 hours, inclusive.

67. The method of claim 64, wherein: At least 90% of the one or more chemical solutions infiltrated into the one or more pieces of natural plant material are consumed by subjecting the one or more pieces of natural plant material to the first temperature for the first time.

68. The method of claim 64, wherein: Subjecting the first temperature for the first time includes heating the one or more pieces of natural plant material having the one or more chemical solutions therein using steam.

69. The method of claim 64, wherein: After being subjected to the first temperature for the first time: (b5) the content of modified lignin in the one or more pieces of lignin-damaged plant materials is at least 90% of the content of the natural lignin in the one or more pieces of natural plant materials on a weight basis; (b6) the content of modified lignin in the one or more pieces of lignin-damaged plant material is at least 20% on a weight basis; or Both (b5) and (b6).

70. The method of claim 64, wherein: After subjecting to the first temperature and for the first time, a salt of an alkaline chemical is fixed within the cellulose-based microstructure of the one or more pieces of lignin-damaged plant material.

71. The method of claim 70, wherein: The salt is substantially pH neutral.

72. The method of claim 70, wherein: The salt is formed by reaction of the one or more chemical solutions with acidic degradation products of native hemicellulose in the one or more pieces of natural plant material resulting from the one or more chemical solutions.

73. The method of claim 57, wherein: After the chemical treatment, the one or more pieces of lignin-damaged plant material are at least partially delignified.

74. The method of claim 73, wherein: Performing the chemical treatment includes partially or completely immersing the one or more pieces of natural plant material in one or more chemical solutions at a second temperature and for a second time to remove at least some lignin from the one or more pieces of natural plant material.

75. The method of claim 74, wherein: The one or more chemical solutions include an alkaline solution.

76. The method of claim 74, wherein: The one or more chemical solutions include sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), sodium sulfite (Na2SO3), sodium sulfate (Na2SO4), sodium sulfide (Na2S), Na n S (where n is an integer), urea (CH4N2O), sodium bisulfite (NaHSO3), NaH2O3, sulfur dioxide (SO2), anthraquinone (C 14 H8O2), methanol (CH3OH), ethanol (C2H5OH), butanol (C4H9OH), formic acid (CH2O2), hydrogen peroxide (H2O2), acetic acid (CH3COOH), butyric acid (C4H8O2), peroxyformic acid (CH2O3), peracetic acid (C2H4O3), ammonia (NH3), toluenesulfonic acid (p-TsOH), sodium hypochlorite (NaClO), sodium chlorite (NaClO2), chlorine dioxide (ClO2), chlorine (Cl2), water (H2O) or any combination of the foregoing.

77. The method of claim 74, wherein: The one or more chemical solutions include a boiling mixture of NaOH and Na2SO3.

78. The method of claim 74, wherein: (b7) the second temperature is in the range of 100-160° C. and including the end values; (b8) the second time is in the range of 0.1 to 96 hours, inclusive; or Both (b7) and (b8).

79. The method of claim 74, wherein: The one or more pieces of lignin-damaged plant material have a lignin content between 5% and 95% of the lignin content of the native plant material, inclusive.

80. The method of claim 74, wherein: The natural plant material is hardwood or bamboo, and the lignin-damaged plant material has a lignin content between 0.9% and 23.8% on a weight basis, inclusive; or The natural plant material is softwood, and the lignin-damaged plant material has a lignin content of between 1.25% and 33.25% on a weight percent basis, inclusive.

81. The method of claim 74, wherein: The lignin-damaged plant material has a lignin content of at least 10% on a weight basis.

82. The method of claim 53, wherein: (b9) each first layer consists essentially of dense plant material; (b10) each second layer consists essentially of non-densified or natural plant material; or Both (b9) and (b10).

83. The method of claim 53, wherein: The corresponding one or more glues include epoxy resin, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, sodium carboxymethyl cellulose (CMC) or any combination thereof.

84. The method of claim 53, wherein: The first layer and the second layer are coupled in the form of a reinforced cross-laminated timber structure, a reinforced glue-laminated structure, a reinforced laminated veneer structure, an oriented strand board structure, an I-beam structure, or a portion of any of the foregoing structures.

85. The method of claim 53, wherein: One, some or all of the one or more second layers comprise non-densified plant material.

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