WO2012040910A1

WO2012040910A1 - Wood modifier, preparation method thereof and method for modifying wood using the same

Info

Publication number: WO2012040910A1
Application number: PCT/CN2010/077415
Authority: WO
Inventors: 曹金珍; 姜卸宏; 赵广杰
Original assignee: 北京林业大学
Priority date: 2010-09-28
Filing date: 2010-09-28
Publication date: 2012-04-05

Abstract

Disclosed are a wood modifier, preparation method thereof and method for modifying wood using the same. The modifier comprises sodium montmorillonite (Na-MMT), quaternary ammonium salt and dispersant polyethylene glycol (PEG). In the preparation method, Na-MMT, quaternary ammonium salt and PEG are mixed and dispersed so as to obtain the final product. After the wood being subjected to impregnating process, complex reaction among MMT, quaternary ammonium salt and PEG occurs to produce complex compound which combines with the hydroxide radicals in the cellulose, hemi-cellulose and lignin in the wood during the impregnating process, so as to improve the dimensional stability and mechanical strength of the wood, effectively upgrade the superficial hardness, compression strength, leach resistance. The modified wood has a better performance.

Description

Wood modifier, preparation method thereof and method for modifying wood using the same

The invention relates to an infiltration liquid for impregnating wood, a preparation method of the infiltrated liquid, and a treatment method for impregnating wood with the infiltrated liquid, in particular to a wood composite treatment liquid, a preparation method thereof and the use of the composite treatment liquid to modify wood Processing method. Background technique

As a biological material composed of natural polymer compounds, wood has the advantages of large weight-to-weight ratio, low processing energy consumption, and relatively small environmental pollution. However, it also has loose materials, large variations in wood properties, and is susceptible to the environment and microorganisms. The inadequacy of the damage, the use of wood is largely limited, and people have been actively researching ways to improve the performance of wood.

There are two kinds of traditional wood modification techniques: one is to treat the wood under high temperature and high humidity under the action of external force, so that the wood size is stable and the densification effect is achieved, thereby improving the dimensional stability of the wood and the strength and strength of the wood. The wood modified by the method has great resilience. In the high temperature and high humidity environment, the inherent defects of the wood will still be manifested. Another technique is to use the inherent permeability of wood to infiltrate inorganic or organic oligomers into the interior of the wood, reducing the moisture absorption and water absorption properties of the wood, thereby improving the dimensional stability and corrosion resistance of the wood. Chemicals in wood are poorly resistant to leaching, and increased resistance to leaching increases the complexity of the process and increases the cost of wood.

Montmorillonite is a 2:1 type of layered silicate compound with extremely high specific surface area and inter-layer reactivity. It is widely distributed in China. Studies have shown that inorganic clay and wood such as montmorillonite are used. After compounding, the composites prepared have significant improvements in mechanical properties, thermal stability, and surface hardness.

The invention disclosed in CN 101161431A discloses a composite preservative treatment liquid for modifying wood, a preparation method thereof and a treatment method for modifying wood with the treatment liquid, to a sodium-based montmorillonite having a concentration of 3-8% The cetyltrimethylammonium bromide is added to the dispersion, and after fully reacting at 60-90 ° C, it is cooled and filtered to obtain an organic montmorillonite, and then the organic montmorillonite is added to the wood preservative solution In the ammonium chloride solution, a composite wood preservative treatment liquid is obtained. After the wood is impregnated with the treatment liquid, the wood/montmorillonite composite material with good preservative fixing effect can be obtained, which not only has certain anti-corrosion properties, but also improves physical and mechanical properties, hardness and dimensional stability. The polymer compound has good toughness, corrosion resistance and moisture resistance, and if it is used as a dispersed phase, the montmorillonite is uniformly distributed in the continuous phase of the polymer compound, and a novel composite material can be formed. Through nano-scale recombination, the respective advantages of polymer compounds and inorganic substances are complementary, which will show unique physical and chemical properties, such as significantly improving the tensile, flexural strength and modulus of the material, and increasing the heat distortion temperature and size of the material. Stability and so on.

The invention disclosed in CN 1974151A discloses a wood/montmorillonite nano-intercalation composite material and a preparation method thereof, the montmorillonite is first dispersed in steamed water, and the inorganic alkali aqueous solution is used to adjust the dispersion to alkaline, and the reaction is 0.5-1.5. After dehydration in an hour, vacuum drying, modification; then the modified montmorillonite is ground and dispersed in an aqueous solution of alcohol, and the long carbon chain halogenated hydrocarbon is added to adjust the pH to 3.5-4.5, after 1.2-1.8 hours. Dehydration, modification; washing the modified montmorillonite with distilled water until there is no halogen ion, drying to constant weight; grinding the obtained montmorillonite, adding it to the intermediate medium, heating and stirring at 70-9CTC to obtain uniformity The montmorillonite dispersion; the wood is immersed in the montmorillonite dispersion by a vacuum impregnation method, vacuum impregnated at 90-110 ° C for 1-5 minutes, and finally the impregnated wood is vacuumed at 130-160 ° C Curing 0. 5-5 minutes, the modified wood was obtained. The modified wood prepared by this method has a two-fold increase in compressive strength compared to ordinary wood, a surface hardness of 80%, and a hygroscopic expansion rate of only 1/6 of that of ordinary materials.

However, since the original soil of montmorillonite is inorganic, hydrophilic, easily swollen in an aqueous solution and aggregated, it cannot be used for infusion and into wood. In response to this situation, the montmorillonite is organically modified to change the hydrophilic inorganic raw soil into a lipophilic organic montmorillonite. After modification, the spacing of the montmorillonite layer increases, and even the montmorillonite layer occurs. Peeling, so that in the process of preparing the composite material, montmorillonite can enter the interior of the wood more easily, and when the montmorillonite enters the wood with its nanosheet, the nano-effect of the layer is effectively exerted in the composite material, so that The properties of the composite material are quickly and effectively improved. However, there are a large number of hydrophilic hydroxyl groups in the wood, which are also hydrophilic. After modification, the oleophilic organic montmorillonite is not easy to enter, so it is necessary to introduce organic montmorillonite into the wood by means of an intermediate medium, such as polymer polymerization. Materials (such as phenolic resins), such as Lu Wenhua of Beijing Forestry University, "Preparation of wood/montmorillonite nano-intercalation composites (China PhD thesis, 2004-10-9)" The composites prepared are in phenolic impregnated wood. Based on the introduction of nano-montmorillonite in wood.

At present, the composite modification of montmorillonite and wood is often carried out by a two-step method, that is, in order to improve the interlayer spacing of montmorillonite, the nano-effect of montmorillonite can be effectively exerted in the composite material, firstly for montmorillonite. Organic modification, organic modification of montmorillonite with cationic surfactant to form organically modified montmorillonite, and then organically modified montmorillonite and then compounded with high molecular polymer, impregnated with wood, two-step method Modified wood mainly The problem of infusion of wood is solved by means of an intermediate medium whose performance is largely dependent on the intermediate medium. In addition, the two-step preparation process is cumbersome and not easy to operate. The montmorillonite is not dispersed after being combined with the intermediate medium, and its larger particle size cannot enter the wood cell wall, so the nano-effect in the composite material cannot be effectively The effect is not significant enough, and the stability and mechanical strength of the modified wood are low. Summary of the invention

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a modifier for improving the dimensional stability of wood and a method for preparing the same, and a treatment method for modifying wood using the modifier, in view of the problems of the prior art described above. The composite modifier of the invention is prepared by a one-step process, and the process is simple and easy to operate; the dimensional stability, surface hardness and compressive strength of the wood treated by the composite modifier are effectively improved, and the properties of the modified wood are more improved. excellent.

In order to achieve the object of the present invention, an aspect of the present invention provides a wood modifier comprising sodium-based montmorillonite, a quaternary ammonium salt and a dispersing agent polyethylene glycol.

Wherein the quaternary ammonium salt is didecyldimethylammonium chloride or dodecyldimethylbenzylammonium chloride, preferably dimercaptodimethylammonium chloride.

Wherein, the ratio of the cation exchange amount of the sodium montmorillonite to the quaternary ammonium salt is 1:0.5. Preferably, the ratio of the cation exchange amount of the sodium montmorillonite to the dimercaptodimethylammonium chloride is 0-1. The weight ratio of the sodium montmorillonite to the dispersing agent polyethylene glycol is 1: 0. 1-0.

In particular, polyethylene glycol has a polyethylene glycol having a polymerization degree of 500 to 4,000, preferably a polyethylene glycol having a polymerization degree of 1,000 to 2,000.

In particular, the wood modifier also includes water, preferably deionized water.

Among them, the ratio of the weight of the montmorillonite having a particle size of lOMffl to the total weight of the montmorillonite in the wood modifier is 50:100.

In particular, the sodium-based montmorillonite has a mass percentage concentration in the wood modifier of 10 to 30%, preferably 20 to 30%, more preferably 20%.

Another aspect of the present invention provides a method for preparing a wood modifier, which comprises mixing a sodium-based montmorillonite, a quaternary ammonium salt, a polyethylene glycol and water, and then performing a dispersion treatment.

Wherein, the dispersing treatment is to uniformly mix sodium-based montmorillonite, quaternary ammonium salt, polyethylene glycol and water, and reduce the particle size of the sodium-based montmorillonite. Among them, the uniformly dispersed sodium-based montmorillonite, quaternary ammonium salt, polyethylene glycol, and water mixture are placed in a dispersion apparatus to carry out the dispersion treatment.

In particular, the dispersing device selects a ball mill, a high pressure homogenizer or a dispersing machine.

Wherein, the diameter of the large ball in the ball mill during the dispersion treatment by the ball mill is 9-l lmm, preferably 10 mm; the diameter of the small ball is 4-6, preferably 5 mm; the ratio of the number of the big ball to the small ball 1 : 6-15, preferably 1: 15

In particular, the dispersion treatment time during the dispersion treatment using the ball mill is 125-195 min; the rotation speed is 100-260 r/min.

In particular, in the ball mill dispersing process, the first ball mill is dispersed and processed for 5-15 min at a speed of 100-150 r/min; then, at a speed of 200_260 r/min, the ball mill is dispersed for 2_3h.

In particular, in the ball mill dispersing process, firstly, the ball mill is dispersed and treated at a speed of lOOr/min for 10 minutes; then, at a speed of 240 r/min, the ball mill is dispersed for 2 hours.

Wherein the quaternary ammonium salt is didecyldimethylammonium chloride or dodecyldimethylbenzylammonium chloride, preferably dimercaptodimethylammonium chloride; The polymerization degree is 500-4000, preferably 1000-2000. In particular, the ratio of the cation exchange amount of the sodium montmorillonite to the quaternary ammonium salt is 1:0.5. Preferably, the sodium montmorillonite and the dimercapto group are used. 0-1. The ratio of the weight ratio of the sodium montmorillonite to the dispersing agent polyethylene glycol is 1: 0. 1-0.

Wherein the ratio of the weight of the sodium montmorillonite to the total weight of the sodium montmorillonite, the quaternary ammonium salt, the polyethylene glycol and the water is 10-30:100, preferably 20-30:100, further preferably 20: 100

In particular, the ratio of the weight of the sodium montmorillonite to the total weight of the sodium montmorillonite, dimercaptodimethylammonium chloride, polyethylene glycol and water is from 10 to 30:100, preferably from 20 to 30: 100, further preferably 20: 100

Wherein the ratio of the weight of the montmorillonite having a particle size of lOMffl to the total weight of the montmorillonite in the wood modifier after the dispersion treatment is 50: 100

According to still another aspect of the present invention, there is provided a method for modifying wood by immersing the wood to be treated with the above wood modifier.

Wherein, the immersion treatment comprises two stages, wherein the first stage is subjected to a vacuum treatment in a vacuum state, and the second stage is subjected to a pressure treatment in a pressurized state.

In particular, the relative vacuum of the vacuum treatment is -0.05~-0. lMPa, preferably -0.07~-0.096MPa, and the treatment time is 20-60min; the relative pressure of the pressurized treatment is 1.0-4.0MPa The processing time is 30-120 min.

Further, the method further comprises adding water to the wood modifier, stirring and diluting, so that the mass percentage concentration of the montmorillonite in the wood modifier is 1-4%, and then performing the immersion treatment.

In particular, the concentration of sodium-based montmorillonite in the diluted wood modifier is 2-3% by mass.

Further, a drying treatment is carried out to dry the immersed wood to a constant weight, wherein the drying temperature is 55 to 65 °C. The advantages of the present invention are reflected in the following aspects:

1. The wood modifier of the invention is prepared by a one-step method, and only needs to disperse the sodium-based montmorillonite, dimercaptodimethylammonium chloride and the dispersing agent polyethylene glycol, and then disperse the treatment. For the two-step preparation, it is not necessary to first organically modify the montmorillonite and then compound with the polymer dispersant, and the process is simple and easy to operate.

2. The wood modifier of the invention has stable quality performance, small particle size, uniform dispersion, no agglomeration and precipitation phenomenon, and polyethylene glycol improves the dispersion stability of montmorillonite by steric hindrance and improves the interlayer spacing of montmorillonite. , to remove more montmorillonite layer, which is beneficial to the organic modification of sodium-based montmorillonite, so that the montmorillonite layer in the form of small pieces smoothly enters the wood cell wall, effectively solving the montmorillonite in aqueous solution. The disadvantage of poor suspension dispersion.

3. The interaction between dimercaptodimethylammonium chloride and sodium montmorillonite in the wood modifier of the invention improves the interlayer spacing of the montmorillonite, changes the hydrophilic environment between the montmorillonite layers, and simultaneously passes the static electricity. The effect is to improve the dispersion stability of the sodium-based montmorillonite, thereby further improving the suspension dispersibility of the sodium-based montmorillonite in the aqueous solution and improving the stability of the wood modifier.

4. The wood treated with the wood modifier of the invention has significantly enhanced wood properties, surface hardness and compressive strength, and can also significantly reduce the moisture absorption and moisture absorption of the wood, and the dimensional stability of the wood. Significant improvement.

5. The wood treated by the wood modifier of the invention has high crystallinity, reaching 86.11-93.94%, and the effective components of the modifier, montmorillonite, dimercaptodimethylammonium chloride and polyethylene glycol, pass through the tube. Channels such as cells, ray tracheids, and pits penetrate into the lumen of the wood cell, and the cations between the polyethylene glycol and the montmorillonite layer are complexed, and the resulting complex enters the wood during the wood modification process. The crystallization zone further combines with the hydroxyl groups in the cellulose, lignin, and hemicellulose in the wood, thereby promoting the intercalation of the montmorillonite layer into the wood cell wall, and the accumulation in the non-crystalline region of the wood enhances the amorphous region. Regularity, which promotes the mechanical properties of the treated wood, Surface hardness, compressive strength and the like have been significantly improved.

6. The ball modifier technology or high pressure homogenization dispersion technology is adopted in the preparation process of the wood modifier of the invention, which greatly reduces the agglomeration degree of the sodium-based montmorillonite particles and promotes the sodium-based montmorillonite and the polyethylene glycol. The opportunity for uniform mixing and contact reaction of dimercaptodimethylammonium chloride increases the chances of the active ingredients of the wood modifier entering and reacting with the wood components, thereby significantly increasing the resistance to loss of wood.

7. The active ingredient in the wood modifier of the present invention enters the wood cell wall in the process of entering the wood cell cavity through passages such as tracheids, pits, etc., the cell wall surface of the treated modified wood and the carbon inside the cell wall. The content is significantly reduced, and the corresponding contents of oxygen, silicon and aluminum are significantly increased. A considerable amount of montmorillonite covers the surface of the wood cell wall and enters the interior of the wood cell wall, thereby promoting the mechanical strength of the wood to be significantly improved. DRAWINGS

Figure 1 is an infrared analysis spectrum of wood;

2 is a scanning electron micrograph of wood, wherein (A) is a scanning electron micrograph of Comparative Example 5 without any treated wood; (B) is a scanning electron micrograph of the wood treated in Example 1; (C) is treated in Example 1. Scanning electron micrograph of the wood grain hole. Specific embodiment

In order to better understand the technical features of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the embodiments are not intended to limit the scope of the invention.

The wood is made of Cunninghamia lanceolate), which is collected in Nanning, Guangxi, without visible defects such as knots and decay, and the annual ring density is uniform; the dimensions are 19mm (longitudinal) x l9mm (chord direction) x l9mm (radial ;) The wood to be treated is placed in a drying oven at 60 ° C for constant weight;

Sodium-based montmorillonite (Na-MMT), 200 mesh, cation exchange capacity (CEC) of 90mmol/100g, Zhejiang Fenghong Clay Chemical Co., Ltd.;

Dimercaptodimethylammonium chloride (DDAC), 70% concentration, provided by Sanbo Biochemical Technology (Shanghai) Co., Ltd.; In addition to the use of dimercaptodimethylammonium chloride in the present invention, the quaternary ammonium salt can also be used. Dodecyldimethylbenzylammonium chloride was chosen.

Polyethylene glycol (PEG), polymerization degree is 500, 1000, 2000, 4000, Fushun Jiahua, Liaoning Province Chemical Co., Ltd. Example 1

1) Formulating wood modifiers

Adding sodium montmorillonite (Na-MMT), dimercaptodimethylammonium chloride (DDAC), polyethylene glycol (PEG-1000) with a degree of polymerization of 1000, and deionized water to the ball mill (Chunlong experimental instrument) In the ball mill, there are 75 ball mills with a diameter of 5mm and 5 balls with a diameter of 10mm. Firstly, after the dispersion treatment at lOOr/min, the ball mill is used. Grinding speed is increased to 240r/min, ball milling for 2h, the particle size of montmorillonite particles is reduced, that is, wood modifier, wherein sodium montmorillonite and dimercaptodimethylammonium chloride (DDAC) The ratio of cation exchange capacity (CEC) is 1:0.7; the weight ratio of sodium-based montmorillonite to polyethylene glycol 1000 (PEG-1000) is 1:0.2; the weight of sodium-based montmorillonite and sodium-based The ratio of the total weight of the soil, the DDAC, the PEG-1000 and the deionized water is 20: 100; the montmorillonite having a particle size of 10 Mm in the prepared wood modifier accounts for 52.48% of the total weight of the montmorillonite.

In the embodiment of the present invention, in addition to the dispersion treatment using a ball mill, the dispersion treatment may be carried out using a high pressure homogenizer.

The invention is subjected to dispersion treatment to mix and mix montmorillonite, DDAC and polyethylene glycol, and at the same time reduce the particle size of the montmorillonite, so that the weight of the montmorillonite having a particle size of 10Mffl in the prepared wood modifier accounts for the montmorillonite More than 50% of the total weight of the soil is suitable for use in the present invention.

2) vacuum pressure infusion treatment of wood

A) Add deionized water to the wood modifier, dilute and stir evenly to obtain a diluted wood modifier. The ratio of the weight of the added deionized water to the weight of the wood modifier is 9:1. The percentage by mass of montmorillonite in the wood modifier is 2%.

B) Place the wood in a vacuum pressurized tank, connect the vacuum equipment and the pressurizing equipment (ie, turn off the pressure pump when the vacuum pump is started to vacuum; turn off the vacuum pump when the pressure pump is turned on).

C) The vacuum pump is turned on for vacuuming, so that the relative vacuum in the vacuum pressurized tank reaches -0.09 MPa. After 30 minutes, the vacuum pump is turned off, and the diluted wood modifier having a mass percentage concentration of 2% prepared in the step A) is introduced. Until the relative vacuum in the vacuum pressurized tank is OMPa;

D) Turn on the pressure pump and continue to introduce the wood modifier with the mass percentage concentration of 2% prepared in step A) into the vacuum pressure tank, so that the relative pressure in the vacuum pressure tank reaches 2 MPa, and the wood is pressurized. , After maintaining this pressure for 60 min, the drain valve was opened, the pressure was released, the wood modifier was slowly drained and the wood treated with the wood modifier was removed.

3) Wood drying

Wipe the excess modifier on the surface of the infused wood and dry it in a blast oven at 60 °C to dryness. Example 2

In the process of formulating wood modifier, in addition to the polymerization degree of polyethylene glycol is 4000, the ratio of cation exchange capacity (CEC) of sodium montmorillonite to dimercaptodimethylammonium chloride is 1:0.5, sodium-based The weight ratio of de-soil to polyethylene glycol 4000 (PEG-4000) is 1:0.3, the weight of sodium-based montmorillonite and the total weight of sodium-based montmorillonite, DDAC, PEG-4000 and deionized water. The ratio is the same as that of the first embodiment except that the ratio is 30:100.

During the vacuum pressure impregnation treatment, the ratio of the weight of deionized water added in step A) to the weight of the wood modifier prepared in step 1) is 6.5: 1, the montmorillonite in the diluted wood modifier The mass percentage concentration was 4%; the relative vacuum degree of the vacuum treatment was -0.096 MPa, the vacuuming time was 20 min, the relative pressure of the pressurization treatment was 3 MPa, and the pressurization time was 40 min, and the rest was the same as in Example 1.

The wood drying process was the same as in Example 1. Example 3

In the process of formulating wood modifier, in addition to the polymerization degree of polyethylene glycol is 2000, the ratio of cation exchange capacity (CEC) of sodium montmorillonite to dimercaptodimethylammonium chloride is 1:0.75, sodium-based The weight ratio of de-soil to polyethylene glycol 2000 (PEG-2000) is 1:0.2, the weight of sodium-based montmorillonite and the total weight of sodium-based montmorillonite, DDAC, PEG-2000 and deionized water. The ratio is the same as that of the first embodiment except that the ratio is 20:100.

During the vacuum pressure impregnation treatment of wood, the ratio of the weight of deionized water added in step A) to the weight of the wood modifier prepared in step 1) is 5.67: 1, the sodium modifier in the diluted wood modifier The mass percentage concentration of the soil removal is 3%; the relative vacuum degree of the vacuum treatment is -0.07 MPa, the vacuuming time is 50 minutes, the relative pressure of the pressure treatment is 4 MPa, and the pressing time is 40 minutes, and the rest is the same as in the first embodiment. .

The wood drying process was the same as in Example 1. Example 4 In the process of formulating wood modifier, the polymerization degree of polyethylene glycol is 500, and the ratio of cation exchange capacity (CEC) of sodium montmorillonite to dimercaptodimethylammonium chloride is 1:1. The weight ratio of de-soil to polyethylene glycol 500 (PEG-500) is 1:0.1, the weight of sodium-based montmorillonite and the total weight of sodium-based montmorillonite, DDAC, PEG-500 and deionized water. The ratio is the same as that of the first embodiment except that the ratio is 10:100.

In vacuum impregnation immersion treatment, the ratio of the weight of deionized water added in step A) to the weight of wood modifier prepared in step 1) is 9: 1, montmorillonite in diluted wood modifier The mass percentage concentration was 1%; the relative vacuum degree of the vacuum treatment was -0.096 MPa, the vacuuming time was 20 min, the relative pressure of the pressurization treatment was 3 MPa, and the pressurization time was 40 min, and the rest was the same as in Example 1.

The wood drying process was the same as in Example 1. Comparative example 1

The rest was the same as in Example 1 except that the wood modifier was prepared as follows.

The wood modifier preparation steps are as follows:

1) Adding sodium montmorillonite (Na-MMT) to dimercaptodimethylammonium chloride (DDAC) to modify the modified organic montmorillonite with a particle size of 200, wherein sodium montmorillonite and The ratio of cation exchange capacity (CEC) of dimercaptodimethylammonium chloride is 1:1.5;

2) mixing the modified organic montmorillonite with dimercaptodimethylammonium chloride (DDAC) and polyethylene glycol 1000 (PEG-1000) having a degree of polymerization of 1000 to obtain a montmorillonite mixture, wherein The ratio of the cation exchange amount of the modified organic montmorillonite to the DDAC in the demineralized mixture is 1:0.7; the weight ratio of the modified organic montmorillonite to the polyethylene glycol 1000 (PEG-1000) is 1:0.2;

3) Next, the montmorillonite mixture was placed in a magnetic stirrer at a constant temperature of 60 ° C, and after heating for 3 hours, it was diluted with deionized water to prepare a wood modifier having a mass percentage concentration of montmorillonite of 2%. . Comparative example 2

In addition to the process of formulating the wood modifier, without adding sodium montmorillonite and without ball milling, directly mixing polyethylene glycol 1000 with dimercaptodimethylammonium chloride (DDAC), the rest and examples 1 is the same. Comparative Example 3

In addition to the preparation of wood modifiers, do not add polyethylene glycol 1000, directly sodium montmorillonite (Na-MMT) was the same as in Example 1 except that the ball milling was uniform with dimercaptodimethylammonium chloride (DDAC). Comparative Example 4

The same procedure as in Example 1 was carried out except that dimercaptodimethylammonium chloride (DDAC) was directly used as the wood modifier. Comparative Example 5

The raw material fir of Examples 1-4 was used as Comparative Example 5. Test example 1 Surface hardness test

The wood treated in Examples 1-4 and Comparative Examples 1-5 was subjected to a surface hardness test.

Wood prepared in Examples 1-4 and Comparative Examples 1-4 was measured using a Vickers microhardness tester (Shimadzu HMV-2, Japan) in accordance with the national standard "Metal Vickers Hardness Test Method" (GB/T 4340.1-1999). Surface hardness. When measuring, the load (test force) applied to the wood string section was 19.614 N, the loading time was 50 s, and each test was repeated 30 times.

The surface hardness test results of wood are shown in Table 1.

Table 1 Wood surface hardness test results

the result shows: 1. The surface hardness values of the wood of Comparative Example 4 and Comparative Example 5 are basically the same, indicating that the DDAC treatment has less influence on the surface hardness of the wood;

2. The surface hardness values of wood treated with Comparative Example 2 and Comparative Example 3 were all improved, indicating that both polyethylene glycol and montmorillonite have a certain effect on improving the surface hardness of wood, and montmorillonite is improved. The surface hardness of wood has a greater effect;

3. The wood treated in the first to fourth embodiments of the present invention has a high surface hardness and a hardness value of 312.4-406.5 HV, which indicates that the wood modifier prepared by the present invention can significantly improve the surface hardness of the wood;

4. The surface hardness of the wood treated in the first to fourth embodiments of the present invention is significantly higher than the surface hardness of the wood treated in the comparative example 1, indicating that the preparation method of the wood modifier of the present invention has a large influence on the surface hardness of the composite material. The wood modifier of the present invention has a remarkable effect on improving the surface hardness of the composite material.

5. The invention adopts DDAC, PEG and sodium-based montmorillonite for ball-milling dispersion, and the wood modifier prepared by the composite, sodium-based montmorillonite adsorbs DDAC and macromolecular PEG into the interlayer during the ball-milling dispersion process. The layer spacing is greatly improved, and some of the layers are even peeled off. The peeled montmorillonite layer enters the wood with a large amount of modifier, so that the nano-effect of montmorillonite is effectively exerted in the wood, so the surface hardness of the wood is remarkably improved. Test example 2 Wood compressive strength test

The striated and transverse grain compressive strength of the woods prepared in Examples 1-4 and Comparative Examples 1-5 were measured using a universal testing machine, and each test was repeated 5 times.

The results of the grain and cross-grain compressive strength of wood are shown in Table 2.

Table 2 Results of compressive strength test of wood

Comparative Example 3 49.74 12.73

Comparative Example 4 44.00 11.26 Comparative Example 5 43.27 10.02 The results indicate that:

1. Examples 1-4, Comparative Example 1-4 The wood treated with respect to the wood of Comparative Example 5 has a different degree of compressive strength and transverse compressive strength;

2. The grain compressive strength and the horizontal compressive strength of the wood treated with the wood modifier prepared by the present invention are remarkably improved.

For the wood grain and grain compressive strength of Example 1, the SPSS software was used to analyze the influence of the wood modifier and its effective components on the compressive properties of the treated material. The results are shown in Fig. 3.

Table 3 Correlation analysis between wood modifier and its active ingredients and compressive strength of treated materials

The analysis results show that the correlation coefficients of the treatment process and montmorillonite on the compressive strength of wood are 0.983 and 0.990, respectively, and the P value is 0.01, which is very statistically significant, while the PEG and DDAC are used in the stabilizer. The correlation coefficient of the compressive strength of the grain is 0.731 and 0.480, respectively, and the value of 1^ is >0.05, which is not statistically significant, indicating that the montmorillonite in the modifier of the present invention can significantly improve the compressive strength of the composite. However, the effect of DDAC and PEG in the modifier on the compressive strength of wood grain is not significant. It can be seen from Table 1 that the correlation coefficients of montmorillonite and PEG on the transverse compressive strength of wood are 0.881 and 0.885, respectively, and the P value is <0.05, which is statistically significant; while the treatment process and DDAC on wood The correlation coefficients were 0.864 and 0.738, respectively, P > 0.05, which was not statistically significant. It shows that under the joint action of montmorillonite and PEG in the modifier, the compressive strength of the grain is improved. The analysis results show that the wood can significantly improve the compressive strength of the wood under the action of the wood modifier of the invention. strength. Test Example 3 Wood moisture resistance rate and expansion and contraction resistance test

The moisture resistance (MEE) and the anti-expansion ratio (ASE) of the wood treated in Examples 1-4 and 1-5 were in accordance with the national standard "Method for Measuring Wood Wetness" (GB1934.2-2009). Wet Expansion Test Method Standards The moisture absorption and water swelling properties of the woods of Examples 1-4 and Comparative Examples 1-5 were measured. The moisture resistance (MEE) and the expansion and contraction resistance (ASE) of the composites were determined by the following formula:

Moisture Resistant Rate (MEE, %) = (W _{2 -} Wi) / Wi X 100% where W ₂ is the weight (g) of the untreated blank sample that absorbs moisture in the wet state.

The weight (g) of moisture absorbed in the wet state after treatment;

Resistance to expansion and contraction (ASE, %) = (S ₂ -Si) / Si X 100% where Si is the volume shrinkage or expansion coefficient (%) of the untreated blank test material,

S ₂ is the volume shrinkage or expansion coefficient (%) of the test material after treatment;

The results of the moisture absorption rate and the expansion and contraction resistance of the wood of Examples 1-4 and Comparative Examples 1-5 are shown in Table 4.

Table 4 Test results of moisture resistance and expansion and contraction rate of wood

the result shows:

1. The wood prepared according to Examples 1-4 of the present invention has a high moisture barrier rate of 33.03-38.39%, indicating that the wood modifier of the present invention can significantly reduce the moisture absorption and water absorption and the water absorption and swelling of the wood, and the dimensional stability of the wood is obtained. Significant improvement:

2. The moisture inhibition rate and the expansion and contraction resistance values of the wood prepared in Examples 1-4 of the present invention are significantly higher than those of the control example 1 The moisture inhibition rate and the anti-bulging and shrinkage ratio of the prepared wood indicate that the ball mill dispersion treatment method can improve the mixing uniformity of sodium-based montmorillonite and DDAC and PEG, and promote the sodium-based montmorillonite. Adsorption of DDAC and PEG molecules can also significantly reduce the particle size of sodium-based montmorillonite particles, making it easier for montmorillonite particles that adsorb large amounts of DDAC and PEG molecules to enter the wood, with more hydrophobic montmorillonite entering. The synergistic compatibilization of wood, PEG and montmorillonite significantly increases the dimensional stability of the wood. Test Example 4 Wood Infrared Spectroscopy Analysis

The wood treated in Examples 1-4 and Comparative Examples 1-5 was subjected to infrared spectrum analysis.

The wood prepared in Example 1 and Comparative Example 1 was characterized by Tensor27 type Fourier transform infrared spectroscopy (FTIR) manufactured by BRUKER, Germany.

The wood prepared in Examples 1-4 and Comparative Examples 1-5 was pulverized and passed through a 100 mesh sieve to obtain wood flour; the KBr tablet was used, wherein the mass ratio of wood powder to KBr was 1:100; Scanning in the mid-infrared region of the infrared spectrometer O^OOOcm- ¹ , the number of scans is 32, the resolution is ^m- ¹ , and the infrared absorption spectrum of the wood is obtained. Fig. 1 is the first embodiment, the comparative example 1, and the comparative example. Infrared spectroscopy comparison of 5 and sodium montmorillonite.

It can be seen from Figure 1:

1. The infrared spectrum of the wood prepared in Comparative Example 1 is basically the same as the infrared spectrum of the Chinese fir blank (ie, Comparative Example 5), indicating that a large amount of montmorillonite only enters the large cell cavity such as wood tracheid, but not Entering the wood cell wall, it does not interact with the three major components of wood (cellulose, hemicellulose, lignin);

2. The wood treated by the modifier of the present invention is near 521 cm- ¹ and 468^, and the coupled vibration of Si-0-M (metal cation) and M-0 of montmorillonite has an absorption peak, indicating that montmorillonite has entered Inside the wood;

3. Located near nSScm- ^{1 and} near η· ¹ are the vibration absorption bands of carboxyl and phenolic hydroxyl groups in wood, and the wood aromatic ring structure groups and vibration absorption peaks located near lS lOcm and MZScm, respectively. The characteristic absorption peaks of cellulose, cellulose and lignin, the infrared absorption peaks of the wood prepared in Comparative Example 1 were significantly weakened, indicating that the wood was subjected to a wood modifier containing DDAC, montmorillonite and polyethylene glycol. After treatment, the carboxylic acid group on the hemicellulose and the aromatic ring structural group of lignin and the phenolic hydroxyl group on the cellulose are dissociated to form a carboxylate anion and a phenolic anion, and the free DDAC ammonium cation And the cation bonding between the montmorillonite layers is a carboxylate and a phenate, resulting in a weakening of the infrared absorption there.

The crystallinity of wood affects the properties of wood strength, surface hardness and so on. The crystallinity of the wood is large, and the strength is raised. High, surface hardness increases, therefore, the crystallinity of wood is determined by infrared spectroscopy, and the crystallinity is determined as follows: Crystallinity (N.O'KI) = ai372cm-l/ a ₂ 900cm-l

Where KI is the crystallization index

a _1372a „ is the intensity of the band at 1372 cm- ¹

a ₂₉ oocm-i is the band intensity at ^Ο η· ¹

The crystallinity results of wood are shown in Table 5.

Table 5 Crystallinity of wood

As can be seen from Table 5, the crystallinity calculated by infrared spectroscopy of the wood prepared in Comparative Examples 2 and 4 was close to that of the untreated wood of Comparative Example 5, and slightly increased, while the wood prepared by Comparative Example 1 had a slightly higher crystallinity than that of Comparative Example 1. The wood treated in the control did not reach 70.37.

The crystallinity of the wood of Examples 1-4 of the present invention reached 86.11-93.94, which was significantly higher than that of the wood of Comparative Examples 1-5, indicating that the strength of the wood was greatly improved and the surface hardness was remarkably enhanced. In the process of grinding and dispersing the wood modifier of the invention, the polyethylene glycol and the sodium montmorillonite are complexed, and the wood modifier is infused with the wood, the polyethylene glycol and the montmorillonite complex In combination with the wood component, entering the amorphous zone of the wood, the accumulation of a large amount of montmorillonite crystals in the amorphous zone of the wood increases the regularity of the amorphous zone, greatly increasing the crystallinity of the treated wood, and correspondingly, the hardness of the wood. And the mechanical properties such as strength have also been significantly improved. Test example 5 Wood scanning electron microscopy analysis

The wood prepared in Example 1 and Comparative Example 5 was prepared into samples having smooth surfaces along different thickness directions. After vacuum gold plating, the surface of the sample was observed by S-3000N scanning electron microscope (SEM) manufactured by Titachi Co., Ltd., and the distribution of the active ingredients in the wood cell cavity was analyzed. The observation results are shown in Fig. 2.

Figure 2 (A) is a scanning electron micrograph of Comparative Example 5 without any treated wood; Figure 2 (B) is a scanning electron micrograph of the wood treated in Example 1; Figure 2 (C) is the wood grain treated in Example 1. Scanning electron micrograph.

It can be seen from Fig. 2(B) that a large amount of montmorillonite particles in the form of particles, agglomerates and flakes in the wood treated by the modifier of the present invention are deposited in the cell cavity of the treated material and on the surface of the cell cavity. . It can be seen from Fig. 2 (C) that the surface, the periphery and the pits of the pit are surrounded and filled with a large number of montmorillonite particles in a sheet structure, indicating that the active ingredients in the wood modifier mainly pass through the trachea, Channels such as ray tracheids and pits penetrate into the lumen of the wood cell. Test Example 6 Energy spectrum analysis of wood

The wood prepared in Example 1 and Comparative Example 5 was prepared into a smooth surface sample along different thickness directions. After vacuum gold plating, the surface of the sample was analyzed by a 7020-HX ray energy spectrometer (EDXA) manufactured by Horiba. selecting wood cell wall layer ₈₂ 5 points measured is the average value of five points of different elements in weight percentage of the value of the wood cell wall, the cell wall select a string section, measuring the weight of the different elements in the cell wall surface of the timber Percentage, the distribution of the active ingredients in the wood stabilizer was analyzed in the wood cell cavity. The analysis results are shown in Table 6.

C (%) 72.79 41. 57 57. 44 25.22 51.00

0 (%) 17.82 32. 98 20. 57 26.65 23.43

Si (%) 0.00 14. 37 1. 06 17.88 5.90

A1 (%) 0.00 4. 05 0. 42 5.51 2.05

Na (%) 0.78 0. 60 0. 40 0.70 0.75

Ca(%) 0.10 0. 07 0. 19 1.09 2.40

The results show:

1. The wood of Comparative Example 5 is mainly composed of carbon (C) and oxygen (0), both of which account for more than 90% by weight, and the contents of silicon (Si) and aluminum (A1) are zero;

2. In the wood of Example 1, the carbon content of the cell wall surface is significantly reduced, corresponding to oxygen, silicon, The aluminum content is significantly increased, the oxygen content is 26.65%, the silicon content is 17.88%, and the aluminum content is 5. 51%, indicating that a large amount of montmorillonite is filled in the cell cavity of the wood and covered. Wood cell wall surface;

3. The content of oxygen, silicon and aluminum in the cell wall of the wood of Example 1 was not higher than that in the cell chamber, but the content of silicon in the sample of Comparative Example 5 and Comparative Example 1 was 5. 9%, the content of the aluminum element reached 2.05%, indicating that the active ingredient of the wood modifier of the present invention enters the wood cell wall in the process of entering the wood cell cavity through channels such as tracheids, pits, etc., thereby promoting the wood Significant improvement in mechanical strength and the like.

Claims

Claim

A wood modifier comprising sodium montmorillonite, a quaternary ammonium salt and a dispersing agent polyethylene glycol.

The nucleus exchange ratio of the sodium montmorillonite to the quaternary ammonium salt is 1:0. 5-1.

The weight ratio of the sodium montmorillonite to the dispersing agent polyethylene glycol is 1: 0. 1-0.

The modifier according to claim 1 or 2, wherein the polyethylene glycol has a degree of polymerization of from 500 to 4,000.

5. A method for preparing a wood modifier, characterized in that a sodium-based montmorillonite, a quaternary ammonium salt, a polyethylene glycol and water are uniformly mixed, and then subjected to dispersion treatment.

The method according to claim 5, wherein the ratio of the cation exchange amount of the sodium montmorillonite to the quaternary ammonium salt is 1:0.5; the sodium montmorillonite and the dispersant重量。 The weight ratio of the polyethylene glycol is 1: 0. 1-0.

7. The method of claim 5 wherein the ratio of the weight of said sodium montmorillonite to the total weight of sodium montmorillonite, quaternary ammonium salt, polyethylene glycol and water is from 10 to 30: 100 .

A method for modifying wood characterized by: immersing the wood to be treated with the wood modifier according to any one of claims 1-4.

A method according to claim 8, wherein said immersion treatment comprises two stages, wherein the first stage is subjected to a vacuum treatment in a vacuum state, and the second stage is subjected to a pressure treatment in a pressurized state.

10. The method according to claim 9, wherein the vacuum treatment has a relative vacuum of -0.05 to -0.096 MPa and a treatment time of 20 to 60 minutes; and the relative pressure of the pressurized treatment is 1.0 to 4.0. MPa, treatment time is 30-120min.