High-strength low-temperature-resistant glass fiber reinforced composite material and preparation method thereof

Abstract

This invention relates to the field of polymer composite materials technology, specifically disclosing a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. Based on 100 wt%, the reinforced composite material comprises the following raw materials: 55–65 wt% matrix resin, 25–35 wt% glass fiber, 5–10 wt% compatibilizer, and the balance being functional additives. The compatibilizer comprises 0.2–0.7 wt% silane coupling agent and 4.8–9.3 wt% reactive compatibilizer. This invention provides a structural basis for high strength and low-temperature toughness through the compounded matrix resin. Based on this, it solves the core problem of insufficient thermal stability of traditional toughening agents by optimizing the compatibilizer system. It effectively promotes full wetting of the glass fiber, inhibits the formation of pores and floating fibers, and improves the dispersion uniformity of the glass fiber and the overall mechanical properties of the composite material.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. Background Technology

[0002] Nylon (polyamide), as the leading engineering plastic, possesses excellent mechanical properties, wear resistance, chemical resistance, and good processability, making it widely used in automotive, electronics, rail transportation, and aerospace industries. However, traditional nylon materials exhibit a significant decrease in toughness and impact strength at extremely low temperatures, making them prone to brittle fracture. This defect severely limits its application in extreme climatic conditions. To broaden the lower limit of nylon's operating temperature, glass fiber reinforcement has become the mainstream technical approach to improve its mechanical properties. The introduction of glass fiber can significantly improve the rigidity and strength of composite materials, but it also exacerbates the material's brittleness at low temperatures, further deteriorating its impact toughness.

[0003] Several low-temperature toughening schemes for glass fiber reinforced nylon have been disclosed in the prior art. CN104387766A discloses a glass fiber reinforced PA66 composite with low-temperature resistance and high transparency, composed of PA66, copolymer nylon, lubricant, and glass fiber. It uses a ternary copolymer nylon of caprolactam, adipic acid, and hexamethylenediamine as a blending component, achieving good low-temperature performance without the addition of a toughening agent. Although this scheme simplifies the formulation system, the synthesis process of the ternary copolymer nylon is complex and costly, and it relies entirely on the internal toughening effect of the copolymer nylon, lacking a specific design for the glass fiber-resin interface. At high glass fiber content, the problem of weak interfacial bonding remains prominent, and the improvement in low-temperature impact strength is limited.

[0004] CN110437611B discloses a reinforced and toughened ultra-low temperature resistant nylon composite material, using a mixture of amino-terminated polydimethylsiloxane, epoxy-terminated polydimethylsiloxane, and organosilicon elastomer toughening agents as toughening agents, while the glass fibers are modified with silane coupling agents containing amino or epoxy groups. This scheme imparts excellent low-temperature toughness to the composite material through the low glass transition temperature of the organosilicon elastomer. However, the compatibility between organosilicon elastomer and nylon matrix is ​​inherently poor, the dispersion stability of the toughening agent is questionable, and the surface energy of organosilicon materials is extremely low, limiting their wetting and anchoring effect on glass fibers. Under high shear processing conditions, phase separation easily occurs, leading to a decrease in batch stability of the product. To address the above shortcomings, this invention provides a glass fiber reinforced composite material that effectively improves its low-temperature resistance. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a structural basis with high strength and low-temperature toughness by compounding the matrix resin; on this basis, the core problem of insufficient thermal stability of traditional toughening agents is solved by optimizing the compatibilization system; it effectively promotes full wetting of glass fibers, inhibits the generation of pores and floating fibers, and improves the dispersion uniformity of glass fibers and the overall mechanical properties of composite materials.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a high-strength, low-temperature resistant glass fiber reinforced composite material, which, based on 100wt%, comprises the following raw materials: 55-65wt% matrix resin, 25-35wt% glass fiber, 5-10wt% compatibilizer system, and the balance being functional additives; The compatibilization system comprises 0.2–0.7 wt% silane coupling agent and 4.8–9.3 wt% reactive compatibilizing toughening agent.

[0007] The compatibilization system employs a dual interface control strategy of chemical bonding and physical adsorption: one end of the silane coupling agent forms a Si-O-Si covalent bond with the silanol groups on the glass fiber surface, while the other end reacts with the terminal amino or carboxyl groups of the nylon matrix to construct a rigid chemical anchoring layer on the glass fiber surface; the reactive compatibility toughening agent forms a flexible physical adsorption layer on the glass fiber surface through its polyether segments. The two interface layers are nested together, with chemical anchoring providing a durable high-strength bond and physical adsorption reducing interfacial friction during processing. The two work synergistically, giving the composite material better flowability during processing and stronger resistance to interfacial debonding during service.

[0008] In some embodiments, the matrix resin comprises at least two of PA66, PA612, PA1012, and PA12.

[0009] Preferably, the matrix resin comprises PA66 and PA612 or PA1012 or PA12 in a mass ratio of 1:(0.2 to 0.8).

[0010] The high density of amide groups and strong hydrogen bonding in short-chain PA66 can impart high crystallinity and high rigidity to the matrix; the high proportion of methylene segments in long-chain nylon (PA612, PA1012, PA12) results in good molecular chain flexibility and a glass transition temperature as low as 35-50℃. The non-uniform crystalline structure formed by blending the two is the structural basis for the composite material to maintain both high strength and low-temperature toughness.

[0011] When PA66 and PA612 are blended, both are semi-crystalline nylons with a moderate difference in amide group density, resulting in the best compatibility. After blending, they form a uniform co-continuous phase structure with a wide processing window. When PA66 and PA1012 are blended, PA1012 has a longer carbon chain, better flexibility, and extremely low water absorption, making it suitable for applications requiring higher low-temperature resistance and dimensional stability. When PA66 and PA12 are blended, PA12 has the best chemical resistance and extremely low water absorption, making it suitable for applications requiring low-temperature toughness, chemical resistance, and dimensional stability.

[0012] In some embodiments, the preparation steps of the reactive compatibility toughening agent are as follows: S1. Under anaerobic conditions, the terminal amino polyether and dimer acid are melted, and triphenyl phosphite is added. The mixture is heated to 200-250℃ and reacted for 1-4 hours. Then, the reaction pressure is adjusted to -0.1-0.1 MPa, and the reaction is stopped when the acid value reaches 5.0-6.0 mgKOH / g. The mixture is then cooled and discharged, and stored under inert gas to obtain the polyether-amide block prepolymer. S2. Under anaerobic conditions, epichlorohydrin is dissolved in toluene, tetrabutylammonium bromide is added and stirred until dissolved, polyether-amide block prepolymer is added dropwise first, followed by NaOH aqueous solution. The temperature is raised to 70-110℃ and the reaction is stopped when the epoxy value is 0.1-0.3 mmol / g. The temperature is lowered, the organic phase is separated, and the organic phase is washed, dried, distilled under reduced pressure, and dried under vacuum to constant weight to obtain the reactive compatibility toughening agent.

[0013] The toughening agent of this invention reacts with the PA end groups of the matrix resin to form a graft in situ, anchoring the elastomer particles. During the reaction, β-hydroxyamide bonds are generated. The formation of β-hydroxyamide bonds involves the nucleophilic addition reaction between the epoxy group and the amino group. After ring opening, the secondary amine and hydroxyl group formed intramolecular hydrogen bonds, which further reduces the free energy of the system. This provides the composite material with stronger resistance to processing heat aging and humid heat aging. In contrast, the maleic anhydride graft system generated by traditional toughening agents containing maleic anhydride has an amide acid bond containing a heat- and hydrolysis-sensitive ortho-carboxyl group. Under the processing temperature of PA66 and in humid heat environments, it is prone to reversible cyclization reactions or hydrolytic ring opening, leading to interfacial bonding failure.

[0014] Furthermore, the high glass fiber content and the mixing of PA66 resin result in a high-viscosity melt, making it prone to porosity during glass fiber impregnation. The polyether segment of the toughening agent in this invention has low surface energy, allowing it to form a physical adsorption layer on the glass fiber surface, reducing the interfacial friction coefficient between the melt and the glass fiber, and promoting wetting. The free rotation of the polyether segment in the toughening agent molecule endows it with conformational adjustment capabilities on the glass fiber surface, forming physical entanglement anchor points. Combined with the chemical bonding of the silane coupling agent, a two-layer interfacial structure is constructed: the silane coupling agent forms a rigid chemical anchoring layer to resist interfacial shear forces, while the polyether adsorption layer forms a flexible stress buffer layer to reduce processing resistance and stress concentration. This synergistic anchoring mechanism makes the interfacial bonding strength and low-temperature impact resistance of the composite material significantly superior to a single-interfacial design system.

[0015] In some embodiments, the molar ratio of the terminal amino polyether to the dimer acid in S1 is 1:(1.01 to 1.09).

[0016] The reaction principle of step S1 is based on the polycondensation reaction between the primary amino group of the terminal amino polyether and the carboxyl group of the dimer acid: under the catalysis of triphenyl phosphite (TPP), the amino and carboxyl groups undergo dehydration condensation to form amide bonds, generating a polyether-amide block copolymer. In this reaction, the molar ratio of the terminal amino polyether to the dimer acid is controlled within the range of 1:(1.01–1.09), with a slight excess of dimer acid to ensure complete reaction of the terminal amino polyether and avoid residual terminal amino groups causing side reactions in the subsequent epichlorohydrin reaction stage.

[0017] In some embodiments, the molar ratio of epichlorohydrin in S2 to amino-terminated polyether in S1 is (2.1-2.5):1.

[0018] The reaction principle of step S2 is based on the ring-opening esterification reaction between the residual terminal carboxyl groups in the polyether-amide block prepolymer and the epoxy groups of epichlorohydrin. Simultaneously, the active hydrogen atoms of the amide groups on the prepolymer chain can also undergo ring-opening addition with epichlorohydrin, introducing epoxy groups. Tetrabutylammonium bromide (TBAB) acts as a phase transfer catalyst, promoting the interaction between OH- ions in the NaOH aqueous solution and the organic phase of epichlorohydrin, catalyzing the formation of epoxy groups. The amount of epichlorohydrin used is carefully designed to ensure sufficient epoxidation of the prepolymer while avoiding excessive crosslinking caused by excess epichlorohydrin.

[0019] In some embodiments, the functional additive comprises 0.3–0.8 wt% of a lubricating dispersant, 0.3–0.8 wt% of an antioxidant, and 0.3–0.8 wt% of a hydrolysis resistant agent.

[0020] In some embodiments, the lubricating dispersant comprises stearamide and pentaerythritol ester.

[0021] In some embodiments, the mass ratio of stearamide to pentaerythritol ester is 1:(0.8 to 1.2).

[0022] Stearamide, a small monoamide molecule with low molecular weight and moderate polarity, can rapidly migrate to the melt surface in the early stages of processing, providing instantaneous internal and external lubrication. Pentaerythritol ester, a large polyester molecule, has high thermal stability and is not easily volatile, providing continuous lubrication in the later stages of processing. When the two lubricating dispersants are used together, the small-molecule stearamide fills the microscopic areas that the large-molecule pentaerythritol ester cannot cover, forming a denser lubricating layer; the large-molecule pentaerythritol ester remains stable at high temperatures, preventing the lubrication effect from being interrupted after the stearamide volatilizes at high temperatures. This complementary molecular size lubrication and dispersion mechanism is more effective than using a single lubricating dispersant in suppressing fiber floating and weld line defects in glass fiber reinforced systems.

[0023] In some embodiments, the raw material further comprises 0.1 to 0.3 wt% of 1-ethyl-3-methylimidazolium acetate.

[0024] 1-Ethyl-3-methylimidazolium acetate is composed of 1-ethyl-3-methylimidazolium cation and acetate anion, exhibiting extremely low vapor pressure and excellent thermal stability, and can exist stably at processing temperatures of 280–310 °C. Its acetate anion can form hydrogen bonds or ion-dipole interactions with the nylon terminal amino groups, inhibiting side reactions and thermal degradation during processing. In addition, it can form a nanoscale ion-conductive lubricating layer on the glass fiber surface, forming a three-layer interface regulation structure with the physical adsorption layer of the toughening agent's polyether segment and the chemical bonding layer of the silane coupling agent, further reducing the interfacial friction between the melt and the glass fiber, improving the dispersion uniformity of the glass fiber and the overall mechanical properties of the composite material.

[0025] Another aspect of the present invention provides a method for preparing the above-mentioned high-strength, low-temperature resistant glass fiber reinforced composite material, the specific steps of which are as follows: Vacuum-dried matrix resin, functional additives, and compatibilizer are added sequentially to a mixer with a speed of 500-800 rpm and mixed for 3-5 minutes. Glass fiber is added by side feeding and extruded using a co-rotating parallel twin-screw extruder at 220-270°C. After cooling, pelletizing, and drying, a high-strength, low-temperature resistant glass fiber reinforced composite material is obtained.

[0026] Compared with the prior art, the present invention has the following beneficial effects: The glass fiber reinforced composite material matrix resin provided by this invention is a blend of at least two of PA66 and PA612, PA1012, or PA12. Short-chain PA66 imparts high rigidity and high heat resistance to the matrix, while long-chain nylon imparts low-temperature flexibility and low water absorption, creating a synergistic effect. The compatibilizing system integrates a silane coupling agent and a reactive compatibilizing toughening agent. The former forms an organic-inorganic interface layer on the glass fiber surface, while the latter combines the flexibility of the polyether segment with the reactivity of the amide segment. This toughening agent reacts with the PA end groups of the matrix resin, forming an in-situ... The grafted material anchors elastomer particles. The β-hydroxyamide bonds generated during the reaction exhibit superior stability at PA66 processing temperatures compared to the ammonic acid bonds generated by traditional maleic anhydride toughening agents, solving the core problem of insufficient thermal stability in traditional toughening agents. Simultaneously, the polyether segment of this toughening agent has low surface energy, forming a physical adsorption layer on the glass fiber surface, reducing the interfacial friction coefficient between the melt and glass fiber. Its chemical bonding with the silane coupling agent forms a chemical-physical synergistic anchoring, promoting full wetting of the glass fiber and inhibiting the formation of porosity and loose fibers. Furthermore, the introduction of 1-ethyl-3-methylimidazolium acetate suppresses side reactions and thermal degradation during processing, and forms a three-layer interface regulation structure with the physical adsorption layer of the polyether segment of the toughening agent and the chemical bonding layer of the silane coupling agent, further reducing the interfacial friction between the melt and glass fiber, improving the dispersion uniformity of the glass fiber, and enhancing the overall mechanical properties of the composite material. Detailed Implementation

[0027] The present invention will be described below with reference to specific implementation schemes. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope. It is worth noting that, unless otherwise specified, the raw materials used in the following preparation examples and embodiments are all from any commercially available manufacturer: High-modulus fiberglass models available include Taishan HMG435TM-10-3.0 and Jushi E7CS10-03-568H; PA66 models available include Shenma PA66 EPR27, Huafeng PA66 EP158, and Invista PA66 U4800; PA612 models available include Guangyin PA612-A150 and PA612-A120; Shandong Dongsheng PA612-medium viscous. The PA1012 model can be selected from Guangyin PA1012-B150 and Shandong Dongsheng PA1012-M20; The PA12 model can be equipped with Arkema XE3300.

[0028] Preparation Example 1 The preparation steps of reactive compatibility toughening agents are as follows: S1. Under nitrogen protection, 0.9 mol of amino-terminated polyether (Jeffamine D-2000) and 0.95 mol of dimer acid (Pripol 1009) were melted at 180°C, and 0.036 mol of triphenyl phosphite was added. The temperature was raised to 220°C and reacted for 2 hours. Then the reaction pressure was adjusted to -0.095 MPa, and the reaction was stopped when the acid value reached 5.5 mgKOH / g. The temperature was lowered to 120°C and the product was discharged. It was stored under nitrogen to obtain the polyether-amide block prepolymer. S2. Under nitrogen protection, 2.1 mol epichlorohydrin was dissolved in 3 L of 80℃ toluene, and 0.045 mol tetrabutylammonium bromide was added. The mixture was stirred and dissolved. The polyether-amide block prepolymer was added dropwise over 1 h, and then a 20 wt% NaOH aqueous solution (containing 2 mol NaOH) was added dropwise over 30 min. The temperature was raised to 90℃ and the reaction was carried out until the epoxy value was 0.2 mmol / g. The temperature was lowered to 60℃, and the organic phase was separated. The organic phase was washed with deionized water until pH=7.0, dried with anhydrous magnesium sulfate, and distilled under reduced pressure (40℃, -0.095 MPa) until no distillate was produced. The mixture was then dried under vacuum at 50℃ to constant weight to obtain the reactive compatibility toughening agent.

[0029] Example 1 A high-strength, low-temperature resistant glass fiber reinforced composite material, based on 100wt%, comprises the following raw materials: 60wt% matrix resin (40wt% PA66, 20wt% PA612), 30wt% high-modulus glass fiber, 7.5wt% compatibilizing system (0.5wt% γ-aminopropyltriethoxysilane, 7wt% reactive compatibilizer), 0.2wt% 1-ethyl-3-methylimidazolium acetate, and 2.3wt% functional additives; The functional additives include 0.8 wt% lubricating dispersant (0.4 wt% ethylene bis-stearamide, 0.4 wt% pentaerythritol stearate), 0.7 wt% antioxidant 1098, and 0.8 wt% hydrolysis resistant agent Stabaxol P.

[0030] The preparation method of the high-strength low-temperature resistant glass fiber reinforced composite material in this embodiment is as follows: Vacuum-dried matrix resin, functional additives, compatibilizer and 1-ethyl-3-methylimidazolium acetate are added sequentially to a mixer with a speed of 700 rpm, and mixed for 4 min. High-modulus glass fiber is added by side feeding, and extruded at 265°C using a co-rotating parallel twin-screw extruder. After cooling, pelletizing and drying, the high-strength low-temperature resistant glass fiber reinforced composite material is obtained.

[0031] Example 2 A high-strength, low-temperature resistant glass fiber reinforced composite material, based on 100wt%, comprises the following raw materials: 57wt% matrix resin (32wt% PA66, 25wt% PA1012), 33wt% high-modulus glass fiber, 9wt% compatibilizing system (0.7wt% γ-aminopropyltriethoxysilane, 8.3wt% reactive compatibilizer), 0.1wt% 1-ethyl-3-methylimidazolium acetate, with the balance being functional additives; The functional additives include 0.3 wt% lubricating dispersant (0.16 wt% ethylene bis-stearamide, 0.14 wt% pentaerythritol stearate), 0.3 wt% antioxidant 1098, and 0.3 wt% hydrolysis resistant agent Stabaxol P.

[0032] The preparation method of the high-strength low-temperature resistant glass fiber reinforced composite material in this embodiment is as follows: Vacuum-dried matrix resin, functional additives, compatibilizer and 1-ethyl-3-methylimidazolium acetate are added sequentially to a mixer with a speed of 500 rpm, and mixed for 5 min. High-modulus glass fiber is added by side feeding, and extruded at 250°C using a co-rotating parallel twin-screw extruder. After cooling, pelletizing and drying, the high-strength low-temperature resistant glass fiber reinforced composite material is obtained.

[0033] Example 3 A high-strength, low-temperature resistant glass fiber reinforced composite material, based on 100wt%, comprises the following raw materials: 65wt% matrix resin (50wt% PA66, 15wt% PA12), 25wt% high-modulus glass fiber, 8.1wt% compatibilizing system (0.5wt% γ-aminopropyltriethoxysilane, 7.6wt% reactive compatibilizer), 0.3wt% 1-ethyl-3-methylimidazolium acetate, with the balance being functional additives; The functional additives include 0.6 wt% lubricating dispersant (0.3 wt% ethylene bis-stearamide, 0.3 wt% pentaerythritol stearate), 0.5 wt% antioxidant 1098, and 0.5 wt% hydrolysis resistant agent Stabaxol P.

[0034] The preparation method of the high-strength low-temperature resistant glass fiber reinforced composite material in this embodiment is as follows: Vacuum-dried matrix resin, functional additives, compatibilizer and 1-ethyl-3-methylimidazolium acetate are added sequentially to a mixer with a speed of 800 rpm, and mixed for 3 min. High-modulus glass fiber is added by side feeding, and extruded at 265°C using a co-rotating parallel twin-screw extruder. After cooling, pelletizing and drying, the high-strength low-temperature resistant glass fiber reinforced composite material is obtained.

[0035] Example 4 This embodiment provides a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the reactive compatibility toughening agent is replaced by an equal amount of POE-g-MAH (grafting rate 1.0±0.2%, MAH content 1.0%).

[0036] Example 5 This embodiment provides a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that 1-ethyl-3-methylimidazolium acetate is replaced by an equal amount of γ-aminopropyltriethoxysilane.

[0037] Example 6 This embodiment provides a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. The specific implementation method is the same as in Embodiment 1, except that the matrix resin is adjusted to: 30wt% PA66, 18wt% PA612, and 12wt% PA1012. Multiple interfaces affect performance.

[0038] Comparative Example 1 This comparative example provides a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. The specific implementation method is the same as that in Example 1, except that the reactive compatibility toughening agent is replaced by an equal amount of γ-aminopropyltriethoxysilane.

[0039] Comparative Example 2 This comparative example provides a high-strength, low-temperature resistant glass fiber reinforced composite material and its preparation method. The specific implementation method is the same as that in Example 1, except that γ-aminopropyltriethoxysilane is replaced by an equal amount of reactive compatibility toughening agent.

[0040] Performance testing The reinforced composite materials obtained in Examples 1-6 and Comparative Examples 1-2 were processed into samples and subjected to the following tests. The results are shown in Table 1: 1. Notched impact strength test: The sample size is 80mm×10mm×4mm, with a V-notch and a notch depth of 2mm. The pendulum energy is 5.5J. The test temperature is 23℃, -40℃, and -60℃, in accordance with standard ISO 180 / 1A.

[0041] 2. Tensile strength test: Type 1A dumbbell-shaped specimen, thickness 4mm, tensile speed 50mm / min, test temperature: 23±2℃.

[0042] 3. Flexural modulus test: Sample size 80mm×10mm×4mm, span 64mm, bending speed 2mm / min, test temperature 23±2℃.

[0043] Table 1

[0044] In Table 1, the reinforced composite materials of Examples 1-3 maintained toughness at -60℃, with Example 1 achieving the best balance between impact toughness and strength; Example 2 is suitable for scenarios requiring both high rigidity and low-temperature resistance; Example 3 achieved high strength with low glass fiber content, suitable for lightweight requirements. Compared to Example 1, Examples 4 and Comparative Example 1 used POE-g-MAH and silane as toughening systems, respectively, resulting in decreased low-temperature toughness and brittle fracture at -60℃; combined with Comparative Example 2, the superiority of the synergistic effect of silane coupling agent and reactive toughening agent can be further demonstrated. Compared to Example 1, the ternary composite in Example 6 may have resulted in decreased low-temperature toughness due to multi-interface effects. As shown in Examples 1 and 5, the addition of 1-ethyl-3-methylimidazolium acetate is beneficial for forming a three-layer interfacial lubrication structure, further improving glass fiber dispersion and interfacial bonding, thus enhancing low-temperature impact toughness.

[0045] The embodiments and comparative examples described above do not limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-strength, low-temperature resistant glass fiber reinforced composite material, characterized in that, Based on 100wt%, it contains the following raw materials: 55-65wt% matrix resin, 25-35wt% glass fiber, 5-10wt% compatibilizer, and the balance is functional additives; The compatibilization system comprises 0.2–0.7 wt% silane coupling agent and 4.8–9.3 wt% reactive compatibilizing toughening agent.

2. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 1, characterized in that, The matrix resin comprises at least two of PA66, PA612, PA1012, and PA12.

3. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 1, characterized in that, The preparation steps of the reactive compatibility toughening agent are as follows: S1. Under anaerobic conditions, the terminal amino polyether and dimer acid are melted, and triphenyl phosphite is added. The mixture is heated to 200-250℃ and reacted for 1-4 hours. Then, the reaction pressure is adjusted to -0.1-0.1 MPa, and the reaction is stopped when the acid value reaches 5.0-6.0 mgKOH / g. The mixture is then cooled and discharged, and stored under inert gas to obtain the polyether-amide block prepolymer. S2. Under anaerobic conditions, epichlorohydrin is dissolved in toluene, tetrabutylammonium bromide is added and stirred until dissolved, polyether-amide block prepolymer is added dropwise first, followed by NaOH aqueous solution. The temperature is raised to 70-110℃ and the reaction is stopped when the epoxy value is 0.1-0.3 mmol / g. The temperature is lowered, the organic phase is separated, and the organic phase is washed, dried, distilled under reduced pressure, and dried under vacuum to constant weight to obtain the reactive compatibility toughening agent.

4. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 3, characterized in that, The molar ratio of the terminal amino polyether to the dimer acid in S1 is 1:(1.01~1.09).

5. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 3, characterized in that, The molar ratio of epichlorohydrin in S2 to amino-terminated polyether in S1 is (2.1-2.5):

1.

6. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 1, characterized in that, The functional additives contain 0.3–0.8 wt% lubricating dispersant, 0.3–0.8 wt% antioxidant, and 0.3–0.8 wt% hydrolysis resistant agent.

7. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 6, characterized in that, The lubricating dispersant comprises stearamide and pentaerythritol ester.

8. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 7, characterized in that, The mass ratio of stearamide to pentaerythritol ester is 1:(0.8-1.2).

9. The high-strength, low-temperature resistant glass fiber reinforced composite material according to claim 1, characterized in that, The raw material also contains 0.1 to 0.3 wt% of 1-ethyl-3-methylimidazolium acetate.

10. A method for preparing a high-strength, low-temperature resistant glass fiber reinforced composite material according to any one of claims 1-8, comprising the following steps: adding vacuum-dried matrix resin, functional additives, and compatibilizer sequentially to a mixer with a speed of 500-800 rpm, mixing for 3-5 minutes, adding glass fiber by side feeding, extruding using a co-rotating parallel twin-screw extruder at 220-270°C, and obtaining the high-strength, low-temperature resistant glass fiber reinforced composite material after cooling, pelletizing, and drying.

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