Freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions

Abstract

The invention belongs to the field of wood-plastic composite materials, and discloses a freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions, WPC comprises the following raw materials: HDPE, hydrophobic modified wood fiber, nano montmorillonite, SEBS elastomer, a titanate coupling agent, an antifreeze modifier and a proper amount of antioxidant. According to the WPC disclosed by the invention, a'pinning-coating 'dual-interface structure is formed through the synergistic effect of nano-montmorillonite intercalation and titanate, and honeycomb micropores are constructed in a matrix by the SEBS elastomer, so that the freeze-thaw cycle resistance of the WPC is effectively improved, and the WPC is suitable for the fields of buildings, traffic, municipal facilities and the like in cold region engineering.

Description

Technical Field

[0001] The invention belongs to the field of wood-plastic composite materials, and in particular relates to a freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions. Background Art

[0002] As infrastructure construction in cold regions expands, traditional engineering materials face severe challenges. Wood-Plastic Composites (WPC) are widely used in temperate regions due to their environmental friendliness and corrosion resistance. However, their performance degradation is particularly prominent in cold environments, where freeze-thaw cycles exceed 50 times annually and temperature swings exceed 60°C. Studies have shown that the difference between the hygroscopic expansion of wood fibers during freeze-thaw (expansion rate can reach 2.5-4.8%) and the contraction of the plastic matrix (thermal expansion coefficient difference of 1-2 orders of magnitude) leads to a 40%-60% decrease in interfacial shear strength, severely restricting the application of WPC in critical applications such as bridge formwork and railway sleepers in cold regions.

[0003] Current approaches to improving WPC's frost resistance focus on two main approaches: First, increasing the plastic matrix, such as raising the HDPE content to 70%, reduces water absorption (<1.5%), but reduces the wood fiber content, leading to a 15% increase in material density and a 30% increase in cost, while also losing the natural wood texture. Second, using coupling agents (such as silanes) improves initial interfacial bonding strength by 20%-30%, but after 50 freeze-thaw cycles, hydrogen bonds break down, leading to coupling failure and a flexural modulus decay rate exceeding 35%. More seriously, existing technologies fail to address the problem of microcrack propagation caused by accumulated frost heave stress, resulting in a service life of the material generally less than five years.

[0004] In-depth analysis reveals three key technical blind spots in existing technologies: 1. Single interface modification cannot withstand the dynamic stress impacts of freeze-thaw cycles; 2. There is a lack of an active mechanism to inhibit ice crystal nucleation and growth; and 3. An effective volume deformation buffering system has not been constructed. Developing new WPCs with a synergistic "stress dissipation-interface strengthening-phase transformation control" approach is key to overcoming the bottleneck of cold-region applications. However, existing research has yet to achieve substantial progress in key indicators such as the uniformity of the nanoreinforced phase dispersion (needing to be controlled below 50nm) and the compatibility of the elastomer and matrix (interface binding energy needs to be >80kJ / mol). A technological breakthrough is urgently needed through innovations in material composition and structure. Summary of the Invention

[0005] The object of the present invention is to overcome at least one disadvantage of the prior art and provide a freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions.

[0006] The technical solution adopted by the present invention is: a freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions, comprising the following components by weight: 40-55 parts of high-density polyethylene (HDPE); 30-45 parts of wood fiber hydrophobically modified with a silane coupling agent; 3-8 parts of nano-montmorillonite, wherein the nano-montmorillonite is an organic montmorillonite modified by cetyltrimethylammonium bromide (CTAB) intercalation; 5-12 parts of SEBS elastomer; 1.5-3 parts of a titanate coupling agent; 2-5 parts of an antifreeze modifier; and an appropriate amount of an antioxidant.

[0007] In some examples, the interlayer spacing of the nano-montmorillonite is 2.8 to 3.2 nm as determined by XRD, and the specific surface area is 200 to 250 m² / g.

[0008] In some embodiments, the wood fiber meets at least one of the following requirements: 1) a particle size of 80 to 200 meshes, 2) an aspect ratio of (30 to 70): 1, 3) selected from at least one of pine wood, bamboo powder or rice husk fiber; 4) the silane coupling agent is selected from at least one of KH-550 (γ-aminopropyltriethoxysilane), KH-560 (γ-glycidyloxypropyltrimethoxysilane), A-151 (vinyltriethoxysilane), A-171 (vinyltrimethoxysilane), KH-570 (γ-methacryloyloxypropyltrimethoxysilane), Si-69 (bis-[γ-triethoxysilylpropyl] tetrasulfide), A-1120 (dodecyltrimethoxysilane), perfluorooctyltriethoxysilane, octadecyltrimethoxysilane, silane-terminated polyether (MS Polymer), and AEM-5700.

[0009] In some examples, the SEBS elastomer has a styrene content of 20-30% and a melt index of 5-10 g / 10 min (230° C., 2.16 kg).

[0010] In some examples, the titanate coupling agent is selected from at least one of KR-TTS (isopropyl triisostearoyl titanate), KR-38S (isopropyl tris(dioctyl pyrophosphate acyloxy) titanate), KR-138S (bis(dioctyl pyrophosphate acyloxy) ethylene titanate), KR-201 (amino group-containing chelate titanate), KR-12 (isopropyl tris(dioctyl pyrophosphate acyloxy) titanate), NDZ-101 (pyrophosphate titanate), and KR-41B (tetraisopropyl di(dioctyl phosphite) titanate).

[0011] In some examples, the antifreeze modifier is selected from at least one of polyethylene glycol, sodium lauryl sulfate, POE (polyolefin elastomer), EPDM (ethylene propylene diene monomer), TPU (thermoplastic polyurethane), nano silicon dioxide (SiO2), nano calcium carbonate (CaCO3), nano clay (montmorillonite), epoxidized soybean oil (ESO), dioctyl adipate (DOA), dibutyl sebacate (DBS), MBS (methyl methacrylate-butadiene-styrene copolymer), polyethylene wax (PE wax), paraffin emulsion, and calcium / zinc stearate.

[0012] In some examples, the antifreeze modifier is prepared by compounding polyethylene glycol and sodium lauryl sulfate in a mass ratio of (2.5-3.5):1.

[0013] In some examples, the antioxidant is selected from at least one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1076 (octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), BHT (butylated hydroxytoluene), 168 (tris[2,4-di-tert-butylphenyl]phosphite), DLTDP (dilauryl thiodipropionate), DSTDP (distearyl thiodipropionate) and antioxidant 4010NA.

[0014] In some examples, the antioxidant is a composite antioxidant system composed of 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and 168 (tris[2,4-di-tert-butylphenyl] phosphite) in a ratio of 1:1.

[0015] In some examples, the preparation method includes: S1) fully premixing HDPE, SEBS elastomer, and nano-montmorillonite in a mixer to obtain a premix; S2) adding a silane coupling agent, hydrophobically modified wood fiber, a titanate coupling agent, an antifreeze modifier, and an antioxidant to the premix and mixing thoroughly; S3) extrusion molding: using a co-rotating twin-screw extruder, during the twin-screw extrusion process, the head pressure fluctuates periodically within the range of 12 to 15 MPa at a frequency of 0.5 to 1 Hz; S4) cooling and shaping, and cutting to obtain the finished product.

[0016] In some examples, the premixing temperature is 80-90° C. and / or the premixing time is 5-10 minutes.

[0017] In some examples, the mixing temperature is 150-160° C. and / or the mixing time is 15-20 minutes.

[0018] In some examples, the temperature zones of the twin-screw extruder are: zone 1 160-165°C; zone 2 170-175°C; zone 3 175-180°C; and die zone 180-185°C.

[0019] In some examples, the SEBS elastomer forms a honeycomb microporous structure in the matrix, with a micropore diameter of 5 to 15 μm and a porosity of 8 to 12%.

[0020] The beneficial effects of the present invention are as follows: the freeze-thaw cycle resistant wood-plastic composite materials of some examples of the present invention have excellent freeze-thaw cycle resistance performance and are suitable for the fields of construction, transportation, municipal facilities, etc. in cold region projects.

[0021] The freeze-thaw cycle resistant wood-plastic composite materials of some embodiments of the present invention form a "pinning-wrapping" dual interface structure through the synergistic effect of nano-montmorillonite intercalation and titanate.

[0022] In some examples of the freeze-thaw cycle resistant wood-plastic composite materials of the present invention, by optimizing the process, the SEBS elastomer constructs honeycomb micropores (diameter 5-15 μm) in the matrix to absorb frost heave stress.

[0023] In some examples of the freeze-thaw cycle resistant wood-plastic composite materials of the present invention, the PEG-SDS composite antifreeze modifier forms a dynamic hydrogen bond network on the fiber surface to inhibit ice crystal growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 SEBS elastomer constructs honeycomb micropores in the matrix.

[0025] Figure 2 Comparison of the wood-plastic interface with antifreeze modifier (a) and without antifreeze modifier (b) after 50 freeze-thaw cycles. DETAILED DESCRIPTION

[0026] A freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions comprises the following components in parts by weight: 40-55 parts of high-density polyethylene (HDPE); 30-45 parts of wood fiber hydrophobically modified with a silane coupling agent; 3-8 parts of nano-montmorillonite, wherein the nano-montmorillonite is an organic montmorillonite modified by cetyltrimethylammonium bromide (CTAB) intercalation; 5-12 parts of SEBS elastomer; 1.5-3 parts of a titanate coupling agent; 2-5 parts of an antifreeze modifier; and an appropriate amount of an antioxidant.

[0027] In some examples, the interlayer spacing of the nano-montmorillonite is 2.8 to 3.2 nm as determined by XRD, and the specific surface area is 200 to 250 m² / g.

[0028] In some examples, the wood fiber meets at least one of the following requirements: 1) the particle size is 80-200 mesh, which can be used for the construction of a variety of wood-plastic materials; 2) the aspect ratio is (30-70): 1, and the fiber is longer, which can bring better mechanical properties; 3) it is selected from at least one of pine wood, bamboo powder or rice husk fiber; these raw materials are widely available, low in cost and easy to handle; 4) the silane coupling agent is selected from KH-550 (γ-aminopropyltriethoxysilane), At least one of KH-560 (γ-glycidoxypropyltrimethoxysilane), A-151 (vinyltriethoxysilane), A-171 (vinyltrimethoxysilane), KH-570 (γ-methacryloyloxypropyltrimethoxysilane), Si-69 (bis-[γ-triethoxysilylpropyl] tetrasulfide), A-1120 (dodecyltrimethoxysilane), perfluorooctyltriethoxysilane, octadecyltrimethoxysilane, silane-terminated polyether (MS Polymer), and AEM-5700. These silane coupling agents react well with wood fiber, promoting compatibility between wood fiber and other raw materials and resulting in products with superior performance.

[0029] In some examples, the SEBS elastomer has a styrene content of 20-30% and a melt index of 5-10 g / 10 min (230°C, 2.16 kg). Data shows that this SEBS elastomer easily forms honeycomb micropores during the preparation process, which can better absorb frost heave stress and improve the freeze-thaw performance of wood-plastic composites.

[0030] In some examples, the titanate coupling agent is selected from at least one of KR-TTS (isopropyl triisostearoyl titanate), KR-38S (isopropyl tri(dioctyl pyrophosphate) titanate), KR-138S (bis(dioctyl pyrophosphate) ethylene titanate), KR-201 (amino-containing chelated titanate), KR-12 (isopropyl tri(dioctyl pyrophosphate) titanate), NDZ-101 (pyrophosphate titanate), and KR-41B (tetraisopropyl di(dioctyl phosphite) titanate). These titanate coupling agents can synergize well with the nano-montmorillonite intercalation layer to form a "pinning-coating" dual interface structure, thereby significantly improving the freeze-thaw cycle resistance of the wood-plastic composite.

[0031] In some examples, the antifreeze modifier is selected from at least one of polyethylene glycol, sodium lauryl sulfate, POE (polyolefin elastomer), EPDM (ethylene propylene diene monomer), TPU (thermoplastic polyurethane), nano silicon dioxide (SiO2), nano calcium carbonate (CaCO3), nano clay (montmorillonite), epoxidized soybean oil (ESO), dioctyl adipate (DOA), dibutyl sebacate (DBS), MBS (methyl methacrylate-butadiene-styrene copolymer), polyethylene wax (PE wax), paraffin emulsion, and calcium / zinc stearate.

[0032] In some examples, the antifreeze modifier is prepared by compounding polyethylene glycol and sodium dodecyl sulfate in a mass ratio of (2.5-3.5):1. The PEG-SDS composite modifier forms a dynamic hydrogen bond network on the fiber surface, inhibiting ice crystal growth.

[0033] In some examples, the antioxidant is selected from at least one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1076 (octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), BHT (butylated hydroxytoluene), 168 (tris[2,4-di-tert-butylphenyl]phosphite), DLTDP (dilauryl thiodipropionate), DSTDP (distearyl thiodipropionate) and antioxidant 4010NA.

[0034] In some examples, the antioxidant is a composite antioxidant system composed of 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and 168 (tris[2,4-di-tert-butylphenyl] phosphite) in a ratio of 1:1.

[0035] In some examples, the preparation method includes: S1) fully premixing HDPE, SEBS elastomer, and nano-montmorillonite in a mixer to obtain a premix; S2) adding a silane coupling agent, hydrophobically modified wood fiber, a titanate coupling agent, an antifreeze modifier, and an antioxidant to the premix and mixing thoroughly; S3) extrusion molding: using a co-rotating twin-screw extruder, during the twin-screw extrusion process, the head pressure fluctuates periodically within the range of 12 to 15 MPa at a frequency of 0.5 to 1 Hz; S4) cooling and shaping, and cutting to obtain the finished product.

[0036] In some examples, the premixing temperature is 80-90° C. and / or the premixing time is 5-10 minutes.

[0037] In some examples, the mixing temperature is 150-160° C. and / or the mixing time is 15-20 minutes.

[0038] In some examples, the temperature zones of the twin-screw extruder are: zone 1 160-165°C; zone 2 170-175°C; zone 3 175-180°C; and die zone 180-185°C.

[0039] In some examples, the SEBS elastomer forms a honeycomb microporous structure in the matrix, with a micropore diameter of 5 to 15 μm and a porosity of 8 to 12%.

[0040] The technical solution of the present invention is further illustrated below in combination with examples and experimental data.

[0041] Example 1

[0042] 1. Raw material ratio (weight parts): HDPE 48 parts, pine fiber (120 mesh, moisture content 2.8%) 35 parts, nano-montmorillonite (CTAB intercalation modified, interlayer spacing 3.0nm) 5 parts, SEBS elastomer (styrene content 25%) 8 parts, titanate coupling agent (TCA-201) 2.2 parts, antifreeze modifier (PEG-4000:SDS=3:1) 3.5 parts, antioxidant (1010:168=1:1) 0.8 parts.

[0043] 2. Preparation process

[0044] 1) Soak pine fiber in an ethanol solution containing 5% KH-550 at 105°C for 2 hours and vacuum dry to a moisture content of 0.9%. 2) Premix: Mix HDPE, SEBS, and nano-montmorillonite at 85°C for 8 minutes. 3) Mix: Add the remaining components and mix at 155°C for 18 minutes. 4) Extrusion: Twin-screw extruder (temperature zones 165 / 175 / 180 / 183°C), speed 40 rpm, die pressure 13 MPa.

[0045] 5) Shape cutting: After water cooling, standard test specimens are made.

[0046] 3. Performance test (GB / T 24508-2020)

[0047] 1) Flexural strength after 50 freeze-thaw cycles: 52.7 MPa (92.3% retention); 2) -40°C notched impact strength: 12.7 kJ / m²; 3) Water absorption (24 hours): 0.85%; 4) Linear expansion coefficient: 1.8×10 -5 / ℃.

[0048] Example 2 (high antifreeze ratio)

[0049] 1. Raw material ratio (parts by weight): the antifreeze modifier was increased to 5 parts (PEG:SDS=3.5:1), and the rest was the same as in Example 1; Performance changes: the flexural strength retention rate after freeze-thaw cycles increased to 94.1%, but the impact strength decreased slightly to 9.1 kJ / m² (due to the relatively lower proportion of elastomer).

[0050] Example 3 (Low Nano-Montmorillonite Ratio)

[0051] 1. Raw material ratio (parts by weight): Nano-montmorillonite is reduced to 3 parts, SEBS is increased to 12 parts, and the rest is the same as in Example 1; Performance changes: The flexural strength retention rate after freeze-thaw cycles is 89.5%, but the impact strength at -40°C is increased to 14.3 kJ / m² (micropore cushioning effect is enhanced).

[0052] Comparative Example 1 (Traditional high plastic content WPC)

[0053] 1. Raw material ratio (parts by weight): 70 parts of HDPE, 25 parts of pine wood flour, 2 parts of maleic anhydride grafted polyethylene (MAPE), and 0.5 parts of antioxidant.

[0054] Performance data: 1) Flexural strength retention after 50 freeze-thaw cycles: 68.5%; 2) -40°C impact strength: 4.2 kJ / m²; 3) Water absorption: 2.3%; 4) Linear expansion coefficient: 3.5×10 -5 / ℃.

[0055] Comparative Example 2 (without antifreeze modifier)

[0056] 1. Raw material ratio (parts by weight): Omit the PEG-SDS composite antifreeze agent, and the rest is the same as in Example 1.

[0057] 2. Performance data: 1) After freeze-thaw cycles, the interface cracks significantly ( Figure 2 ); 2) The flexural strength retention rate dropped sharply to 74.6%; the water absorption rate increased to 1.9% (ice crystals destroyed the density of the material); 4) The impact strength dropped to 7.1kJ / m².

[0058] Comparative Example 3 (without SEBS elastomer)

[0059] 1. Raw material ratio (parts by weight): Remove SEBS elastomer and increase HDPE to 53 parts. Other proportions are the same as in Example 1.

[0060] 1) Performance data: Impact strength is reduced to 5.8kJ / m²; linear expansion coefficient is increased to 3.2×10 -5 / ℃.

[0061] Comparative Analysis Table

[0062] Test indicators Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Bending strength retention rate 92.3% 68.5% 74.6% 81.2% -40℃ impact strength 12.7 kJ / m² 4.2 kJ / m² 7.1 kJ / m² 5.8 kJ / m² Water absorption 0.85% 2.3% 1.9% 1.2% Freeze-thaw cycle life >100 times 35 times 60 times 45 times

[0063] Note: Freeze-thaw cycle life is defined as the number of cycles when the flexural strength drops to 80% of the initial value.

[0064] Figure 1 This is a partial photo of the matrix of Example 1, from which it can be clearly seen that the SEBS elastomer creates honeycomb-like micropores in the matrix. These micropores can effectively absorb frost heave stress, thereby improving the freeze-thaw resistance of WPC.

[0065] Figure 2 This figure compares the interface of a WPC with an antifreeze modifier (a, Example 1) and without an antifreeze modifier (b, Comparative Example 2) after 50 freeze-thaw cycles. It can be seen that the interface of the WPC in the example remains intact after 50 freeze-thaw cycles, while the interface of the comparative example shows obvious delamination, and the overall structure of the WPC has been destroyed.

[0066] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art, simple deductions or substitutions that do not depart from the concept of the present invention are within the scope of protection of the present invention.

Claims

1. A freeze-thaw cycle resistant wood-plastic composite material suitable for cold regions, characterized in that: The composition comprises the following components in parts by weight: 40-55 parts of high-density polyethylene; 30-45 parts of hydrophobically modified wood fiber with a silane coupling agent; 3-8 parts of nano-montmorillonite, wherein the nano-montmorillonite is an organic montmorillonite modified by cetyltrimethylammonium bromide (CTAB) intercalation; 5-12 parts of SEBS elastomer; 1.5-3 parts of a titanate coupling agent; 2-5 parts of an antifreeze modifier; and an appropriate amount of an antioxidant.

2. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The interlayer spacing of the nano-montmorillonite is 2.8-3.2 nm as detected by XRD, and the specific surface area is 200-250 m² / g.

3. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The wood fiber meets at least one of the following requirements: 1) a particle size of 80 to 200 meshes, 2) an aspect ratio of (30 to 70):1, 3) is selected from at least one of pine wood, bamboo powder or rice husk fiber; 4) the silane coupling agent is selected from at least one of KH-550 (γ-aminopropyltriethoxysilane), KH-560 (γ-glycidyloxypropyltrimethoxysilane), A-151 (vinyltriethoxysilane), A-171 (vinyltrimethoxysilane), KH-570 (γ-methacryloyloxypropyltrimethoxysilane), Si-69 (bis-[γ-triethoxysilylpropyl] tetrasulfide), A-1120 (dodecyltrimethoxysilane), perfluorooctyltriethoxysilane, octadecyltrimethoxysilane, silane-terminated polyether (MS Polymer), and AEM-5700.

4. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The SEBS elastomer has a styrene content of 20-30% and a melt index of 5-10 g / 10 min (230° C., 2.16 kg).

5. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The titanate coupling agent is selected from at least one of KR-TTS (isopropyl triisostearoyl titanate), KR-38S (isopropyl tris (dioctyl pyrophosphate acyloxy) titanate), KR-138S (bis (dioctyl pyrophosphate acyloxy) ethylene titanate), KR-201 (amino-containing chelate titanate), KR-12 (isopropyl tris (dioctyl pyrophosphate acyloxy) titanate), NDZ-101 (pyrophosphate titanate), and KR-41B (tetraisopropyl di (dioctyl phosphite) titanate).

6. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The antifreeze modifier is selected from at least one of polyethylene glycol, sodium lauryl sulfate, POE (polyolefin elastomer), EPDM (ethylene propylene diene monomer rubber), TPU (thermoplastic polyurethane), nano silicon dioxide (SiO2), nano calcium carbonate (CaCO3), nano clay (montmorillonite), epoxy soybean oil (ESO), dioctyl adipate (DOA), dibutyl sebacate (DBS), MBS (methyl methacrylate-butadiene-styrene copolymer), polyethylene wax (PE wax), paraffin emulsion, and calcium / zinc stearate; preferably, the antifreeze modifier is compounded by polyethylene glycol and sodium lauryl sulfate in a mass ratio of (2.5-3.5):

1.

7. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The antioxidant is selected from at least one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1076 (octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), BHT (butylated hydroxytoluene), 168 (tris[2,4-di-tert-butylphenyl]phosphite), DLTDP (dilauryl thiodipropionate), DSTDP (distearyl thiodipropionate) and antioxidant 4010NA; preferably, the antioxidant is a composite antioxidant system composed of 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and 168 (tris[2,4-di-tert-butylphenyl]phosphite) in a 1:1 ratio.

8. The freeze-thaw cycle resistant wood-plastic composite material according to claim 1, characterized in that: The preparation method includes: S1) fully premixing HDPE, SEBS elastomer, and nano-montmorillonite in a mixer to obtain a premix; S2) adding a silane coupling agent, hydrophobically modified wood fiber, a titanate coupling agent, an antifreeze modifier, and an antioxidant to the premix and mixing them thoroughly; S3) extrusion molding: using a co-rotating twin-screw extruder, during the twin-screw extrusion process, the head pressure fluctuates periodically within the range of 12 to 15 MPa at a frequency of 0.5 to 1 Hz; S4) cooling and shaping, and cutting to obtain the finished product.

9. The freeze-thaw cycle resistant wood-plastic composite material according to claim 8, characterized in that: The premixing temperature is 80-90°C and / or the premixing time is 5-10 minutes; the mixing temperature is 150-160°C and / or the mixing time is 15-20 minutes; the temperature zones of the twin-screw extruder are: zone 1 160-165°C; zone 2 170-175°C; zone 3 175-180°C; and die zone 180-185°C.

10. The freeze-thaw cycle resistant wood-plastic composite material according to claim 8 or 9, characterized in that: The SEBS elastomer forms a honeycomb microporous structure in the matrix, the micropore diameter is 5 to 15 μm, and the porosity is 8 to 12%.

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