Anti-deformation environment-friendly composite board and production process thereof

Abstract

The application relates to the technical field of composite boards, and particularly discloses an anti-deformation environment-friendly composite board and a production process thereof. The composite board is made of amino-siloxane modified bamboo fibers, pyroglutamic acid-polyethylene glycol ester and poly-lactic acid which are mixed and then hot-pressed, secondarily compressed and shaped. The used materials have good degradability and reusability, meet the green environmental protection concept, have good stability and impact resistance, and can meet the demands of most users.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite board, in particular to an anti-deformation environment-friendly composite board and a production process thereof. BACKGROUND

[0002] Wood-plastic composite board is a new material produced by using polymer instead of adhesive and mixing with plant fiber and then extruding, injection molding and other plastic processing technology, which is widely used in building material construction, home decoration, logistics packaging and other industries. Because the raw material of wood-plastic composite board is polymer and plant fiber, it can replace solid wood in many fields, save resources, meet the concept of environmental protection, and is favored by people. Compared with solid wood board, wood-plastic composite board has the characteristics of wide raw material source, good processability, good corrosion resistance, good coloring performance, good reusability and green environmental protection. However, due to the poor combination between plant fiber and plastic, wood-plastic composite board has the problems of poor stability and impact resistance. SUMMARY

[0003] The present application relates to the technical field of composite board, in particular to an anti-deformation environment-friendly composite board and a production process thereof.

[0004] In order to solve the above technical problems, the present application provides the following technical scheme:

[0005] A preparation method of an anti-deformation environment-friendly composite board, the preparation method comprises the following steps:

[0006] The amino-siloxane modified bamboo fiber, pyroglutamic acid-polyethylene glycol ester and polylactic acid are uniformly mixed, and then mixed at 180-200 DEG C for 25-35 min. After the mixing is completed, the mixture is cooled, crushed, and then the composite board particles are obtained. The composite board particles are hot-pressed, the hot-pressing pressure is 4-6 MPa, the hot-pressing temperature is 170-190 DEG C, the hot-pressing time is 50-70 min, and then the hot-pressing is completed. After cooling to 110-130 DEG C, the second time is pressed and shaped, the second time shaping pressure is 4-6 MPa, the second time shaping time is 10-20 min, and then the shaped product is naturally cooled to room temperature. After taking out, the edge is processed, and the anti-deformation environment-friendly composite board is obtained.

[0007] As a limitation of the present application, the mass ratio of amino-siloxane modified bamboo fiber, pyroglutamic acid-polyethylene glycol ester and polylactic acid is (18-22):(24-26):(53-57).

[0008] As a limitation of the present application, the preparation method of the modified bamboo fiber is as follows:

[0009] Bamboo fibers were washed with deionized water to remove dust and impurities, and then dried at 55–65°C to obtain dried bamboo fibers. 2,2,6,6-Tetramethylpiperidine oxide, sodium bromide, sodium hypochlorite, and deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. The dried bamboo fibers and the tetramethylpiperidine oxidation solution were mixed, the pH was adjusted to alkaline, and the reaction was carried out at 55–65°C and 200–400 rpm for 0.5–1.5 h. After the reaction was completed, the bamboo fibers were filtered out, washed with deionized water, and dried at 25–30°C for 22–26 h to obtain carboxylated bamboo fibers.

[0010] Tetramethylammonium hydroxide, triethylamine, ethanol, acetonitrile, and deionized water were mixed to obtain a mixed amine solution. KH-550 was slowly added dropwise to the mixed amine solution, and the mixture was refluxed at 65-75°C and 200-400 rpm for 16-20 h. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain an amino-modified silsesquioxane.

[0011] Aminated silsesquioxane and deionized water were mixed and ultrasonically dispersed for 3-5 hours to obtain an aminated silsesquioxane dispersion. The aminated silsesquioxane dispersion was then mixed with carboxylated bamboo fiber and reacted at 35-45°C for 10-14 hours. After the reaction was completed, the mixture was filtered and dried at 55-65°C to obtain aminated siloxane-modified bamboo fiber.

[0012] As a limitation of the present invention, the tetramethylpiperidine oxidation solution comprises, by weight, 1.56 to 1.58 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.0 to 10.4 parts of sodium bromide, 44.2 to 44.6 parts of sodium hypochlorite, and 43.5 to 44.5 parts of deionized water.

[0013] As a limitation of the present invention, the mixed amine solution comprises, by weight, 0.2 to 0.4 parts tetramethylammonium hydroxide, 0.2 to 0.4 parts triethylamine, 18 to 22 parts ethanol, 8 to 12 parts acetonitrile, and 28 to 32 parts deionized water.

[0014] As a limitation of the present invention, the aminosiloxane-modified bamboo fiber, by weight, comprises 0.3 to 0.5 parts aminosilsesquioxane, 3 to 5 parts carboxylated bamboo fiber, and 90 to 100 parts deionized water.

[0015] As a limitation of the present invention, the preparation method of the pyroglutamic acid-polyethylene glycol ester is as follows:

[0016] Pyroglutamic acid, polyethylene glycol, and scandium trifluoromethanesulfonate were mixed and reacted at 170–190°C for 2–4 hours under nitrogen as a protective gas. The temperature was then raised to 195–205°C and the reaction continued for 1–3 hours. After the reaction was completed, the temperature was lowered to 125–135°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

[0017] As a limitation of the present invention, the pyroglutamic acid-polyethylene glycol ester comprises, by weight, 12.3 to 12.7 parts of pyroglutamic acid, 48.1 to 48.5 parts of polyethylene glycol, and 0.03 to 0.05 parts of scandium trifluoromethanesulfonate.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] Bamboo fibers are oxidized using a 2,2,6,6-tetramethylpiperidine oxide / sodium bromide / sodium hypochlorite system. This oxidizes the hydroxyl groups on the surface of the bamboo fibers to carboxyl groups, allowing amino-substituted silsesquioxanes to be grafted onto the bamboo fibers. This increases the contact area and roughness of the fiber surface, promotes the formation of hydrogen bonds between the fibers and polymers, enhances the bonding strength between the fibers and polymers, improves the compatibility between bamboo fibers and polymers, and also improves the mechanical properties of bamboo fibers. As a result, the strength, toughness, and impact resistance of the composite material are enhanced.

[0020] Modifying polyethylene glycol (PEG) with pyroglutamic acid improves PEG's structure, increases its molecular weight, and forms intermolecular hydrogen bonds with PEG, resulting in a two-dimensional hydrogen bond network. This reduces the migration rate of PEG within polylactic acid (PLA), decreases the tendency for phase separation, increases the compatibility between PEG and PLA, reduces the interaction forces between PLA molecular chains, and enhances the activity of PLA molecular chain segments. Consequently, it improves the toughness and elongation at break of the composite material. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Bamboo fiber (120 mesh) was provided by Anhui Sentai, polyethylene glycol (Mn=2000) was provided by Jiangsu Runfeng, and pyroglutamic acid (H815789), 2,2,6,6-tetramethylpiperidine oxide (T819129), and KH-550 (A800523) were provided by Shanghai Maclean.

[0023] Example 1: A method for preparing a deformation-resistant and environmentally friendly composite board, specifically as follows:

[0024] Step 1: Preparation of carboxylated bamboo fiber

[0025] Bamboo fiber was washed with deionized water to remove dust and impurities by weight, and then dried at 60°C to obtain dried bamboo fiber. 1.57 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.2 parts of sodium bromide, 44.4 parts of sodium hypochlorite, and 43.9 parts of deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. 5 parts of dried bamboo fiber and 100 parts of tetramethylpiperidine oxidation solution were mixed, and the pH was adjusted to 10.0 with sodium hydroxide solution. The mixture was reacted at 60°C and 300 rpm for 1.0 h. After the reaction was completed, the bamboo fiber was filtered out, washed with deionized water, and dried at 27°C for 24 h to obtain carboxylated bamboo fiber.

[0026] Step 2: Preparation of Aminated Silsesquioxanes

[0027] By mass, 0.3 parts tetramethylammonium hydroxide, 0.3 parts triethylamine, 20 parts ethanol, 10 parts acetonitrile, and 30 parts deionized water were mixed to obtain a mixed amine solution. 20 parts KH-550 were slowly added dropwise to 60.6 parts of the mixed amine solution, and the mixture was refluxed at 70°C and 300 rpm for 18 h. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain an amino-modified silsesquioxane.

[0028] Step 3: Preparation of Aminosiloxane-Modified Bamboo Fiber

[0029] By weight, 0.4 parts of aminated silsesquioxane and 95.6 parts of deionized water were mixed and ultrasonically dispersed for 4 hours to obtain an aminated silsesquioxane dispersion. 96 parts of the aminated silsesquioxane dispersion and 4 parts of carboxylated bamboo fiber were mixed and reacted at 40°C for 12 hours. After the reaction was completed, the mixture was filtered and dried at 60°C to obtain aminated siloxane-modified bamboo fiber.

[0030] Step 4: Preparation of pyroglutamic acid-polyethylene glycol ester

[0031] By weight, 12.5 parts of pyroglutamic acid, 48.3 parts of polyethylene glycol, and 0.04 parts of scandium trifluoromethanesulfonate were mixed and reacted at 180°C for 3 hours under nitrogen as a protective gas. The temperature was then raised to 200°C and the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 130°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

[0032] Step 5: Preparation of Deformation-Resistant and Environmentally Friendly Composite Board

[0033] By weight, 20 parts of aminosiloxane-modified bamboo fiber, 25 parts of pyroglutamic acid-polyethylene glycol ester, and 55 parts of polylactic acid are mixed evenly and kneaded at 190℃ for 30 minutes. After kneading, the mixture is cooled, pulverized, and composite board particles are obtained. The composite board particles are hot-pressed together at a pressure of 5 MPa, a temperature of 180℃, and a time of 60 minutes. After hot pressing, the mixture is cooled to 120℃ and then pressed and shaped again at a pressure of 5 MPa for 15 minutes. After shaping, the mixture is allowed to cool naturally to room temperature, removed, and trimmed to obtain an anti-deformation environmentally friendly composite board.

[0034] Example 2: A method for preparing a deformation-resistant and environmentally friendly composite board, specifically as follows:

[0035] Step 1: Preparation of carboxylated bamboo fiber

[0036] Bamboo fiber was washed with deionized water to remove dust and impurities by weight, and then dried at 60°C to obtain dried bamboo fiber. 1.57 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.2 parts of sodium bromide, 44.4 parts of sodium hypochlorite, and 43.9 parts of deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. 5 parts of dried bamboo fiber and 100 parts of tetramethylpiperidine oxidation solution were mixed, and the pH was adjusted to 10.0 with sodium hydroxide solution. The mixture was reacted at 60°C and 300 rpm for 1.0 h. After the reaction was completed, the bamboo fiber was filtered out, washed with deionized water, and dried at 27°C for 24 h to obtain carboxylated bamboo fiber.

[0037] Step 2: Preparation of Aminated Silsesquioxanes

[0038] By mass, 0.3 parts tetramethylammonium hydroxide, 0.3 parts triethylamine, 20 parts ethanol, 10 parts acetonitrile, and 30 parts deionized water were mixed to obtain a mixed amine solution. 20 parts KH-550 were slowly added dropwise to 60.6 parts of the mixed amine solution, and the mixture was refluxed at 70°C and 300 rpm for 18 h. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain an amino-modified silsesquioxane.

[0039] Step 3: Preparation of Aminosiloxane-Modified Bamboo Fiber

[0040] By weight, 0.4 parts of aminated silsesquioxane and 95.6 parts of deionized water were mixed and ultrasonically dispersed for 4 hours to obtain an aminated silsesquioxane dispersion. 96 parts of the aminated silsesquioxane dispersion and 4 parts of carboxylated bamboo fiber were mixed and reacted at 40°C for 12 hours. After the reaction was completed, the mixture was filtered and dried at 60°C to obtain aminated siloxane-modified bamboo fiber.

[0041] Step 4: Preparation of pyroglutamic acid-polyethylene glycol ester

[0042] By weight, 12.5 parts of pyroglutamic acid, 48.3 parts of polyethylene glycol, and 0.04 parts of scandium trifluoromethanesulfonate were mixed and reacted at 180°C for 3 hours under nitrogen as a protective gas. The temperature was then raised to 200°C and the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 130°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

[0043] Step 5: Preparation of Deformation-Resistant and Environmentally Friendly Composite Board

[0044] By weight, 18 parts of aminosiloxane-modified bamboo fiber, 24 parts of pyroglutamic acid-polyethylene glycol ester, and 53 parts of polylactic acid were mixed evenly and kneaded at 190℃ for 30 minutes. After kneading, the mixture was cooled and pulverized to obtain composite board particles. The composite board particles were then hot-pressed together at a pressure of 5 MPa, a temperature of 180℃, and a time of 60 minutes. After hot pressing, the mixture was cooled to 120℃ and then pressed and shaped again at a pressure of 5 MPa for 15 minutes. After shaping, the mixture was allowed to cool naturally to room temperature, removed, and trimmed to obtain an anti-deformation environmentally friendly composite board.

[0045] Example 3: A method for preparing a deformation-resistant and environmentally friendly composite board, specifically as follows:

[0046] Step 1: Preparation of carboxylated bamboo fiber

[0047] Bamboo fiber was washed with deionized water to remove dust and impurities by weight, and then dried at 60°C to obtain dried bamboo fiber. 1.57 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.2 parts of sodium bromide, 44.4 parts of sodium hypochlorite, and 43.9 parts of deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. 5 parts of dried bamboo fiber and 100 parts of tetramethylpiperidine oxidation solution were mixed, and the pH was adjusted to 10.0 with sodium hydroxide solution. The mixture was reacted at 60°C and 300 rpm for 1.0 h. After the reaction was completed, the bamboo fiber was filtered out, washed with deionized water, and dried at 27°C for 24 h to obtain carboxylated bamboo fiber.

[0048] Step 2: Preparation of Aminated Silsesquioxanes

[0049] By mass, 0.3 parts tetramethylammonium hydroxide, 0.3 parts triethylamine, 20 parts ethanol, 10 parts acetonitrile, and 30 parts deionized water were mixed to obtain a mixed amine solution. 20 parts KH-550 were slowly added dropwise to 60.6 parts of the mixed amine solution, and the mixture was refluxed at 70°C and 300 rpm for 18 h. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain an amino-modified silsesquioxane.

[0050] Step 3: Preparation of Aminosiloxane-Modified Bamboo Fiber

[0051] By weight, 0.4 parts of aminated silsesquioxane and 95.6 parts of deionized water were mixed and ultrasonically dispersed for 4 hours to obtain an aminated silsesquioxane dispersion. 96 parts of the aminated silsesquioxane dispersion and 4 parts of carboxylated bamboo fiber were mixed and reacted at 40°C for 12 hours. After the reaction was completed, the mixture was filtered and dried at 60°C to obtain aminated siloxane-modified bamboo fiber.

[0052] Step 4: Preparation of pyroglutamic acid-polyethylene glycol ester

[0053] By weight, 12.5 parts of pyroglutamic acid, 48.3 parts of polyethylene glycol, and 0.04 parts of scandium trifluoromethanesulfonate were mixed and reacted at 180°C for 3 hours under nitrogen as a protective gas. The temperature was then raised to 200°C and the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 130°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

[0054] Step 5: Preparation of Deformation-Resistant and Environmentally Friendly Composite Board

[0055] By weight, 22 parts of aminosiloxane-modified bamboo fiber, 26 parts of pyroglutamic acid-polyethylene glycol ester, and 57 parts of polylactic acid were mixed evenly and kneaded at 190℃ for 30 minutes. After kneading, the mixture was cooled and pulverized to obtain composite board particles. The composite board particles were then hot-pressed together at a pressure of 5 MPa, a temperature of 180℃, and a time of 60 minutes. After hot pressing, the mixture was cooled to 120℃ and then pressed and shaped again at a pressure of 5 MPa for 15 minutes. After shaping, the mixture was allowed to cool naturally to room temperature, removed, and trimmed to obtain an anti-deformation environmentally friendly composite board.

[0056] Based on Example 1, the following comparative experiments were conducted, specifically Comparative Example 1, Comparative Example 2, and Comparative Example 3, as described below:

[0057] Comparative Example 1: No amino-modified silsesquioxane was added, and the remaining conditions were the same as in Example 1.

[0058] A method for preparing a deformation-resistant and environmentally friendly composite panel, specifically comprising:

[0059] Step 1: Preparation of carboxylated bamboo fiber

[0060] Bamboo fiber was washed with deionized water to remove dust and impurities by weight, and then dried at 60°C to obtain dried bamboo fiber. 1.57 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.2 parts of sodium bromide, 44.4 parts of sodium hypochlorite, and 43.9 parts of deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. 5 parts of dried bamboo fiber and 100 parts of tetramethylpiperidine oxidation solution were mixed, and the pH was adjusted to 10.0 with sodium hydroxide solution. The mixture was reacted at 60°C and 300 rpm for 1.0 h. After the reaction was completed, the bamboo fiber was filtered out, washed with deionized water, and dried at 27°C for 24 h to obtain carboxylated bamboo fiber.

[0061] Step 2: Preparation of pyroglutamic acid-polyethylene glycol ester

[0062] By weight, 12.5 parts of pyroglutamic acid, 48.3 parts of polyethylene glycol, and 0.04 parts of scandium trifluoromethanesulfonate were mixed and reacted at 180°C for 3 hours under nitrogen as a protective gas. The temperature was then raised to 200°C and the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 130°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

[0063] Step 3: Preparation of Deformation-Resistant and Environmentally Friendly Composite Board

[0064] By weight, 20 parts of carboxylated bamboo fiber, 25 parts of pyroglutamic acid-polyethylene glycol ester, and 55 parts of polylactic acid are mixed evenly and kneaded at 190℃ for 30 minutes. After kneading, the mixture is cooled, pulverized, and composite board particles are obtained. The composite board particles are then hot-pressed together at a pressure of 5 MPa, a temperature of 180℃, and a time of 60 minutes. After hot pressing, the mixture is cooled to 120℃ and then pressed and shaped again at a pressure of 5 MPa for 15 minutes. After shaping, the mixture is allowed to cool naturally to room temperature, removed, and trimmed to obtain an anti-deformation environmentally friendly composite board.

[0065] Comparative Example 2: Non-aminated modified silsesquioxane, with other conditions as in Example 1.

[0066] A method for preparing a deformation-resistant and environmentally friendly composite panel, specifically comprising:

[0067] Step 1: Preparation of carboxylated bamboo fiber

[0068] Bamboo fiber was washed with deionized water to remove dust and impurities by weight, and then dried at 60°C to obtain dried bamboo fiber. 1.57 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.2 parts of sodium bromide, 44.4 parts of sodium hypochlorite, and 43.9 parts of deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. 5 parts of dried bamboo fiber and 100 parts of tetramethylpiperidine oxidation solution were mixed, and the pH was adjusted to 10.0 with sodium hydroxide solution. The mixture was reacted at 60°C and 300 rpm for 1.0 h. After the reaction was completed, the bamboo fiber was filtered out, washed with deionized water, and dried at 27°C for 24 h to obtain carboxylated bamboo fiber.

[0069] Step 2: Preparation of silsesquioxane

[0070] By mass, 20 parts KH-550, 20 parts ethanol, 10 parts acetonitrile, and 30 parts deionized water were mixed, and hydrochloric acid was added dropwise to adjust the pH. The mixture was refluxed at 70°C and 300 rpm for 18 hours. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain sesquioxane.

[0071] Step 3: Preparation of modified bamboo fiber

[0072] By weight, 0.4 parts of silsesquioxane and 95.6 parts of deionized water were mixed and ultrasonically dispersed for 4 hours to obtain a silsesquioxane dispersion. 96 parts of the silsesquioxane dispersion and 4 parts of carboxylated bamboo fiber were mixed and reacted at 40°C for 12 hours. After the reaction was completed, the mixture was filtered and dried at 60°C to obtain silsesquioxane-modified bamboo fiber.

[0073] Step 4: Preparation of pyroglutamic acid-polyethylene glycol ester

[0074] By weight, 12.5 parts of pyroglutamic acid, 48.3 parts of polyethylene glycol, and 0.04 parts of scandium trifluoromethanesulfonate were mixed and reacted at 180°C for 3 hours under nitrogen as a protective gas. The temperature was then raised to 200°C and the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 130°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

[0075] Step 5: Preparation of Deformation-Resistant and Environmentally Friendly Composite Board

[0076] By weight, 20 parts modified bamboo fiber, 25 parts pyroglutamic acid-polyethylene glycol ester and 55 parts polylactic acid are mixed evenly and kneaded at 190℃ for 30 minutes. After kneading, the mixture is cooled and pulverized to obtain composite board particles. The composite board particles are then hot-pressed together at a pressure of 5 MPa, a temperature of 180℃ and a time of 60 minutes. After hot pressing, the mixture is cooled to 120℃ and then pressed and shaped again at a pressure of 5 MPa for 15 minutes. After shaping, the mixture is allowed to cool naturally to room temperature, removed and trimmed to obtain an anti-deformation environmentally friendly composite board.

[0077] Comparative Example 3: No pyroglutamic acid was added, and the other conditions were the same as in Example 1.

[0078] A method for preparing a deformation-resistant and environmentally friendly composite panel, specifically comprising:

[0079] Step 1: Preparation of carboxylated bamboo fiber

[0080] Bamboo fiber was washed with deionized water to remove dust and impurities by weight, and then dried at 60°C to obtain dried bamboo fiber. 1.57 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.2 parts of sodium bromide, 44.4 parts of sodium hypochlorite, and 43.9 parts of deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. 5 parts of dried bamboo fiber and 100 parts of tetramethylpiperidine oxidation solution were mixed, and the pH was adjusted to 10.0 with sodium hydroxide solution. The mixture was reacted at 60°C and 300 rpm for 1.0 h. After the reaction was completed, the bamboo fiber was filtered out, washed with deionized water, and dried at 27°C for 24 h to obtain carboxylated bamboo fiber.

[0081] Step 2: Preparation of Aminated Silsesquioxanes

[0082] By mass, 0.3 parts tetramethylammonium hydroxide, 0.3 parts triethylamine, 20 parts ethanol, 10 parts acetonitrile, and 30 parts deionized water were mixed to obtain a mixed amine solution. 20 parts KH-550 were slowly added dropwise to 60.6 parts of the mixed amine solution, and the mixture was refluxed at 70°C and 300 rpm for 18 h. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain an amino-modified silsesquioxane.

[0083] Step 3: Preparation of Aminosiloxane-Modified Bamboo Fiber

[0084] By weight, 0.4 parts of aminated silsesquioxane and 95.6 parts of deionized water were mixed and ultrasonically dispersed for 4 hours to obtain an aminated silsesquioxane dispersion. 96 parts of the aminated silsesquioxane dispersion and 4 parts of carboxylated bamboo fiber were mixed and reacted at 40°C for 12 hours. After the reaction was completed, the mixture was filtered and dried at 60°C to obtain aminated siloxane-modified bamboo fiber.

[0085] Step 4: Preparation of Deformation-Resistant and Environmentally Friendly Composite Board

[0086] By weight, 20 parts of aminosiloxane-modified bamboo fiber, 25 parts of polyethylene glycol, and 55 parts of polylactic acid are mixed evenly and kneaded at 190°C for 30 minutes. After kneading, the mixture is cooled, pulverized, and composite board particles are obtained. The composite board particles are then hot-pressed together at a pressure of 5 MPa, a temperature of 180°C, and a time of 60 minutes. After hot pressing, the mixture is cooled to 120°C and then pressed and shaped again at a pressure of 5 MPa for 15 minutes. After shaping, the mixture is allowed to cool naturally to room temperature, removed, and trimmed to obtain an anti-deformation environmentally friendly composite board.

[0087] Testing experiment:

[0088] The deformation-resistant and environmentally friendly composite panels required for the experiment were prepared according to the preparation methods in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively.

[0089] Bending strength test: According to the "Wood-Plastic Composite Decorative Board" (GB / T 24137-2009), a universal testing machine was used to test the flexural strength of the six types of high-strength wear-resistant coated boards. The test specimens were cut from the six types of high-strength wear-resistant coated boards. The specimen size was 170mm×50mm×6mm. The specimens were placed flat on the support and a load was applied uniformly to the center of the specimen. The maximum load applied when the specimen was damaged was recorded and the bending strength of each specimen was calculated.

[0090] Impact resistance test: The test was conducted in accordance with the "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels" (GB / T 17657-2013). Samples were cut from the six types of high-strength wear-resistant coated boards. The sample size was 300mm×180mm×6mm. The sample was fixed on the fixture, and a piece of carbon paper was placed on the sample. A steel ball with a diameter of 42.8mm and a mass of 324g was used to strike the middle of the sample vertically from 1.75m above the sample. The diameter of the indentation was measured.

[0091] Dimensional stability test: Tests were conducted according to the "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels" (GB / T 17657-2013). Two batches of samples were cut from each of the six types of high-strength wear-resistant coated boards prepared, with sample sizes of 120mm × 120mm × 6mm. The samples were cured for 72 hours in a constant temperature and humidity environment at 23℃ and 50% relative humidity. The midpoint of each side was marked, and the distance between the midpoints of opposite sides (passing through the center point of the sample) was measured. One batch of samples was dried in a forced-air environment at 70℃ for 24 hours, then cooled to room temperature for 1 hour, and the distance between the opposite midpoints was measured again. The other batch of samples was treated in a constant temperature and humidity environment at 40℃ and 90% relative humidity for 96 hours. After treatment, the distance between the opposite midpoints was also measured, and the dimensional stability of the samples was calculated.

[0092]

[0093] Conclusion: The experiment shows that the anti-deformation environmentally friendly composite board prepared by the preparation method of Example 1 is superior to the anti-deformation environmentally friendly composite boards prepared by the preparation methods of Comparative Examples 1, 2, and 3 in bending strength test, impact resistance test, and dimensional stability test, effectively solving the problem of insufficient stability and impact resistance of wood-plastic composite boards.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a deformation-resistant and environmentally friendly composite panel, characterized in that: The preparation method is as follows: Aminosiloxane-modified bamboo fiber, pyroglutamic acid-polyethylene glycol ester, and polylactic acid are mixed evenly and kneaded at 180-200℃ for 25-35 minutes. After kneading, the mixture is cooled and pulverized to obtain composite board particles. The composite board particles are then hot-pressed together at a pressure of 4-6 MPa, a temperature of 170-190℃, and a time of 50-70 minutes. After hot pressing, the mixture is cooled to 110-130℃ and then pressed and shaped again at a pressure of 4-6 MPa for 10-20 minutes. After shaping, the mixture is allowed to cool naturally to room temperature, removed, and trimmed to obtain a deformation-resistant and environmentally friendly composite board. The preparation method of aminosiloxane-modified bamboo fiber is as follows: Bamboo fibers were washed with deionized water to remove dust and impurities, and then dried at 55–65°C to obtain dried bamboo fibers. 2,2,6,6-Tetramethylpiperidine oxide, sodium bromide, sodium hypochlorite, and deionized water were mixed and stirred evenly to obtain a tetramethylpiperidine oxidation solution. The dried bamboo fibers and the tetramethylpiperidine oxidation solution were mixed, the pH was adjusted to alkaline, and the reaction was carried out at 55–65°C and 200–400 rpm for 0.5–1.5 h. After the reaction was completed, the bamboo fibers were filtered out, washed with deionized water, and dried at 25–30°C for 22–26 h to obtain carboxylated bamboo fibers. Tetramethylammonium hydroxide, triethylamine, ethanol, acetonitrile, and deionized water were mixed to obtain a mixed amine solution. KH-550 was slowly added dropwise to the mixed amine solution, and the mixture was refluxed at 65-75°C and 200-400 rpm for 16-20 h. After reflux, the mixture was heated under vacuum to remove the solvent and washed with toluene to obtain an amino-modified silsesquioxane. Aminated silsesquioxane and deionized water were mixed and ultrasonically dispersed for 3-5 hours to obtain an aminated silsesquioxane dispersion. The aminated silsesquioxane dispersion was then mixed with carboxylated bamboo fiber and reacted at 35-45°C for 10-14 hours. After the reaction was completed, the mixture was filtered and dried at 55-65°C to obtain aminated siloxane-modified bamboo fiber. The preparation method of pyroglutamic acid-polyethylene glycol ester is as follows: Pyroglutamic acid, polyethylene glycol, and scandium trifluoromethanesulfonate were mixed and reacted at 170–190°C for 2–4 hours under nitrogen as a protective gas. The temperature was then raised to 195–205°C and the reaction continued for 1–3 hours. After the reaction was completed, the temperature was lowered to 125–135°C, and the mixture was vacuum filtered and dried to obtain pyroglutamic acid-polyethylene glycol ester.

2. The method for preparing a deformation-resistant and environmentally friendly composite board according to claim 1, characterized in that: The mass ratio of modified bamboo fiber, pyroglutamic acid-polyethylene glycol ester, and polylactic acid is (18-22):(24-26):(53-57).

3. The method for preparing a deformation-resistant and environmentally friendly composite panel according to claim 1, characterized in that: By weight, the tetramethylpiperidine oxidation solution comprises 1.56–1.58 parts of 2,2,6,6-tetramethylpiperidine oxide, 10.0–10.4 parts of sodium bromide, 44.2–44.6 parts of sodium hypochlorite, and 43.5–44.5 parts of deionized water.

4. The method for preparing a deformation-resistant and environmentally friendly composite panel according to claim 1, characterized in that: The mixed amine solution comprises, by mass, 0.2–0.4 parts tetramethylammonium hydroxide, 0.2–0.4 parts triethylamine, 18–22 parts ethanol, 8–12 parts acetonitrile, and 28–32 parts deionized water.

5. The method for preparing a deformation-resistant and environmentally friendly composite board according to claim 1, characterized in that: By weight, the aminosiloxane-modified bamboo fiber includes 0.3 to 0.5 parts aminosilsesquioxane, 3 to 5 parts carboxylated bamboo fiber, and 90 to 100 parts deionized water.

6. The method for preparing a deformation-resistant and environmentally friendly composite panel according to claim 1, characterized in that: By weight, pyroglutamic acid-polyethylene glycol ester comprises 12.3 to 12.7 parts pyroglutamic acid, 48.1 to 48.5 parts polyethylene glycol, and 0.03 to 0.05 parts scandium trifluoromethanesulfonate.

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