A mildew-proof and corrosion-resistant bamboo-plastic composite material and its preparation method

Abstract

The present application relates to the technical field of composite materials, and more particularly to a mildew- and corrosion-resistant bamboo-plastic composite material and its preparation method. The method comprises a mildew- and corrosion-resistant bamboo-plastic composite material comprising 40-45 parts of modified bamboo powder, 2-8 parts of ultrafine bamboo charcoal, and 60-65 parts of thermoplastic. The modified bamboo powder is plasma-treated and treated with a treatment solution containing PDMS. The plasma treatment enhances the interfacial bonding between the modified bamboo powder and the thermoplastic, and the dispersion forms a film layer on the surface of the modified bamboo powder, thereby enhancing the hydrophobicity of the modified bamboo powder surface and its compatibility with the thermoplastic. This improves the moisture resistance, flexural properties, impact strength, tensile strength, and mildew resistance of the mildew- and corrosion-resistant bamboo-plastic composite material.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to a mildew-proof and corrosion-resistant bamboo-plastic composite material and a preparation method thereof. Background Art

[0002] The bamboo industry is a pillar sector in our province, but currently, the industry faces a critical situation in terms of new product development, declining bamboo prices, and declining economic returns. Large quantities of bamboo processing residues, such as bamboo flour, are often burned as fuel, resulting in inefficient utilization and low added value. Combining bamboo flour with plastic to create composite materials is an effective way to efficiently utilize bamboo and increase its added value.

[0003] Bamboo-plastic composite material is a composite material made by mixing bamboo fiber and thermoplastic plastic in a certain proportion and then melt-extruded. Bamboo-plastic composite material has good product processing performance and is often used as building exterior walls, floors, outdoor plank roads, fences, pavilions, etc., becoming a composite material that is currently widely used in households.

[0004] However, bamboo-plastic composite materials are prone to mildew if placed in a humid environment for a long time; and when hydrophilic bamboo fiber is compounded with hydrophobic polymer plastic, the interfacial force between the two is greatly weakened, and the compatibility between the two is very poor, resulting in a decrease in the physical and mechanical properties of the composite material.

[0005] Currently, bamboo-plastic composites are often prepared by adding polyethylene grafted with maleic anhydride to improve the interfacial compatibility between bamboo powder and thermoplastics. However, this lack of compatibility provides poor protection against mildew and corrosion. Improving the interfacial compatibility between bamboo powder and thermoplastics while also enhancing their anti-mildew and anti-corrosion properties is crucial in today's world of promoting the principles of "eliminating waste, improving resource utilization, and creating a conservation-oriented society." Manufacturing bamboo-plastic composites with superior mechanical properties and mildew and corrosion resistance is crucial. Summary of the Invention

[0006] In order to solve the problem that existing bamboo-plastic composite materials are difficult to have high mechanical and mildew and anti-corrosion properties at the same time, the present application provides a mildew and anti-corrosion bamboo-plastic composite material and a preparation method thereof.

[0007] In a first aspect, the present application provides a method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material.

[0008] A mildew-proof and anti-corrosion bamboo-plastic composite material, comprising, by weight, 40-45 parts of modified bamboo powder, 2-8 parts of ultrafine bamboo charcoal, and 60-65 parts of thermoplastic plastic, wherein the thermoplastic plastic is PP or PE;

[0009] The modified bamboo powder is prepared by plasma treatment of bamboo powder;

[0010] The mildew-proof and anti-corrosion bamboo-plastic composite material is prepared by blending, melting, extruding, cooling and granulating modified bamboo powder, ultrafine bamboo charcoal and thermoplastic plastic.

[0011] By adopting the above technical solution, 40-45 parts of modified bamboo powder, 2-8 parts of ultrafine bamboo charcoal and 60-65 parts of thermoplastic plastic are used in combination, and the modified bamboo powder is subjected to plasma treatment, the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance level of the prepared mildew-proof and anti-corrosion bamboo-plastic composite material are significantly improved.

[0012] The reason may be that the ultrafine bamboo charcoal promotes the dispersion between modified bamboo powder and thermoplastic plastics; further, the plasma treatment improves the adsorption of the modified bamboo powder surface, increases the adsorption degree of the bamboo powder surface modification treatment liquid, and improves the interfacial bonding strength with the thermoplastic plastics, so that the prepared mildew-proof and anti-corrosion bamboo-plastic composite material has better moisture resistance, bending performance, impact strength, tensile strength and mildew resistance grade.

[0013] Preferably, the plasma treatment process is to use DBD plasma to treat the bamboo powder, with a flow meter flow rate of 0.5-0.8 L / min, a power of 500-1000 W, and a treatment time of 10-15 s.

[0014] By adopting the above technical solution, the polar groups on the surface of bamboo powder are increased, and the bonding force between bamboo powder and thermoplastic plastics or other raw materials is enhanced, thereby improving the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance level of the prepared mildew-proof and anti-corrosion bamboo-plastic composite material.

[0015] Preferably, in the preparation process of the modified bamboo powder, after plasma treatment, the bamboo powder is soaked in a treatment liquid for 5-10 minutes with a bath ratio of (1-5):100, and then dried at 30-40°C for 18-24 hours to prepare the modified bamboo powder; the treatment liquid comprises, by mass, 5-7 parts of PDMS, 40-45 parts of ethanol and 50-55 parts of petroleum ether.

[0016] By adopting the above technical solution, after the bamboo powder is treated with plasma, it is then immersed in a dispersion containing PDMS as soon as possible. The siloxy groups contained in the film layer formed on the surface of the bamboo powder improve the hydrophobicity of the surface of the modified bamboo powder, and improve the moisture resistance and mildew resistance of the modified bamboo powder. The alkyl side groups in the PDMS molecular chain have good compatibility with thermoplastic plastics, so that the prepared mildew-proof and anti-corrosion bamboo-plastic composite material has good moisture resistance, bending performance, impact strength, tensile strength and mildew resistance.

[0017] Preferably, the particle size of the bamboo powder is 40-200 mesh, the viscosity of the PDMS is 1000-2000 cps; and the particle size of the ultrafine bamboo charcoal is greater than 300 mesh.

[0018] By adopting the above technical solution, bamboo powder with appropriate particle size is preferably used in combination with PDMS with moderate viscosity, and the modified bamboo powder with good dispersibility reduces the crystallinity of the thermoplastic, making it easier for PDMS to migrate to the surface of the mildew-proof and anti-corrosion bamboo-plastic composite material to form a hydrophobic film layer, thereby reducing the moisture entering the mildew-proof and anti-corrosion bamboo-plastic composite material and improving the moisture resistance and mildew resistance level.

[0019] When the particle size of bamboo powder is too small, the viscosity of PDMS is too high, which is not conducive to the migration of PDMS to the surface of the mildew-proof and anti-corrosion bamboo-plastic composite material; when the particle size of bamboo powder is too large, when subjected to external force, stress concentration is more likely to occur inside the mildew-proof and anti-corrosion bamboo-plastic composite material, resulting in a decrease in mechanical properties.

[0020] Preferably, the treatment liquid further comprises, by weight, 0.5-1 parts of a silane coupling agent, 1-2 parts of a silane-modified polymer, 1-2 parts of vinyl silicone oil, and 0.5-0.8 parts of water.

[0021] By adopting the above technical solution, high-vinyl silicone oil, silane coupling agent, and silane-modified polymer form a film layer containing both siloxy groups and alkane groups. The siloxy groups improve the hydrophobicity of the film layer, and the alkane groups improve the compatibility of the modified bamboo powder with thermoplastic plastics. The silane coupling agent, on the one hand, promotes the dispersibility of various raw materials in the treatment liquid; on the other hand, the silanol formed by the aqueous siloxane improves the bonding force between the modified bamboo powder and thermoplastic plastics, thereby improving the hydrophobicity of the surface film layer of the modified bamboo powder, and the compatibility and bonding force between the modified bamboo powder and thermoplastic plastics, thereby further improving the moisture resistance, bending properties, impact strength, tensile strength and mildew resistance grade of the prepared mildew-proof and anti-corrosion bamboo-plastic composite material.

[0022] Preferably, the vinyl silicone oil is high vinyl silicone oil.

[0023] By adopting the above technical solution, the vinyl content of high-vinyl silicone oil is higher than that of terminal vinyl silicone oil, which is more conducive to improving the compatibility of modified bamboo powder and thermoplastic plastics, and improving the moisture resistance, bending properties, impact strength and tensile strength of the prepared mildew-proof and anti-corrosion bamboo-plastic composite material.

[0024] Preferably, the treatment liquid further comprises 1-2 parts by mass of hydrogen-containing silicone oil; the hydrogen-containing silicone oil has a viscosity of 40-100 MPa·s and a hydrogen content of 1.1-4.2 mmol / g.

[0025] By employing this technical solution, the low-viscosity hydrogenated silicone oil improves the film's density, strength, and bonding strength. The synergistic performance of the high-vinyl silicone oil, silane coupling agent, silane-modified polymer, and hydrogenated silicone oil further enhances the resulting mildew- and corrosion-resistant bamboo-plastic composite's moisture resistance, flexural properties, impact strength, tensile strength, and mildew resistance.

[0026] Preferably, the PE is polyethylene using high-density polyethylene 5000s.

[0027] By adopting the above technical solution, high-density polyethylene and modified bamboo powder have a better compatibility effect. Compared with low-density polyethylene, the molecules of high-density polyethylene are arranged regularly and stacked tightly, which is beneficial to improving the moisture resistance and mildew resistance of the mildew-proof and anti-corrosion bamboo-plastic composite material; the better strength of high-density polyethylene is beneficial to improving the comprehensive mechanical properties of the mildew-proof and anti-corrosion bamboo-plastic composite material.

[0028] Preferably, the granulation temperature is 165-170°C;

[0029] The temperatures of each section of the screw extruder are as follows: zone 1 140-170°C, zone 2 140-170°C, zone 3 145-170°C, zone 4 160-175°C, zone 5 170-180°C, zone 6 170-180°C, zone 7 175-180°C, zone 8 170-190°C, zone 9 160-190°C, and the die head temperature is 160-180°C.

[0030] By adopting the above technical solution, the raw materials for preparing the mildew-proof and anti-corrosion bamboo-plastic composite material are evenly dispersed, and the hydrogenated silicone oil in the film layer on the surface of the modified bamboo powder in a high-temperature molten state reacts with the active groups, vinyl groups, silanols, etc. on the surface of the bamboo powder, thereby improving the strength of the formed film layer, thereby improving the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance grade of the prepared mildew-proof and anti-corrosion bamboo-plastic composite material.

[0031] On the other hand, the present application provides a mildew-proof and corrosion-resistant bamboo-plastic composite material.

[0032] A mildew-proof and anti-corrosion bamboo-plastic composite material is prepared by the method for preparing the mildew-proof and anti-corrosion bamboo-plastic composite material in this application. The mildew-proof and anti-corrosion bamboo-plastic composite material has high moisture resistance, bending performance, impact strength, tensile strength and mildew-proof and anti-corrosion performance.

[0033] In summary, this application has the following beneficial effects:

[0034] 1. The mildew-proof and anti-corrosion bamboo-plastic composite material of the present application uses 40-45 parts of modified bamboo powder, 2-8 parts of ultrafine bamboo charcoal, and 60-65 parts of thermoplastic plastic in combination. The modified bamboo powder is plasma-treated and treated with a treatment solution containing PDMS. The plasma treatment improves the interfacial bonding between the modified bamboo powder and the thermoplastic plastic. The dispersion forms a film layer on the surface of the modified bamboo powder, thereby improving the hydrophobicity of the modified bamboo powder surface and its compatibility with the thermoplastic plastic, thereby improving the moisture resistance, flexural properties, impact strength, tensile strength, and mildew resistance level of the mildew-proof and anti-corrosion bamboo-plastic composite material.

[0035] 2. Optimize the particle size of bamboo powder and the viscosity of PDMS to further improve the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance of the mildew-proof and anti-corrosion bamboo-plastic composite material.

[0036] 3. Furthermore, hydrogenated silicone oil, high vinyl silicone oil, silane coupling agent, silane-modified polymer and water are used in the treatment liquid, which further improves the hydrophobicity of the surface film layer of the modified bamboo powder, the compatibility and bonding strength with thermoplastic plastics, and further improves the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance level of the mildew-proof and anti-corrosion bamboo-plastic composite material. DETAILED DESCRIPTION

[0037] raw material

[0038] Polypropylene (brand: B8101, standard material, injection molding grade, Vicat softening point: 154°C), high-density polyethylene 5000s (standard material, melt flow rate 1.2 g / 10 min).

[0039] Preparation examples of intermediates

[0040] Preparation Example 1, a method for preparing modified bamboo powder, using raw materials as shown in Table 1, including the following preparation steps:

[0041] Preparation of treatment liquid: PDMS (polydimethylsiloxane) was mixed with ethanol and petroleum ether (C30-C60), and then ultrasonically dispersed at 40 kHz for 10 minutes to prepare a treatment liquid for use.

[0042] Plasma treatment of bamboo powder: O2 is used as the plasma working gas, the bamboo powder is placed in the PG-3000HDBD plasma reaction chamber, the lid is closed, the O2 cylinder is opened, the O2 flow rate is set to 0.5L / min through the flow meter, and the plasma reaction chamber is kept ventilated for more than 30s (the air in the reaction chamber is removed), then the plasma is turned on and the power is set to 1000W. After 10s of treatment, the plasma gas is turned off and the O2 cylinder is closed, and the plasma treatment of the bamboo powder is completed.

[0043] Preparation of modified bamboo powder: After the bamboo powder is treated with plasma, it is immersed in the treatment solution within 8±2 minutes, treated under ultrasonic conditions of 60KHz for 10 minutes, with a bath ratio of 1:100, and then dried at 30°C for 70 hours to prepare the modified bamboo powder.

[0044] Preparation Example 2-3, a preparation method of modified bamboo powder, differs from Preparation Example 1 in that the types and weights of raw materials used and the preparation process settings are different, as shown in Table 1.

[0045] Table 1. Types and weights of raw materials used in the preparation method of modified bamboo powder of Preparation Example 1 and the setting list of the preparation process

[0046]

[0047] Preparation Example 4, a method for preparing modified bamboo powder, differs from Preparation Example 1 in that no impregnation liquid treatment is performed after plasma treatment.

[0048] Preparation Example 5, a method for preparing modified bamboo powder, differs from Preparation Example 1 in that the treatment liquid further includes hydrogenated silicone oil, vinyl silicone oil, silane coupling agent, silane-modified polymer, and water. PDMS, ethanol, petroleum ether, vinyl silicone oil, silane coupling agent, silane-modified polymer, and water are mixed and stirred at 50±5°C for 30 minutes, then cooled to 25±5°C and hydrogenated silicone oil is added. The specific amount is shown in Table 2.

[0049] Table 2. Types and weights of raw materials and preparation process settings for the treatment solutions in Preparation Examples 5-7

[0050]

[0051] Preparation Example 8, a preparation method for modified bamboo powder, is different from Preparation Example 5 in that the particle size of the bamboo powder is set to 60 mesh.

[0052] Preparation Example 9 is a method for preparing modified bamboo powder. The difference from Preparation Example 5 is that bamboo powder with a particle size of 30 mesh is used; and PDMS with a viscosity of 3000 cps is used.

[0053] Preparation Example 10 is a method for preparing modified bamboo powder. The difference from Preparation Example 5 is that bamboo powder with a particle size of 300 mesh is used; and PDMS with a viscosity of 500 cps is used.

[0054] Preparation Example 11, a method for preparing modified bamboo powder, differs from Preparation Example 5 in that an equal amount of vinyl-terminated silicone oil with a viscosity of 10,000 MPa·s and a vinyl content of 0.36 mmol / g is used to replace the high-vinyl silicone oil; and water is not used.

[0055] Preparation Example 12 is a method for preparing modified bamboo powder, which differs from Preparation Example 5 in that no silane coupling agent, silane-modified polymer, and water are used.

[0056] Preparation Example 13, a preparation method for modified bamboo powder, differs from Preparation Example 5 in that vinyl silicone oil and hydrogen-containing silicone oil are not used.

[0057] Preparation Example 14, a method for preparing modified bamboo powder, differs from Preparation Example 5 and Example 1 in that maleic anhydride-grafted polyethylene is used to replace the vinyl silicone oil, silane coupling agent, silane-modified polymer and hydrogen-containing silicone oil in equal amounts.

[0058] Preparation Example 15, a preparation method for modified bamboo powder, differs from Preparation Example 5 in that, in the preparation of the modified bamboo powder, the drying temperature is 50° C., the drying time is 75 h, and ethanol and water are not used.

[0059] Example

[0060] Example 1, a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material, using raw materials as shown in Table 3, and the preparation process is as follows:

[0061] The modified bamboo powder, ultrafine bamboo charcoal and polyethylene are blended and melt-extruded by a twin-screw extruder, and then cooled and granulated at a granulation temperature of 160°C.

[0062] The temperatures of each section of the screw extruder are as follows: zone 1 140°C, zone 2 140°C, zone 3 145°C, zone 4 160°C, zone 5 170°C, zone 6 170°C, zone 7 180°C, zone 8 170°C, zone 9 160°C, die head temperature 160°C, extrusion pressure 30 MPa; screw speed 15 rpm.

[0063] Example 2, a mildew-proof and anti-corrosion bamboo-plastic composite material, differs from Example 1 in that the types, weights, and preparation processes of the raw materials used are different. The raw materials used are shown in Table 3, and the preparation process is as follows:

[0064] Granulation temperature 165℃.

[0065] The temperatures of each section of the screw extruder are as follows: zone 1 150°C, zone 2 145°C, zone 3 150°C, zone 4 165°C, zone 5 172°C, zone 6 175°C, zone 7 175°C, zone 8 173°C, zone 9 165°C, die head temperature 165°C, extrusion pressure 30 MPa; screw speed 18 rpm.

[0066] Example 3, a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material, differs from Example 1 in that the types, weights, and preparation processes of the raw materials used are different. The raw materials used are shown in Table 3, and the preparation process is as follows:

[0067] Granulation temperature 170℃.

[0068] The temperatures of each section of the screw extruder are as follows: zone 1 170°C, zone 2 170°C, zone 3 170°C, zone 4 175°C, zone 5 180°C, zone 6 180°C, zone 7 185°C, zone 8 190°C, zone 9 190°C, die head temperature 180°C, extrusion pressure 35 MPa; screw speed 20 rpm.

[0069] Table 3. List of types and weights of raw materials used in the preparation method of mildew-proof and anti-corrosion bamboo-plastic composite materials of Examples 1-3

[0070]

[0071] Example 4-15 is a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material. The difference from Example 1 is that the modified bamboo powder is prepared by the preparation methods of the modified bamboo powder of Preparation Examples 4-15.

[0072] Comparative Example

[0073] Comparative Example 1 is a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material. The difference from Example 1 is that an equal amount of bamboo powder is used to replace the modified bamboo powder.

[0074] Comparative Example 2 is a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material. The difference from Example 1 is that bamboo powder is used in equal amount to replace the modified bamboo powder; and ultrafine bamboo charcoal is not used.

[0075] Comparative Example 3 is a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material. The difference from Example 1 is that plasma treatment is not used in the process of modifying bamboo powder; ultrafine bamboo charcoal is not used.

[0076] Comparative Example 4, a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material, differs from Example 1 in that an equal amount of bamboo powder is used to replace the modified bamboo powder; 9 kg of ultrafine bamboo charcoal is used; and 75 kg of high-density polyethylene 5000s is used.

[0077] Comparative Example 5, a method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material, differs from Example 1 in that an equal amount of bamboo powder is used to replace the modified bamboo powder; 1 kg of ultrafine bamboo charcoal is used; and 55 kg of high-density polyethylene 5000s is used.

[0078] Performance testing

[0079] Test 1: Moisture resistance

[0080] Evaluate the test samples with reference to GB / T1034-2008. Place the test sample particles in a 50°C oven and dry for 24 hours. Take them out and cool them to room temperature in a desiccator. The mass is weighed as m1. Then, place the test sample in a constant temperature and humidity chamber with a relative humidity of 55% and a temperature of 25°C. After 24 hours and 48 hours, weigh the test sample masses as m2 and m3 respectively. Calculate the water absorption after 24 hours and 48 hours according to the following formulas: c1 = (m2-m1) / m1*100% and c2 = (m3-m1) / m1*100%. Test at least 3 parallel samples for each set of test data and take the average value.

[0081] Test 2: Bending properties

[0082] The flexural strength and flexural elastic modulus of the test samples were evaluated according to GB / T9341-2008.

[0083] Test 3: Impact strength

[0084] The impact strength of the test samples was evaluated in accordance with GB / T1043.1-2008.

[0085] Test 4: Tensile Strength

[0086] The Type V specimen in the reference standard "ASTM D 638-10 Standard Test Method for Tensile Properties of Plastics" was prepared, with a total length of 63.5 cm, a middle parallel section width of 3.18 mm, a thickness of 3.54 mm, a test gauge length of 25 mm, and a loading speed of 10 mm / min.

[0087] Test 5: Mildew resistance level

[0088] The test samples were evaluated according to ASTM G21. 0 - no mold growth; 1 - mold growth area less than 10%; 2 - mold growth coverage of 10-30%; 3 - mold growth coverage of 30-60%; 4 - mold growth coverage greater than 60%.

[0089] Test samples: The mildew-proof and anti-corrosion bamboo-plastic composite materials prepared by using Examples 1-15 are used as example samples; the mildew-proof and anti-corrosion bamboo-plastic composite materials prepared by using Comparative Examples 1-5 are used as comparative example samples.

[0090] Test results: For the test results of the moisture resistance, bending properties, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 1-15 and Comparative Examples 1-5, refer to Table 4.

[0091] Table 4. Test results of moisture resistance, bending properties, impact strength, tensile strength and mildew resistance of the mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 1-15 and Comparative Examples 1-5

[0092]

[0093]

[0094] Combining Examples 1-15 and Comparative Examples 1-5 and Table 4, it can be seen that:

[0095] The mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 1-15 have better moisture resistance, flexural properties, impact strength, tensile strength and mildew resistance grade than those in Comparative Examples 1-5, indicating that the mildew-proof and anti-corrosion bamboo-plastic composite materials use a combination of 40-45 parts of modified bamboo powder, 2-8 parts of ultrafine bamboo charcoal and 60-65 parts of thermoplastic plastic, and the modified bamboo powder is treated with plasma and a treatment solution containing PDMS, which significantly improves the moisture resistance, flexural properties, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials.

[0096] The reasons may be that: the ultrafine bamboo charcoal promotes the dispersion between the modified bamboo powder and the thermoplastic plastic; further, the plasma treatment improves the bonding strength of the interface between the modified bamboo powder and the thermoplastic plastic; further, the siloxy groups in the film layer on the surface of the modified bamboo powder improve the hydrophobic properties of the modified bamboo powder surface, improve the moisture resistance and mildew resistance of the modified bamboo powder, and the alkyl side groups in the PDMS molecular chain have good compatibility with thermoplastic plastics, so that the mildew-proof and anti-corrosion bamboo-plastic composite material has good moisture resistance, bending performance, impact strength, tensile strength and mildew resistance.

[0097] The moisture resistance, bending performance, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 1-3 are better than those in Example 4, indicating that the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials are significantly improved after the bamboo powder is treated with plasma and then immersed in the treatment liquid.

[0098] The reason may be that the active groups on the surface of bamboo powder increase after plasma treatment, which increases the interaction between the modified bamboo powder and PDMS. The siloxy groups in the molecular chain of PDMS have good hydrophobic properties and adhere to the surface of bamboo powder, reducing the water absorption of bamboo powder and thus reducing mildew. The alkyl part in PDMS improves the compatibility between modified bamboo powder and thermoplastic plastics, thereby making the mildew-proof and anti-corrosion bamboo-plastic composite material have better moisture resistance, bending performance, impact strength, tensile strength and mildew resistance level.

[0099] The mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 5-8 have better moisture resistance, flexural properties, impact strength, tensile strength and mildew resistance grade than Examples 1-3 and Examples 12-13, indicating that the combination of hydrogenated silicone oil, high vinyl silicone oil, silane coupling agent, silane-modified polymer and water in the treatment liquid further improves the moisture resistance, flexural properties, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials.

[0100] The reason for this may be that high-vinyl silicone oil, silane coupling agent, silane-modified polymer, and hydrogenated silicone oil form a dense, hydrophobic film on the surface of bamboo powder. The resulting film contains both siloxy and alkane groups. The siloxy groups enhance the film's hydrophobicity, while the alkane groups improve the modified bamboo powder's compatibility with thermoplastics. The silane coupling agent promotes the dispersion of the various raw materials in the treatment solution. Furthermore, the silanols formed by the hydrolysis of siloxane enhance the bonding between the modified bamboo powder and thermoplastics. The low-viscosity hydrogenated silicone oil improves the film's density, strength, and bonding. The combination of high-vinyl silicone oil, silane coupling agent, silane-modified polymer, and hydrogenated silicone oil, along with the plasma treatment of bamboo powder, creates a synergistic effect, further enhancing the moisture resistance, flexural properties, impact strength, tensile strength, and mildew resistance of the mildew- and corrosion-resistant bamboo-plastic composite.

[0101] The moisture resistance, bending performance, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 5-8 are better than those in Examples 9-10, indicating that the particle size of bamboo powder and the viscosity of PDMS are preferred, which further improves the moisture resistance, bending performance, impact strength, tensile strength and mildew resistance grade of the mildew-proof and anti-corrosion bamboo-plastic composite materials.

[0102] The reason may be that: bamboo powder with appropriate particle size is preferably used in combination with PDMS with moderate viscosity. The modified bamboo powder with better dispersibility reduces the crystallinity of thermoplastic, making it easier for PDMS to migrate to the surface of the mildew-proof and anti-corrosion bamboo-plastic composite material, forming a hydrophobic film layer, thereby reducing the moisture entering the mildew-proof and anti-corrosion bamboo-plastic composite material and improving the moisture resistance and mildew resistance level.

[0103] When the particle size of bamboo powder is too small, the viscosity of PDMS is too high, which is not conducive to the migration of PDMS to the surface of the mildew-proof and anti-corrosion bamboo-plastic composite material; when the particle size of bamboo powder is too large, when subjected to external force, stress concentration is more likely to occur inside the mildew-proof and anti-corrosion bamboo-plastic composite material, resulting in a decrease in mechanical properties.

[0104] The mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 5-8 have better moisture resistance, bending properties, impact strength, tensile strength and mildew resistance grade than Example 11, indicating that the use of high-vinyl silicone oil in the vinyl silicone oil and the use of water in the treatment liquid can improve the moisture resistance, bending properties, impact strength and tensile strength of the mildew-proof and anti-corrosion bamboo-plastic composite materials.

[0105] The reason may be that the vinyl content of high-vinyl silicone oil is higher than that of terminal vinyl silicone oil, which is more conducive to improving the compatibility of modified bamboo powder and thermoplastic plastics; furthermore, the addition of a small amount of water is conducive to the hydrolysis of siloxy groups of silane coupling agent and silane-modified polymer into silanols, thereby enhancing the interaction between the film formed by the treatment liquid and the thermoplastic plastic. The type of vinyl silicone oil and its compatibility with silane coupling agent, silane-modified polymer and water are optimized, thereby improving the moisture resistance, flexural properties, impact strength and tensile strength of the mildew-proof and anti-corrosion bamboo-plastic composite material.

[0106] The mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 5-8 have better moisture resistance, flexural properties, impact strength, tensile strength and mildew resistance grade than Example 14. This may be because the polyethylene-modified bamboo powder grafted with maleic anhydride is used, and the film layer formed does not have hydrophobic properties. In addition, a silane coupling agent and a silane-modified polymer are used in the film layer of the present application. After hydrolysis, silanols are formed, which improve the bonding force between the modified bamboo powder and the thermoplastic plastic, thereby improving the moisture resistance, flexural properties, impact strength and tensile strength of the mildew-proof and anti-corrosion bamboo-plastic composite materials.

[0107] The mildew-proof and anti-corrosion bamboo-plastic composite materials prepared in Examples 5-8 have better moisture resistance, flexural properties, impact strength, tensile strength and mildew resistance grade than those in Example 15. This may be because in Example 15, a higher drying temperature was used during the drying process, resulting in more hydrogenated silicone oil reacting on the film layer on the surface of the modified bamboo powder during drying, and more adhesion between the modified bamboo powder particles occurred, resulting in a decrease in the dispersibility of the modified bamboo powder in the thermoplastic plastic.

[0108] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material, characterized in that: The raw materials include 40-45 parts of modified bamboo powder, 2-8 parts of ultrafine bamboo charcoal and 60-65 parts of thermoplastic plastic, and the thermoplastic plastic is PP or PE. The modified bamboo powder is prepared by plasma treatment of bamboo powder; The mildew-proof and anti-corrosion bamboo-plastic composite material is prepared by blending, melting, extruding, cooling and granulating modified bamboo powder, ultrafine bamboo charcoal and thermoplastic plastic. In the preparation process of the modified bamboo powder, after plasma treatment, the bamboo powder is soaked in a treatment liquid for 5-10 minutes at a bath ratio of (1-5):100, and then dried at 30-40°C for 18-24 hours to prepare the modified bamboo powder; the treatment liquid includes, by weight, 5-7 parts of PDMS, 40-45 parts of ethanol, and 50-55 parts of petroleum ether.

2. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 1, characterized in that: The plasma treatment process is to use DBD plasma to treat bamboo powder, with a flow meter flow rate of 0.5-0.8 L / min, a power of 500-1000 W, and a treatment time of 10-15 s.

3. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 1, characterized in that: The particle size of the bamboo powder is 40-200 meshes, the viscosity of the PDMS is 1000-2000 cps; and the particle size of the ultrafine bamboo charcoal is greater than 300 meshes.

4. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 2, characterized in that: The treatment liquid further comprises, by weight, 0.5-1 parts of a silane coupling agent, 1-2 parts of a silane-modified polymer, 1-2 parts of vinyl silicone oil and 0.5-0.8 parts of water.

5. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 4, characterized in that: The vinyl silicone oil is high vinyl silicone oil.

6. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 4, characterized in that: The treatment liquid further comprises 1-2 parts by mass of hydrogen-containing silicone oil; the hydrogen-containing silicone oil has a viscosity of 40-100 MPa·s and a hydrogen content of 1.1-4.2 mmol / g.

7. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 1, characterized in that: The PE is polyethylene and adopts high-density polyethylene 5000s.

8. The method for preparing a mildew-proof and corrosion-resistant bamboo-plastic composite material according to claim 1, characterized in that: The granulation temperature is 165-170°C; The temperatures of each section of the screw extruder are as follows: zone 1 140-170°C, zone 2 140-170°C, zone 3 145-170°C, zone 4 160-175°C, zone 5 170-180°C, zone 6 170-180°C, zone 7 175-180°C, zone 8 170-190°C, zone 9 160-190°C, and die head temperature 160-180°C.

9. A mildew-proof and anti-corrosion bamboo-plastic composite material prepared by the method for preparing a mildew-proof and anti-corrosion bamboo-plastic composite material according to any one of claims 1 to 8.

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