A method for preparing biodegradable hydrophobic poplar veneer

Abstract

The invention discloses a method for preparing a biodegradable hydrophobic poplar veneer, comprising: immersing the poplar veneer in an alkali solution, reacting at 50-80°C for 4-8h, bleaching with a hydrogen peroxide solution after washing, and freeze-drying after washing to obtain a pretreated poplar veneer; adding triglycidyl isocyanurate and fumaric pimaric acid to a solvent, stirring and mixing to obtain a mixed solution; immersing the pretreated poplar veneer in the mixed solution, and impregnating under vacuum conditions; heating and curing the impregnated poplar veneer to obtain a biodegradable hydrophobic poplar veneer. The invention uses triglycidyl isocyanurate and fumaric pimaric acid as raw materials, and improves the hydrophobicity, flame retardancy, corrosion resistance, and heat resistance of the poplar veneer by curing and cross-linking the poplar veneer after impregnation.

Description

Technical Field

[0001] The invention relates to a method for preparing a biodegradable hydrophobic poplar veneer, and belongs to the technical field of natural resource modification. Background Art

[0002] Wood is a natural renewable material, mostly used in furniture, flooring and some buildings. It easily absorbs moisture from the air because it contains abundant fiber tissue, micropores and ducts that can produce capillary phenomena. Due to its inherent hydrophilicity and porous structure, natural wood is easily affected by the natural environment (such as light, humidity and temperature), causing some diseases (such as swelling and shrinkage, cracking, mildew, deformation, etc.), affecting its use value and ornamental value, and greatly shortening its service life.

[0003] The methods for hydrophobic treatment of the surface of general wood materials include: acetylation, impregnation, sol-gel, vapor deposition, hydrothermal, self-assembly, plasma, electrospinning, etc. Impregnation and coating are the more traditional and widely used methods for preparing super-hydrophobic wood. The coating used is a polymer with specific functions dissolved in an organic solvent and diluted to a certain proportion, and then some inorganic fillers are added to form a uniform and transparent coating. The impregnation method is to immerse the wood in the above-mentioned coating so that it penetrates into the interior of the wood to obtain hydrophobicity. The coating method is a method of forming a film on the surface of the wood by spraying or brushing.

[0004] Rosin is one of the main forest products in my country, with an annual output of 400,000 to 800,000 tons, ranking first in the world. Rosin derivatives (fumaric acid, propylene pimaric acid, maleopimaric acid, etc.) can significantly improve the thermal stability and mechanical properties of materials. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method for preparing a biodegradable hydrophobic poplar veneer. The biodegradable hydrophobic poplar veneer is obtained by adding triglycidyl isocyanurate and fumaric pimaric acid for cross-linking reaction.

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a biodegradable hydrophobic poplar veneer, comprising the following steps:

[0007] 1) immersing the poplar veneer in an alkali solution, reacting at 50-80° C. for 4-8 hours, washing and bleaching with a hydrogen peroxide aqueous solution, washing and freeze-drying to obtain a pretreated poplar veneer;

[0008] 2) adding triglycidyl isocyanurate and fumaric acid to a solvent, stirring and mixing to obtain a mixed solution;

[0009] 3) immersing the pretreated poplar veneer into the mixed solution under vacuum conditions;

[0010] 4) The impregnated poplar veneer is heated and cured to obtain a biodegradable hydrophobic poplar veneer.

[0011] Preferably, the alkali solution is a mixed aqueous solution of 2-5 mol / L sodium hydroxide and 0.1-1 mol / L anhydrous sodium sulfite.

[0012] Preferably, the concentration of the aqueous hydrogen peroxide solution is 2-5 mol / L.

[0013] Preferably, the solvent in step 2) is at least one of dichloromethane, acetonitrile, ethanol or ethyl acetate.

[0014] Preferably, the stirring and mixing temperature in step 2) is 20-40° C., the molar ratio of triglycidyl isocyanurate to fumaric acid in step 2) is 1:0.8-1:1.2, and the mass concentration of the mixed solution in step 2) is 20%-40%.

[0015] Preferably, the vacuum conditions in step 3) are a vacuum degree of 0.05 to 0.10 MPa, a temperature of 10 to 30° C., and an immersion time of 20 to 60 min.

[0016] Preferably, the heating and curing process described in step 4) is:

[0017] After curing at 40-80°C for 0.5-1h, curing at 110-150°C for 4-6h, and then curing at 160-200°C for 2-4h, cool down.

[0018] Preferably, the cooling process is to cool down to room temperature at a cooling rate of 5 to 8°C / min.

[0019] The beneficial effects achieved by the present invention are:

[0020] (1) A method for preparing a biodegradable hydrophobic poplar veneer of the present invention uses triglycidyl isocyanurate and fumaric pimaric acid as raw materials, and improves the hydrophobicity, flame retardancy, corrosion resistance and heat resistance of the poplar veneer by a method of curing and crosslinking after impregnation of the poplar veneer. By adding triglycidyl isocyanurate and fumaric pimaric acid to form a crosslinking network, the contact angle of the biodegradable hydrophobic poplar veneer reaches 110°, which significantly improves the hydrophobicity of the poplar veneer; at the same time, the maximum limiting oxygen index reaches 34.9, which has a good flame retardant effect; the mass loss rate of the obtained biodegradable hydrophobic poplar veneer is reduced to 9.6%, achieving Class I strong corrosion resistance, and at the same time, the thermal decomposition temperature is also increased, which effectively improves the heat resistance of the poplar veneer;

[0021] (2) The method for preparing a biodegradable hydrophobic poplar veneer of the present invention is easy to implement, and the biodegradable hydrophobic poplar veneer is obtained through simple reaction steps, which is suitable for industrial production;

[0022] (3) The method for preparing a biodegradable hydrophobic poplar veneer of the present invention modifies the poplar veneer by cross-linking and curing the natural modified derivatives, thereby avoiding the use of petroleum resources and complying with green and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a contact angle diagram of the biodegradable hydrophobic poplar veneer obtained by the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described below. The following examples are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0025] Take 5-8 mg of sample and perform TGA analysis on the sample. Under nitrogen protection, heat the temperature from room temperature to 800°C at a heating rate of 10°C / min.

[0026] The contact angle test was measured using a Drop Meter A-200 contact angle meter.

[0027] The corrosion resistance of plywood was tested according to GB / T 13942.1-2009, and the mass loss rate of each sample after decay was calculated and expressed as a percentage.

[0028] The flame retardancy is tested according to the limiting oxygen index standard GB / T2406.2-2009.

[0029] Example 1

[0030] A method for preparing a biodegradable hydrophobic poplar veneer comprises the following steps:

[0031] 1) immersing a poplar veneer of 50 mm in length×50 mm in width×2 mm in height into an aqueous solution containing 2.5 mol / L sodium hydroxide and 0.4 mol / L anhydrous sodium sulfite, reacting at 60° C. for 6 h, washing with distilled water, bleaching with a 2.5 mol / L hydrogen peroxide aqueous solution for 3 h, and freeze-drying for 24 h after washing to obtain a pretreated poplar veneer;

[0032] 2) adding 29.7 g of triglycidyl isocyanurate and 41.8 g of fumaric pimaric acid to 250 mL of acetonitrile, stirring and mixing to obtain a mixed solution;

[0033] 3) Immersing the pretreated poplar veneer in the mixed solution for 40 minutes under vacuum conditions of 0.10 MPa and 20°C;

[0034] 4) The impregnated poplar veneer is heated and cured at 60° C. for 1 hour, at 120° C. for 5 hours, and at 180° C. for 3 hours, and then cooled to room temperature at a cooling rate of 6° C. / min to obtain a biodegradable hydrophobic poplar veneer.

[0035] The contact angle diagram of the obtained biodegradable hydrophobic poplar veneer is as follows: Figure 1 As shown in a, the contact angle is 110°. Other performance test data of the obtained biodegradable hydrophobic poplar veneer are shown in Table 1.

[0036] Example 2

[0037] A method for preparing a biodegradable hydrophobic poplar veneer comprises the following steps:

[0038] 1) immersing a poplar veneer of 50 mm in length×50 mm in width×2 mm in height in an aqueous solution containing 5 mol / L sodium hydroxide and 1 mol / L anhydrous sodium sulfite, reacting at 80° C. for 8 h, washing with distilled water, bleaching with a 5 mol / L hydrogen peroxide aqueous solution for 2 h, and freeze-drying for 24 h after washing to obtain a pretreated poplar veneer;

[0039] 2) adding 29.7 g of triglycidyl isocyanurate and 41.8 g of fumaric pimaric acid to 300 mL of acetonitrile, stirring and mixing to obtain a mixed solution;

[0040] 3) Immersing the pretreated poplar veneer in the mixed solution for 60 minutes under vacuum conditions of 0.05 MPa and 30°C;

[0041] 4) The impregnated poplar veneer is heated and cured at 80°C for 1 hour, at 150°C for 6 hours, and at 200°C for 4 hours, and then cooled to room temperature at a cooling rate of 5°C / min to obtain a biodegradable hydrophobic poplar veneer.

[0042] The contact angle diagram of the obtained biodegradable hydrophobic poplar veneer is as follows: Figure 1 As shown in b, the contact angle is 105°. Other performance test data of the obtained biodegradable hydrophobic poplar veneer are shown in Table 1.

[0043] Example 3

[0044] A method for preparing a biodegradable hydrophobic poplar veneer comprises the following steps:

[0045] 1) immersing a poplar veneer of 50 mm in length × 50 mm in width × 2 mm in height in an aqueous solution containing 2 mol / L sodium hydroxide and 0.1 mol / L anhydrous sodium sulfite, reacting at 50° C. for 4 h, washing with distilled water, bleaching with a 2 mol / L hydrogen peroxide aqueous solution for 3 h, and freeze-drying for 24 h after washing to obtain a pretreated poplar veneer;

[0046] 2) adding 29.7 g of triglycidyl isocyanurate and 41.8 g of fumaric pimaric acid to 500 mL of acetonitrile, stirring and mixing to obtain a mixed solution;

[0047] 3) Immersing the pretreated poplar veneer in the mixed solution for 20 minutes under vacuum conditions of 0.08 MPa and 10°C;

[0048] 4) The impregnated poplar veneer is heated and cured at 40°C for 1 hour, at 110°C for 4 hours, and at 160°C for 2 hours, and then cooled to room temperature at a cooling rate of 8°C / min to obtain a biodegradable hydrophobic poplar veneer.

[0049] The contact angle diagram of the obtained biodegradable hydrophobic poplar veneer is as follows: Figure 1 As shown in c, the contact angle is 99°. Other performance test data of the obtained biodegradable hydrophobic poplar veneer are shown in Table 1.

[0050] Comparative Example

[0051] A method for preparing a poplar veneer comprises the following steps:

[0052] A poplar veneer with a size of 50 mm in length × 50 mm in width × 2 mm in height was immersed in an aqueous solution containing 2.5 mol / L sodium hydroxide and 0.4 mol / L anhydrous sodium sulfite, reacted at 60°C for 6 hours, washed with distilled water, bleached with a 2.5 mol / L hydrogen peroxide aqueous solution for 3 hours, and freeze-dried for 24 hours after washing to obtain a poplar veneer.

[0053] The contact angle diagram of poplar veneer is as follows: Figure 1 As shown in (d), the contact angle is 72°. Other performance test data of the obtained poplar veneer are shown in Table 1.

[0054] Table 1 Performance test

[0055]

[0056] As can be seen from Table 1, after the poplar veneer is impregnated with triglycidyl isocyanurate and fumaric acid for cross-linking and curing, the corrosion resistance, flame retardancy and heat resistance of the modified poplar veneer are improved, and as the concentration of triglycidyl isocyanurate and fumaric acid decreases, its performance also decreases. This is because the network cross-linked compounds formed by triglycidyl isocyanurate and fumaric acid help to improve the performance of the poplar veneer.

[0057] By adding triglycidyl isocyanurate and fumaric pimaric acid to form a cross-linked network, the contact angle of the biodegradable hydrophobic poplar veneer reaches 110°, significantly improving the hydrophobicity of the poplar veneer. At the same time, the maximum limiting oxygen index reaches 34.9, with good flame retardant effect. The mass loss rate of the obtained biodegradable hydrophobic poplar veneer is reduced to 9.6%, reaching Class I strong corrosion resistance, and the thermal decomposition temperature is also increased, effectively improving the heat resistance of the poplar veneer.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a biodegradable hydrophobic poplar veneer, characterized in that: The following steps are involved: 1) immersing the poplar veneer in an alkali solution, reacting at 50-80° C. for 4-8 hours, washing and bleaching with a hydrogen peroxide aqueous solution, washing and freeze-drying to obtain a pretreated poplar veneer; 2) adding triglycidyl isocyanurate and fumaric acid to a solvent, stirring and mixing to obtain a mixed solution; 3) immersing the pretreated poplar veneer into the mixed solution under vacuum conditions; 4) heating and curing the impregnated poplar veneer to obtain a biodegradable hydrophobic poplar veneer; The stirring and mixing temperature in step 2) is 20-40° C., the molar ratio of triglycidyl isocyanurate to fumaric acid in step 2) is 1:0.8-1:1.2, and the mass concentration of the mixed solution in step 2) is 20%-40%.

2. The method for preparing the biodegradable hydrophobic poplar veneer according to claim 1, characterized in that: The alkali solution is a mixed aqueous solution of 2-5 mol / L sodium hydroxide and 0.1-1 mol / L anhydrous sodium sulfite.

3. The method for preparing the biodegradable hydrophobic poplar veneer according to claim 1 or 2, characterized in that: The concentration of the aqueous hydrogen peroxide solution is 2-5 mol / L.

4. The method for preparing the biodegradable hydrophobic poplar veneer according to claim 1, characterized in that: The solvent in step 2) is at least one of dichloromethane, acetonitrile, ethanol or ethyl acetate.

5. The method for preparing the biodegradable hydrophobic poplar veneer according to claim 1, characterized in that: The vacuum conditions described in step 3) are as follows: vacuum degree of 0.05-0.10 MPa, temperature of 10-30° C., and immersion time of 20-60 min.

6. The method for preparing the biodegradable hydrophobic poplar veneer according to claim 1, characterized in that: The heating and curing process described in step 4) is: After curing at 40~80 °C for 0.5~1 h, cure at 110~150 °C for 4~6 h, and then cure at 160~200 °C for 2~4 h, then cool down.

7. The method for preparing the biodegradable hydrophobic poplar veneer according to claim 6, characterized in that: The cooling process is to cool the temperature to room temperature at a cooling rate of 5-8°C / min.

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