Reinforced engineered structural materials and methods for their manufacture and use

Abstract

The engineered structure can include a first laminate having a plurality of constituent plant material layers. The plurality of constituent plant material layers can include one or more first layers and one or more second layers. Each constituent plant material layer can be bonded to an adjacent constituent plant material layer via an adhesive. Each first layer can have a density of 1.15 g / cm. 3 Each second layer may be a densified plant material layer having a density and a first mechanical strength of 1.15 g / cm or more. 3 The constituent plant material layers may have a density less than 100 Å and a second mechanical strength less than the first mechanical strength. For example, the plant material of each layer may be wood or bamboo.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 399,795, filed August 22, 2022, entitled "Reinforced Engineered Structural Materials and Methods of Manufacturing and Uses Thereof," the entire contents of which are incorporated herein by reference.

[0002] (Statement Regarding Federally Sponsored Research) This invention was made with United States government support under DEAR0001025 awarded by the U.S. Department of Energy Advanced Research Projects Agency-Energy (DOE ARPA-E). The United States government has certain rights in this invention.

[0003] (Technical field) The present disclosure relates generally to engineered structural materials, and more particularly to strength-enhanced structures using plant materials (e.g., wood, bamboo, etc.), such as, but not limited to, cross-laminated timber (CLT), glued laminated lumber (glulam), laminated veneer lumber (LVL), oriented strand board (OSB), and / or oriented structural straw board (OSSB). [Background technology]

[0004] Engineered wood is attractive for replacing CO2-intensive building materials (e.g., concrete, steel, ceramics, etc.) to achieve carbon dioxide-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 referred to as mass timber) that can replace concrete in buildings in weight and part of its carbon footprint. While CLT typically possess sufficient strength, they lack the stiffness to match the span of reinforced concrete slabs, thereby requiring thicker floor systems and more closely spaced columns compared to their concrete counterparts, which in turn increases construction costs. Summary of the Invention [Problem to be solved by the invention]

[0005] Embodiments of the disclosed subject matter may address, among other things, one or more of the problems and shortcomings set forth above. [Means for solving the problem]

[0006] Embodiments of the system of the disclosed subject matter provide engineered structural materials with enhanced mechanical strength. In some embodiments, the engineered structural materials include multiple plant material layers (e.g., including one or more pieces of plant material) that are glued, adhered, bonded, or otherwise joined together to form a laminate. At least one of the plant material layers in the laminate may be a densified plant material layer (e.g., including one or more pieces of densified plant material), e.g., having a density of at least 1.15 g / cm 3 The native cellulosic microstructure may be compressed to collapse the lumens of the native cellulosic microstructure so as to have a high density of about 1000 MPa (0.01 MPa). In some embodiments, the densified plant material layer can be formed from lignin-impaired material, such as in situ lignin-modified plant material or partially delignified plant material. In some embodiments, the densified plant material layer can strengthen 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.

[0007] In one or more embodiments, the engineered structure can include a first laminate. The first laminate can include a plurality of constituent plant material layers. The plurality of constituent plant material layers can include one or more first layers and one or more second layers. Each plant material layer can be adhered to an adjacent plant material layer via one or more respective adhesives. Each first plant material layer can have a density of 1.15 g / cm 3Each second plant material layer may have a density of 1.15 g / cm or greater and a mechanical strength of 1.15 g / cm or greater. 3 The plant material layer may have a density less than a first value and a mechanical strength less than a second value.

[0008] In one or more embodiments, the engineered structural material can include one or more laminate structures. Each laminate structure can have a plurality of constituent plant material layers. Each plant material layer can be bonded to an adjacent plant material layer via one or more respective adhesives. At least one of the plurality of constituent plant material layers can have a viscosity of 1.15 g / cm. 3 The layer may be a densified plant material layer having a density equal to or greater than 1000 sq m.

[0009] In one or more embodiments, the method can include providing one or more first layers, each of which has a density of 1.15 g / cm 3 The method may include providing one or more second layers, each of the second layers having a density of 1.15 g / cm or greater and a mechanical strength of 1.15 g / cm or greater. 3 The plant material may include a plant material having a density less than a first value and a mechanical strength less than a first value. The method may also include bonding the one or more first layers to the one or more second layers via one or more respective adhesives to form a laminate.

[0010] Any of the various innovations of the present disclosure can be used in combination or separately. This Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detailed Description below. This Summary is not intended to identify 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 objects, features, and advantages of the disclosed technology will become more apparent from the following Detailed Description, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0011] Embodiments will now be described 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 explain the underlying features. Like reference numerals refer to like elements throughout the drawings. [Figures 1A-1G] 1A-1G are simplified schematic illustrations of various strength-enhanced engineered structures formed from one or more plant materials, in accordance with one or more embodiments of the disclosed subject matter. [Figure 2A-2B] 2A-2B are partial isometric views of a strength-reinforced cross-laminated timber (CLT) structure in accordance with one or more embodiments of the disclosed subject matter. [Figures 3A-3D] 3A-3D are partial isometric views of various strength-reinforced adhesive laminate (glulam) structures in accordance with one or more embodiments of the disclosed subject matter. [Figures 4A-4D] 4A-4D are partial isometric views of various strength-reinforced laminated veneer lumber (LVL) structures in accordance with one or more embodiments of the disclosed subject matter. [Figures 5A-5E] 5A-5E illustrate various strength-enhanced I-joist structures in accordance with one or more embodiments of the disclosed subject matter. [Figure 6] FIG. 6 is a simplified process flow diagram for fabricating strength-enhanced engineered structures from one or more plant materials in accordance with one or more embodiments of the disclosed subject matter. DETAILED DESCRIPTION OF THE INVENTION

[0012] General Considerations For purposes of this specification, certain aspects, advantages, and novel features of the disclosed embodiments are described herein. The disclosed methods and systems should not be construed as limiting in any way. Instead, the present disclosure covers all novel and non-obvious features and aspects of the various disclosed embodiments, alone and in various combinations and subcombinations with each other. The methods and systems are not limited to any particular aspect, feature, or combination thereof, and the disclosed embodiments do not require that any one or more particular advantages be present or problems be solved. Techniques from any embodiment or example can be combined with techniques described in any one or more of the other embodiments or examples. Given the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are illustrative only and should not be construed as limiting the scope of the disclosed technology.

[0013] Although some operations of the disclosed methods are described in a particular order for convenient presentation, it should be understood that this description encompasses reordering unless a specific ordering is required by specific language described below. For example, operations described sequentially may in some cases be reordered or performed simultaneously. Moreover, for simplicity, the accompanying drawings may not show the various ways in which the disclosed methods may be used in conjunction with other methods. Furthermore, the description may use terms such as "provide" or "achieve" to describe the disclosed methods. These terms are high-level abstractions of the actual operations that are performed. The actual operations corresponding to these terms may vary depending on the particular implementation and are readily discernible by those skilled in the art.

[0014] The disclosure of a numerical range should be understood to refer to each discrete point within the range, including the endpoints, unless otherwise specified. Unless otherwise indicated, all numbers expressing amounts of ingredients, molecular weights, percentages, temperatures, times, etc., used in this specification or claims should be understood to be modified by the term "about." Thus, unless otherwise implicitly or explicitly indicated, or unless the context would be understood by one of ordinary skill in the art to have a clearer configuration, the numerical parameters described are approximations that may depend on the desired properties sought and / or the limits of detection under standard testing conditions / methods, as known to those skilled in the art. To directly and explicitly distinguish the embodiments from the discussed prior art, the numbers in the embodiments are not approximations unless the words "about," "substantially," or "approximately" are recited. Whenever "substantially," "approximately," "about," or similar language is expressly used in conjunction with a particular value, a variation of up to 10% of that value is intended, unless expressly stated otherwise.

[0015] Directions and other relative references may be used to facilitate explanation of the figures and principles herein but are not intended to be limiting. For example, specific terms such as "inside," "outside," "up," "down," "top," "bottom," "internal," "external," "left," "right," "front," "rear," "rear side," and the like may be used. Such terms are used, where applicable, to provide some clarity of description when dealing with 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, with respect to an object, an "upper" portion may become a "lower" portion simply by flipping the object over. Nevertheless, it is still the same portion, and the object remains the same.

[0016] As used herein, "comprising" means "including," and the singular forms "a" or "an" or "the" include plural references unless the context clearly dictates otherwise. The term "or" refers to a single element or a combination of two or more of the referenced alternative elements, unless the context clearly dictates otherwise.

[0017] Although there are alternatives for the various components, parameters, operating conditions, etc. described herein, these alternatives are not necessarily equivalent and / or perform equally well. Nor are the alternatives listed in order of preference unless otherwise specified. Unless otherwise specified, any of the groups defined below can be substituted or unsubstituted.

[0018] Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. The materials, methods, and examples are illustrative only and are not intended to be limiting. Features of the subject matter of this disclosure will become apparent from the following detailed description and the appended claims.

[0019] Terminology Overview The following is provided to facilitate a description of various aspects of the disclosed subject matter and to guide those of ordinary skill in the art in practicing the disclosed subject matter.

[0020] Plant material: A portion (e.g., a section or portion, by mechanical or other means) of any photosynthetic eukaryote of the kingdom Plantae, in its natural, as-grown state. In some embodiments, the plant material is wood (e.g., hardwood or softwood), bamboo (any of the Bambusaceae family, for example, Moso bamboo, Phyllostachys vivax, Phyllostachys viridis, Phyllostachys bambusoides, and Phyllostachys nigra, but not limited to Kora et al.), reed (e.g., common reed (Phragmites australis), Danchiku (Arundo donax), Burmese reed (Neyraudia reynaudiana), Phalaris arundinacea, reed sweetgrass (Glyceria maxima), small reed (Calamagrostis), paper reed (Cyperus papyrus), Japanese chestnut (Sparganium species), cattail (Typha species), Cape thatched reed (Elegia tectorum), and Cape thatched reed (Thamnochrtus insignis) ching), or Poaceae (e.g., a species selected from the Poales or Poaceae family). For example, the plant material can be any type of hardwood (e.g., having a natural lignin content ranging from 18 to 25% by weight) or softwood (e.g., having a natural lignin content ranging from 25 to 35% by weight), including, but not limited to, basswood, oak, poplar, ash, alder, aspen, balsa, beech, birch, cherry, butternut, chestnut, cobolo, elm, hickory, maple, oak, padauk, plum, walnut, willow, yellow poplar, bald cypress, cedar, cypress, Douglas-fir, fir, hemlock, larch, pine, redwood, spruce, tamarack, juniper, and yew. Alternatively, in some embodiments, the plant material can be any type of fibrous plant composed of lignin, hemicellulose, and cellulose.For example, the plant material can be bagasse (e.g., formed from the processing residues of sugarcane or sorghum stalks) or straw (e.g., formed from the processing residues of cereal plants such as rice, wheat, millet, or corn).

[0021] Engineered Structure or Engineered Structural Material: A structure formed from multiple pieces or layers of natural or modified plant material bonded together using adhesives or other bonding agents to form a structure with improved strength and / or durability. Examples of such structures / materials include, but are not limited to, cross-laminated lumber (CLT), glue-laminated lumber (glulam), laminated veneer lumber (LVL), oriented strand board (OSB), and / or oriented structural straw board (OSSB).

[0022] Lignin-impaired 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-impaired plant material can substantially retain the native microstructure of the native plant material formed by the cellulosic cell walls.

[0023] Partial delignification: The removal of some (e.g., at least 1%), but not all (e.g., 90% or less) of the native lignin from the native plant material (e.g., on a weight percent basis). In some embodiments, partial delignification can be carried out by subjecting the native 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 to 23.8 weight percent for hardwoods or 1.25 to 33.25 weight percent for softwoods. The lignin content within the plant material before and after partial delignification can be assessed using techniques known in the art, such as Laboratory Analytical Procedure (LAP) TP-510-42618, Version 08-03-2012, for "Determination of Structural Carbohydrates and Lignin in Biomass," published by the National Renewable Energy Laboratory (NREL), and ASTM E1758-01(2020), published by ASTM International as "Standard Test Method for Acid-Insoluble Lignin in Wood," both of which are incorporated herein by reference. In some embodiments, partial delignification processes are described, for example, in U.S. Patent Application Publication No. 2020 / 0223091, published July 16, 2020, entitled "Structural Wood Materials, Manufacturing Methods Thereof, and Uses Thereof," and U.S. Patent Application Publication No. 2022 / 0412002, published December 29, 2022, entitled "Bamboo Structures, Manufacturing Methods Thereof, and Uses Thereof," which delignification and densification processes are incorporated herein by reference.

[0024] Complete delignification: The removal of substantially all (e.g., 90-100%) of native lignin from naturally occurring plant material. In some embodiments, complete delignification can be carried out by subjecting the native plant material to one or more chemical treatments. The lignin content within the plant material before and after complete delignification can be assessed using the same or similar techniques as those described above for partial delignification. In some embodiments, the complete delignification process can be, for example, as described in U.S. Patent Application Publication No. 20200238565, entitled "Delignified Wood Material and Methods for Making and Using the Same," published July 30, 2020, which delignification process is incorporated herein by reference.

[0025] Lignin modification: The in situ modification of one or more properties of native lignin in a native plant material without removing the modified lignin from the plant material. In some embodiments, the lignin content of the plant material before and after in situ modification can be substantially the same, e.g., such that the in situ modified plant material retains at least 95% of the native lignin content (e.g., removing 1% or less, or 0.5% or less of the native lignin content). In some embodiments, the plant material is treated with hydroxylase (e.g., OH) to depolymerize the lignin. -The depolymerized lignin can be modified in situ (by chemical reaction with lignin), and the depolymerized lignin is retained within the plant material microstructure. The lignin content within 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, version 08-03-2012, for "Determination of Structural Carbohydrates and Lignin in Biomass," published by the National Renewable Energy Laboratory (NREL), ASTM E1758-01 (2020), published by ASTM International as "Standard Test Method for Acid-Insoluble Lignin in Wood," and / or TAPPI Standard T 222-om-83, published as "Standard Test Method for Acid-Insoluble Lignin in Wood," all of which are incorporated herein by reference. In some embodiments, the lignin modification process is described, for example, in International Publication No. WO 2023 / 028356, published March 2, 2023, entitled "Waste-Free Process for Lignin Modification of Fibrous Plant Material, and Lignin-Modified Fibrous Plant Material," which lignin modification process is incorporated herein by reference.

[0026] Densified plant material or densified wood: Plant material (e.g., wood) that has been compressed to have a reduced thickness. In some embodiments, the thickness is reduced by at least three times. In some embodiments, densified plant material (e.g., wood) has a density higher than that of the natural plant material, e.g., at least 1.15 g / cm. 3 , e.g., at least 1.2 g / cm 3 , or even at least 1.3 g / cm 3 (e.g., 1.4 to 1.5 g / cm 3For example, but not by way of limitation, densified plant material can be formed as described in U.S. Pat. No. 11,130,256, issued September 28, 2021, entitled "Strong Structural Wood and Methods for Manufacturing and Using the Same," and International Publication No. WO 2021 / 108576, published June 3, 2021, entitled "Bamboo Structures and Methods for Manufacturing and Using the Same."

[0027] Non-densified plant material or non-densified wood: Plant material (e.g., wood) that substantially retains its natural density. In some embodiments, non-densified plant material (e.g., wood) has a density of, for example, 1.15 g / cm 3 Less than, for example, 1.0 g / cm 3 Less than or equal to 0.9 g / cm 3 (e.g., 0.1 to 0.9 g / cm 3 In some embodiments, the lumens of the cellulosic microstructure of the non-densified plant material can remain substantially open, at least prior to being contained within the engineered structure.

[0028] Longitudinal growth direction: The direction in which a plant grows from its roots or stem, and in which cellulose fibers form the plant's cell walls and are generally aligned with the longitudinal growth direction. In some cases, the longitudinal growth direction may be generally vertical or correspond to the direction of the water transpiration flow. This is in contrast to the radial direction, which extends outward from the center of the plant and may be approximately horizontal.

[0029] Introduction Disclosed herein are engineered structural materials formed from one or more plant materials. In some embodiments, the engineered structural materials can have enhanced mechanical strength, for example, compared to existing engineered structural materials (e.g., formed from natural or undensified wood alone). As a result of the enhanced strength (e.g., stiffness, tensile strength, compressive strength, etc.), the engineered structural materials can be fabricated with smaller cross-sections (e.g., compared to existing engineered structural materials) for specific applications (e.g., requiring a specific strength rating). Alternatively, in some embodiments, as a result of the enhanced strength, engineered structural materials having the same cross-section can be used in more demanding applications (e.g., compared to existing engineered structural materials), for example, by spanning longer distances. Alternatively or additionally, in some embodiments, the size and / or strength of the engineered structural material can be custom-designed for a specific application by including an appropriate number and / or arrangement of densified plant material layers in the engineered structural material.

[0030] In some embodiments, the engineered structural material comprises a laminated structure having multiple constituent plant material layers bonded, adhered, or otherwise joined together via an adhesive, at least one of the layers having a viscosity of, for example, at least 1.15 g / cm 3 (e.g., ≥ 1.2 g / cm 3 or ≥ 1.3 g / cm 3 , for example, 1.4 to 1.5 g / cm 3 In some embodiments, one, some, or all of the other layers of the laminated structure have a density of, for example, 1.15 g / cm 3 Less than (e.g., ≦1.0 g / cm 3 or ≦0.9g / cm 3 , for example, 0.1 to 0.9 g / cm 3In some embodiments, the non-densified plant material layer can be formed from natural plant material (e.g., without compression). Alternatively or additionally, in some embodiments, one or all of the other layers of the laminate can be a densified plant material layer (e.g., before being included in the laminate or after being included in the laminate), but with a densified density of, for example, 1.15 g / cm or less. 3 The densification strength of a densified plant material layer can be greater than that of a densified plant material layer, so that the densification strength remains less than 100 MPa (e.g., 15-65 MPa). In the following description, reference to a non-densified plant material layer is intended to include such a de-densified plant material layer. In some embodiments, a densified plant material layer can have a mechanical strength greater than the mechanical strength of other plant material layers (e.g., non-densified or de-densified). For example, each densified plant material layer can have a strength of at least 100 MPa (e.g., 100-600 MPa), while each non-densified plant material layer can have a strength of less than 100 MPa (e.g., 15-65 MPa).

[0031] A laminated structure can have any number of plant material layers. For example, FIG. 1A shows a laminated structure 100 having a pair of plant material layers, specifically a densified plant material layer 102 bonded to a non-densified plant material layer 106 via an intervening adhesive layer 104. For example, adhesive layer 104 can include any type of adhesive, such as, but not limited to, epoxy, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, and / or sodium carboxymethyl cellulose (CMC). Alternatively or additionally, in some embodiments, one, some, or all of the plant material layers comprising the laminated structure can be formed from multiple pieces of plant material.

[0032] In some embodiments, at least one of the densified plant material layers can be positioned within the laminated structure at a location that will experience stresses exceeding a predetermined threshold and / or maximum stress. In some embodiments, the densified plant material layer can be used as the outermost layer of the laminated structure in cross-section, as shown, for example, in FIG. 1B . In the illustrated example of FIG. 1B , the laminated structure 110 has three plant material layers: a pair of densified plant material layers 102a, 102b bonded to either side of a centrally located, non-densified plant material layer 106 via respective intervening adhesive layers 104a, 104b. Alternatively or additionally, the densified plant material layer can be positioned anywhere within the laminated structure. For example, as shown in FIG. 1C , the densified plant material layer can be used as the interior or central layer of the laminated structure in cross-section. In the example shown in FIG. 1C, the laminated structure 120 has three plant material layers, namely a pair of non-densified plant material layers 106a, 106b bonded to a centrally located densified plant material layer 102 via respective intervening adhesive layers 104a, 104b.

[0033] While Figures 1A-1C depict a single densified or non-densified plant material layer, embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, multiple densified and non-densified plant material layers can be provided together in a single laminated structure. For example, Figure 1D shows a laminated structure 130 having more than three plant material layers. In the illustrated example, the laminated structure 130 has a stack 132 of three non-densified plant material layers 106a-106c bonded to one another via intervening adhesive layers 108a, 108b (which may be the same or a different formulation as adhesive layers 104a, 104b). Other numbers of layers for the stack 132, such as three, five, or seven layers for a CLT structure or 12-15 layers for an LVL structure, are also possible according to one or more contemplated embodiments. 1B , laminated structure 130 has a pair of densified plant material layers 102a, 102b bonded to a centrally located stack 132 via respective intervening adhesive layers 104a, 104b. In some embodiments, stack 132 can be a conventional engineered structure (e.g., CLT, glulam, LVL, OSB, etc.), and the pair of densified plant material layers 102a, 102b can serve to reinforce or reinforce the strength of stack 132.

[0034] 1A-1D , the sides of the non-densified plant material layer may be exposed. However, in some embodiments, a densified plant material layer may also be provided on one, some, or all of these exposed surfaces, e.g., to contain, bond, or otherwise encapsulate the non-densified plant material layer within a surrounding structure formed by the densified plant material layer. In some embodiments, providing a densified plant material layer to encapsulate the non-densified plant material layer can form a column or beam with improved aesthetics (e.g., a more desirable appearance due to the densified layer compared to the non-densified layer), improved durability (e.g., due to greater fire and / or weather resistance of the densified layer compared to the non-densified layer), and / or installation flexibility (e.g., providing enhanced strength regardless of orientation). For example, Figure 1E shows a laminated structure 140 in which a stack 132 of undensified plant material layers 106a is capped on its left and right sides by densified plant material layers 102c, 102d and corresponding adhesive layers 142a, 142b (which may have the same or different formulation and / or thickness as adhesive layers 108a, 108b and / or adhesive layers 104a, 104b). Similar to Figure 1D, the top and bottom sides of the stack 132 of the laminated structure 140 are capped by densified plant material layers 102a, 102b, thereby enclosing the stack 132 within the circumferential peripheral wall formed by densified plant material layers 102a-102d.

[0035] While Figures 1D-1E show non-densified plant material layers arranged in a laminate along the thickness direction of the laminate structure, embodiments of the disclosed subject matter are not limited in this regard. Rather, in some embodiments, non-densified plant material layers can be stacked across the width and / or length of the laminate structure. For example, Figure 1F shows a laminate structure 150 having a lateral stack 152 of three non-densified plant material layers 106a-106c arranged along the width direction and bonded to one another via intervening layers 108a, 108b (which may be of the same or different composition and / or thickness as adhesive layers 104a, 104b). As shown in Figure 1F, the height of each non-densified plant material layer 106a-106c can be greater than its width. In another example, Figure 1G shows a laminated structure 160 having a lateral stack of three non-densified plant material layers 162a-162c arranged along the width direction and bonded to one another via intervening adhesive layers 164a, 164b (which may be of the same or different composition and / or thickness as adhesive layers 104a, 104b). As shown in Figure 1G, the height of each non-densified plant material layer 162a-162c can be less than its width. Other sizes and / or numbers of layers for the lateral stack are possible according to one or more contemplated embodiments.

[0036] 1B and 1D , laminated structures 150 and 160 have a pair of densified plant material layers 102 a, 102 b bonded to a centrally located lateral stack via respective intervening adhesive layers 104 a, 104 b. In some embodiments, the lateral stack can be a conventional engineered structure (e.g., CLT, glulam, LVL, OSB, etc.), and the pair of densified plant material layers 102 a, 102 b can serve to reinforce or reinforce the strength of the lateral stack.

[0037] 1A-1G show laminate structures having at least one non-densified plant material layer as described above, embodiments of the disclosed subject matter are not so limited. Rather, in some embodiments, each of the layers of the laminate comprises a densified plant material layer (e.g., each 1.15 g / cm 3In such embodiments, the separate densified plant material layers may be bonded to one another via an intervening adhesive layer (e.g., similar to adhesive layer 104) or otherwise (e.g., without an adhesive and / or by relying on hydrogen bonding between opposing surfaces of the densified plant material layers).

[0038] While FIGS. 1A-1G depict one or two densified plant material layers, embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, three or more densified plant material layers can be included in a laminated structure. For example, in some embodiments, the densified plant material layers can comprise 5-50% of the laminated structure (e.g., based on the number and / or thickness and / or weight of layers), while the remaining 50-95% can comprise non-densified plant material layers. Alternatively, in some embodiments, the densified plant material layers can comprise the majority (e.g., >50%) of the laminated structure, with the remainder formed from non-densified plant material layers. While FIGS. 1A-1G depict densified plant material layers in specific locations (e.g., top, bottom, or middle) of the laminated structure, embodiments of the disclosed subject matter are not limited thereto. Rather, in some embodiments, the densified plant material layers can be located anywhere within the laminated structure, for example, replacing any of the non-densified wood layers shown in FIGS. 1A-1G.

[0039] While Figures 1A-1G show a single piece of plant material in each layer, embodiments of the disclosed subject matter are not so limited. Rather, in some embodiments, multiple plant material pieces can be joined together at adjacent edges (e.g., via mechanical joining techniques such as finger joints and / or adhesives) to form each layer, for example, to extend the width and / or length of the layer. In some embodiments, the plant material in each layer of the laminated structure can be derived from the same plant, or at least the same species. Alternatively, in some embodiments, the plant material for at least one of the layers in the laminated structure can be derived from a different species than the plant material for at least one other layer. Alternatively or additionally, in some embodiments, each of the densified plant material layers can be formed from the same species, and / or each of the non-densified plant material layers can be formed from the same species (which can be the same or different from the densified plant material layer).

[0040] In some embodiments, the plant material layers may be arranged in the laminated structure such that their orientations (e.g., based on their respective longitudinal growth directions) are substantially aligned or parallel. Alternatively, in some embodiments, at least one of the plant material layers may be arranged in the laminated structure such that its orientation is substantially orthogonal to, or at least intersects, the orientation of at least another of the plant material layers. Alternatively or additionally, in some embodiments, each of the densified plant material layers can have a substantially aligned orientation. Alternatively or additionally, each of the non-densified plant material layers can have a substantially aligned, intersecting, or substantially orthogonal orientation (which may be the same as or different from the densified plant material layers). Alternatively or additionally, in some embodiments, one, some, or all of the plant material layers can have a random orientation (e.g., without regard to the orientation of the other plant material layers).

[0041] Although the following sections focus primarily on engineered structural materials formed from wood, embodiments of the disclosed subject matter are not limited thereto. Rather, the teachings of the present disclosure can be readily extended to other plant materials (e.g., bamboo, straw, etc.).

[0042] Examples of engineered wood structures FIG. 2A illustrates a strength-reinforced cross-laminated timber (CLT) structure 200 having a laminated structure (e.g., having a thickness t1 or t2 of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm), e.g., 3 / 8 inch (9.35 mm)) with a stack 202 between outer layers of densified wood panels 204a, 204b. In some embodiments, the stack 202 can be a conventional CLT structure having, for example, three layers (or five, or seven) of wood boards. For example, in cross section perpendicular to their respective longitudinal growth directions, each wood board in 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 strength-reinforced CLT structure 200 can have a length L of at least 6 feet (1.83 m), e.g., about 8 feet (2.43 m). Alternatively or additionally, in some embodiments, the strength-reinforced CLT structure 200 can have a width W of at least 1 foot (0.30 m), e.g., about 2 feet (0.61 m). Alternatively or additionally, in some embodiments, the strength-reinforced CLT structure 200 can have a height H of at least 6 inches (15.2 cm), e.g., about 8 inches (20.3 cm). Other dimensions are possible according to one or more contemplated embodiments. In some embodiments, the wood boards in each layer can be connected to each other, for example, by joining finger joints and / or structural adhesive.

[0043] The stack 202 can be formed by stacking wood boards horizontally at 90-degree angles and gluing them in place. For example, the outermost wood boards 208a, 208b can have orientations 210a, 210b that are substantially aligned with one another, and the central wood board 212 can have an orientation 214 that is orthogonal to the orientations 210a, 210b. In the illustrated example, the densified wood panels 204a, 204b can have orientations 206a, 206b that are substantially aligned with one another, as well as the orientation 214 of the central wood board 212. Alternatively, in some embodiments, the orientations 206a, 206b of one or both of the densified wood panels 204a, 204b can be substantially aligned with the orientations 210a, 210b of the outer wood boards 208a, 208b, or can be aligned with none of the orientations 210a, 210b, 214 of the stack 202. In some embodiments, in addition to providing densified wood as the top and bottom layers 204a, 204b, additional densified wood can be provided as side layers 204c, 204d (e.g., with orientation 206d substantially aligned with one another and orientation 214 of central wood board 212) to encapsulate stack 202 (e.g., circumferentially), as shown for CLT structure 220 in FIG. 2B . In some embodiments, using densified wood as the top and bottom tensile layers can improve (e.g., double) the planar bending stiffness of stack 202 and / or increase the spanning capacity of stack 202. Strength-enhanced CLT, such as CLT structure 200 and / or CLT structure 220, can be used in a wide range of applications, such as, but not limited to, flooring, walls, and roofing, for example, to replace reinforced concrete in residential and commercial buildings.

[0044] FIG. 3A illustrates a strength-enhanced glued laminated timber (glulam) structure 300 having a laminated structure with a transverse array 302 of wood layers 308 (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)) between outer layers of densified wood panels 304a, 304b. In some embodiments, the array 302 can be a conventional glulam structure. For example, in cross section perpendicular to their respective longitudinal growth directions, each wood 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). Other dimensions are possible according to one or more contemplated embodiments. In some embodiments, the wood segments of each layer can be connected to each other, for example, by finger joints and / or bonding with a structural adhesive. The array 302 can be formed by arranging and gluing together individual wood layers 308 (and / or their constituent segments) having a substantially aligned orientation 310 (e.g., substantially parallel wood fibers). In some embodiments, in addition to providing densified wood as the top and bottom layers 304a, 304b, additional densified wood can be provided as side layers 304c, 304d to encapsulate the stack 302 (e.g., along the circumferential direction), as shown for example for the glulam structure 350 in FIG. 3D . In the illustrated example of FIGS. 3A and 3D , the densified wood panels 304a-304d can have orientations 306a-306d that are substantially aligned with one another, as well as the orientation 310 of the wood layers 308. Alternatively, in some embodiments, the orientations 306a-306d of one, some, or all of the densified wood panels 304a-304d can be substantially perpendicular to, or at least intersect with, the orientation 310 of the wood layers 308.

[0045] FIG. 3B illustrates another strength-enhanced glulam structure 320 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 densified wood panels 324a, 324b. Similar to the structure of FIG. 3B, the array 322 can be a conventional glulam structure, for example, with each wood panel of the array 322 having 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). Other dimensions are possible according to one or more contemplated embodiments. In some embodiments, the wood segments of each layer can be connected to each other, for example, by finger joints and / or bonding with a structural adhesive. The array 322 can be formed by arranging and gluing together individual wood layers 328 (and / or their constituent segments) having a substantially aligned orientation 330 (e.g., substantially parallel wood fibers). In the illustrated example, the densified wood panels 324a, 324b can have orientations 326a, 326b that are substantially aligned with one another, as well as with the orientation 330 of the wood layer 328. Alternatively, in some embodiments, the orientations 326a, 326b of one or both of the densified wood panels 324a, 324b can be substantially perpendicular to, or at least intersect with, the orientation 330 of the wood layer 328.

[0046] FIG. 3C illustrates another strength-enhanced glulam structure 340 that uses a vertical array 322 of wood layers 328 between outer layers 324a, 324b of densified wood segments. The top layer 324a can be formed by multiple densified wood segments 342a-342c, and the bottom layer 324b can be formed by multiple densified wood segments 344a-344c. Similarly, each wood layer 328 in the vertical array 322 can be formed by multiple wood segments 346a-346d (which can be offset from one another along the length direction L and / or width direction W). In some embodiments, the wood segments within each layer 324a, 324b, 328 can be connected to one another by, for example, finger joints and / or structural adhesive bonding. In some embodiments, using multiple wood segments in each layer allows the glulam structure 340 to be formed to any length without limit. In the illustrated example, each top densified wood segment 342a-342c can be substantially aligned (e.g., along the length direction L and / or width direction W) with a corresponding one of the bottom densified wood segments 344a-344c. Alternatively, in some embodiments, the top and bottom densified wood segments can be offset from one another (e.g., in a manner similar to wood segments 346a-346d comprising wood layer 328 of array 322), e.g., to further enhance mechanical rigidity.

[0047] FIG. 4A illustrates a strength-enhanced laminated lumber (LVL) structure 400 having a laminated structure comprising a stack 402 of wood veneers 408 (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)) between outer layers of densified wood panels 404a, 404b. Alternatively, in some embodiments, one or more densified wood panels may be provided as part of the stack 402, e.g., instead of or in addition to one or more densified wood panels 404a, 404b. In some embodiments, the stack 402 may be a conventional LVL structure. For example, in a cross section perpendicular to their respective longitudinal growth directions, each wood veneer 408 of the stack 402 may have a thickness of 2.5 to 4.8 mm. Other dimensions are possible according to one or more contemplated embodiments. The LVL stack 402 may be fabricated, for example, by rotating the veneers (e.g., using a peeling lathe) and gluing them together (e.g., while pressing). The veneers can be assembled along their length (e.g., with orientation 410 substantially aligned). In the illustrated example, densified wood panels 404a, 404b can have orientations 406a, 406b that are substantially aligned with one another, as well as with the orientation 410 of the wood veneer 408. Alternatively, in some embodiments, the orientation 406a, 406b of one or both of densified wood panels 404a, 404b can be substantially perpendicular to, or at least intersect with, the orientation 410 of the wood veneer 408. In some embodiments, the load 412 can be applied substantially parallel to the width of the strength-reinforced LVL structure 400 and / or substantially perpendicular to the direction in which the veneers 408 are stacked (e.g., along the height of the stack 402).

[0048] FIG. 4B shows another strength-enhanced LVL structure 420 that uses a stack 422 of wood veneers 408 between outer layers 404a, 404b of densified wood segments. The top layer 404a can be formed by multiple densified wood segments 424a-424c, and the bottom layer 404b can be formed by multiple densified wood segments 444a-444c. In some embodiments, the wood segments within each layer 404a, 404b can be connected to each other, for example, by finger joints and / or bonding with structural adhesive. In the illustrated example, each top densified wood segment 424a-424c can be substantially aligned (e.g., along the length direction L and / or width direction W) with a corresponding one of the bottom densified wood segments 444a-444c. Alternatively, in some embodiments, the top and bottom densified wood segments can be offset from each other, for example, to further increase mechanical rigidity.

[0049] FIG. 4C shows another strength-enhanced LVL structure 430 having a laminated structure with a stack 432 of wood veneers 408 (e.g., having a thickness of 3 / 16 inch to 1 / 4 inch (4.76 mm to 6.35 mm)) between outer layers of densified wood panels 404a, 404b. In the illustrated example of FIG. 4C, the densified wood panels 404a, 404b are provided on either side of the stack 432 along a direction substantially perpendicular to the stacking direction. Similar to the structure 400 of FIG. 4A, the stack 432 can be a conventional LVL structure, e.g., each wood veneer 408 of the stack 432 has a thickness of 2.5 to 4.8 mm in a cross section perpendicular to the longitudinal growth direction 410, although other dimensions are possible according to one or more contemplated embodiments. The LVL stack 432 can be manufactured, for example, by rotary peeling and gluing the veneers together (e.g., while pressing). The veneers can be assembled along their length (eg, with orientation 410 substantially aligned).

[0050] In some embodiments, in addition to providing densified wood as the top and bottom layers 404a, 404b, additional densified wood can be provided as side layers 404c, 404d to encapsulate the stack 432 (e.g., circumferentially), as shown for example for the LVL structure 440 in FIG. 4D. In the illustrated example, the densified wood panels 404a-404d can have orientations 406a-406d that are substantially aligned with and parallel to the orientation 410 of the wood veneers 408. Alternatively, in some embodiments, the orientation 406a-406d of one or both of the densified wood panels 404a-404d can be substantially perpendicular to, or at least intersect with, the orientation 410 of the wood veneers 408. In some embodiments, the load 434 can be applied substantially parallel to the width of the strength-enhanced LVL structure 430 or 450 and / or substantially perpendicular to the direction in which the veneers 408 are stacked (e.g., the height of the stack 432). In the illustrated example of Figures 4C-4D, the load 434 can be applied substantially perpendicular to the exposed surfaces of the densified wood panels 404a, 404b.

[0051] In some embodiments, LVL structure 400, LVL structure 420, LVL structure 430, and / or LVL structure 440 can be used as part of another engineered structure, for example, in place of one or both of outermost layers 304a, 304b of glulam structure 300 of FIG. 3A, in place of one or both of outermost layers 324a, 324b of glulam structure 320 of FIG. 3B, in place of one or both of outermost layers 324a, 324b of glulam structure 340 of FIG. 3C, or in place of one, some, or all of outermost layers 304a-304d of glulam structure 350 of FIG. 3D.

[0052] In some embodiments, LVL structure 400, LVL structure 420, LVL structure 430, and / or LVL structure 440 can be used as part of the flanges of an I-joist. For example, FIG. 5A shows a cross section of an I-joist 500 that uses strength-reinforced LVLs for flanges 502a, 502b. In the illustrated example, top flange 502a has an LVL stack 504a disposed between a pair of densified wood layers 506a, 508a, and bottom flange 502b has an LVL stack 504b disposed between a pair of densified wood layers 506b, 508b. A web 512 can be inserted into grooves 510a, 510b of flanges 502a, 502b, respectively, and glued thereto (the adhesive can be the same or a different formulation as that making up the adhesive layer of the flange). For example, the web can be formed from plywood, LVL, oriented strand board (OSB), or other engineered wood structures. After assembly, the I-joist 500 can be end-trimmed and heat-cured or left at room temperature to reach approximately equilibrium moisture content.

[0053] Figure 5B shows another I-joist 520 that uses LVLs for the flanges. Similar to Figure 5A, a web 512 is bonded to each groove 510a, 510b and extends between top and bottom flanges 502a, 502b. However, in contrast to Figure 5A, the flanges use only densified wood as the flange's outermost layer. In the illustrated example, top flange 522a has LVL stack 524a and densified wood layer 506a at the end of LVL stack 524a opposite web 512, and bottom flange 522b has LVL stack 524b and LVL stack 524b opposite web 512.

[0054] In some embodiments, the flanges of an I-joist can be formed of strength-reinforced solid wood instead of LVL. For example, FIG. 5C shows another I-joist 540 that uses strength-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 illustrated example, top flange 542a has solid wood panel 544a and densified wood layer 546a glued to the end of wood panel 544a opposite web 552, and bottom flange 542b has solid wood panel 544b and densified wood layer 546b glued to the end of wood panel 544b. Web 552 can be inserted into grooves 550a, 550b of solid wood panels 544a, 544b, respectively, and glued thereto (the adhesive can be the same or a different formulation as that making up the adhesive layer of the flanges). For example, web 552 may be formed of plywood, LVL, oriented strand board (OSB), or other engineered wood construction. After assembly, I-joist 540 may be end-trimmed and heat-cured or left at room temperature to reach approximately equilibrium moisture content.

[0055] While FIG. 5C illustrates strength enhancement via a single layer of densified wood for each flange of the I-joist, embodiments of the disclosed subject matter are not so limited. Rather, in some embodiments, multiple densified wood layers can be combined with solid wood within each flange. For example, FIG. 5D illustrates a cross section of another I-joist 560. Similar to the I-joist of FIG. 5A, a web 512 is coupled to each groove 510a, 510b and extends between a top flange 562a and a bottom flange 562b. However, in contrast to FIG. 5C, the top flange 562a includes a solid wood panel 564a disposed and bonded between a pair of densified wood layers 506a, 508a, and the bottom flange 562b includes a solid wood planar surface 564b disposed and bonded between a pair of densified wood layers 506b, 508b.

[0056] While the use of densified wood is limited to the flanges of the I-joists in FIGS. 5A-5D , embodiments of the disclosed subject matter are not so limited. Rather, in some embodiments, densified wood can be used as part of the web, for example, to allow for an open structure for the web. For example, FIG. 5E shows a side view of another I-joist 580 having a mesh 584 extending between a top flange 582 a and a bottom flange 582 b. In the illustrated example, densified wood can be used to form the mesh 584 or as part of an engineered wood structure used to form the mesh 584. For example, the mesh 584 can take the form of a truss or other open structure that can otherwise support the loads experienced by the I-joist 580. While the above description of FIGS. 2A-5E focuses on the use of wood, embodiments of the disclosed subject matter are not so limited. Rather, according to one or more contemplated embodiments, any or all of the wood components described above can be replaced with other plant materials.

[0057] Manufacturing method FIG. 6 illustrates an embodiment of a method 600 for creating an engineered structure from one or more pieces of plant material. The method 600 can begin with a processing step 602, in which one or more pieces of natural plant material can be provided. In some embodiments, providing the processing step 602 can include cutting, removing, or otherwise separating the pieces of plant material from a parent plant (e.g., wood, bamboo stalks, etc.). In some embodiments, the cutting can form the natural plant material into a substantially flat, planar structure, with the direction of the cellulose fibers extending parallel to the plane of the structure (e.g., longitudinal cuts or rotary cuts) or perpendicular to the plane of the structure (e.g., radial cuts). Optionally, in some embodiments, the preparing can include pre-processing the pieces of natural plant material, e.g., washing to remove any undesirable material or contamination, in preparation for subsequent processing, forming the natural plant material into a particular shape in preparation for subsequent processing (e.g., slicing into strips), or any combination of the foregoing. For example, in some embodiments, cutting can form the piece(s) of plant material into any one-dimensional (e.g., an elongated structure whose thickness and width are both at least an order of magnitude less than its length), two-dimensional (e.g., a substantially flat, planar structure whose thickness is at least an order of magnitude less than its length and width), or three-dimensional (e.g., a structure whose thickness, width, and length are all within an order of magnitude of each other) structure. In some embodiments, providing treatment step 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 treatment, for example, after the optional pre-press modification of treatment step 617 but before the compression of treatment step 618, or after the compression of treatment step 618 but before the combining of treatment step 626.

[0058] Method 600 may proceed to decision step 604, where it is determined whether the plant material should be subjected to a treatment that damages the lignin. In some embodiments, damaging the lignin may not be desired, for example, if a lower degree of densification is desired for the plant material. In such embodiments, method 600 may proceed directly from decision step 604 to optional treatment step 617. Alternatively, if in situ lignin modification is desired at decision step 604, method 600 may proceed to treatment step 606, where the plant material pieces may be infiltrated with one or more chemical solutions to modify the lignin therein. For example, in some embodiments, infiltration may be performed by immersing the plant material pieces under vacuum in a solution containing one or more chemicals. In some embodiments, the chemical solution may be OH. - ions or else in solution - The chemical solution may include at least one of the chemical components described above that can generate 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 chemicals may include, but are not limited to, p-toluenesulfonic acid, NaOH, NaOH+Na2SO3 / Na2SO4, NaOH+Na2S, NaHSO3+SO2+HO, NaHSO3+Na2SO3, NaOH+Na2SO3, NaOH / NaH2O3+AQ, NaOH / Na2S+AQ, NaOH+Na2SO3+AQ, Na2SO3+NaOH+CH3OH+AQ, NaHSO3+SO2+AQ, NaOH+Na2Sx (where AQ is anthraquinone), any of the above where NaOH is replaced with LiOH or KOH, or any combination of the above. In some embodiments, chemiosmosis can be carried out without heating, for example, at room temperature (20-30°C, e.g., ∼22-23°C). In some embodiments, the chemical solution is not stirred to avoid disruption to the native cellulosic microstructure of the plant material piece(s).

[0059] For example, in some embodiments, 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 subjected to a vacuum. In this way, air can be drawn out of the wood, creating a negative pressure. When the vacuum pump is turned off, the negative pressure within the wood can draw the solution into the wood through the natural channels (e.g., lumens defined by longitudinal cells) within the wood. This process can be repeated more than once (e.g., three times) (e.g., for about two hours) to allow the channels within the wood to fill with the chemical solution. After this process, the moisture content can increase from ~10.2% (e.g., for natural wood) to ~70% or more.

[0060] The method 600 may proceed to a treatment step 608, where modification may be activated by subjecting the infiltrated plant material pieces to an elevated temperature, e.g., greater than 80°C (e.g., 80-180°C, e.g., 120-160°C), thereby resulting in softened plant material pieces (e.g., softened compared to the native plant material piece(s)). In some embodiments, the heating in treatment step 608 may be achieved via steam heating, e.g., via steam generated in a closed reactor, via steam flow in a flow-through reactor, and / or via steam from a superheated steam generator. Alternatively or additionally, in some embodiments, the heating in treatment step 608 may be achieved by dry heating without the separate use of steam, e.g., via conduction and / or radiation of thermal energy from one or more heating elements. In some embodiments, during treatment step 608, the infiltrated plant material pieces may be exposed 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 pieces, thicker pieces requiring longer heating times). In some embodiments, after the first period of time, any steam generated by heating the infiltrated plant material pieces can be released, for example, by opening a pressure relief valve (e.g., a relief valve) on the reactor. For example, in some embodiments, the pressure relief can be effective to remove about 50% of the moisture in the modified plant material piece(s). For example, in some embodiments, the softened plant material pieces can have a moisture content in the range of 30-50% by weight, inclusive.

[0061] From processing step 608, method 600 can proceed to processing step 610, where the plant material pieces can be optionally dried to reduce the moisture content of the plant material pieces, for example, without removing excessive moisture that would cause the plant material pieces to lose their softened properties (e.g., so that the moisture content is about 8-10% by weight or more). In some embodiments, the optional drying in processing step 610 can be effective to reduce the moisture content of the plant material pieces from greater than 30% by weight (e.g., 30-50% by weight), for example, to within a range of 10-20% by weight (e.g., about 15% by weight). While the heating in processing step 608 and / or the drying (e.g., by evaporation) in processing step 610 can remove moisture from the softened plant material pieces, the removed moisture can be substantially free of residual salts and / or chemicals from the in situ lignin modification. Rather, in some embodiments, the chemicals can be substantially consumed by the modification, and the residual salts can be retained within the microstructure of the softened plant material pieces.

[0062] Alternatively, if delignification is desired in determining step 604, method 600 can proceed to treating step 612, where the plant material pieces can be subjected to one or more chemical treatments to remove at least some lignin therefrom, for example, by immersing the plant material pieces (or portions thereof) in a chemical solution associated with the treatment. In some embodiments, each or only some of the chemical treatments can be performed under vacuum to encourage the solution associated with the treatment to fully penetrate the cell walls and lumens of the plant material pieces. Alternatively, in some embodiments, the chemical treatments can be performed under ambient or elevated pressure conditions (e.g., ∼6-8 bar). In some embodiments, each or only some of the chemical treatments can be performed at any temperature between ambient temperature (e.g., ∼23°C) and an elevated temperature at which the solvent associated with the chemical treatment is boiling (e.g., ∼70-160°C). In some embodiments, the solution is not agitated to minimize the amount of disruption to the native cellulosic microstructure of the plant material pieces.

[0063] In some embodiments, the soaking time can range from 0.1 to 96 hours, inclusive, for example, from 1 to 12 hours, inclusive. The amount of soaking time in the solution can be a function of the amount of lignin removed, the type of plant material, the size of the plant material pieces, the temperature of the solution, the treatment pressure, and / or the agitation. For example, less lignin removal, smaller plant material piece size (e.g., cross-sectional thickness), higher solution temperature, higher treatment pressure, and agitation can be associated with shorter soaking times, while more lignin removal, larger plant material piece size, lower solution temperature, lower treatment pressure, and no agitation can be associated with longer soaking times.

[0064] In some embodiments, each chemical treatment of the treatment step 612, or at least one of the chemical treatments described herein, can include leaching, infiltrating, or otherwise exposing the pieces of plant material to one or more first chemical solutions at a first temperature. In some embodiments, the first chemical solution can be an alkaline solution, and the first temperature can be less than 100°C. For example, the first temperature can be between 5 and 95°C, inclusive, such as room temperature (e.g., up to 23°C). Alternatively or additionally, one or more chemical treatments of the treatment step 612 can include partially or fully immersing the pieces of plant material in a second chemical solution at a second temperature higher than the first temperature. Alternatively or additionally, at least one of the chemical treatments can include leaching, infiltrating, or otherwise exposing the plant material to the second chemical solution at the second temperature. In some embodiments, the second chemical solution can be an alkaline solution, and the second temperature can be greater than 100°C. For example, the second temperature can be between 120 and 180°C, such as 160°C. For example, the chemical solution can be raised to 50-180°C for 0.1-10 hours to remove 5-95% of the lignin and hemicellulose from the plant material. In some embodiments, the second chemical solution can be the same solution as the first chemical solution. In such cases, the first chemical solution can be heated from a first temperature to a second temperature while the plant material pieces remain 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 solution for use as the second chemical solution (e.g., by removing the plant material pieces from the first chemical solution and immersing them 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.

[0065] In some embodiments, the chemical treatment solution may be sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), sodium sulfite (NaSO), sodium sulfide (NaS), Na nS (where n is an integer), urea (CH4N2O), sodium sulfite (NaHSO3), sulfur dioxide (SO2), anthraquinone (AQ) (C 14 HO), methanol (CHOH), ethanol (CHOH), butanol (CHOH), formic acid (CHO), hydrogen peroxide (HO), acetic acid (CHCOOH), butyric acid (CHO), peroxyformic acid (CHO), peracetic acid (CHO), ammonia (CH), tosylic acid (p-TsOH), sodium hypochlorite (NaClO), sodium chlorite (NaClO), chlorine dioxide (ClO), chlorine (Cl), or any combination of the foregoing. Exemplary combinations of chemicals for chemical treatment include 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 The chemical solutions may include, but are not limited to, S (n is an integer), Na2SO3 + NaOH + CH3OH + AQ, C2H5OH + NaOH, CH3OH + HCOOH, NH3 + HO, and NaClO2 + acetic acid. For example, the first and second chemical solutions may be ≦2 wt% NaOH and Na2SO3 (e.g., formed by adding H2SO3 acid to NaOH).

[0066] The chemical treatment can be continued (or repeated with subsequent solutions) until the desired reduction in lignin content in the plant material pieces is achieved. In some embodiments, the lignin content can be reduced to between 0.1% (where the lignin content is 0.1% of the original lignin content in the native plant material) and 99% (where the lignin content is 99% of the original lignin content in the native plant material). In some embodiments, the chemical treatment simultaneously reduces the lignin content, e.g., to a similar or lesser extent than the reduction in lignin content. In some embodiments, if the plant material pieces are hardwood, the lignin content after the chemical treatment of treatment step 612 can be at least 10% by weight (e.g., in the range of 10-15% by weight). In some embodiments, if the plant material pieces are softwood, the lignin content after the chemical treatment of treatment step 612 can be at least 12.5% ​​by weight (e.g., in the range of 12.5-17.5% by weight). In some embodiments, when the pieces of plant material are bamboo, the lignin content after chemical treatment in treatment step 612 can be at least 13% by weight (eg, including 13-18% by weight).

[0067] The method 600 can proceed from process step 612 to process step 614, where rinsing can be performed. For example, rinsing can be used to remove residual chemicals or particles resulting from chemical treatment. For example, the delignified plant material pieces can be partially or completely immersed in one or more rinse solutions. The rinse solution can be a solvent, such as, but not limited to, deionized (DI) water, alcohol (e.g., ethanol, methanol, isopropanol, etc.), or any combination of the foregoing. For example, the rinse solution can be formed with equal amounts of water and ethanol. In some embodiments, rinsing can be performed without agitation, for example, to avoid disrupting the microstructure. In some embodiments, rinsing can be repeated multiple times (e.g., at least three times) using a fresh mixture rinse solution for each iteration, or until a substantially neutral pH is measured for the chemically treated plant material pieces.

[0068] Method 600 can proceed to an optional processing step 616, in which the chemically treated plant material pieces can be dried, for example, to a moisture content of less than 15% by weight (e.g., 8-12% by weight). The drying in either processing step 610 or processing step 616 can include any of a conductive, convective, and / or radiative 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 of the foregoing. For example, an air drying step can include naturally drying the treated plant material pieces in still or moving air, which can be at any temperature, such as room temperature (e.g., 23°C) or an elevated temperature (e.g., greater than 23°C). For example, a vacuum-assisted drying process can include subjecting the treated plant material pieces to a reduced pressure, e.g., less than 1 bar, e.g., in a vacuum chamber or vacuum oven. For example, an oven drying process can involve using an oven, hot plate, or other conductive, convective, or radiative heating device to heat the treated plant material pieces to an elevated temperature (e.g., above 23°C), e.g., 70°C or higher. For example, a freeze drying process can involve reducing the temperature of the treated plant material pieces to below the freezing point of the fluid therein (e.g., below 0°C) and then reducing the pressure to sublimate the frozen fluid therein (e.g., below a few millibars). For example, a critical point drying process can involve immersing the treated plant material pieces in a fluid (e.g., liquid carbon dioxide), raising the temperature and pressure of the plant material pieces 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 gaseous fluid, in turn. For example, a microwave drying process can involve using a microwave oven or other microwave generating device to induce dielectric heating within the treated pieces of plant material by exposing the treated pieces of plant material to electromagnetic radiation having a frequency in the microwave range (e.g., 300 MHz to 300 GHz), e.g., a frequency of up to 915 MHz or up to 2.45 GHz.

[0069] After treatment step 610 or any treatment step 616, or if lignin-damaging treatment is not desired in determining step 604, method 600 can proceed to treatment step 617, where the treated plant material piece(s) can optionally undergo one or more internal modifications before pressing. While the term "internal" is used to refer to the modifications of treatment step 617, it is contemplated that in some embodiments, the modifications may be applied to external as well as internal features of the treated plant material pieces, while in other embodiments, the modifications may be applied to either internal or external features of the treated plant material pieces without affecting the other features. In some embodiments, the internal modification can include forming, depositing, or otherwise providing non-native particles on the surface of the processed plant material piece(s). Such surfaces can include at least the interior surfaces, e.g., cell walls lining the lumens, but can also include the exterior surfaces of the treated plant material pieces. Non-natural particles incorporated onto the surface of the processed plant material pieces can stimulate the final structure to have certain advantageous properties, such as hydrophobicity, weather resistance, corrosion resistance (e.g., saltwater resistance), and / or flame resistance, among other properties. For example, in some embodiments, hydrophobic nanoparticles (e.g., SiO nanoparticles) can be formed on the surface of the processed plant material pieces.

[0070] Alternatively or additionally, in some embodiments, the internal modification can include performing a further chemical treatment that modifies the surface chemistry of the treated plant material pieces. For example, in some embodiments, the further chemical treatment can provide weathering and corrosion resistance and can be selected from a wide variety of chemicals, including cuprate (CDDC), ammoniacal copper quaternary (ACQ), copper chromate arsenate (CCA), ammoniacal zinc arsenate (ACZA), copper naphthenate, copper acid chromate, copper citrate, copper azole, copper 8-hydroxyquinolinate, pentachlorophenol, zinc naphthenate, copper naphthenate, creosote, titanium dioxide, propiconazole, tebuconazole, cyproconazole, boric acid, borax, organic iodides (IPBC), and Na2B8O 134H2O.

[0071] Alternatively or additionally, in some embodiments, the internal modification of treatment step 617 can include infiltrating the treated plant material pieces with one or more polymers (or polymer precursors). For example, the treated plant material pieces can be immersed in a polymer solution under vacuum to form a hybrid material. The polymer can be any type of polymer that can infiltrate the pores of the processed plant material piece(s), such as a synthetic polymer, a natural polymer, a thermosetting polymer, or a thermoplastic polymer.For example, in some embodiments, the polymer is polyvinyl alcohol (PVA), polyvinyl glycol (PEO), polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene 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 adipate terephthalate (PBAT), polybutylene succinate-co-butylene adipate (PBSA), polyhydroxybutyrate (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(glycolic acid) (PGA), polypyrrole (PPy), polythiophene Phenol (PTh), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), ethylene vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), polyxylylene adipamide (MXD6), polyethylene (PE), polyvinyl chloride (PVC), poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS), polyimide (PI), polyethyleneimine (PEI), polylactic acid (PLA), octadecyltrichlorosilane (OTS), polyoctahedral silane The binder may be sesquioxane (POSS), paramethylstyrene (PMS), polydimethylsiloxane (PDMS), poly(ethylene naphthalate) (PEN), a graft copolymer of acrylonitrile-butadiene-styrene-methyl methacrylate (ABSM), dodecyltrimethoxysilane (DTMS), rosin, chitin, chitosan, protein, vegetable oil, lignin, hemicellulose, carboxymethyl cellulose, cellulose acetate, starch, agar, or any combination of the foregoing.

[0072] The method 600 may proceed to a processing step 618, in which the treated pieces of plant material are pressed in a direction transverse to their longitudinal direction. In some embodiments, the pressing may be in a direction substantially perpendicular to the longitudinal direction, while in other embodiments, the pressing may have a force component perpendicular to the longitudinal direction. In either case, the pressing may be effective to reduce the thickness of the treated pieces of plant material, thereby increasing their density, as well as to (at least partially) collapse natural lumens (e.g., blood vessels, lumens of individual fibers, parenchyma cells, etc.), voids, and / or interstices within the cross-section of the treated pieces of plant material. In some embodiments, the pressing may be performed along a single direction (e.g., along the radial direction R), e.g., to reduce the thickness of the processed pieces of plant material (e.g., reduce the dimensions by at least 5:2 compared to the pieces of plant material before pressing). Alternatively or additionally, in some embodiments, the processed plant material pieces can be pressed simultaneously in two directions (e.g., along the radial direction R and along a second direction perpendicular to both the radial direction R and the longitudinal direction L) to, for example, reduce the cross-sectional area of ​​the plant material pieces (e.g., to produce a densified rectangular bar). Alternatively or additionally, in some embodiments, the processed plant material pieces can be pressed sequentially in different directions (e.g., first along the radial direction R, then along a second direction perpendicular to the radial direction R and the longitudinal direction L).

[0073] In some embodiments, pressing can be performed without prior drying of the piece(s) of plant material, or while the piece(s) of plant material retain at least some water or other fluid therein. Thus, pressing can be effective to remove at least some water or other fluid from the pieces of plant material while simultaneously reducing their dimensions and increasing their density. In some embodiments, a separate drying process can be combined with the pressing process. For example, the piece(s) of plant material can be first compressed to cause densification and removal of at least some water or fluid therefrom, followed by a drying process (e.g., air drying) to remove remaining water or fluid. Alternatively, in some embodiments, the plant material pieces can be first dried to remove at least some water or fluid therefrom (e.g., initial drying in a humidity chamber, followed by air drying at room temperature, so that the moisture content of the plant material pieces approaches but maintains greater than 15% by weight, e.g., 10% by weight), and then pressed to cause compaction (and potentially further removal of water or other fluid, e.g., moisture content less than 10% by weight, e.g., 3-8% by weight).

[0074] In some embodiments, pressing can promote hydrogen bond formation between cellulosic fibers in the cell walls of the pieces of plant material, thereby improving the mechanical properties of the pieces of plant material. Additionally, any particles or materials formed on the surface of or within the pieces of plant material (e.g., via any modification in processing step 617) can be retained after pressing, with particles / materials on the interior surface becoming embedded within the collapsed lumens and intertwined cell walls.

[0075] The pressure and timing of pressing can depend on the size of the plant material pieces before pressing, the desired size of the plant material pieces after pressing, the water or fluid content (if any) within the plant material pieces, the temperature at which pressing is performed, the relative humidity, the properties of the material (e.g., the impregnating polymer) from internal modification (if any), and / or other factors. For example, the plant material pieces can be held under pressure for a period of 1 minute to several hours (e.g., 1 to 180 minutes, inclusive). In some embodiments, the plant material pieces can be held under pressure for 3 to 72 hours, inclusive. In some embodiments, pressing can be performed at a pressure of 0.5 MPa to 20 MPa, inclusive, e.g., 5 MPa. 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 20 to 160°C, e.g., 100°C or higher. In some embodiments, the pressing may be effective to completely collapse the lumens of the native cellulosic microstructure of the plant material and / or to achieve a pressure of at least 1.15 g / cm 3 (e.g., ≥ 1.2 g / cm 3 or ≥ 1.3 g / cm 3 , for example, 1.4 to 1.5 g / cm 3 ) can result in a density of the compressed plant material.

[0076] Method 600 may proceed to processing step 620, where the now-densified plant material pieces may optionally undergo external modification. While the term "external" is used to refer to the optional modification of processing step 620, it is contemplated that in some embodiments, the modification may be applied to internal and external features of the densified plant material pieces, while in other embodiments, the modification may be applied to either internal or external features of the densified plant material pieces without affecting the other features. In some embodiments, the external modification may include forming, depositing, or otherwise providing a coating on one or more external surfaces of the densified plant material pieces. The coating may impart certain advantageous properties to the densified plant material piece(s), such as, but not limited to, hydrophobicity, weather resistance, corrosion resistance (e.g., saltwater resistance), and / or flame resistance. For example, the coating may include an oil-based paint, a hydrophobic paint, a polymer coating, and / or a fire-resistant coating. In some embodiments, the fire-resistant coating can include nanoparticles (e.g., boron nitride nanoparticles). Alternatively or additionally, in some embodiments, the coating for the densified plant material pieces can include boron nitride (BN), montmorillonite clay, hydrotalcite, silicon dioxide (SiO), sodium silicate, calcium carbonate (CaCO), aluminum hydroxide (Al(OH)), magnesium hydroxide (Mg(OH)), magnesium carbonate (MgCO), aluminum sulfate, iron sulfate, zinc borate, boric acid, borax, triphenyl phosphate (TPP), melamine, ammonium polyphosphate, phosphate, phosphite ester, ammonium phosphate, ammonium sulfate, phosphonate, diammonium phosphate (DAP), ammonium dihydrogen phosphate, monoammonium phosphate (MAP), guanylurea phosphate (GUP), dihydrogen phosphate, guanidine, antimony pentoxide, or any combination thereof.

[0077] The method 600 may proceed to a processing step 622, where the densified plant material pieces may optionally be machined, cut, and / or otherwise physically manipulated in preparation for their 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 abrasive tumbling. Manipulation processes may include, but are not limited to, bending, molding, and other shaping techniques. In some embodiments, manipulating may include assembling multiple treated plant material pieces into a single layer. For example, in some embodiments, processed plant material strands may be mixed with a waterproofing resin and interleaved together to form a mat, which may then be exposed to heat and / or pressure to bond the strands and resin together.

[0078] The method 600 may proceed to a processing step 624, where one or more non-densified plant material pieces may be provided. In some embodiments, the provision of processing step 624 may be similar to the provision of processing step 602. For example, the plant material of the non-densified pieces may be the same type of plant material as used in processing step 602 or a different type of plant material. In some embodiments, the non-densified plant material pieces may have a density of 1.15 g / cm 3 Less than (e.g., ≦1.0 g / cm 3 or ≦0.9g / cm 3 , for example, 0.1 to 0.9 g / cm 3 ). In some embodiments, providing processing step 624 can include machining, cutting, or otherwise physically manipulating the plant material to form layers of a size appropriate for the desired configuration of the engineered structure. For example, the number of non-densified plant material pieces (or non-densified plant material layers) can be greater than the number of densified plant material pieces (or densified plant material layers), e.g., at least two times greater.

[0079] Method 600 can proceed to processing step 626, where the non-densified and densified plant material pieces can be bonded together (e.g., via an adhesive or other adhesive layer) to form an engineered structure. In some embodiments, processing step 626 can include layering, aligning, or otherwise positioning the non-densified and densified plant material pieces relative to one another. In some embodiments, the non-densified and / or densified plant material pieces can be bonded together using epoxy, polyurethane adhesive, polyvinyl acetate-isocyanate adhesive, resorcinol formaldehyde resin adhesive, phenolic resin, and / or sodium carboxymethyl cellulose (CMC). In some embodiments, the bonding of the non-densified and densified plant material pieces can form a laminated structure or portion thereof, such as any of the engineered structures shown in FIGS. 1A-5E.

[0080] The method 600 can proceed to processing step 628, where the engineered structure formed from the densified and non-densified pieces of plant material can be used for a particular application. For example, the engineered structure can be adapted 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 the engineered structures disclosed herein can be readily adapted for use in a variety of applications based on the teachings of the present disclosure.

[0081] While steps 602-628 of method 600 have been described as being performed once, in some embodiments, multiple iterations of a particular processing step may be used before proceeding to the next decision or processing step. Additionally, while steps 602-628 of method 600 are illustrated and described separately, in some embodiments, the processing steps may be combined and performed together (concurrently or sequentially). Furthermore, while FIG. 6 illustrates a particular order for steps 602-628, embodiments of the disclosed subject matter are not limited thereto. Indeed, in certain embodiments, steps may occur in a different order than illustrated or simultaneously with other steps. In some embodiments, method 600 may include steps or other aspects not specifically illustrated in FIG. 6. Alternatively or additionally, in some embodiments, method 600 may comprise only some of steps 602-628 of FIG. 6.

[0082] Further Examples of the Disclosed Technology In view of the above-described implementations of the disclosed subject matter, this application discloses additional examples in the appendices listed below. It should be noted that the features described in one of the appendices alone, or two or more features of the appendices taken in combination, and optionally in combination with one or more features of one or more additional appendices, also fall within the scope of the disclosure of this application.

[0083] Appendix 1. a first laminate including a plurality of component plant material layers, the plurality of component plant material layers including one or more first layers and one or more second layers, each component plant material layer being adhered to an adjacent component plant material layer via one or more respective adhesives; Each first plant material layer has a density of 1.15 g / cm 3 a densified plant material layer having a density equal to or greater than a first value and a mechanical strength equal to or greater than a first value; Each second constituent plant material layer has a density of 1.15 g / cm 3 and a density less than a first value.

[0084] Appendix 2. 10. The engineered structure of any section or example herein, particularly Appendix 1, wherein the plant material forming one, some, or all of the constituent layers in the first laminate is wood or bamboo.

[0085] Appendix 3. 10. The engineered structure of any section or example herein, particularly any one of Appendices 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.

[0086] Appendix 4. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1-3, wherein the plant material forming one, some, or all of the one or more second layers is natural wood or natural bamboo.

[0087] Appendix 5. An engineered structure according to any section or example herein, particularly any one of Appendices 1 to 4, wherein the plant material forming one, a portion, or all of one or more first layers is the same plant material as one, a portion, or all of one or more second layers.

[0088] Appendix 6. The engineered structure of any section or example herein, particularly any one of Appendices 1 to 5, wherein the plant material forming one, part, or all of one or more first layers is a different plant material from one, part, or all of one or more second layers.

[0089] Appendix 7. An engineered structure according to any of the sections or examples of the present specification, in particular any one of Appendices 1 to 6, (a1) The density of one, some, or all of the one or more first layers is 1.2 g / cm 3 That's all, (a2) The density of one, some, or all of the one or more second layers is 1.0 g / cm3 is less than or equal to: Both (a1) and (a2) are true, Engineering structures.

[0090] Appendix 8. An engineered structure according to any of the sections or examples of the present specification, in particular any one of Appendices 1 to 7, (a3) The density of one, some, or all of the one or more first layers is 1.3 g / cm 3 That's all, (a4) The density of one, some, or all of the one or more second layers is 0.9 g / cm 3 is less than or equal to: Both (a3) ​​and (a4) are true, Engineering structures.

[0091] Appendix 9. 10. The engineered structure of any section or example herein, particularly any one of Appendices 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 native microstructure of the cellulosic lumen of the plant material.

[0092] Appendix 10. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1-9, wherein one, some, or all of the one or more first layers comprise one or more pieces of densified plant material, and the cellulosic lumen of the natural microstructure of the plant material is substantially collapsed.

[0093] Appendix 11. 11. The engineered structure of any section or example herein, particularly any one of Appendices 1-10, wherein one, some, or all of the one or more first layers comprise lignin-impaired plant material.

[0094] Appendix 12. 12. The engineered structure of any section or example herein, in particular Appendix 11, wherein the lignin-compromised plant material comprises modified lignin therein, the modified lignin having shorter macromolecular chains than native lignin in the native plant material.

[0095] Appendix 13. 13. The engineered structure of any section or example herein, in particular Appendix 12, wherein the content of modified lignin in one, some, or all of the one or more first layers is at least 90% by weight percentage of the content of native lignin in the native plant material.

[0096] Appendix 14. 14. The engineered structure of any section or example herein, particularly any one of Appendices 12-13, wherein the content of modified lignin in one, some, or all of the one or more first layers is at least 20 wt.%.

[0097] Appendix 15. 15. The engineered structure of any section or example herein, particularly any one of Appendices 12-14, wherein one, some, or all of the one or more first layers comprise a salt of an alkaline chemical immobilized within a cellulosic microstructure of lignin-impaired plant material.

[0098] Appendix 16. 10. The engineered structure according to any section or example herein, in particular Appendix 5, wherein the salt is substantially pH neutral.

[0099] Appendix 17. 12. The engineered structure of any section or example herein, in particular Appendix 11, wherein the lignin-impaired plant material comprises at least partially delignified wood.

[0100] Appendix 18. 18. The engineered structure of any section or example herein, in particular Appendix 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 native plant material.

[0101] Appendix 19. An engineered structure according to any of the sections or examples of the present specification, particularly any one of Appendices 17-18, 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% by weight, inclusive; or the plant material is a softwood, and the lignin content of the at least partially delignified plant material is between 1.25% and 33.25% by weight, inclusive; Engineering structures.

[0102] Appendix 20. 20. The engineered structure of any section or example herein, in particular any one of Appendices 17 to 19, wherein the lignin content of the at least partially delignified plant material is at least 10% by weight.

[0103] Appendix 21. An engineered structure according to any of the sections or examples of the present specification, in particular any one of Appendices 1 to 20, (a5) each first layer consists essentially of densified plant material; (a6) each second layer consists essentially of non-densified wood, or Consists of both (a5) and (a6), Engineering structures.

[0104] Appendix 22. 22. The engineered structure of any section or example herein, particularly any one of Appendices 1-21, wherein the one or more respective adhesives comprise an epoxy, a polyurethane adhesive, a polyvinyl acetate-isocyanate adhesive, a resorcinol formaldehyde resin adhesive, a phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination of the foregoing.

[0105] Appendix 23. An engineered structure according to any of the sections or examples of this specification, in particular any one of Appendices 1 to 22, some or all of the one or more first layers are formed from the same wood species as some or all of the one or more second layers; An engineered structure in which part or all of one or more first layers are formed from a different wood species than part or all of one or more second layers.

[0106] Appendix 24. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1-23, wherein one, some, or all of the one or more first layers are disposed within the first laminate at respective locations where the first laminate experiences the highest stress.

[0107] Appendix 25. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1-24, wherein one, some, or all of the one or more first layers are disposed as respective outermost layers of the first laminate.

[0108] Appendix 26. The engineered structure described in any section or example herein, particularly any one of Appendices 1-25, wherein the one or more first layers surround the one or more second layers in a cross-sectional view.

[0109] Appendix 27. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1-26, wherein the one or more first layers completely surround the one or more second layers on all sides.

[0110] Appendix 28. An engineered structure according to any of the sections or examples of this specification, in particular any one of Appendices 1 to 27, the second layer includes a stack of plant material boards arranged such that adjacent plant material boards have an orthogonal orientation; An engineered structure in which a stack of plant material boards is placed between a pair of first layers to form a reinforced cross-laminated timber (CLT) structure.

[0111] Appendix 29. An engineered structure described in any section or example herein, particularly any one of Appendices 1 to 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 segments, the second layers being arranged in a stack such that adjacent second layers have a parallel orientation, and the stack being disposed between the pair of first layers to form a reinforced bonded laminate (glulam) structure.

[0112] Appendix 30. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1 to 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 in a stack such that adjacent second layers have a parallel orientation, and the stack being disposed between the pair of first layers to form a reinforced laminated veneer lumber (LVL) structure.

[0113] Appendix 31. An engineered structure according to any of the sections or examples of the present specification, in particular any one of Appendices 1 to 30, a second laminate including a second plurality of component plant material layers, the second plurality of component plant material layers including one or more third layers and one or more fourth layers, each component plant material layer adhered to an adjacent component plant material layer via one or more respective adhesives; a web extending between the first laminate and the second laminate; Each third layer is 1.15 g / cm 3 a densified plant material layer having a density equal to or greater than a first value and a mechanical strength equal to or greater than a second value; Each fourth layer is 1.15 g / cm 3 a plant material layer having a density less than a second value and a mechanical strength less than a third value; The first and second laminates form first and second flanges, respectively, of an I-joist, in an engineered structure.

[0114] Appendix 32. The engineered structure of any section or example herein, particularly of Appendix 31, wherein the web comprises one or more pieces of non-densified plant material that retain the natural microstructure of the cellulosic lumens of the plant material.

[0115] Appendix 33. 10. The engineered structure of any section or example herein, particularly any one of Appendices 31-32, wherein the web comprises one or more pieces of densified plant material, and the cellulosic lumen of the natural microstructure of the plant material is substantially collapsed.

[0116] Appendix 34. 31. The engineered structure of any section or example herein, particularly any one of Appendices 31 to 33, wherein the plant material forming one, some, or all of the constituent layers in the second laminate is wood or bamboo.

[0117] Appendix 35. An engineered structure according to any of the sections or examples of this specification, in particular any one of Appendices 31 to 34, (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 (a7) and (a8) are both true, Engineering structures.

[0118] Appendix 36. The engineered structure of any section or example herein, particularly any one of Appendices 31-35, wherein one of the one or more first layers forms an exposed side of a first flange facing the web, and / or one of the one or more third layers forms an exposed side of a second flange facing the web.

[0119] Appendix 37. An engineered structure according to any of the sections or examples of this specification, in particular any one of Appendices 31 to 35, (a9) one of the one or more second layers forms an exposed side of the first flange facing the web, and one of the one or more first layers is disposed 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 facing the web, and one of the one or more third layers is disposed within the second flange between the exposed side of the second flange and the web; or Both (a9) and (b10) are true. Engineering structures.

[0120] Appendix 38. 10. The engineered structure of any section or example herein, particularly any one of Appendices 31-37, wherein the first value, the second value, or both values ​​are 100 MPa.

[0121] Appendix 39. 10. The engineered structure of any section or example herein, particularly any one of Appendices 31 to 37, wherein the mechanical strength of each first layer, the mechanical strength of each third layer, or both, is in the range of 100 to 600 MPa, inclusive.

[0122] Appendix 40. 100. The engineered structure of any section or example herein, particularly any one of Appendices 1 to 39, wherein the first value is about 100 MPa, or the first value is within the range of 100 to 600 MPa, inclusive.

[0123] Appendix 41. 1. The engineered structure of any section or example herein, particularly any one of Appendices 1-40, wherein the first laminate has a first cross-sectional area, the first laminate having greater mechanical strength than a laminate structure having the first cross-sectional area, and wherein the engineered structure is formed using only one or more second layers with one or more adhesives.

[0124] Appendix 42. 10. The engineered structure of any section or example herein, particularly any one of Appendices 1-40, wherein the first laminate has a first cross-sectional area and mechanical strength, the first cross-sectional area being smaller than the cross-sectional area of ​​a laminate structure having the same mechanical strength but formed using only one or more second layers with one or more adhesives.

[0125] Appendix 43. one or more laminated structures, each laminated structure having a plurality of constituent plant material layers, each constituent plant material layer bonded to an adjacent constituent plant material layer via one or more respective adhesives, and at least one of the plurality of constituent plant material layers having a viscosity of 1.15 g / cm 3 1. An engineered structural material that is a densified plant material layer having a density equal to or greater than 1000 .mu.m.

[0126] Appendix 44. The engineered structural material according to any of the sections or examples of the present specification, in particular paragraph 43, wherein the densified plant material layer is densified wood or densified bamboo.

[0127] Appendix 45. The engineered structural material according to any of the sections or examples of the present specification, particularly any one of Appendices 43-44, wherein the densified plant material has a density of 1.2 g / cm 3 An engineered structural material with a density of at least 1000 MPa.

[0128] Appendix 46. The engineered structural material according to any of the sections or examples of the present specification, particularly any one of appendices 43 to 45, wherein the densified plant material has a density of 1.3 g / cm 3 An engineered structural material with a density of at least 1000 MPa.

[0129] Appendix 47. 46. ​​The engineered structural material according to any section or example herein, particularly any one of Appendices 43 to 46, wherein the densified plant material layer comprises one or more pieces of densified wood or densified bamboo, and the cellulosic lumens of the natural microstructure of the wood or bamboo are substantially collapsed.

[0130] Appendix 48. The engineered structural material described in any section or example of the present specification, particularly any one of Appendices 43 to 47, wherein the densified plant material layer comprises at least partially delignified plant material or lignin-modified plant material.

[0131] Appendix 49. The engineered structural material described in any section or example herein, particularly any one of Appendices 43-48, wherein the one or more adhesives comprise an epoxy, a polyurethane adhesive, a polyvinyl acetate-isocyanate adhesive, a resorcinol formaldehyde resin adhesive, a phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination of the foregoing.

[0132] Appendix 50. 50. The engineered structural material according to any section or example herein, particularly any one of Appendices 43-49, wherein the one or more laminate structures are formed as part of a cross-laminated timber (CLT) structure, a glued laminated timber (Glulam) structure, a laminated veneer lumber (LVL) structure, an oriented strand board (OSB) structure, or an I-joist structure.

[0133] Appendix 51. The engineered structural material according to any of the sections or examples of the present specification, particularly any one of appendices 43 to 50, wherein each of the plurality of constituent plant material layers has a density of 1.15 g / cm 3 a non-densified plant material layer having a density of less than, or at least 1.15 g / cm 3 2. An engineered structural material, which is either a layer of densified plant material having a density of

[0134] Appendix 52. The engineered structural material according to any of the sections or examples of the present specification, particularly any one of appendices 43 to 50, wherein each of the plurality of constituent plant material layers has a density of 1.15 g / cm 3 a layer of natural plant material having a density of less than, or at least 1.15 g / cm 3 2. An engineered structural material, which is either a layer of densified plant material having a density of

[0135] Appendix 53. 1.15g / cm 3 providing one or more first layers comprising densified plant material having a density equal to or greater than a first value and a mechanical strength equal to or greater than a first value; 1.15g / cm 3 providing one or more second layers comprising plant material having a density less than the first value and a mechanical strength less than the first value; bonding one or more first layers to one or more second layers via one or more respective adhesives to form a laminate; A method comprising:

[0136] Appendix 54. The method according to any of the sections or examples herein, in particular appendix 53, comprising: (b1) one, some, or all of the plant material of the one or more first layers comprises densified wood or densified bamboo; (b2) one, some, or all of the plant material of the one or more second layers comprises non-densified wood or non-densified bamboo; or Contains both (b1) and (b2), method.

[0137] Appendix 55. The method described in any section or example of the present specification, particularly any one of Appendices 53 to 54, (b3) one, some, or all of the plant material of the one or more first layers comprises densified wood or densified bamboo; (b4) one, some, or all of the plant material of the one or more second layers comprises natural wood or natural bamboo; or Contains both (b3) and (b4), method.

[0138] Appendix 56. The method described in any section or example of this specification, particularly any one of Appendices 53 to 55, The density of one, some, or all of the one or more first layers is 1.2 g / cm 3 That's all, The density of one, some, or all of the one or more first layers is 1.3 g / cm 3 That's all, The density of one, some, or all of the one or more second layers is 1.0 g / cm 3 is as follows: The density of one, some, or all of the one or more second layers is 0.9 g / cm 3 is less than or equal to: any combination of the foregoing; method.

[0139] Appendix 57. The method described in any section or example herein, particularly any one of Appendices 53 to 56, comprising: Providing one or more first layers includes: subjecting one or more pieces of native plant material having native lignin to a chemical treatment to damage the native lignin, thereby forming one or more pieces of lignin-damaged plant material; and compressing one or more pieces of lignin-impaired plant material to form one or more first layers of densified plant material; Including, The method wherein the density of the densified plant material after compression is greater than the density of the native plant material before being subjected to chemical treatment.

[0140] Appendix 58. The method described in any section or example herein, particularly Appendix 57, wherein the compression is performed in a direction transverse to the longitudinal growth direction of the one or more pieces of lignin-impaired plant material.

[0141] Appendix 59. 59. The method described in any section or example herein, particularly any one of Appendices 57-58, wherein the compressing comprises pressing one or more pieces of lignin-impaired plant material at a pressure of at least 1 MPa.

[0142] Appendix 60. 59. The method according to any section or example herein, in particular any one of Appendices 57 to 59, wherein the compressing comprises compressing one or more pieces of lignin-impaired plant material at a pressure in the range of 5 to 20 MPa, inclusive.

[0143] Appendix 61. 61. The method described in any section or example herein, in particular any one of Appendices 57 to 60, wherein the compressing comprises pressing one or more pieces of the lignin-impaired plant material while subjecting them to a temperature of at least 50°C.

[0144] Appendix 62. 10. The method described in any section or example herein, in particular any one of Appendices 57 to 61, wherein the compressing comprises pressing one or more pieces of the lignin-impaired plant material while exposing them to a temperature of 80 to 180°C, inclusive.

[0145] Appendix 63. 10. A method as described in any section or example of the present specification, particularly as described in Appendices 57 to 62, wherein after being subjected to chemical treatment, one or more pieces of lignin-compromised plant material have modified lignin therein, the modified lignin having shorter polymer chains than native lignin in the pieces of native plant material.

[0146] Appendix 64. A method as described in any of the sections or examples herein, particularly in Appendix 63, comprising: Subjecting to chemical treatment infiltrating one or more pieces of natural plant material with one or more chemical solutions; and After infiltrating, subjecting the one or more chemical solutions therein to a first temperature of at least 80°C for a first period of time to form one or more pieces of lignin-impaired plant material; A method comprising:

[0147] Appendix 65. A method as described in any clause or appendix herein, particularly appendix 64, comprising: The method 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 (where AQ is anthraquinone), any of the foregoing with LiOH or KOH substituted for NaOH, or any combination of the foregoing.

[0148] Appendix 66. The method according to any of the sections or examples of this specification, particularly any one of Appendices 64 to 65, the first temperature is in the range of 120 to 160°C (inclusive); and / or The first time period is in the range of 1 to 5 hours, inclusive. method.

[0149] Appendix 67. The method described in any section or example herein, particularly any one of Appendices 64 to 66, 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 them to a first temperature for a first time.

[0150] Appendix 68. The method described in any section or example herein, particularly any one of Appendices 64 to 67, wherein subjecting to a first temperature for a first period of time comprises using steam to heat one or more pieces of natural plant material having one or more chemical solutions therein.

[0151] Appendix 69. The method according to any section or example herein, particularly any one of paragraphs 64 to 68, wherein after being subjected to a first temperature for a first time period, (b5) the content of modified lignin in the one or more pieces of lignin-impaired plant material is at least 90% by weight of the content of native lignin in the one or more pieces of native plant material; (b6) the content of modified lignin in the one or more pieces of lignin-impaired plant material is at least 20% by weight; or (b5) and (b6) are both true, method.

[0152] Appendix 70. 69. The method described in any section or example herein, particularly any one of Appendices 64 to 69, wherein after being subjected to a first temperature for a first time period, a salt of an alkaline chemical is immobilized within the cellulosic microstructure of the one or more pieces of lignin-impaired plant material.

[0153] Appendix 71. A method according to any section or example herein, particularly section 70, wherein the salt is substantially pH neutral.

[0154] Appendix 72. The method described in any section or example herein, particularly any one of Appendices 70-71, wherein the salt is formed by reaction of one or more chemical solutions with acidic degradation products of native hemicellulose in one or more pieces of native plant material produced by the one or more chemical solutions.

[0155] Appendix 73. 62. The method described in any section or example herein, in particular any one of Appendices 57 to 62, wherein after subjecting the one or more pieces of lignin-compromised plant material to chemical treatment, the one or more pieces of lignin-compromised plant material are at least partially delignified.

[0156] Appendix 74. The method described in any section or example herein, particularly Appendix 73, wherein subjecting to chemical treatment comprises partially or fully immersing the one or more pieces of natural plant material in one or more chemical solutions at a second temperature for a second period of time to remove at least some lignin from the one or more pieces of natural plant material.

[0157] Appendix 75. The method described in any section or example herein, particularly in Appendix 74, wherein the one or more chemical solutions include an alkaline solution.

[0158] Appendix 76. The method according to any of the sections or examples herein, particularly any one of Appendixes 74-75, wherein the one or more chemical solutions are selected from the group consisting of sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), sodium sulfite (NaSO), sodium sulfate (NaSO), sodium sulfide (NaS), Na n S (where n is an integer), urea (CH4N2O), sodium sulfite (NaHSO3), NaH2O3, sulfur dioxide (SO2), anthraquinone (C 14 HO), methanol (CHOH), ethanol (CHOH), butanol (CHOH), formic acid (CHO), hydrogen peroxide (HO), acetic acid (CHCOOH), butyric acid (CHO), peroxyformic acid (CHO), peroxyacetic acid (CHO), ammonia (NH), tosylic acid (p-TsOH), sodium hypochlorite (NaClO), sodium chlorite (NaClO), chlorine dioxide (ClO), chlorine (Cl), water (HO), or any combination of the foregoing.

[0159] Appendix 77. The method described in any section or example herein, particularly any one of Appendices 74 to 76, wherein the one or more chemical solutions comprise a boiling mixture of NaOH and Na2SO3.

[0160] Appendix 78. A method according to any section or example herein, particularly any one of Appendices 74 to 77, comprising: (b7) the second temperature is 100 to 160°C; (b8) the second time period is within the range of 0.1 to 96 hours, inclusive; or (b7) and (b8) are both true, method.

[0161] Appendix 79. 10. The method described in any section or example herein, particularly any one of Appendices 74 to 78, wherein the lignin content of the one or more pieces of lignin-impaired plant material is between 5% and 95%, inclusive, of the lignin content of the native plant material.

[0162] Appendix 80. A method as described in any section or example herein, particularly any one of Appendices 74 to 79, comprising: the natural plant material is a hardwood or bamboo, and the lignin content of the lignin-damaged plant material is between 0.9% and 23.8% by weight, inclusive; or The method, wherein the natural plant material is a coniferous tree and the lignin-impaired plant material has a lignin content of 1.25% by weight to 33.25% by weight, inclusive.

[0163] Appendix 81. The method according to any section or example herein, in particular any one of Appendices 74 to 80, wherein the lignin content of the lignin-impaired plant material is at least 10% by weight.

[0164] Appendix 82. A method according to any section or example herein, particularly any one of Appendices 53 to 81, comprising: (b9) each first layer consists essentially of densified plant material; (b10) each second layer consists essentially of non-densified or natural plant material; or Consists of both (b9) and (b10), method.

[0165] Appendix 83. The method described in any section or example herein, particularly any one of Appendices 53 to 82, wherein the one or more respective adhesives comprise an epoxy, a polyurethane adhesive, a polyvinyl acetate-isocyanate adhesive, a resorcinol formaldehyde resin adhesive, a phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination of the foregoing.

[0166] Appendix 84. The method described in any section or example herein, particularly any one of Appendices 53 to 83, wherein the first and second layers are joined in the form of a reinforced cross-laminate structure, a reinforced glued laminate structure, a reinforced laminate veneer structure, an oriented strand board structure, an I-joist structure, or some form of any of the foregoing.

[0167] Appendix 85. The method described in any section or example herein, particularly any one of Appendices 53 to 84, wherein one, some, or all of the one or more second layers comprise non-densified plant material.

[0168] conclusion Any of the features shown or described herein, for example, with respect to Figures 1A-6 and Appendices 1-85, can be combined with any other feature shown or described herein, for example, with respect to Figures 1A-6 and Appendices 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 one another and can be used in combination with any other feature described herein, except where structurally impossible. In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are examples only and should not be construed as limiting the scope of the disclosed technology. Rather, the scope is defined by the following claims. Accordingly, the inventors claim all that comes within the scope and spirit of these claims.

Claims

1. a first laminate including a plurality of component plant material layers, the plurality of component plant material layers including one or more first layers and one or more second layers, each component plant material layer being adhered to an adjacent component plant material layer via one or more respective adhesives; Each first plant material layer has a density of 1.15 g / cm ３ a densified plant material layer having a density equal to or greater than a first value and a mechanical strength equal to or greater than a first value; Each second component plant material layer has a density of 1.15 g / cm ３ a plant material layer having a density less than a first value and a mechanical strength less than a second value; Engineering structures.

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

3. 10. The engineered structure of 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. 10. The engineered structure of 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. 10. The engineered structure of claim 1, 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 one or more second layers.

6. 10. The engineered structure of claim 1, wherein the plant material forming one, some, or all of the one or more first layers is a different plant material than the plant material of one, some, or all of the one or more second layers.

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

8. (a3) the density of one, some, or all of the one or more first layers is 1.3 g / cm ３ That's all, (a4) the density of one, some, or all of the one or more second layers is 0.9 g / cm ３ is less than or equal to: (a3) and (a4), The engineered structure of claim 1 .

9. 10. The engineered structure of claim 1, 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 cellulosic lumen of the plant material.

10. 10. The engineered structure of claim 1, wherein one, some, or all of the one or more first layers comprise one or more pieces of densified plant material, wherein the cellulosic lumen of the natural microstructure of the plant material is substantially disrupted.

11. 10. The engineered structure of claim 1, wherein one, some, or all of the one or more first layers comprise lignin-impaired plant material.

12. 12. The engineered structure of claim 11, wherein the lignin-impaired plant material includes modified lignin therein, the modified lignin having shorter polymer chains than native lignin in the native plant material.

13. 13. The engineered structure of claim 12, wherein the modified lignin content in one, some, or all of the one or more first layers is at least 90% by weight percentage of the native lignin content in the natural plant material.

14. 13. The engineered structure of claim 12, wherein the modified lignin content in one, some, or all of the one or more first layers is at least 20% by weight.

15. 13. The engineered structure of claim 12, wherein one, some, or all of the one or more first layers comprise salts of alkaline chemicals immobilized within cellulosic microstructures of the lignin-impaired plant material.

16. 16. The engineered structure of claim 15, wherein the salt is substantially pH neutral.

17. 12. The engineered structure of claim 11, wherein the lignin-impaired plant material comprises at least partially delignified wood.

18. 18. The engineered structure of claim 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 native plant material.

19. 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% by weight, inclusive; or the plant material is a softwood, and the lignin content of the at least partially delignified plant material is between 1.25% and 33.25% by weight, inclusive; 20. The engineered structure of claim 17.

20. 20. The engineered structure of claim 17, wherein the at least partially delignified plant material has a lignin content of at least 10% by weight.

21. (a5) each first layer consists essentially of densified plant material; (a6) each second layer consists essentially of non-densified wood, or Consists of both (a5) and (a6); The engineered structure of claim 1 .

22. 10. The engineered structure of claim 1, wherein the one or more respective adhesives comprise an epoxy, a polyurethane adhesive, a polyvinyl acetate-isocyanate adhesive, a resorcinol formaldehyde resin adhesive, a phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination thereof.

23. some or all of the one or more first layers are formed from the same wood species as some or all of the one or more second layers; or some or all of the one or more first layers are formed from a different wood species than some or all of the one or more second layers; The engineered structure of claim 1 .

24. 10. The engineered structure of claim 1, wherein one, some, or all of the one or more first layers are disposed within the first stack at respective locations where the first stack experiences the highest stress.

25. 10. The engineered structure of claim 1, wherein one, some, or all of the one or more first layers are disposed as outermost layers of each of the first laminates.

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

28. the second layer comprises a stack of plant material boards arranged such that adjacent plant material boards have an orthogonal orientation; The stack of plant material boards is disposed between the pair of first layers to form a reinforced cross-laminated timber (CLT) structure. The engineered structure of claim 1 .

29. 2. The engineered structure of claim 1, wherein the first laminate comprises a plurality of the second layers and a pair of first layers, each second layer comprising one or more plant material segments, the second layers arranged in a stack such that adjacent second layers have a parallel orientation, and the stack is disposed between the pair of first layers so that the stack forms a reinforced bonded laminate (glulam) structure.

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

31. a second laminate comprising a second plurality of component plant material layers, the second plurality of component plant material layers comprising one or more third layers and one or more fourth layers, each component plant material layer adhered to an adjacent component plant material layer via one or more respective adhesives; a web extending between the second plurality of constituent plant material layers and the first laminate and the second laminate; further comprising Each third layer has a density of 1.15 g / cm ３ a densified plant material layer having a density equal to or greater than a first value and a mechanical strength equal to or greater than a second value; Each fourth layer has a density of 1.15 g / cm ３ a plant material layer having a density less than a second value and a mechanical strength less than a third value; the web, the first laminate, and the second laminate together form an I-joist; the first laminate and the second laminate form first and second flanges, respectively, of the I-joist; The engineered structure of claim 1 .

32. 32. The engineered structure of claim 31 , wherein the web comprises one or more pieces of non-densified plant material that retains the natural microstructure of the cellulosic lumen of the plant material.

33. 32. The engineered structure of claim 31 , wherein the web comprises one or more pieces of densified plant material, wherein the cellulosic lumen of the natural microstructure of the plant material is substantially disrupted.

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

35. (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 (a7) and (a8), 32. The engineered structure of claim 31.

36. 32. The engineered structure of claim 31 , wherein one of the one or more first layers forms an exposed side of the first flange facing the web, and / or one of the one or more third layers forms an exposed side of the second flange facing the web.

37. (a9) one of the one or more second layers forms an exposed side of a first flange facing the web, and one of the one or more first layers is disposed 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 a second flange facing the web, and one of the one or more third layers is disposed within the second flange between the exposed side of the second flange and the web; or Both (a9) and (b10), 32. The engineered structure of claim 31.

38. 32. The engineered structure of claim 31 , wherein the first value, the second value, or both values ​​is 100 MPa.

39. 32. The engineered structure of claim 31, wherein the mechanical strength of each first layer, the mechanical strength of each third layer, or both, is in the range of 100 to 600 MPa, inclusive.

40. The engineered structure of claim 1 , wherein the first value is 100 MPa.

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

42. 10. The engineered structure of claim 1, wherein the first laminate has a first cross-sectional area and mechanical strength, the first cross-sectional area being less than the cross-sectional area of ​​a laminate structure having the same mechanical strength and formed using only the one or more second layers with the one or more adhesives.

43. one or more laminated structures, each having a plurality of constituent plant material layers, each constituent plant material layer bonded to an adjacent constituent plant material layer via one or more respective adhesives, and at least one of the plurality of constituent plant material layers having a viscosity of 1.15 g / cm ３ 1. An engineered structural material that is a densified plant material layer having a density equal to or greater than 1000 .mu.m.

44. 44. The engineered structural material of claim 43, wherein the densified plant material layer is densified wood or densified bamboo.

45. The densified plant material has a density of 1.2 g / cm ３ 44. The engineered structural material of claim 43 having a density greater than or equal to

46. The densified plant material has a density of 1.3 g / cm ３ 44. The engineered structural material of claim 43 having a density greater than or equal to

47. 44. The engineered structural material of claim 43, wherein the densified plant material layer comprises one or more pieces of densified wood or densified bamboo, and wherein the cellulosic lumens of the natural microstructure of the wood or bamboo are substantially collapsed.

48. 44. The engineered structural material of claim 43, wherein the densified plant material layer comprises at least partially delignified plant material or lignin-modified plant material.

49. 44. The engineered structural material of claim 43, wherein the one or more adhesives comprise an epoxy, a polyurethane adhesive, a polyvinyl acetate-isocyanate adhesive, a resorcinol formaldehyde resin adhesive, a phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination thereof.

50. 44. The engineered structural material of claim 43, wherein the one or more laminate structures are formed as part of a cross-laminated timber (CLT) structure, a glued laminated timber (Glulam) structure, a laminated veneer (LVL) structure, an oriented strand board (OSB) structure, or an I-joist structure.

51. Each of the plurality of constituent plant material layers has a density of 1.15 g / cm ３ a non-densified plant material layer having a density of less than or equal to 1.15 g / cm ３ 44. The engineered structural material of claim 43, wherein the engineered structural material is any of a densified plant material layer having a density of

52. Each of the plurality of constituent plant material layers has a density of 1.15 g / cm ３ a natural plant material layer having a density of less than or equal to 1.15 g / cm ３ 44. The engineered structural material of claim 43, wherein the engineered structural material is any of a densified plant material layer having a density of

53. 1.15 g / cm ３ providing one or more first layers comprising densified plant material having a density equal to or greater than a first value and a mechanical strength equal to or greater than a first value; 1.15 g / cm ３ providing one or more second layers comprising plant material having a density less than the first value and a mechanical strength less than the first value; bonding one or more first layers to one or more second layers via one or more respective adhesives to form a laminate; A method comprising:

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

55. (b3) one, some, or all of the plant material of the one or more first layers comprises densified wood or densified bamboo; (b4) one, some, or all of the plant material of the one or more second layers comprises natural wood or natural bamboo; or (b3) and (b4) 54. The method of claim 53.

56. The density of one, some, or all of the one or more first layers is 1.2 g / cm ３ That's all, The density of one, some, or all of the one or more first layers is 1.3 g / cm ３ That's all, 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 is as follows: The density of one, some, or all of the one or more second layers is 0.9 g / cm ３ Below is the 54. The method of claim 53.

57. Providing the one or more first layers includes: subjecting one or more pieces of natural plant material having native lignin to a chemical treatment to damage the native lignin, thereby forming one or more pieces of lignin-damaged plant material; and compressing one or more pieces of lignin-impaired plant material to form one or more first layers of densified plant material; the density of the densified plant material after compression is greater than the density of the native plant material before being subjected to said chemical treatment; 54. The method of claim 53.

58. 58. The method of claim 57, wherein the compression is performed in a direction transverse to a longitudinal growth direction of the one or more pieces of the lignin-impaired plant material.

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

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

61. 58. The method of claim 57, wherein said compressing comprises pressing one or more pieces of said lignin-impaired plant material while subjecting them to a temperature of at least 50°C.

62. 58. The method of claim 57, wherein the compressing comprises pressing one or more pieces of the lignin-impaired plant material while subjecting them to a temperature in the range of 80 to 180°C, inclusive.

63. 58. The method of claim 57, wherein after said treating, the one or more pieces of lignin-impaired plant material have modified lignin therein, the modified lignin having shorter polymer chains than the polymer chains of native lignin in the pieces of native plant material.

64. The chemical treatment includes: infiltrating one or more pieces of natural plant material with one or more chemical solutions; and after said infiltration, subjecting the one or more pieces of plant material having the one or more chemical solutions therein to a first temperature of at least 80°C for a first period of time to form one or more pieces of lignin-impaired plant material; 64. The method of claim 63, comprising:

65. The one or more chemical solutions may be p-toluenesulfonic acid, NaOH, NaOH+Na ２ SO ３ / Na ２ SO ４ , NaOH + Na ２ S, NaHSO ３ +SO ２ +H ２ O, NaHSO ３ +Na ２ SO ３ , NaOH + Na ２ SO ３ , NaOH / NaH ２ O ３ +AQ, NaOH / Na ２ S+AQ, NaOH+Na ２ SO ３ + AQ, Na ２ SO ３ + NaOH + CH ３ OH+AQ, NaHSO ３ +SO ２ +AQ, NaOH+Na ２ 65. The method of claim 64, comprising any of the foregoing with NaOH replaced by Sx (wherein AQ is anthraquinone), LiOH, or KOH, or any combination of the foregoing.

66. the first temperature is in the range of 120 to 160°C inclusive; and / or the first period of time is in the range of 1 to 5 hours, inclusive; 65. The method of claim 64.

67. 65. 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 them to the first temperature for the first period of time.

68. 65. The method of claim 64, wherein subjecting to the first temperature for the first time period comprises using steam to heat the one or more pieces of the natural plant material having the one or more chemical solutions therein.

69. After initial exposure to the first temperature, (b5) the content of modified lignin in the one or more pieces of lignin-impaired plant material is at least 90% by weight of the content of native lignin in the one or more pieces of native plant material; (b6) the content of modified lignin in the one or more pieces of lignin-impaired plant material is at least 20% by weight; or (b5) and (b6), 65. The method of claim 64.

70. 65. The method of claim 64, wherein after being subjected to the first temperature for the first period of time, a salt of an alkaline chemical is immobilized within the cellulosic microstructure of the one or more pieces of lignin-impaired plant material.

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

72. 71. The method of claim 70, wherein the salts are formed by reaction of the one or more chemical solutions with acidic degradation products of native hemicellulose in the one or more pieces of native plant material produced by the one or more chemical solutions.

73. 58. The method of claim 57, wherein after being subjected to the chemical treatment, the one or more pieces of lignin-impaired plant material are at least partially delignified.

74. 74. The method of claim 73, wherein the subjecting to chemical treatment comprises partially or fully immersing the one or more pieces of natural plant material in one or more chemical solutions at a second temperature for a second period of time to remove at least some lignin from the one or more pieces of natural plant material.

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

76. The one or more chemical solutions may be sodium hydroxide (NaOH), lithium hydroxide (LiOH), potassium hydroxide (KOH), sodium sulfate (Na ２ SO ３ ), sodium sulfate (Na ２ SO ４ ), sodium sulfide (Na ２ S), Na n S (n is an integer), urea (CH ４ N ２ O), sodium sulfite (NaHSO ３ ), NaH ２ O ３ , sulfur dioxide (SO ２ ), anthraquinone (C １４ H ８ O ２ ), methanol (CH 3 OH), ethanol (C ２ H 5 OH), butanol (C ４ H 9 OH), formic acid (CH ２ O ２ ), hydrogen peroxide (H ２ O ２ ), acetic acid (CH ３ COOH), butyric acid (C ４ H ８ O ２ ), peroxyformic acid (CH ２ O ３ ), peroxyacetic acid (C ２ H ４ O ３ ), ammonia (NH ３ ), tosylic acid (p-TsOH), sodium hypochlorite (NaClO), sodium chlorite (NaClO ２ ), chlorine dioxide (ClO ２ ), chlorine (Cl ２ ), water (H ２ O) or any combination of the foregoing.

77. The one or more chemical solutions may comprise NaOH and Na ２ SO ３ 75. The method of claim 74, comprising a boiling mixture of

78. (b7) the second temperature is 100 to 160°C, inclusive; (b8) the second period of time is in the range of 0.1 to 96 hours, inclusive; or (b7) and (b8), 75. The method of claim 74.

79. 75. The method of claim 74, wherein the lignin content of the one or more pieces of lignin-impaired plant material is between 5% and 95%, inclusive, of the lignin content of the native plant material.

80. the natural plant material is a hardwood or bamboo, and the lignin content of the lignin-impaired plant material is between 0.9% and 23.8% by weight, inclusive; or the natural plant material is a coniferous tree, and the lignin-damaged plant material has a lignin content of 1.25% to 33.25% by weight, inclusive; 75. The method of claim 74.

81. 75. The method of claim 74, wherein the lignin-impaired plant material has a lignin content of at least 10% by weight.

82. (b9) each first layer consists essentially of densified plant material; (b10) each second layer consists essentially of non-densified or natural plant material; or Consists of both (b9) and (b10); 54. The method of claim 53.

83. 54. The method of claim 53, wherein the one or more adhesives comprise an epoxy, a polyurethane adhesive, a polyvinyl acetate-isocyanate adhesive, a resorcinol formaldehyde resin adhesive, a phenolic resin, sodium carboxymethyl cellulose (CMC), or any combination thereof.

84. 54. The method of claim 53, wherein the first and second layers are joined in the form of a reinforced cross-laminate structure, a reinforced glued laminate structure, a reinforced laminate veneer structure, an oriented strand board structure, an I-joist structure, or a portion of any of the foregoing.

85. 54. 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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