阅读说明：本技术 一种木质基选择性近红外吸收材料的制备方法 (Preparation method of wood-based selective near-infrared absorbing material ) 是由 *** 陆袁威 王美琪 田雪峰 廖圆圆 于 2020-06-24 设计创作，主要内容包括：一种木质基选择性近红外吸收材料的制备方法,它属于木材改性技术领域,具体涉及一种透明木材料的制备方法。本发明的目的是要解决现有透明木材不具备近红外吸收特性。制备方法：一、去除发色基团得到去木素木材基板；二、制备掺有近红外吸热材料的树脂；三、将去木素木材基板浸渍到掺有近红外吸热材料的树脂中,再加入固化剂和乙醇,先通过真空渗透-加压渗透循环处理,再常压固化,得到木质基选择性近红外吸收材料。优点：一、透光率可达到85％以上,近红外吸收率超过85％；二、极大程度的增强木材的机械性能,导热系数仅为0.175W/(m·K)；三、成本低、工艺简单、制备周期短。本发明主要用于制备木质基选择性近红外吸收材料。(A preparation method of a wood-based selective near-infrared absorbing material belongs to the technical field of wood modification, and particularly relates to a preparation method of a transparent wood material. The invention aims to solve the problem that the existing transparent wood does not have the near-infrared absorption characteristic. The preparation method comprises the following steps: firstly, removing chromophoric groups to obtain a delignified wood substrate; secondly, preparing resin doped with near-infrared heat-absorbing materials; and thirdly, soaking the delignified wood substrate into the resin doped with the near-infrared heat-absorbing material, adding a curing agent and ethanol, performing vacuum permeation-pressure permeation cyclic treatment, and curing at normal pressure to obtain the wood-based selective near-infrared absorbing material. The advantages are that: firstly, the light transmittance can reach more than 85 percent, and the near infrared absorption rate exceeds 85 percent; secondly, the mechanical property of the wood is enhanced to a great extent, and the heat conductivity coefficient is only 0.175W/(m.K); thirdly, the cost is low, the process is simple and the preparation period is short. The method is mainly used for preparing the wood-based selective near-infrared absorption material.)

1. The preparation method of the wood-based selective near-infrared absorption material is characterized by comprising the following steps of:

firstly, removing chromophoric groups in wood to obtain a delignified wood substrate;

doping the metal tungsten organic chelate and the tungsten oxide nanowire serving as near-infrared absorbents into resin to obtain the resin doped with the near-infrared heat-absorbing material, wherein the mass fraction of the tungsten oxide nanowire in the resin doped with the near-infrared heat-absorbing material is 0.03-1%, and the mass fraction of the metal tungsten organic chelate in the resin doped with the near-infrared heat-absorbing material is 3-15%;

dipping the delignified wood substrate into resin doped with a near-infrared heat absorption material, adding a curing agent and ethanol, uniformly mixing, performing vacuum permeation-pressure permeation cyclic treatment for 1-2 h, and curing at normal pressure for 8-24 h to obtain a wood-based selective near-infrared absorption material; the single treatment of the vacuum infiltration-pressurization infiltration cyclic treatment comprises the following specific processes: vacuum infiltration is carried out for 5min under the vacuum pressure of 0.05 atm-0.1 atm, and then pressurized infiltration is carried out for 5min under the pressurizing pressure of 7 atm-8 atm; the volume ratio of the resin doped with the near-infrared heat-absorbing material to the curing agent is 3-4: 1; the volume ratio of the resin doped with the near-infrared heat-absorbing material to the ethanol is 90-100: 1.

2. The method for preparing a wood-based selective near infrared absorbing material according to claim 1, wherein the specific process for removing chromophoric groups in wood in the first step is as follows: firstly, drying a wood sheet at the temperature of 103-105 ℃ for 12-14 h to obtain a dried wood sheet; immersing the dried wood sheet into delignification solution, adjusting the pH of the delignification solution to 4-5 by using glacial acetic acid, and then treating for 8-12 h at the water bath temperature of 75-95 ℃ to obtain treated wood; the delignification solution is a sodium chlorite solution with the mass fraction of 2.5-3.5%; bleaching the treated wood by adopting hydrogen peroxide with the mass fraction of 7-25% to obtain bleached wood; fourthly, the bleached wood is washed by deionized water for 10s to 30s, and then extracted and dehydrated by a dehydrating agent to obtain the delignified wood substrate.

3. The method of claim 2, wherein the wood sheet is basswood in the step ①, and the density of the wood sheet is 500kg/m³～550kg/m³。

4. The method for preparing a wood-based selective near-infrared absorbing material according to claim 2 or 3, wherein the dehydrating agent in step (i) is a mixed solution of ethanol and acetone, and is prepared by mixing acetone and 99.5% by mass of ethanol in a volume ratio of 1: 1.

5. The method of claim 1, wherein the metal tungsten organic chelate in step two is prepared by the following steps: uniformly mixing tungsten hexachloride and tributyl phosphate, and then heating and stirring at the temperature of 75-85 ℃ to react for 15-20 min to obtain a metal tungsten organic chelate; the volume ratio of the mass of the tungsten hexachloride to the tributyl phosphate is 1g:100 mL.

6. The method for preparing the wood-based selective near infrared absorption material according to claim 1 or 5, wherein the tungsten oxide nanowires in the second step are prepared by the following steps: putting tungsten hexachloride into absolute ethyl alcohol, and then putting the tungsten hexachloride at high temperatureReacting for 10 to 15 hours in a pressure reaction kettle at the temperature of 180 ℃ to obtain the tungsten oxide nanowire with the chemical formula of WO_2.72(ii) a The volume ratio of the mass of the tungsten hexachloride to the absolute ethyl alcohol is (0.1-0.12) g:20 mL.

7. The method for preparing the wood-based selective near infrared absorption material according to claim 1 or 6, wherein the particle size of the tungsten oxide nanowires in the second step is 20nm to 40 nm.

8. The method of claim 1, wherein in step two the resin is a benzyl alcohol-based composite resin, a homopolymer of 2, 2' - [ (1-methylethylene) bis (4, 1-phenylethanecarboxaldehyde) ] dioxirane, or a- (2-aminomethylethyl) - ω - (2-aminomethylethoxy) poly [ oxy (methyl-1, 2-ethylene) ].

Technical Field

The invention belongs to the technical field of wood modification, and particularly relates to a preparation method of a transparent wood material.

Background

The wood is a natural polymer material with high mechanical strength, low thermal conductivity and a plurality of micro-nano pore structures. The main chemical compositions of the cellulose-lignin composite material are cellulose, hemicellulose and lignin. At present, the research on the transparentization modification of wood at home and abroad is few, the problem of insufficient polymer permeation is generally solved by adopting single vacuum permeation or pressurization permeation, the cost is higher, the permeation effect is poorer, and the existing transparent wood does not have the near infrared absorption characteristic.

Disclosure of Invention

The invention aims to solve the problem that the existing transparent wood does not have the near-infrared absorption characteristic, and provides a preparation method of a wood-based selective near-infrared absorption material.

A preparation method of a wood-based selective near-infrared absorption material comprises the following steps:

firstly, removing chromophoric groups in wood to obtain a delignified wood substrate;

doping the metal tungsten organic chelate and the tungsten oxide nanowire serving as near-infrared absorbents into resin to obtain the resin doped with the near-infrared heat-absorbing material, wherein the mass fraction of the tungsten oxide nanowire in the resin doped with the near-infrared heat-absorbing material is 0.03-1%, and the mass fraction of the metal tungsten organic chelate in the resin doped with the near-infrared heat-absorbing material is 3-15%;

dipping the delignified wood substrate into resin doped with a near-infrared heat absorption material, adding a curing agent and ethanol, uniformly mixing, performing vacuum permeation-pressure permeation cyclic treatment for 1-2 h, and curing at normal pressure for 8-24 h to obtain a wood-based selective near-infrared absorption material; the single treatment of the vacuum infiltration-pressurization infiltration cyclic treatment comprises the following specific processes: vacuum infiltration is carried out for 5min under the vacuum pressure of 0.05 atm-0.1 atm, and then pressurized infiltration is carried out for 5min under the pressurizing pressure of 7 atm-8 atm; the volume ratio of the resin doped with the near-infrared heat-absorbing material to the curing agent is 3-4: 1; the volume ratio of the resin doped with the near-infrared heat-absorbing material to the ethanol is 90-100: 1.

The principle and the advantages of the invention are as follows: the wood-based selective near-infrared absorbing material prepared by the invention not only has high light transmittance (the light transmittance can reach more than 80%), but also has extremely strong near-infrared absorbing capacity (the near-infrared absorptivity exceeds 85%), and can capture a large amount of solar radiant heat; secondly, under the condition of keeping the original fiber structure of the wood, the invention fills the polymer with the refractive index similar to that of the cellulose, on one hand, the light transmittance of the wood can be improved, and simultaneously, the mechanical property and the heat preservation property of the wood are enhanced to a great extent, and the heat conductivity coefficient is only 0.175W/(m.K); the preparation method has the advantages of low cost, simple process and short preparation period, and can be used for commercial production and processing. The application of the composite material in the fields of energy-saving buildings and the like can play a good role in social value.

Detailed Description