Kenaf powder modified plastic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a hibiscus cannabinus powder modified plastic material as well as a preparation method and application thereof. The hibiscus cannabinus powder modified plastic material comprises the following raw materials in parts by weight: 60-70 parts of polypropylene, 10-20 parts of hibiscus cannabinus powder, 4-6 parts of modified cellulose fibers, 5-8 parts of a compatilizer, 1-2 parts of a dispersant, 0.3-0.5 part of an antioxidant, 0.1-0.3 part of an anti-ultraviolet agent, 5-7 parts of a flexibilizer and 1-3 parts of a lubricant. According to the hibiscus cannabinus powder modified plastic material provided by the invention, the polypropylene is used as a main matrix raw material and is combined with the hibiscus cannabinus powder, the modified cellulose fibers, the lubricant and the like for use, and the prepared hibiscus cannabinus powder modified plastic material has relatively high mechanical properties and excellent flame retardance and meets the use requirements of various industrial products.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a kenaf powder modified plastic material and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP), a thermoplastic synthetic resin derived from the polymerization of propylene monomer, is the lightest polymer currently available. It boasts advantages such as excellent transparency, heat resistance, water absorption, and low price. It is widely used in electronics, the automotive industry, and household appliances, and currently commands significant consumption. However, PP also has certain drawbacks, such as poor impact resistance and flammability, which limit its application in some areas.

[0003] In recent years, with the gradual improvement of people's environmental awareness, the development of high-performance, degradable plastic materials using plant fibers as reinforcement materials has become one of the current research hotspots. High-end plastic substitutes require the use of large amounts of corn starch and sweet potato starch, which are extremely expensive, unsafe to use, and have low decomposition and degradation effects. Plastic substitutes made from hemp wood powder have the characteristics of high transparency, good hardness, heat resistance, antibacterial properties, and safety in use. Introducing hemp powder into the plastic matrix can not only reduce dependence on petroleum-based raw materials, but also solve the problem of white waste disposal and improve the eco-friendliness of composite materials. However, the comprehensive properties of existing polypropylene plastic materials such as cantilever beam notched impact, flexural modulus, flexural strength, and flame retardancy still need to be improved.

[0004] Based on this, it is of great significance to develop biodegradable plastic composite materials with both high performance and high flame retardancy. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the first object of the present invention is to provide a kenaf powder modified plastic material.

[0006] The second object of the present invention is to provide a method for preparing a kenaf powder modified plastic material.

[0007] The third object of the present invention is to provide an application of kenaf powder modified plastic material.

[0008] The purpose of the present invention is achieved through the following technical solutions: A kenaf powder modified plastic material comprises the following raw materials in parts by weight: 60-70 parts of polypropylene, 10-20 parts of kenaf powder, 4-6 parts of modified cellulose fiber, 5-8 parts of a compatibilizer, 1-2 parts of a dispersant, 0.3-0.5 parts of an antioxidant, 0.1-0.3 parts of an anti-ultraviolet agent, 5-7 parts of a toughening agent, and 1-3 parts of a lubricant; The preparation process of the modified cellulose fiber is as follows: (1) Adding cellulose fibers to water containing a surfactant, then adding a silane coupling agent, heating to react, filtering, washing with water, and drying to obtain cellulose fibers modified with a silane coupling agent; (2) adding the cellulose fiber modified with the silane coupling agent in step (1) into a solvent containing polyethylene glycol methacrylate phosphate, then adding an initiator, heating for reaction, filtering, washing, and drying to obtain the product.

[0009] Furthermore, in step (1), the mass ratio of the cellulose fiber, the surfactant and the silane coupling agent is 1:0.5-1.2:(0.1-0.3), the mass fraction of the surfactant in water is 0.5-1%; the surfactant is sodium dodecyl sulfate, and the silane coupling agent is γ-methacryloxypropyltrimethoxysilane.

[0010] Furthermore, in step (1), the heating reaction temperature is 50-60°C and the time is 3-5h.

[0011] Furthermore, in step (2), the mass ratio of the silane coupling agent-modified cellulose fiber, polyethylene glycol methacrylate phosphate, and initiator is 100:(10-15):(0.5-1.2); the initiator is azobisisobutyronitrile, the mass fraction of the polyethylene glycol methacrylate phosphate in the solvent is 1.5-3%; and the solvent is DMF.

[0012] Furthermore, in step (2), the heating reaction temperature is 60-70°C and the time is 3-5 hours.

[0013] Furthermore, the preparation process of the lubricant is as follows: calcium stearate is added to silica sol, heated and stirred to obtain the lubricant.

[0014] Furthermore, the mass ratio of the calcium stearate to the silica sol is 1:(0.4-0.6); the heating and stirring temperature is 50-60° C., and the time is 2-3 hours.

[0015] Furthermore, the compatibilizer is maleic anhydride grafted polypropylene, the dispersant is ethylene bisstearamide, the antioxidant is antioxidant 1010 or antioxidant 168, the anti-ultraviolet agent is UV-531, and the toughening agent is POE.

[0016] The method for preparing the kenaf powder modified plastic material of the present invention comprises the following steps: S1 weighed the raw materials in parts by weight, stirred and mixed, and dried to obtain a mixture; the mixture was melt extruded and granulated by a twin-screw extruder to obtain pellets; S2. Add the pellets to a mold and hot-press at 150°C-180°C and 5-10 MPa for 30-50 minutes. After forming, remove the mold.

[0017] The invention discloses an application of the kenaf powder modified plastic material in the preparation of automobile accessories, plastic replacement particles or biofuel.

[0018] The present invention has the following effects compared to the prior art: The present invention provides a kenaf powder-modified plastic material, which uses polypropylene as the main matrix raw material and is used in combination with kenaf powder, modified cellulose fiber, a lubricant, etc. The prepared kenaf powder-modified plastic material has high mechanical properties and excellent flame retardant properties, and meets the use requirements of various plastic products.

[0019] In addition, the modified cellulose fiber introduced in the present invention is first modified by a silane coupling agent to introduce double bonds on the surface of the cellulose fiber. Then, under the action of an initiator, the double bonds of the silane coupling agent react with polyethylene glycol methacrylate phosphate to achieve polyethylene glycol methacrylate phosphate coating on the surface of the cellulose fiber. On the one hand, the compatibility of the cellulose fiber in the plastic matrix can be improved, and the cellulose fiber can be better dispersed in the plastic material, thereby increasing the bending modulus of the plastic material. On the other hand, the phosphorus element decomposes when heated to generate strong dehydrating agents such as phosphoric acid and polyphosphoric acid, which catalyze the dehydration of the polymer into carbon, forming a dense carbon layer, which can isolate oxygen and heat, inhibit the release of combustible gas, significantly reduce the combustion rate, and have a good flame retardant effect.

[0020] At the same time, the present invention introduces modified calcium stearate as a lubricant. After being coated with silicon dioxide, calcium stearate can improve the fluidity and lubricity of the plastic melt on the one hand; on the other hand, it can improve the density of the plastic material and improve its mechanical properties.

[0021] The present invention provides a method for preparing a kenaf powder-modified plastic material. The preparation process is simple to operate, suitable for large-scale industrial production, and is conducive to expanding the application of the plastic material in the preparation of automotive accessories, plastic-replacing particles, and biofuels. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an electron microscope image of the modified cellulose fiber obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] The application will be further described in detail below with reference to the examples, but the embodiments of the application are not limited thereto. Unless otherwise specified, the reagents, methods and apparatus used in the application are conventional reagents, methods and apparatus in the art. The test methods in the following examples, unless otherwise specified, are generally in accordance with conventional test conditions or in accordance with the test conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the application are commercially available.

[0024] The compatilizer is maleic anhydride grafted polypropylene, the maleic anhydride grafting rate is 1%; the dispersing agent is ethylene bis-stearamide (EBS), the antioxidant is antioxidant 1010 or antioxidant 168; the anti-ultraviolet agent is UV-531, and the toughening agent is POE.

[0025] The cellulose fiber has a diameter of 5-50 µm and a fiber length of 1-3 mm.

[0026] The preparation process of kenaf powder is as follows: the bast and stem of mature kenaf are cut into small pieces of about 3 cm, placed in an oven, baked at 100℃ for 4h, and then the bast and stem are separately pulverized by a pulverizer, sieved through a 100 mesh sieve, and then uniformly mixed to obtain the kenaf powder.

[0027] Example 1 A kind of kenaf powder modified plastic material, including the following weight parts of raw materials: polypropylene 67.5 parts, kenaf powder 10 parts, modified cellulose fiber 5.5 parts, compatilizer (maleic anhydride grafted polypropylene) 7 parts, dispersing agent (EBS) 2 parts, antioxidant (antioxidant 1010) 0.3 parts, anti-ultraviolet agent (UV-531) 0.2 parts, toughening agent (POE) 6 parts, lubricant 1.5 parts; The preparation process of modified cellulose fiber is as follows: (1) take cellulose fiber and add it to water containing sodium dodecyl sulfate, then add γ-methacryloyloxypropyltrimethoxysilane, the mass ratio of cellulose fiber, sodium dodecyl sulfate and γ-methacryloyloxypropyltrimethoxysilane is 1:1:0.2, the mass fraction of sodium dodecyl sulfate in water is 0.8%; place it in a 55℃ environment for 4h, filter, wash with water and dry to obtain silane coupling agent modified cellulose fiber; (2) add the silane coupling agent modified cellulose fiber of step (1) to N,N-dimethylformamide (DMF) containing polyethylene glycol methacrylic acid phosphate ester, then add azobisisobutyronitrile, the mass ratio of silane coupling agent modified cellulose fiber, polyethylene glycol methacrylic acid phosphate ester and initiator is 100:12:1; the mass fraction of polyethylene glycol methacrylic acid phosphate ester in DMF is 2%; react at 65℃ for 4h, after the reaction is completed, filter, wash and dry to obtain modified cellulose fiber.

[0028] The preparation process of the lubricant is as follows: calcium stearate is added to silica sol, the mass ratio of calcium stearate to silica sol is 1:0.5, heated and stirred at 55° C. for 2.5 hours, placed in an oven at 60° C., and then ball-milled to 2000 mesh to obtain the lubricant.

[0029] The present invention also provides a method for preparing the kenaf powder modified plastic material, comprising the following steps: S1 weighed the raw materials in parts by weight, stirred and mixed, and dried to obtain a mixture; the mixture was melt extruded and granulated by a twin-screw extruder to obtain pellets; S2. Add the pellets into a mold, hot-press at 160°C and 7 MPa for 40 minutes, and demold after forming.

[0030] Example 2 A kenaf powder modified plastic material comprises the following raw materials in parts by weight: 60 parts of polypropylene, 15 parts of kenaf powder, 5 parts of modified cellulose fiber, 8 parts of a compatibilizer (maleic anhydride grafted polypropylene), 2 parts of a dispersant (EBS), 0.4 parts of an antioxidant (antioxidant 168), 0.2 parts of an anti-ultraviolet agent (UV-531), 7 parts of a toughening agent (POE), and 2.4 parts of a lubricant; The preparation process of modified cellulose fiber is as follows: (1) Cellulose fiber was added to water containing sodium dodecyl sulfate, and then γ-methacryloxypropyltrimethoxysilane was added, wherein the mass ratio of the cellulose fiber, sodium dodecyl sulfate and γ-methacryloxypropyltrimethoxysilane was 1:1:0.2, and the mass fraction of the sodium dodecyl sulfate in water was 0.75%; the mixture was placed at 55°C for 4 hours, filtered, washed with water, and dried to obtain cellulose fiber modified with a silane coupling agent; (2) The cellulose fiber modified with the silane coupling agent in step (1) is added to DMF containing polyethylene glycol methacrylate phosphate, and then azobisisobutyronitrile is added, wherein the mass ratio of the cellulose fiber modified with the silane coupling agent, polyethylene glycol methacrylate phosphate and the initiator is 100:14:1; the mass fraction of the polyethylene glycol methacrylate phosphate in DMF is 2.5%; the reaction is carried out at 65°C for 4 hours. After the reaction is completed, the modified cellulose fiber is filtered, washed and dried to obtain the modified cellulose fiber.

[0031] The preparation process of the lubricant is as follows: calcium stearate is added to silica sol, the mass ratio of calcium stearate to silica sol is 1:0.5, heated and stirred at 50°C for 2.5 hours, placed in an oven at 60°C, and then ball-milled to 2000 mesh to obtain the lubricant.

[0032] The present invention also provides a method for preparing the kenaf powder modified plastic material, comprising the following steps: S1 weighed the raw materials in parts by weight, stirred and mixed, and dried to obtain a mixture; the mixture was melt extruded and granulated by a twin-screw extruder to obtain pellets; S2. Add the pellets into a mold, hot-press at 170°C and 9 MPa for 40 minutes, and demold after forming.

[0033] Example 3 A kenaf powder modified plastic material comprises the following raw materials in parts by weight: 62 parts of polypropylene, 20 parts of kenaf powder, 4 parts of modified cellulose fiber, 5 parts of a compatibilizer (maleic anhydride grafted polypropylene), 1.2 parts of a dispersant (EBS), 0.5 parts of an antioxidant (antioxidant 1010), 0.3 parts of an anti-ultraviolet agent (UV-531), 5 parts of a toughening agent (POE), and 2 parts of a lubricant; The preparation process of modified cellulose fiber is as follows: (1) Cellulose fiber was added to water containing sodium dodecyl sulfate, and then γ-methacryloxypropyltrimethoxysilane was added, wherein the mass ratio of the cellulose fiber, sodium dodecyl sulfate and γ-methacryloxypropyltrimethoxysilane was 1:1.2:0.3, and the mass fraction of the sodium dodecyl sulfate in water was 1%; the mixture was placed at 60°C for reaction for 3 hours, filtered, washed with water, and dried to obtain cellulose fiber modified with a silane coupling agent; (2) The cellulose fiber modified with the silane coupling agent in step (1) is added to DMF containing polyethylene glycol methacrylate phosphate, and then azobisisobutyronitrile is added, wherein the mass ratio of the cellulose fiber modified with the silane coupling agent, polyethylene glycol methacrylate phosphate and the initiator is 100:15:1.2; the mass fraction of the polyethylene glycol methacrylate phosphate in DMF is 3%; the reaction is carried out at 70°C for 3 hours, and after the reaction is completed, the modified cellulose fiber is filtered, washed and dried to obtain the modified cellulose fiber.

[0034] The preparation process of the lubricant is as follows: calcium stearate is added to silica sol, the mass ratio of calcium stearate to silica sol is 1:0.6, heated and stirred at 60°C for 3h, placed in an oven at 60°C, and then ball-milled to 2000 mesh to obtain the lubricant.

[0035] The present invention also provides a method for preparing the kenaf powder modified plastic material, comprising the following steps: S1 weighed the raw materials in parts by weight, stirred and mixed, and dried to obtain a mixture; the mixture was melt extruded and granulated by a twin-screw extruder to obtain pellets; S2. Add the pellets into a mold, hot-press at 180°C and 5 MPa for 30 minutes, and demold after forming.

[0036] Comparative Example 1 Comparative Example 1 is substantially the same as Example 1, except that the modified cellulose fiber is replaced by cellulose fiber.

[0037] Comparative Example 2 Comparative Example 2 is substantially the same as Example 1, except that the modified cellulose fibers are replaced with cellulose fibers modified with a silane coupling agent.

[0038] Comparative Example 3 This comparative example 3 is substantially the same as Example 1, except that the lubricant is replaced with calcium stearate.

[0039] Test Case In order to test the properties of the plastic materials obtained in Examples 1-3 of the present invention and Comparative Examples 1-3, the following tests were performed: (1) Tensile strength and elongation at break: tested according to ASTM D-638.

[0040] (2) Flexural modulus: tested according to ASTM D-790.

[0041] (3) Flexural strength: tested according to ASTM D-790 standard.

[0042] (4) Notched impact strength: tested according to ASTM D-256.

[0043] (5) Limiting oxygen index (LOI) test: The test was conducted in accordance with the standard of GB / T 2406.2-2009. The sample size was 130 mm × 10 mm × 3 m.

[0044] The above test results are shown in Table 1.

[0045] Table 1 It can be seen from the data in Table 1 that the yield tensile strength, flexural modulus, flexural strength, Izod notched impact strength and other properties of the plastic materials obtained in Examples 1-3 of the present invention are higher than those in Comparative Examples 1-3, and have excellent flame retardant properties.

[0046] Compared to Example 1, in Comparative Example 1, the modified cellulose fiber was replaced with cellulose fiber, and in Comparative Example 2, the modified cellulose fiber was replaced with cellulose fiber modified with a silane coupling agent. In Comparative Example 3, the lubricant was replaced with calcium stearate. The mechanical properties of the resulting plastic materials were inferior to those of Example 1, demonstrating that the modified cellulose fiber plays an important role in improving the flame retardancy and mechanical properties of the material, and that the lubricant can further improve the material's mechanical properties.

[0047] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A kenaf powder modified plastic material, characterized in that: The invention comprises the following raw materials in parts by weight: 60-70 parts of polypropylene, 10-20 parts of kenaf powder, 4-6 parts of modified cellulose fiber, 5-8 parts of compatibilizer, 1-2 parts of dispersant, 0.3-0.5 parts of antioxidant, 0.1-0.3 parts of anti-ultraviolet agent, 5-7 parts of toughening agent and 1-3 parts of lubricant; The preparation process of the modified cellulose fiber is as follows: (1) Adding cellulose fibers to water containing a surfactant, then adding a silane coupling agent, heating to react, filtering, washing with water, and drying to obtain cellulose fibers modified with a silane coupling agent; (2) adding the cellulose fiber modified with the silane coupling agent in step (1) into a solvent containing polyethylene glycol methacrylate phosphate, then adding an initiator, heating for reaction, filtering, washing, and drying to obtain the product.

2. The kenaf powder modified plastic material according to claim 1, characterized in that: In step (1), the mass ratio of the cellulose fiber, the surfactant and the silane coupling agent is 1:0.5-1.2:(0.1-0.3), the mass fraction of the surfactant in water is 0.5-1%; the surfactant is sodium lauryl sulfate, and the silane coupling agent is γ-methacryloxypropyltrimethoxysilane.

3. The kenaf powder modified plastic material according to claim 1, characterized in that: In step (1), the heating reaction temperature is 50-60°C and the time is 3-5 hours.

4. The kenaf powder modified plastic material according to claim 1, characterized in that: In step (2), the mass ratio of the silane coupling agent-modified cellulose fiber, polyethylene glycol methacrylate phosphate, and initiator is 100:(10-15):(0.5-1.2); the initiator is azobisisobutyronitrile, the mass fraction of the polyethylene glycol methacrylate phosphate in the solvent is 1.5-3%; and the solvent is DMF.

5. The kenaf powder modified plastic material according to claim 1, characterized in that: In step (2), the heating reaction temperature is 60-70°C and the time is 3-5 hours.

6. The kenaf powder modified plastic material according to claim 1, characterized in that: The preparation process of the lubricant is as follows: calcium stearate is added to silica sol, heated and stirred to obtain the lubricant.

7. The kenaf powder modified plastic material according to claim 6, characterized in that: The mass ratio of the calcium stearate to the silica sol is 1:(0.4-0.6); the heating and stirring temperature is 50-60° C., and the time is 2-3 hours.

8. The kenaf powder modified plastic material according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted polypropylene, the dispersant is ethylene bisstearamide, the antioxidant is antioxidant 1010 or antioxidant 168, the anti-ultraviolet agent is UV-531, and the toughening agent is POE.

9. The method for preparing a kenaf powder modified plastic material according to any one of claims 1 to 8, characterized in that: The steps include: S1 weighed the raw materials in parts by weight, stirred and mixed, and dried to obtain a mixture; the mixture was melt extruded and granulated by a twin-screw extruder to obtain pellets; S2. Add the pellets to a mold and hot-press at 150°C-180°C and 5-10 MPa for 30-50 minutes. After forming, remove the mold.

10. Use of the kenaf powder modified plastic material according to any one of claims 1 to 8 in the preparation of automobile accessories, plastic replacement particles or biofuel.

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