Biobased polyethylene-based composite material and preparation method thereof

Abstract

The present invention relates to a composite material based on bio-based polyethylene and a preparation method thereof, belonging to the technical field of polymer composite materials. The composite material comprises, by weight: 100 parts of bio-based polyethylene, 8-13 parts of ethylene-octene copolymer, 6.5-9.5 parts of strengthening aid, 90-100 parts of inorganic metal flame retardant, and 1.5-2 parts of lubricant; the strengthening aid is prepared by subjecting diallylamine and alkyl acyl chloride to amidation reaction to form an alkylated monomer having an alkyl chain and a diallyl structure, and subjecting the alkylated monomer to click addition with a diene and ethylene dithiol under initiation to form a macromolecular block polymer; after the composite material is blended and modified by compounding the strengthening aid, the comprehensive properties of strength and toughness are significantly improved, and good flame retardancy is maintained at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composite materials, and in particular, relates to a composite material based on bio-based polyethylene and a preparation method thereof. Background Art

[0002] The main raw material of bio-based polyethylene is usually sucrose, which is converted into ethylene through fermentation and other chemical processes, and then further polymerized to form polyethylene, which is an environmentally friendly plastic material and can serve as a sustainable alternative to traditional petroleum-based polyethylene. In recent years, with the increasing attention to reducing plastic waste and lowering carbon footprint, the development and application of bio-based polyethylene has received widespread attention.

[0003] However, the molecular structure of bio-based polyethylene is different from the raw materials of petroleum-based polyethylene, resulting in different molecular states and properties of the final polymer, which leads to generally lower mechanical properties of bio-based polyethylene than petroleum-based polyethylene. In long-term studies, it was found that the difference in mechanical properties is related to the high content of unsaturated bonds in bio-based polyethylene. These unsaturated bonds are weak points in the molecular chain. They are more likely to break when subjected to external forces, resulting in a decrease in the overall performance of the material. The presence of unsaturated bonds will interrupt the continuity of the polyethylene molecular chain, reduce the effective interaction between the molecular chains, and thus reduce the mechanical strength of the material. Therefore, this application aims to improve the comprehensive mechanical properties of existing bio-based polyethylene materials. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a composite material based on bio-based polyethylene and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The composite material based on bio-based polyethylene comprises, by weight: 100 parts of bio-based polyethylene, 8-13 parts of ethylene-octene copolymer, 6.5-9.5 parts of reinforcing additive, 90-100 parts of inorganic metal flame retardant and 1.5-2 parts of lubricant.

[0007] The strengthening aid is prepared by the following method:

[0008] Step A1: diallylamine, anhydrous aluminum chloride and toluene are mixed, dry nitrogen is introduced for protection, the temperature is pre-raised to 50-75°C, stirring is applied at 60-90 rpm, alkyl acyl chloride is added intermittently for reaction for 3.5-5 hours, and then the temperature is continued to be raised to 110°C for reflux reaction for 1.2-1.8 hours. After the reaction is completed, toluene is removed by vacuum rotary evaporation to obtain an alkylated monomer;

[0009] Furthermore, the dosage ratio of diallylamine, alkyl acyl chloride, anhydrous aluminum trichloride and toluene is 0.1 mol: 0.1 mol: 25 - 35 mg: 40 - 50 mL. Under the promotion of anhydrous aluminum trichloride, diallylamine and alkyl acyl chloride carry out amidation reaction to form a compound with an alkyl chain and a diallyl structure;

[0010] Preferably, the alkyl chain length of the alkyl acyl chloride is C10 - C18. Introducing the alkyl chain of this length into the molecular side chain of the strengthening agent can have a good toughening effect on the polyethylene matrix.

[0011] Step A2: Mix the alkylated monomer, diene, ethylene dithiol, photoinitiator TPO and dimethylacetamide, heat up to 55 - 80 °C, apply stirring at 90 - 120 rpm and ultraviolet irradiation at 150 - 200 W / m 2 for 4 - 6 h, then add tert-butyl peroxybenzoate and continue to heat up to 110 - 125 °C and react for 1.5 - 2 h. After the reaction, rotary evaporate under reduced pressure to remove dimethylacetamide, wash the substrate with water and dry it to obtain the strengthening agent;

[0012] Furthermore, the dosage ratio of the alkylated monomer, diene, ethylene dithiol, photoinitiator TPO, tert-butyl peroxybenzoate and dimethylacetamide is 10 mmol: 60 - 80 mmol: 0.1 - 0.12 mol: 8 - 12 mg: 5 - 10 mg: 16 - 24 mL. Under photoinitiation and peroxide initiation, the alkylated monomer and diene copolymerize with ethylene dithiol;

[0013] Preferably, the diene is one or more of 1,5 - hexadiene, 1,7 - octadiene and 1,9 - decadiene.

[0014] Furthermore, the inorganic metal flame retardant is composed of a mixture of magnesium hydroxide and aluminum hydroxide.

[0015] Furthermore, the lubricant is oxidized polyethylene wax.

[0016] The preparation method of the composite material based on bio-based polyethylene is as follows: Mix the raw materials with a high-speed mixer, transfer the mixture into a twin-screw extruder for plasticizing extrusion and pelletizing to obtain the composite material.

[0017] Furthermore, during the plasticizing extrusion process, the temperature zones of the twin-screw extruder are set as follows: zone 1 is 170 - 180 °C, zone 2 is 180 - 190 °C, zone 3 is 190 - 195 °C, and the die head temperature is 200 °C.

[0018] The beneficial effects of the present invention:

[0019] The composite material disclosed in the present invention uses bio-based polyethylene as the matrix, and is compounded with a self-made strengthening additive for blending modification, effectively improving the comprehensive strength and toughness of the composite material.

[0020] Based on the existing flame-retardant bio-based polyethylene system, the present invention is compounded with a self-developed strengthening additive for blending modification. The comprehensive strength and toughness of the obtained composite material are significantly improved, and at the same time, good flame retardancy is maintained. The strengthening additive is prepared by amidation reaction of diallylamine and alkyl acyl chloride to form an alkylated monomer with an alkyl chain and a diallyl structure. It is subjected to click addition with a diene and ethylene dithiol under initiation to form a macromolecular block polymer. The macromolecular chain of the strengthening additive is capped with active mercapto groups introduced by excessive ethylene dithiol. During the melt blending process, the terminal mercapto groups of the strengthening additive undergo addition reaction with the residual unsaturated bonds in the bio-based polyethylene under high-temperature environment, playing a bridging role instead of the traditional cross-linking role, avoiding a sharp drop in the toughness of the composite material, improving the molecular continuity of the bio-based polyethylene, and being beneficial to the improvement of mechanical properties. In addition, a nitrogen-sulfide structure is formed in the block chain of the alkylated monomer and ethylene dithiol in the strengthening additive, which chelates with the inorganic metal flame retardant, forms a force between the flame retardant and the polyethylene macromolecular chain, enables the flame retardant to strengthen the macromolecular chain, is beneficial to the improvement of the overall mechanical properties. At the same time, the strengthening additive plays a role of binding and fixing the flame retardant, avoiding the dripping of the combustibles, and further improving the overall flame retardant performance. In addition, a large number of alkyl chains on the molecular side chain of the strengthening additive are interspersed in the matrix on the surface of the aggregate formed by chelating the flame retardant, playing a good toughening role, compensating for the reduction in toughness caused by the introduction of the inorganic metal flame retardant, and enabling the composite material to have excellent comprehensive strength and toughness. Specific Embodiments

[0021] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0022] Example 1, preparing a composite material based on bio-based polyethylene, the specific implementation process is as follows:

[0023] (1) Preparation of the strengthening additive

[0024] Step A1: Mix diallylamine, anhydrous aluminum trichloride, and toluene, introduce dry nitrogen for protection, preheat to 50 °C, apply stirring at 60 rpm, intermittently add alkyl acyl chloride and react for 3.5 h, then continue to heat up to 110 °C and reflux for 1.2 h. Among them, the alkyl acyl chloride is selected from decanoyl chloride with a carbon chain length of C10. The dosage ratio of diallylamine, alkyl acyl chloride, anhydrous aluminum trichloride, and toluene is 0.1 mol: 0.1 mol: 25 mg: 40 mL. After the reaction, quickly remove toluene by rotary evaporation under reduced pressure to obtain the alkylated monomer.

[0025] Step A2: Mix the alkylated monomer, diene, ethylene glycol dimercaptan, photoinitiator TPO, and dimethylacetamide, heat up to 55 °C, apply stirring at 90 rpm and ultraviolet irradiation at 150 W / m 2 and react for 4 h. Then add tert-butyl peroxybenzoate and continue to heat up to 110 °C and react for 1.5 h. Among them, the diene is selected from 1,5-hexadiene. The dosage ratio of the alkylated monomer, diene, ethylene glycol dimercaptan, photoinitiator TPO, tert-butyl peroxybenzoate, and dimethylacetamide is 10 mmol: 60 mmol: 0.1 mol: 8 mg: 5 mg: 16 mL. After the reaction, remove dimethylacetamide by rotary evaporation under reduced pressure, wash the substrate with water and dry it to obtain the strengthening aid.

[0026] (2) Preparation of the composite material

[0027] Ingredient preparation: Weigh the raw materials by weight. 100 parts of bio-based polyethylene, using the STN7006 type of raw material during implementation; 13 parts of ethylene-octene copolymer, using the 851L type of raw material during implementation; 6.5 parts of the strengthening aid, self-made in this example; 90 parts of inorganic metal flame retardant, using a mixture of magnesium hydroxide and aluminum hydroxide with a weight ratio of 10:1 during implementation; 1.5 parts of lubricant, using the OA9 type of oxidized polyethylene wax during implementation.

[0028] Pelletizing: Add each raw material to a high-speed mixer and mix at 600 rpm for 10 min, then transfer the mixture to a twin-screw extruder for plasticizing extrusion and pelletizing. During this process, the temperature zones of the twin-screw extruder are set as follows: zone 1 at 170 °C, zone 2 at 180 °C, zone 3 at 190 °C, and the die head at 200 °C to obtain the bio-based polyethylene-based composite material.

[0029] Example 2, preparation of the bio-based polyethylene-based composite material, the specific implementation process is as follows:

[0030] (1) Preparation of the strengthening aid

[0031] Step A1: Mix diallylamine, anhydrous aluminum chloride and toluene, introduce dry nitrogen protection, preheat to 75°C, apply stirring at 90rpm, intermittently add alkyl acyl chloride to react for 5h, then continue to heat to 110°C and reflux to react for 1.8h, wherein the alkyl acyl chloride is selected from octadecanoyl chloride with a carbon chain length of C18, and the amount ratio of diallylamine, alkyl acyl chloride, anhydrous aluminum chloride and toluene is 0.1mol:0.1mol:35mg:50mL. After the reaction is completed, the toluene is quickly removed by reduced pressure rotary evaporation to obtain an alkylated monomer.

[0032] Step A2: Mix the alkylated monomer, diene, ethanedithiol, photoinitiator TPO and dimethylacetamide, raise the temperature to 80°C, apply 120 rpm stirring and 200 W / m 2 The reaction was carried out under ultraviolet irradiation for 6 hours, and then tert-butyl perbenzoate was added and the temperature was continued to rise to 125°C and the reaction was continued for 2 hours, wherein the diene was selected from 1,9-decadiene, and the amount ratio of the alkylation monomer, the diene, ethanedithiol, the photoinitiator TPO, tert-butyl perbenzoate and dimethylacetamide was 10mmol:80mmol:0.12mol:12mg:10mg:24mL. After the reaction was completed, the dimethylacetamide was removed by reduced pressure rotary evaporation, and the substrate was washed with water and dried to obtain a strengthening auxiliary agent.

[0033] (2) Preparation of composite materials

[0034] Ingredients: The raw materials are calculated by weight: 100 parts of bio-based polyethylene, and STN7006 raw material is used in the implementation process; 8 parts of ethylene-octene copolymer, and 851L raw material is used in the implementation process; 9.5 parts of reinforcing additives are homemade in this embodiment; 100 parts of inorganic metal flame retardant, and magnesium hydroxide and aluminum hydroxide are compounded in a weight ratio of 10:1 in the implementation process; 2 parts of lubricant, and OA9 type oxidized polyethylene wax is used in the implementation process.

[0035] Granulation: Add all raw materials into a high-speed mixer and mix at 600 rpm for 10 minutes. Then transfer the mixture into a twin-screw extruder for plasticization, extrusion and pelletization. During this process, the temperature zones of the twin-screw extruder are set as follows: zone 1 is 180°C, zone 2 is 190°C, zone 3 is 195°C, and the die head temperature is 200°C to obtain a composite material based on bio-based polyethylene.

[0036] Example 3, preparation of a composite material based on bio-based polyethylene, the specific implementation process is as follows:

[0037] (1) Preparation of strengthening additives

[0038] Step A1: Mix diallylamine, anhydrous aluminum trichloride, and toluene, introduce dry nitrogen for protection, preheat to 65°C, apply stirring at 90 rpm, intermittently add alkyl acyl chloride and react for 4 h, then continue to heat to 110°C and reflux for 1.5 h. Here, the alkyl acyl chloride is selected from myristoyl chloride with a carbon chain length of C14. The dosage ratio of diallylamine, alkyl acyl chloride, anhydrous aluminum trichloride, and toluene is 0.1 mol: 0.1 mol: 30 mg: 45 mL. After the reaction, quickly remove toluene by rotary evaporation under reduced pressure to obtain the alkylated monomer.

[0039] Step A2: Mix the alkylated monomer, diene, ethylene glycol dimercaptan, photoinitiator TPO, and dimethylacetamide, heat to 70°C, apply stirring at 120 rpm and ultraviolet irradiation at 180 W / m 2 for 5 h, then add tert-butyl peroxybenzoate and continue to heat to 115°C and react for 1.8 h. Here, the diene is selected from 1,7-octadiene. The dosage ratio of the alkylated monomer, diene, ethylene glycol dimercaptan, photoinitiator TPO, tert-butyl peroxybenzoate, and dimethylacetamide is 10 mmol: 70 mmol: 0.1 mol: 10 mg: 8 mg: 20 mL. After the reaction, remove dimethylacetamide by rotary evaporation under reduced pressure, wash the substrate with water and dry it to obtain the strengthening additive.

[0040] (2) Preparation of the composite material

[0041] Ingredient preparation: Weigh the raw materials by weight parts. Take 100 parts of bio-based polyethylene, and use the STN7006 type of raw material during the implementation process; take 11 parts of ethylene-octene copolymer, and use the 851L type of raw material during the implementation process; take 7.5 parts of the strengthening additive, which is self-made in this example; take 95 parts of inorganic metal flame retardant, and use a mixture of magnesium hydroxide and aluminum hydroxide in a weight ratio of 10:1 during the implementation process; take 1.8 parts of lubricant, and use the OA9 type of oxidized polyethylene wax during the implementation process.

[0042] Pelletizing: Add each raw material to a high-speed mixer and mix at 600 rpm for 10 min, then transfer the mixture to a twin-screw extruder for plasticizing and extrusion granulation. During this process, the temperature zones of the twin-screw extruder are set as follows: zone 1 is 175°C, zone 2 is 180°C, zone 3 is 190°C, and the die head temperature is 200°C to obtain the composite material based on bio-based polyethylene.

[0043] Example 4: The preparation of the composite material based on bio-based polyethylene is as follows:

[0044] (1) Preparation of the strengthening additive

[0045] Step A1: Mix diallylamine, anhydrous aluminum chloride and toluene, introduce dry nitrogen protection, preheat to 60°C, apply stirring at 90rpm, intermittently add alkyl acyl chloride to react for 4.5h, then continue to heat to 110°C and reflux to react for 1.4h, wherein the alkyl acyl chloride is selected from dodecanoyl chloride with a carbon chain length of C12, and the amount ratio of diallylamine, alkyl acyl chloride, anhydrous aluminum chloride and toluene is 0.1mol: 0.1mol: 28mg: 45mL. After the reaction is completed, the toluene is quickly removed by reduced pressure rotary evaporation to obtain an alkylated monomer.

[0046] Step A2: Take the alkylated monomer, diene, ethanedithiol, photoinitiator TPO and dimethylacetamide and mix them, raise the temperature to 75°C, apply 120 rpm stirring and 200 W / m 2 The reaction was carried out under ultraviolet irradiation for 5.5 hours, and then tert-butyl perbenzoate was added and the temperature was continued to rise to 120°C and the reaction was continued for 1.6 hours, wherein the diene was selected from 1,5-hexadiene and 1,7-octadiene and premixed in an equimolar ratio, and the amount ratio of the alkylation monomer, diene, ethanedithiol, photoinitiator TPO, tert-butyl perbenzoate and dimethylacetamide was 10mmol:70mmol:0.11mol:11mg:7mg:22mL. After the reaction was completed, the dimethylacetamide was removed by reduced pressure rotary evaporation, and the substrate was washed with water and dried to obtain a reinforcing auxiliary agent.

[0047] (2) Preparation of composite materials

[0048] Ingredients: The raw materials are calculated by weight: 100 parts of bio-based polyethylene, and STN7006 raw material is used in the implementation process; 11 parts of ethylene-octene copolymer, and 851L raw material is used in the implementation process; 8 parts of reinforcing additives are homemade in this embodiment; 35 parts of inorganic metal flame retardant, and magnesium hydroxide and aluminum hydroxide are compounded in a weight ratio of 10:1 in the implementation process; 1.7 parts of lubricant, and OA9 type oxidized polyethylene wax is used in the implementation process.

[0049] Granulation: Add all raw materials into a high-speed mixer and mix at 600 rpm for 10 minutes. Then transfer the mixture into a twin-screw extruder for plasticization, extrusion and pelletization. During this process, the temperature zones of the twin-screw extruder are set as follows: zone 1 at 170°C, zone 2 at 185°C, zone 3 at 195°C, and die head temperature at 200°C to obtain a composite material based on bio-based polyethylene.

[0050] Comparative Example 1

[0051] This comparative example refers to Example 4, except that no reinforcing agent is added to the raw materials of the composite material, and the rest of the implementation process is exactly the same.

[0052] Comparative Example 2

[0053] This comparative example refers to Example 4, replacing the strengthening agent with 1.1 parts of silane coupling agent KH-580 and 6 parts of B20 polybutadiene toughening agent, and the rest of the implementation process is exactly the same.

[0054] To detect the relevant properties of the above composite materials, the composite materials were hot-pressed into sheets by a flat vulcanizer, with a hot-pressing temperature of 200 °C, a hot-pressing pressure of 5 MPa, and a sheet thickness of 3.2 mm;

[0055] Samples were taken from the above sheets, and tensile tests were carried out with reference to the ASTM D638-22 standard, impact tests were carried out with reference to the ASTM D256-10 standard, and flame retardancy tests were carried out with reference to the UL94 standard. The specific test results are shown in Table 1:

[0056] Table 1

[0057]

[0058] It can be seen from the test results in Table 1 that the composite materials prepared in the examples have more excellent comprehensive properties of strength and toughness, and have good flame retardancy under the compounding system of inorganic metal flame retardants.

[0059] In the description of the specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0060] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of this patent, they should all belong to the protection scope of the present invention.

Claims

1. A composite material based on bio-based polyethylene, characterized in that, Comprising by weight parts: 100 parts of bio-based polyethylene, 8 - 13 parts of ethylene-octene copolymer, 6.5 - 9.5 parts of strengthening aid, 90 - 100 parts of inorganic metal flame retardant, and 1.5 - 2 parts of lubricant; The strengthening aid is prepared by the following method: Step A1: Mix diallylamine, anhydrous aluminum trichloride, and toluene, introduce dry nitrogen for protection, preheat to 50 - 75 °C, stir and intermittently add alkyl acyl chloride and react for 3.5 - 5 h, then continue to heat up to 110 °C for reflux reaction for 1.2 - 1.8 h. After the reaction is completed, remove toluene by rotary evaporation under reduced pressure to obtain an alkylated monomer, wherein the alkyl chain length of the alkyl acyl chloride is C10 - C18; Step A2: Mix the alkylated monomer, diene, ethylene dimercaptan, photoinitiator TPO and dimethylacetamide, heat up to 55 - 80 °C, stir and apply 150 - 200 W / m 2 Ultraviolet irradiation reaction for 4 - 6 h, then add tert-butyl peroxybenzoate and continue to heat up to 110 - 125 °C for reaction for 1.5 - 2 h. After the reaction, rotary evaporate under reduced pressure to remove dimethylacetamide, wash the substrate with water and dry it to obtain the strengthening auxiliary agent. Among them, the dosage ratio of the alkylated monomer, diene, ethylene dimercaptan, photoinitiator TPO, tert-butyl peroxybenzoate and dimethylacetamide is 10 mmol: 60 - 80 mmol: 0.1 - 0.12 mol: 8 - 12 mg: 5 - 10 mg: 16 - 24 mL; The model of the bio-based polyethylene is STN7006.

2. The composite material based on bio-based polyethylene according to claim 1, wherein The dosage ratio of diallylamine, alkyl acyl chloride, anhydrous aluminum trichloride, and toluene is 0.1 mol : 0.1 mol : 25 - 35 mg : 40 - 50 mL.

3. The composite material based on bio-based polyethylene according to claim 1, characterized in that, The diolefin is one or more of 1,5 - hexadiene, 1,7 - octadiene, and 1,9 - decadiene.

4. The composite material based on bio-based polyethylene according to claim 1, wherein The inorganic metal flame retardant is composed of a compound of magnesium hydroxide and aluminum hydroxide.

5. The composite material based on bio-based polyethylene according to claim 1, characterized in that, The lubricant is oxidized polyethylene wax.

6. The preparation method of the composite material based on bio-based polyethylene according to any one of claims 1-5, characterized in that, The specific method is: Mix each raw material with a high-speed mixer, transfer it to a twin-screw extruder, and control the temperature zones as follows: the first zone is 170 - 180 °C, the second zone is 180 - 190 °C, the third zone is 190 - 195 °C, and the die head temperature is 200 °C. Plasticize and extrude the mixture into pellets to obtain a composite material.

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