阅读说明：本技术 一种木塑复合材料制备方法 (Preparation method of wood-plastic composite material ) 是由 宋艳江 许李燕 羊海棠 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种木塑复合材料制备方法。目前市场上基本上没有工程塑料类木塑复合材料。本发明方法首先将待处理植物纤维粉溶剂抽提处理,脱水干燥后得到植物纤维粉干粉；然后将植物纤维粉干粉与增强填料和偶联剂置于高速混合机中,对干粉进行表面处理；再加入树脂基体ABS、增容剂和润滑剂,进行物料初步混合；将加入混炼机中进行熔融混炼,得到的木塑复合材料混炼料经过挤出、注射或模压成型,即得到木塑复合材料制品。本发明方法经溶剂洗涤去除易挥发和可溶性小分子的植物纤维粉的表面更利于改性,经偶联剂表面处理的植物纤维粉与树脂基体间界面黏结力更强,得到的复合材料力学性能更优,所制备木塑复合材料的耐热性能也有一定程度提高。(The invention discloses a preparation method of a wood-plastic composite material. At present, no engineering plastic wood-plastic composite material exists on the market basically. Firstly, extracting a plant fiber powder to be treated by using a solvent, and dehydrating and drying to obtain plant fiber powder dry powder; then placing the dry powder of the plant fiber powder, the reinforcing filler and the coupling agent into a high-speed mixer, and carrying out surface treatment on the dry powder; then adding resin matrix ABS, compatibilizer and lubricant to carry out primary mixing of materials; adding the mixture into a mixing roll for melting and mixing, and extruding, injecting or compression molding the obtained wood-plastic composite mixed material to obtain the wood-plastic composite product. The method removes the surfaces of the plant fiber powder with volatile and soluble micromolecules by washing with the solvent, is more convenient for modification, the interface bonding force between the plant fiber powder subjected to surface treatment by the coupling agent and the resin matrix is stronger, the mechanical property of the obtained composite material is better, and the heat resistance of the prepared wood-plastic composite material is also improved to a certain extent.)

1. A preparation method of a wood-plastic composite material is characterized by comprising the following steps:

washing treatment of the plant fiber powder in the step (1): extracting the plant fiber powder to be treated with a solvent for more than 6 hours by using a Soxhlet extraction device to remove polysaccharide substances such as starch, pectic substances and other components, and micromolecular substances such as tannin, pigment, alkaloid and the like; taking out the plant fiber powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 95-105 ℃ for 6-12 hours to obtain plant fiber powder dry powder;

placing 20-40 parts by weight of plant fiber powder dry powder, 2-20 parts by weight of reinforcing filler and 0.1-1 part by weight of coupling agent into a high-speed mixer, stirring at a high speed for 5-10 minutes, and performing surface treatment on the plant fiber powder dry powder;

adding 50-70 parts by weight of resin matrix, 1-5 parts by weight of compatibilizer and 0.2-1 part by weight of lubricant into a high-speed mixer, stirring for 1-2 minutes, and performing primary mixing on materials;

adding the materials which are uniformly mixed in the preliminary step into a mixing roll, and melting and mixing at the temperature of 200-230 ℃ to obtain a wood-plastic composite material;

and (5) extruding, injecting or compression molding the wood-plastic composite mixed material to obtain the wood-plastic composite product.

2. A method of preparing a wood-plastic composite as claimed in claim 1, wherein: the plant fiber powder to be treated in the step (1) is a mixture of one or more of wood powder, bamboo powder and straw powder with the particle size of less than or equal to 20 meshes; the solvent is one of water, absolute ethyl alcohol, acetone, water-ethyl alcohol azeotrope and benzene-ethyl alcohol mixed solution.

3. A method of preparing a wood-plastic composite as claimed in claim 1, wherein: the reinforcing filler in the step (2) is one or a mixture of calcium carbonate, talcum powder and glass fiber; the coupling agent is a commercially available titanate coupling agent or silane coupling agent.

4. A method of preparing a wood-plastic composite as claimed in claim 1, wherein: the resin matrix in the step (3) is acrylonitrile-butadiene-styrene copolymer.

5. A method of preparing a wood-plastic composite as claimed in claim 1, wherein: the compatibilizer in the step (3) is one of maleic anhydride grafted ABS, maleic anhydride grafted styrene-butadiene-styrene copolymer and maleic anhydride grafted hydrogenated styrene-butadiene block copolymer.

Technical Field

The invention belongs to the technical field of new materials, relates to a preparation method of a wood-plastic composite material, and particularly relates to a preparation method of a plant fiber powder filled acrylonitrile-butadiene-styrene plastic (ABS) based wood-plastic composite material through solvent washing treatment.

Background

The wood-plastic composite material is a novel composite material prepared by filling natural plant fibers such as wood powder, bamboo fibers, crop straws and the like into a thermoplastic plastic matrix, and carrying out processes such as melting, mixing, extrusion, injection molding or hot die pressing and the like. The composite material has the practical performance of wood and the forming processing and recycling performance of thermoplastic plastics, the plastic matrix can be recycled plastics, and the plant fibers are completely agricultural and forestry wastes and are a real green and environment-friendly material. However, the conventional plant fiber has a complex composition, contains a plurality of temperature-resistant and volatile small molecular components such as aliphatic compounds, alkaloids, carbohydrate substances and the like besides main components such as cellulose, hemicellulose, lignin and the like, and can generate volatilization and degradation of small molecules at a slightly high temperature (180 ℃), so that the color becomes dark, a 'scorched smell' is released, and even some released acid or alkali substances can catalyze the thermal degradation of polymers. Therefore, the wood-plastic composite materials successfully developed in the market are basically general plastic-based wood-plastic composite materials suitable for lower molding and processing temperatures, such as: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and other wood-plastic composite materials. The method is limited by the defects of low strength, poor rigidity and poor heat resistance of the general plastic, and the prepared wood-plastic composite material has obvious technical bottleneck in performance and limited application field.

ABS is an engineering plastic with the advantages of excellent impact resistance, heat resistance, dimensional stability, easy processing and the like, is widely applied to the fields of the automobile industry, household appliances, office machines and the like, and has comprehensive performance obviously superior to general plastics such as PP, PE, PVC and the like. But because the engineering plastics are limited by higher molding processing temperature (more than or equal to 200 ℃), the wood-plastic composite materials of the engineering plastics are basically not available in the market.

Disclosure of Invention

The invention aims to provide a preparation method of a wood-plastic composite material.

The method comprises the following steps:

washing treatment of the plant fiber powder in the step (1): extracting the plant fiber powder to be treated with a solvent for more than 6 hours by using a Soxhlet extraction device to remove polysaccharide substances such as starch, pectic substances and other components, and micromolecular substances such as tannin, pigment, alkaloid and the like; and taking out the plant fiber powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 95-105 ℃ for 6-12 hours to obtain the plant fiber powder dry powder.

The plant fiber powder to be treated is one or a mixture of wood powder, bamboo powder and straw powder with the particle size of less than or equal to 20 meshes; the solvent is one of water, absolute ethyl alcohol, acetone, water-ethyl alcohol azeotrope and benzene-ethyl alcohol mixed solution.

And (2) placing 20-40 parts by weight of plant fiber powder dry powder, 2-20 parts by weight of reinforcing filler and 0.1-1 part by weight of coupling agent into a high-speed mixer, stirring at a high speed for 5-10 minutes, and performing surface treatment on the plant fiber powder dry powder.

The reinforcing filler is one or a mixture of calcium carbonate, talcum powder and glass fiber; the coupling agent is a commercially available titanate coupling agent or silane coupling agent.

And (3) adding 50-70 parts by weight of resin matrix, 1-5 parts by weight of compatibilizer and 0.2-1 part by weight of lubricant into a high-speed mixer, stirring for 1-2 minutes, and performing primary mixing on the materials.

The resin matrix is acrylonitrile-butadiene-styrene copolymer (ABS); the compatibilizer is one of maleic anhydride grafted ABS, maleic anhydride grafted styrene-butadiene-styrene copolymer (SBS-g-MAH) and maleic anhydride grafted hydrogenated styrene-butadiene block copolymer (SEBS-g-MAH); the lubricant is various commercially available lubricants, such as stearic acid or oleic acid amide.

And (4) adding the uniformly mixed materials into a mixing roll, and melting and mixing at 200-230 ℃ to obtain the wood-plastic composite material.

And (5) extruding, injecting or compression molding the wood-plastic composite mixed material to obtain the wood-plastic composite product.

The beneficial effects of the invention include:

(1) the thermal decomposition temperature of the plant fiber powder washed by the solvent is obviously improved, the plant fiber powder can be suitable for higher molding processing temperature, and can be used for preparing engineering plastic (ABS) based wood-plastic composite materials;

(2) the surface of the plant fiber powder which is washed by the solvent and removed with volatile and soluble micromolecules is more convenient for modification, the interface bonding force between the plant fiber powder which is subjected to the surface treatment by the coupling agent and the resin matrix is stronger, and the mechanical property of the prepared wood-plastic composite material is better;

(3) the plant fiber powder washed by the solvent removes micromolecular components which can promote the degradation of the resin matrix at high temperature, so that the heat resistance of the prepared wood-plastic composite material is improved to a certain extent.

Detailed Description

The technical scheme of the invention is further illustrated by the following specific examples. The embodiment described is only an example of the implementation form of the inventive concept, and the protection scope of the invention should not be considered as being limited to the specific form set forth in the embodiment, and the protection scope of the invention is equivalent to the technical means that can be conceived by those skilled in the art according to the inventive concept.

Example 1:

and (2) carrying out solvent extraction treatment on the wood flour with the particle size of less than 20 meshes for 6 hours by using a Soxhlet extraction device, wherein the solvent is water, and removing polysaccharide substances such as starch, pectic substances and other components, and micromolecular substances such as tannin, pigment, alkaloid and the like. Taking out the wood powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 95 ℃ for 12 hours to obtain dry powder of the wood powder;

placing 400g of wood powder dry powder, 200g of glass fiber and 2g of commercially available titanate coupling agent in a high-speed mixer, stirring at high speed for 8 minutes, and performing surface treatment on the dry powder;

adding 650g of ABS, 20g of maleic anhydride grafted ABS and 4g of commercially available stearic acid into a high-speed mixer in the step (3), stirring for 1 minute, and performing primary mixing on the materials;

adding the materials which are uniformly mixed preliminarily into a parallel double-screw extruder, and extruding at 200 ℃ to obtain a wood-plastic composite material mixing material;

and (5) carrying out extrusion molding on the wood-plastic composite mixed material to obtain a wood-plastic composite product.

The impact strength of a simply supported beam of the ABS-based wood-plastic composite material product prepared by the embodiment is 5.7kJ/m²Tensile strength of 38.2MPa, bending strength of 70.6MPa and elastic modulus of 3676.6 MPa; the temperature for 5% decomposition was 286.2 ℃ and the decomposition termination temperature was 484.8 ℃. Compared with the wood powder filled composite material without extraction treatment, the impact strength, the tensile strength and the bending strength are respectively improved by 8 percent, 5 percent and 8 percent; meanwhile, the decomposition temperature is increased by 5 percent and the decomposition finishing temperature is increased by 8.1 ℃ and 11.4 ℃ respectively. The method for washing and treating the wood powder by using the hot water fully shows that the mechanical property of the ABS wood-plastic composite material is improved while the heat resistance of the ABS wood-plastic composite material is improved.

Example 2:

in the step (1), a Soxhlet extraction device is adopted to extract bamboo powder with the grain diameter of 15 meshes for 7 hours by using a solvent, and the solvent is absolute ethyl alcohol. Taking out the bamboo powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 105 ℃ for 6 hours to obtain dry powder of the bamboo powder;

step (2) placing 200g of bamboo powder dry powder, 20g of calcium carbonate, 20g of talcum powder and 1g of commercially available titanate coupling agent in a high-speed mixer, stirring at high speed for 5 minutes, and carrying out surface treatment on the dry powder;

adding 600g of ABS, 10g of maleic anhydride grafted styrene-butadiene-styrene copolymer and 2g of commercially available stearic acid into a high-speed mixer, stirring for 1 minute and 30 seconds, and performing primary mixing on the materials;

adding the materials which are uniformly mixed in the preliminary step into a torque rheometer, and melting and mixing for 10 minutes at 210 ℃ to obtain a wood-plastic composite material mixed material;

and (5) carrying out compression molding on the wood-plastic composite mixed material to obtain a wood-plastic composite product.

The simple supported beam of the ABS-based wood-plastic composite material product prepared by the embodiment has no notchImpact strength of 4.4kJ/m²Tensile strength of 31.5MPa, bending strength of 60.6MPa, and elastic modulus of 3602.6 MPa; the decomposition temperature of 5% was 281.7 ℃ and the decomposition termination temperature was 484.6 ℃. Compared with the wood powder filled composite material without extraction treatment, the decomposition temperature is increased by 5 percent and the decomposition finishing temperature is increased by 3.7 ℃ and 11.2 ℃ respectively. The method for washing the bamboo powder by the ethanol solution improves the heat resistance of the ABS wood-plastic composite material.

Example 3:

and (2) extracting the straw powder with the particle size of 20 meshes for 8 hours by using a solvent, wherein the solvent is acetone, by using a Soxhlet extraction device. Taking out the straw powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 100 ℃ for 9 hours to obtain dry powder of the straw powder;

step (2), 300g of straw powder dry powder, 50g of calcium carbonate, 50g of talcum powder, 50g of glass fiber and 10g of commercially available silane coupling agent are placed in a high-speed mixer to be stirred at high speed for 7 minutes, and the dry powder is subjected to surface treatment;

adding 700g of ABS, 50g of maleic anhydride grafted hydrogenated styrene-butadiene block copolymer and 10g of commercially available stearic acid into a high-speed mixer, stirring for 2 minutes, and performing primary mixing on the materials;

adding the materials which are uniformly mixed in the preliminary step into a torque rheometer, and melting and mixing for 5 minutes at 230 ℃ to obtain a wood-plastic composite material mixed material;

and (5) carrying out compression molding on the wood-plastic composite mixed material to obtain a wood-plastic composite product.

The impact strength of a simply supported beam of the ABS-based wood-plastic composite material product prepared by the embodiment is 4.2kJ/m²Tensile strength 32.3MPa, bending strength 61.3MPa, and elastic modulus 3876.6 MPa.

Example 4:

in the step (1), a Soxhlet extraction device is adopted to extract and treat the mixture of the wood powder and the bamboo powder with the grain size of less than 20 meshes for 9 hours by using a solvent, wherein the solvent is a water-ethanol azeotrope. Taking out the mixture of the wood powder and the bamboo powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 105 ℃ for 8 hours to obtain a dry powder mixture of the wood powder and the bamboo powder;

step (2), placing 250g of dry powder mixture of wood powder and bamboo powder, 20g of calcium carbonate and 5g of commercially available titanate coupling agent in a high-speed mixer, stirring at high speed for 6 minutes, and performing surface treatment on the dry powder;

adding 500g of ABS, 25g of maleic anhydride grafted ABS and 6g of commercially available oleamide into a high-speed mixer in the step (3), stirring for 1 minute and 40 seconds, and performing primary mixing on materials;

adding the materials which are uniformly mixed in the preliminary step into an internal mixer, and melting and mixing for 10 minutes at 210 ℃ to obtain a wood-plastic composite material mixed material;

and (5) carrying out injection molding on the wood-plastic composite mixed material to obtain a wood-plastic composite product.

The impact strength of a simply supported beam of the ABS-based wood-plastic composite material product prepared by the embodiment is 5.2kJ/m²Tensile strength of 35.2MPa, bending strength of 68.6MPa, and elastic modulus of 3582.6 MPa.

Example 5:

and (1) extracting the mixture of the wood powder, the bamboo powder and the straw powder with the grain size of less than 20 meshes for 10 hours by using a solvent through a Soxhlet extraction device, wherein the solvent is a benzene-ethanol mixed solution. Taking out the mixture of the wood powder, the bamboo powder and the straw powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 102 ℃ for 10 hours to obtain a dry powder mixture of the wood powder, the bamboo powder and the straw powder;

placing 350g of dry powder mixture of wood powder, bamboo powder and straw powder, 80g of talcum powder and 5g of commercially available silane coupling agent in a high-speed mixer, stirring at high speed for 10 minutes, and performing surface treatment on the dry powder;

550g of ABS, 30g of maleic anhydride grafted styrene-butadiene-styrene copolymer and 7g of commercially available oleamide are added into a high-speed mixer in the step (3), and the mixture is stirred for 1 minute and 20 seconds to carry out primary mixing of materials;

adding the materials which are uniformly mixed preliminarily into a parallel double-screw extruder, and extruding at 220 ℃ to obtain a wood-plastic composite material mixing material;

and (5) carrying out injection molding on the wood-plastic composite mixed material to obtain a wood-plastic composite product.

The impact strength of a simply supported beam of the ABS-based wood-plastic composite material product prepared by the embodiment is 4.8kJ/m²Tensile strength of 34.8MPa, bending strength of 67.5MPa, and elastic modulus of 3721.3 MPa.

Example 6:

in the step (1), a Soxhlet extraction device is adopted to extract bamboo powder with the particle size of 20 meshes for 8 hours by using a solvent, and the solvent is water. Taking out the bamboo powder, centrifugally dewatering, placing in a vacuum drying oven, and drying at 98 deg.C for 8 hr to obtain dry powder of bamboo powder.

And (2) placing 320g of bamboo powder dry powder, 120g of talcum powder and 5g of commercially available silane coupling agent in a high-speed mixer, stirring at high speed for 9 minutes, and carrying out surface treatment on the dry powder.

Adding 700g of ABS, 40g of maleic anhydride grafted hydrogenated styrene-butadiene block copolymer and 8g of commercially available oleamide into a high-speed mixer in the step (3), stirring for 1 minute and 30 seconds, and performing primary mixing on the materials;

adding the materials which are uniformly mixed in the preliminary step into a torque rheometer, and melting and mixing for 8 minutes at 220 ℃ to obtain a wood-plastic composite material mixed material;

and (5) carrying out compression molding on the wood-plastic composite mixed material to obtain a wood-plastic composite product.

The impact strength of a simply supported beam of the ABS-based wood-plastic composite material product prepared by the embodiment is 4.3kJ/m²Tensile strength 33.3MPa, bending strength 62.3MPa, and elastic modulus 3621.8 MPa.