阅读说明：本技术 一种络合木材的制备方法 (Preparation method of complex wood ) 是由 余养伦 于文吉 张耀明 闫昊鹏 于 2019-09-20 设计创作，主要内容包括：本发明涉及一种络合木材的制备方法,属于木材加工技术领域。上述络合木材的制备方法包括：步骤1：准备适量木材；步骤2：把植物多酚导入木材,得到多酚木材；步骤3：在多酚木材中导入金属盐,得到多酚金属盐木材；步骤4：干燥多酚金属盐木材,得到络合木材。本发明通过在木材中引入“纤维素-植物多酚-金属盐”动态多重牺牲键网络结构,支撑起纤维素和/或半纤维素,使其在吸湿或解吸时减小甚至不产生膨胀或收缩,同时在牺牲键不断地断裂和重构的动态作用下,耗散了木质材料体系内的大量能量,消除或削弱了内应力,保护了纤维素骨架共价键网络的完整,为解决木材的开裂问题提供了新方法。(The invention relates to a preparation method of complex wood, and belongs to the technical field of wood processing. The preparation method of the complex wood comprises the following steps: step 1: preparing a proper amount of wood; step 2: introducing plant polyphenol into wood to obtain polyphenol wood; and step 3: introducing metal salt into the polyphenol wood to obtain polyphenol metal salt wood; and 4, step 4: and drying the polyphenol metal salt wood to obtain the complex wood. The invention introduces a dynamic multi-sacrifice bond network structure of 'cellulose-plant polyphenol-metal salt' into wood to support cellulose and/or hemicellulose, so that the dynamic multi-sacrifice bond network structure reduces or even does not generate expansion or shrinkage when absorbing or desorbing moisture, simultaneously dissipates a large amount of energy in a wood material system under the dynamic action of continuous fracture and reconstruction of sacrifice bonds, eliminates or weakens internal stress, protects the integrity of a cellulose skeleton covalent bond network, and provides a new method for solving the cracking problem of wood.)

1. A method for preparing complex wood, which is characterized by comprising the following steps:

step 1: preparing a proper amount of wood;

step 2: introducing plant polyphenol into wood to obtain polyphenol wood;

and step 3: introducing metal salt into the polyphenol wood to obtain polyphenol metal salt wood;

and 4, step 4: and drying the polyphenol metal salt wood to obtain the complex wood.

2. The method according to claim 1, wherein the plant polyphenol is introduced into cells of the wood, and is bound to the polysaccharide in the wood through hydrogen bonding, and the metal salt is bound to the plant polyphenol through a complexing reaction.

3. The method for preparing complexed wood according to claim 1, wherein the step 2 is:

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

22) soaking the wood in plant polyphenol water solution;

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

4. The method according to claim 3, wherein the concentration of the plant polyphenol aqueous solution is 1g/L to 250g/L, the average molecular weight is 170 to 50000, and the plant polyphenol aqueous solution is 1 to 40 polymers; the impregnation time of the wood in the plant polyphenol water solution is 10min-48h, the impregnation temperature is 0-80 ℃, and the impregnation method is normal pressure, pressurization or pressurization after vacuum pumping.

5. The method of claim 4, wherein said plant polyphenol is one or more of tannin extract, tannin, tannic acid, terminal food acid, and pyrogen terminal food acid.

6. The method for preparing complexed wood according to claim 1, wherein the step 3 is:

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

32) immersing the polyphenol wood in a metal salt aqueous solution.

7. The method of claim 6, wherein the concentration of the aqueous solution of the metal salt is 0.3g/L to 300 g/L; the wood 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 normal pressure, pressurization or pressurization after vacuum pumping.

8. The method of claim 7, wherein the metal salt is one or more of iron salt, copper salt, aluminum salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt, potassium salt, and double salts thereof.

9. The method of claim 6 wherein the aqueous solution of metal salt has a pH of 3.5 to 4.5.

10. The method according to claim 1, wherein in the step 4, the absolute moisture content of the dried polyphenol metal salt wood is 25 to 50%, and then the oxygen content in the air is adjusted to 22 to 50% until the absolute moisture content of the polyphenol metal salt wood is 6 to 12%.

Technical Field

The invention relates to the technical field of wood processing, in particular to a preparation method of complex wood.

Background

Along with the technological progress and social development, the demand of human beings on wood is larger and larger, the application range is wider and wider, and the required quality is higher and higher. However, the lack of forest resources in China and the inherent properties of wood make wood materials difficult to meet the increasing market demands in the fields of products and applications. The wood functional improvement technology aims at improving the quality of wood materials, endows the wood materials with new performance, expands the application range of the wood materials and becomes an important component part for sustainable development of the society and the economy in China.

Wood materials and wood products have outstanding properties such as environmental properties-visual, tactile, auditory, olfactory and regulatory properties of wood, material properties-processability, 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.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a preparation method of complex wood; the complex wood prepared by the method has the advantages of cracking reduction, even no cracking, stable size and the like.

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

the invention provides a preparation method of complex wood, which comprises the following steps:

step 1: preparing a proper amount of wood;

step 2: introducing plant polyphenol into wood to obtain polyphenol wood;

and step 3: introducing metal salt into the polyphenol wood to obtain polyphenol metal salt wood;

and 4, step 4: and drying the polyphenol metal salt wood to obtain the complex wood.

Preferably, the absolute water content of the wood is 6-300%.

Further, the step 2 is as follows:

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

22) soaking the wood in plant polyphenol water solution to introduce plant polyphenol into cell cavity, cell wall or cell gap;

23) drying the wood impregnated with the aqueous solution of plant polyphenols to form a polyphenol wood.

Further, the concentration of the plant polyphenol water solution is 1-250 g/L, the average molecular weight is 170-50000, and the plant polyphenol water solution is 1-40 polymers; the ratio of plant polyphenol to wood is as follows: 0% -15%; the impregnation time of the wood in the plant polyphenol water solution is 10min-48h, the impregnation temperature is 0-80 ℃, and the impregnation method is normal pressure, pressurization or pressurization after vacuum pumping.

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

Further, the step 3 is:

31) dissolving metal salt in the aqueous solution, and stirring uniformly to form a metal salt aqueous solution;

32) immersing the polyphenol wood in a metal salt aqueous solution to introduce metal ions into the cell cavities, cell walls or intercellular spaces.

Further, the concentration of the metal salt water solution is 0.3 g/L-300 g/L; the ratio of the metal salt to wood is as follows: 0.1% -12%; the wood 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 normal pressure, pressurization or pressurization after vacuum pumping.

Preferably, the metal salt is one or more of iron salt, copper salt, aluminum salt, titanium salt, calcium salt, molybdenum salt, tungsten salt, chromium salt, magnesium salt, potassium salt and double salts thereof, and the pH value of the aqueous solution of the metal salt is 3.5-4.5.

Preferably, the absolute water content of the dried polyphenol metal salt wood is 25-50%, and then the oxygen content in the air is adjusted to 22-50% until the absolute water content of the polyphenol metal salt wood is 6-12%.

The existing research considers that the causes of wood cracking are many, and the main factor is that polysaccharides (cellulose, hemicellulose and other substances) in wood absorb or release water in the processes of moisture absorption and desorption to cause wood expansion or shrinkage, so that the wood is unstable in size and cracks.

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

according to the invention, plant polyphenol and metal salt are introduced into the cell wall of wood, phenolic hydroxyl groups of the plant polyphenol are combined with hydroxyl groups of cellulose and hemicellulose, and meanwhile, ortho-position phenolic hydroxyl groups are complexed with metal ions to crosslink adjacent molecular chains of the cellulose/hemicellulose into a net structure, just as if a plurality of supports are supported on the molecular chains of the cellulose/hemicellulose, the expansion or contraction of the molecular chains is reduced or even not generated during moisture absorption or desorption; on the basis of the above, a large number of multiple sacrificial bond networks consisting of hydrogen bonds (the plant polyphenol phenolic hydroxyl groups are combined with the hydroxyl groups in the wood 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 bond (covalent bond network is formed between cellulose, hemicellulose, lignin and phenolic resin), the sacrificial bond is broken in preference to the covalent bond when the wood is subjected to internal stress or external force. The dynamic action of the continuous breakage and reconstruction of the sacrificial bonds dissipates a large amount of energy in a wood system, eliminates or weakens internal stress, and protects the integrity of a cellulose skeleton covalent bond network. This provides a new approach to the problem of wood cracking.

Firstly, introducing plant polyphenol into wood to swell the wood; then introducing metal salt into the wood, combining plant polyphenol with cellulose and hemicellulose in the wood to form a multi-point hydrogen bond, complexing the plant polyphenol with the metal salt, and combining the cellulose-plant polyphenol-metal salt into a whole just like forming a plurality of support supports in cellulose skeleton molecules; then, accompanied by evaporation and oxidation reactions of water, the "cellulose-plant polyphenol-metal salt" is further cross-linked and oxidized, finally forming a complex wood. The dynamic multi-sacrifice bond network structure of the invention 'cellulose-plant polyphenol-metal salt' supports cellulose and/or hemicellulose, so that the expansion or shrinkage of the structure is reduced or even not generated when the structure absorbs moisture or desorbs, and simultaneously, under the dynamic action of continuous fracture and reconstruction of sacrifice bonds, a great deal of energy in a wood recombination material system is dissipated, the internal stress is eliminated or weakened, the integrity of a cellulose skeleton covalent bond network is protected, and the problem of easy cracking of wood is solved from the molecular level.

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 cellulose framework in dry and wet states;

FIG. 3 shows the condition of lignum Pini nodi before and after treatment in example 1;

FIG. 4 is a comparative graph of oak treatment in example 2 of the present invention;

FIG. 5 is a graph of catalpa bungei before and after complexation in example 3 of the present invention;

FIG. 6 is a graph of complexed pre-and post-quercus acutissima veneers in example 5 of the present invention;

FIG. 7 is a graph comparing the contact angles of complexed pre-and post-quercus acutissima veneers in example 5 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.