阅读说明：本技术 一种络合木质材料及其原位络合方法 (Complexing wood material and in-situ complexing method thereof ) 是由 余养伦 张世锋 于文吉 祝荣先 于 2019-09-20 设计创作，主要内容包括：本发明涉及一种络合木质材料及其原位络合方法,属于木材加工技术领域。上述络合木质材料的原位络合方法,以木质细胞为微反应器,通过植物多酚与金属盐在所述木质细胞细胞壁、细胞腔和细胞间隙中原位络合得到。本发明在木质材料细胞壁、细胞腔和细胞间隙中导入植物多酚-金属盐,利用植物多酚与金属盐的络合反应,将植物多酚和金属盐固定在木质材料的细胞内,具有减少开裂甚至不开裂、改善尺寸稳定、增强纹理层次感、丰富色泽、防腐、防霉等优点。(The invention relates to a complex wood material and an in-situ complexing method thereof, belonging to the technical field of wood processing. The in-situ complexing method for complexing the wood material takes the wood cells as the microreactor and is obtained by in-situ complexing plant polyphenol and metal salt in cell walls, cell cavities and cell gaps of the wood cells. The plant polyphenol-metal salt is introduced into cell walls, cell cavities and intercellular spaces of the wood material, and the plant polyphenol and the metal salt are fixed in the cells of the wood material by utilizing the complex reaction of the plant polyphenol and the metal salt, so that the wood material has the advantages of reducing cracking even not cracking, improving the dimensional stability, enhancing the texture layering, enriching the color and luster, preventing corrosion, preventing mildew and the like.)

1. A complex wood material is characterized in that plant polyphenol is combined with polysaccharide in the wood material through hydrogen bonds to form a first structural unit; the metal salt and the plant polyphenol are combined through a coordination bond; the plant polyphenol is flavanol plant polyphenol to form a structural unit II; or the gallate plant polyphenol forms a structural unit III; the structural formulas of the structural unit I, the structural unit II and the structural unit III are as follows:

in the second structural unit and the third structural unit, M is one or more of iron, zinc, copper, aluminum, titanium, calcium, molybdenum, tungsten, chromium, magnesium and potassium; n is the number of valence electrons of the metal ion.

2. The complexed wood-based material according to claim 1, wherein said complexed wood-based material comprises 0.3 to 15% by mass of the plant polyphenol and 0.1 to 12% by mass of the metal salt, said plant polyphenol and metal salt being present as a complex in the cell walls, cell cavities and intercellular spaces of said wood-based material.

3. The complexed wood-based material of claim 1, wherein said wood-based material is selected from the group consisting of logs, sawn timber, laminated wood, cross-laminated wood, laminated veneer lumber, oriented strand board, laminated wood, plywood, reconstituted wood, particle board, fiber board, plywood, veneer, wood strands, wood shavings, and fibers.

4. An in-situ complexing method for complexing wood materials is characterized in that wood cells are used as a microreactor, and plant polyphenol and metal salt are subjected to in-situ complexing in cell walls, cell cavities and/or intercellular spaces of the wood cells.

5. The method of in situ complexing of complexed wood material of claim 4, comprising:

step 1: preparing a proper amount of wood material;

step 2: introducing plant polyphenol and metal salt, and complexing to obtain a polyphenol metal salt wood material;

and step 3: and drying the polyphenol metal salt wood material to obtain the complex wood material.

6. The in situ complexing method for complexing wood-based material according to claim 5, wherein said step 2 is: introducing plant polyphenols into cells of the woody material; then introducing metal salt into the wood material cells, and carrying out in-situ complexation on the plant polyphenol and the metal salt in cell walls, cell cavities and/or cell gaps to obtain the polyphenol metal salt wood material;

alternatively, introducing a metal salt into cells of the woody material; then introducing the plant polyphenol into the wood material cells, and carrying out in-situ complexation on the metal salt and the plant polyphenol in cell walls, cell cavities and/or cell gaps to obtain the polyphenol metal salt wood material;

or synchronously introducing plant polyphenol and metal salt into the cell wall, the cell cavity or the intercellular space of the wooden material, and carrying out in-situ complexation on the metal salt and the plant polyphenol in the cell wall, the cell cavity and/or the intercellular space to obtain the polyphenol metal salt wooden material.

7. The method of claim 6, wherein the step of introducing the plant polyphenol into the cells of the woody material comprises:

21) dissolving plant polyphenol in water, and stirring uniformly to form a plant polyphenol water solution;

22) soaking the wood material in plant polyphenol water solution;

23) drying the wood material impregnated with the aqueous solution of plant polyphenol.

8. The in-situ complexing method for complexing wood material according to claim 7, wherein said aqueous solution of plant polyphenol has a concentration of 1-25.0 g/L, an average molecular weight of 170-50000, and is 1-40 polymer; the wood material is soaked in the plant polyphenol water solution for 10min to 48h at the temperature of 0 to 80 ℃, and the soaking method is a normal pressure soaking method, a pressure soaking method or a vacuum pressure soaking method;

the plant polyphenol is one or more of tannin extract, tannin, tannic acid, terminal food acid, and charred terminal food acid.

9. The in situ complexation method according to claim 6, wherein the introducing of the metal salt into the wood material cell is specifically:

24) dissolving metal salt in water, and stirring uniformly to form a metal salt water solution;

25) the wooden material is immersed in an aqueous solution of a metal salt.

10. The in situ complexing method for complexing wood-based material according to claim 9, wherein said aqueous metal salt solution has a concentration of 0.3g/L to 30.0g/L and a pH of 3.5 to 4.5; the wood material is soaked in the metal salt water solution for 10min to 180 days at the soaking temperature of 0 to 80 ℃, and the soaking method is a normal pressure soaking method, a pressure soaking method or a vacuum pressure soaking method;

the metal salt is one or more of iron salt, zinc salt, copper salt, aluminum salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt, potassium salt and complex salt thereof.

Technical Field

The invention relates to the technical field of wood processing, in particular to a complex wood material and an in-situ complexing method thereof.

Background

Along with the technological progress and social development, the demand of human beings on wood materials is larger and larger, the application range is wider and wider, and the required quality is higher and higher. However, forest resources in China are deficient, and the inherent properties of wood materials make the wood materials difficult to meet the increasing market demands in the fields of products and applications.

Wood material products and wood materials have outstanding properties such as environmental properties-visual properties, tactile properties, auditory properties, olfactory properties and regulatory properties of wood materials, material properties-workability, high strength to weight ratio, thermal and electrical insulation, biological functions-renewability and degradability-which are well recognized by mankind, but their application is limited by swelling and drying shrinkage, cracking and deformation, decay and mildew, discoloration and the like of wood materials.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a complexing wood material and an in-situ complexing method thereof; the complex wood material prepared by the invention has the advantages of reducing cracking even not cracking, improving dimensional stability, enhancing texture layering, enriching color and luster, being antiseptic and mildew-proof, and the like.

In order to solve the technical problems, the invention provides the following technical scheme:

in one aspect, the invention provides a complexed wood material, wherein the plant polyphenol is combined with polysaccharide in the wood material through hydrogen bond to form a first structural unit; the metal salt and the plant polyphenol are combined through a coordination bond; the plant polyphenol is flavanol plant polyphenol to form a structural unit II; or the gallate plant polyphenol forms a structural unit III; the structural formulas of the structural unit I, the structural unit II and the structural unit III are as follows:

wherein, the plant polyphenol is reacted with each other through hydrogen bonds, such as:

the plant polyphenol and cellulose are reacted through hydrogen bonds, such as:

the plant polyphenol and water react through hydrogen bonds, such as:

water interacts with cellulose through hydrogen bonds, such as:

in the second structural unit and the third structural unit, M is one or more of iron, zinc, copper, aluminum, titanium, calcium, molybdenum, tungsten, chromium, magnesium and potassium; n is the number of valence electrons of the metal ion.

Further, the complexing wood material contains 0.3-15% of plant polyphenol and 0.1-12% of metal salt by mass, and the plant polyphenol and the metal salt exist in a complex form in cell walls, cell cavities and/or cell gaps of the wood material.

Preferably, the wood material is one or more of raw wood, sawn timber, laminated wood, cross-laminated wood, laminated veneer lumber, oriented strand board, laminated wood, plywood, reconstituted wood, flakeboard, fiberboard, plywood, veneer, wood beam, wood shavings and fiber.

On the other hand, the invention also provides an in-situ complexing method for complexing the wood material, which takes the wood cells as a microreactor and is obtained by in-situ complexing plant polyphenol and metal salt in cell walls, cell cavities and/or intercellular spaces of the wood cells.

The in-situ complexing method for complexing the wood material comprises the following steps:

step 1: preparing a proper amount of wood material;

step 2: introducing plant polyphenol and metal salt, and complexing to obtain a polyphenol metal salt wood material;

and step 3: and drying the polyphenol metal salt wood material to obtain the complex wood material.

Further, the step 2 is as follows: introducing plant polyphenol into cells of a woody material to obtain a polyphenol woody material; then introducing metal salt into polyphenol wood material cell, plant polyphenol and metal salt in cell wall and cell cavityAnd &Or in-situ complexing in intercellular spaces to obtain the polyphenol metal salt wood material;

or introducing metal salt into wood material cells to obtain a metal salt wood material; then plant polyphenol is introduced into the wooden material cell of metal salt, and the metal salt and the plant polyphenol are introduced into the cell wall and the cell cavityAnd &Or in-situ complexing in intercellular spaces to obtain the polyphenol metal salt wood material;

or simultaneously introducing plant polyphenol and metal salt into the cell wall, cell cavity or intercellular space of the woody material, wherein the metal salt and the plant polyphenol are introduced into the cell wall and cell cavityAnd &Or in-situ complexing in intercellular spaces to obtain the polyphenol metal salt wood material.

Further, the step of introducing the plant polyphenol into the wood cells specifically comprises:

21) dissolving plant polyphenol in water, and stirring uniformly to form a plant polyphenol water solution;

22) soaking the wood material in plant polyphenol water solution;

23) drying the wood material impregnated with the aqueous solution of plant polyphenol.

Preferably, the concentration of the plant polyphenol water solution is 1-25.0 g/L, the average molecular weight is 170-50000, and the plant polyphenol water solution is 1-40 polymers; the wood material is soaked in plant polyphenol water solution for 10min-48h at 0-80 deg.C under normal pressure, pressure or vacuum pressure.

Preferably, the plant polyphenol is one or more of tannin extract, tannin, tannic acid, terminal food acid and pyrogen terminal food acid.

Further, the introduction of the metal salt into the wood cells specifically comprises:

24) dissolving metal salt in water, and stirring uniformly to form a metal salt water solution;

25) the wooden material is immersed in an aqueous solution of a metal salt.

Preferably, the concentration of the metal salt aqueous solution is 0.3 g/L-30.0 g/L, and the pH value is 3.5-4.5; the wood material is soaked in the metal salt water solution for 10min to 180 days at the soaking temperature of 0 to 80 ℃, and the soaking method is a normal pressure soaking method, a pressure soaking method or a vacuum pressure soaking method.

Preferably, the metal salt is one or more of iron salt, zinc salt, copper salt, aluminum salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt, potassium salt, and double salts thereof.

The existing research considers that the cracking of the wood material is caused by a plurality of reasons, wherein the main factor is that polysaccharides (cellulose, hemicellulose and the like) in the wood material absorb or release water in the processes of moisture absorption and desorption to cause the expansion or shrinkage of the wood material, so that the size of the wood material is unstable and the cracking is caused.

Compared with the prior art, the invention has the following beneficial effects:

in the invention, the plant polyphenol is obtained by in-situ complexing plant polyphenol and metal salt by taking the wooden cells as a microreactor. According to the invention, plant polyphenol and metal salt are introduced into the cell wall of the wood material, phenolic hydroxyl groups of the plant polyphenol are combined with hydroxyl groups of cellulose and hemicellulose, meanwhile, ortho-position phenolic hydroxyl groups are complexed with metal ions, and molecular chains of adjacent cellulose/hemicellulose are crosslinked into a net structure, just as a plurality of supports are supported on the molecular chain branches of the cellulose/hemicellulose, so that the expansion or contraction of the molecular chains is reduced or even not generated during moisture absorption or desorption; on the basis, a large number of multiple sacrificial bond networks consisting of hydrogen bonds (the plant polyphenol phenolic hydroxyl groups are combined with hydroxyl groups in the wood material to form multi-point hydrogen bonds) and coordination bonds (the ortho hydroxyl groups on the plant polyphenol phenolic rings are complexed with metal salts to form coordination bonds) are formed in the cellulose skeleton. Because the sacrificial bond energy is less than the covalent bonds (covalent bond network is formed between cellulose, hemicellulose, lignin and phenolic resin), the sacrificial bonds break in preference to the covalent bonds when the wood material is subjected to internal or external stresses. The dynamic action of the continuous breakage and reconstruction of the sacrificial bonds dissipates a large amount of energy in a wood material system, eliminates or weakens internal stress, and protects the integrity of a cellulose skeleton covalent bond network. This provides a new approach to solving the cracking problem of wood materials.

Firstly, introducing plant polyphenol and/or metal salt into a wood material to swell the wood material; then introducing metal salt and/or plant polyphenol into the wood material, wherein the plant polyphenol is combined with cellulose and hemicellulose in the wood material to form a multi-point hydrogen bond, and meanwhile, the plant polyphenol and the metal salt are subjected to in-situ complexation to combine the 'cellulose-plant polyphenol-metal salt' into a whole just like forming a plurality of bracket supports in a cellulose skeleton molecule and forming steric hindrance between cellulose and/or hemicellulose skeletons; then, after drying, the concentration of the plant polyphenol and the metal salt is increased along with the evaporation of water, the water in the cell wall is replaced by a drying medium, the oxygen content is increased, and the cellulose-plant polyphenol-metal salt is promoted to be further crosslinked and oxidized to finally form the complex wood material. The dynamic multiple sacrificial bond network structure of the cellulose-plant polyphenol-metal salt forms steric hindrance between cellulose and/or hemicellulose frameworks, so that the dynamic effect of continuous fracture and reconstruction of the sacrificial bonds is realized, a large amount of energy in a wood material system is dissipated, internal stress is eliminated or weakened, the integrity of the covalent bond network of the cellulose framework is protected, and the problem that the wood material is easy to crack at a molecular level is solved.

According to the invention, the metal salt is subjected to in-situ complexation through the plant polyphenol and is fixed in the wood material cell in situ, and the metal salt has good functions of mildew resistance, corrosion resistance, flame retardance, color change and the like, so that the wood material is endowed with the functions of mildew resistance, corrosion resistance, flame retardance, color change and the like.

Drawings

FIG. 1 is a diagram of a dry shrinkage and wet swelling molecular chain of a cell wall cellulose skeleton in the prior art;

FIG. 2 is a molecular chain structure diagram of the complex wood material cellulose framework in dry and wet states;

FIG. 3 is a drawing of birch, poplar and beech sawn timber untreated and treated in example 1 of the present invention;

fig. 4 is an electronic scanning and energy spectrum of poplar complex wood according to example 1 of the present invention, fig. 4a is an electronic scanning and carbon, oxygen, aluminum and potassium energy spectrum, fig. 4b is a distribution diagram of aluminum ions in poplar cells, and fig. 4c is a distribution diagram of potassium ions in poplar cells;

FIG. 5 is a CT image of poplar complex wood in example 1 of the present invention;

FIG. 6 is a graph of untreated oak, eucalyptus, persimmon and larch logs treated in accordance with example 3 of the present invention;

FIG. 7 is a diagram of a laminated veneer lumber in example 4 of the present invention;

FIG. 8 is a diagram of a laminated veneer in example 5 of the present invention;

FIG. 9 is a comparison of contact angle and surface before and after treatment of eucalyptus veneer in example 6 of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following detailed description is given with reference to specific embodiments.

In the present invention, the materials and reagents used are not specifically described, and are commercially available.

The invention provides a complexing wood material and an in-situ complexing method thereof, and the specific embodiment is as follows.