Polyamide glass fiber composite foam material and application thereof in radiator water chamber

Abstract

The invention discloses a polyamide glass fiber composite foam material and application thereof to a radiator water chamber, and belongs to the technical field of high polymer materials, the material comprises the following components by weight: 46-76.25 parts of nylon 66 resin, 20-40 parts of chopped glass fiber, 1-4 parts of an epoxy chain extender, 0.2-0.7 part of a lubricant, 0.1-1 part of a heat stabilizer, 0.05-1 part of an antioxidant, and 2.2-7.3 parts of foaming agent master batch; the epoxy type chain extender comprises 0.3 to 2 parts of a long-chain aliphatic hydrocarbon epoxy type chain extender and 0.5 to 2.7 parts of a hydrophobic aromatic hydrocarbon epoxy type chain extender. Through the synergistic effect of the chopped glass fibers and the epoxy type chain extender, the melt strength is enhanced, cell growth is supported, and the material which is light in weight, resistant to impact and shock, high in strength and capable of preventing continuous cracking and can be used for the radiator water chamber is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a polyamide glass fiber composite foaming material and application thereof to a radiator water chamber. BACKGROUND

[0002] Polyamide, especially nylon 66, has become the first choice material in the fields of automobile, electronics, aerospace, construction, etc. due to its excellent mechanical strength, heat resistance and chemical resistance. The automobile radiator water tank, as the core component of the engine cooling system, is in high temperature working condition of 80-120 DEG C for a long time, and needs to withstand the cooling liquid pressure fluctuation, engine vibration and assembly impact, which puts forward strict requirements on the heat resistance, mechanical strength and service life of the material. Polyamide glass fiber composite material is thus born, which improves the mechanical strength and heat resistance through glass fiber reinforcement, but the high rigidity leads to poor processing fluidity, and the high density of glass fiber leads to the increase of the density of polyamide glass fiber composite material, which increases the energy consumption of the automobile and does not conform to the concept of energy saving and emission reduction. In addition, the unfoamed polyamide glass fiber composite material has poor toughness, and in the case of cracking after impact, continuous cracking may occur, which exists the safety hazard of water tank leakage.

[0003] Foamed materials have low thermal conductivity, insulation, buffering and low density characteristics due to a large number of closed cells, which is an important means to realize lightweight. Although polyamide foaming material can realize lightweight, the melt strength and melt viscosity are low in the process of melt extrusion continuous foaming, the bubble structure is difficult to control, and problems such as bubble merging and collapse are easy to occur, which greatly reduces the mechanical properties and limits its engineering application. Therefore, it is urgent to develop a polyamide glass fiber composite foaming material with lightweight, high strength, excellent heat resistance and shock absorption performance. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the application provides a polyamide glass fiber composite foaming material and its application on a radiator water chamber. The polyamide glass fiber composite foaming material is prepared by mixing and melting foaming agent master batch prepared by foaming agent carrier resin, foaming agent and nucleating agent and nylon 66 resin granules prepared by melting and extruding nylon 66 resin, short glass fiber, epoxy type chain extender, lubricant, heat stabilizer and antioxidant. The short glass fiber and the epoxy type chain extender synergistically enhance the high strength and impact resistance of the material. The rigid biphenyl and pi-pi stacking effect of the hydrophobic aromatic hydrocarbon epoxy type chain extender can enhance the intermolecular interaction of the melt and increase the rigidity of the molecular chain. The long-chain aliphatic hydrocarbon epoxy type chain extender has multifunctionality to increase the crosslinking degree and flexible long-chain chain entanglement to increase the viscosity, thereby improving the melt strength, supporting the growth of the bubble hole, preparing the foaming material with lower density, more compact bubble hole and smaller bubble hole diameter, and realizing lightweight. At the same time, the bubble hole can endow the material with toughness, effectively disperse external force, improve the impact strength, reduce the maximum impact strength, and thereby realize shock absorption and prevent crack propagation. In addition, the hydrophobic F atom is introduced into the hydrophobic aromatic hydrocarbon epoxy type chain extender to reduce the water absorption rate, inhibit the water absorption and expansion of the material, and prolong the service life.

[0005] The application aims to provide a polyamide glass fiber composite foaming material and its application on a radiator water chamber.

[0006] The application is implemented by the following technical scheme: The polyamide glass fiber composite foaming material comprises the following components in parts by weight: 46-75.45 parts of nylon 66 resin, 20-40 parts of short glass fiber, 1-4 parts of epoxy type chain extender, 0.5-1 part of lubricant, 0.1-1 part of heat stabilizer, 0.05-1.3 parts of antioxidant and 2.2-7.3 parts of foaming agent master batch. The epoxy type chain extender comprises 0.3-2 parts of long-chain aliphatic hydrocarbon epoxy type chain extender and 0.7-2.7 parts of hydrophobic aromatic hydrocarbon epoxy type chain extender. The long-chain aliphatic hydrocarbon epoxy type chain extender is obtained by modifying oleyl alcohol with chloro-tetrakis(dimethylsiloxanyl)silane and then double bond epoxidation, and the hydrophobic aromatic hydrocarbon epoxy type chain extender is obtained by modifying santalonal with (3,3,3-trifluoropropyl)dichloromethylsilane and then double bond epoxidation, and the structural formulas are shown in formula 1 and formula 2 respectively. Formula 1; Formula 2.

[0007] In one specific embodiment, the foaming agent master batch comprises 1.4-3.75 parts of foaming agent carrier resin, 0.6-1.25 parts of foaming agent and 0.1-2 parts of nucleating agent.

[0008] In one specific embodiment, the lubricant is one or a combination of polyethylene wax, calcium stearate; In one specific embodiment, the heat stabilizer is cuprous iodide; In one specific embodiment, the antioxidant is antioxidant 1010 and / or antioxidant 168; In one specific embodiment, the blowing agent carrier resin is polypropylene grafted maleic anhydride; In one specific embodiment, the blowing agent is any two or three of azodicarbonamide, p-toluene sulfonyl semicarbazide, sodium bicarbonate; In one specific embodiment, the nucleating agent is one or a combination of talc, calcium carbonate, kaolin; In one specific embodiment, the preparation of the long-chain aliphatic hydrocarbon epoxy chain extender comprises the following steps: S1. Dissolve phosphorus pentachloride in anhydrous dichloromethane under nitrogen, ice bath; add tetra(dimethylsiloxane) silane dropwise, react at room temperature for 8-10 hours; distill under reduced pressure, and purify by column chromatography to obtain product A; S2. Dissolve dry oleyl alcohol and amine catalyst in anhydrous dichloromethane under nitrogen; add product A solution dissolved in a small amount of anhydrous dichloromethane dropwise within 30 minutes, stir below 0 ℃ for 1.5-3 hours; stir at room temperature for 5-8 hours, filter, concentrate the filtrate, and purify by column chromatography to obtain product B; S3. Dissolve product B in anhydrous dichloromethane, ice bath; add oxidizing agent in batches; stir at room temperature for 10-18 hours; wash with 10% sodium bicarbonate solution, dry and concentrate the organic phase, and purify by column chromatography to obtain long-chain aliphatic hydrocarbon epoxy chain extender.

[0009] In one specific embodiment, the amount of phosphorus pentachloride used in step S1 is 4.05-4.1 times the molar amount of tetra(dimethylsiloxane) silane.

[0010] In one specific embodiment, the amount of oleyl alcohol used in step S2 is 4.05-4.1 times the molar amount of product A; the amine catalyst is triethylamine, and the amount used is 4.1-4.5 times the molar amount of product A.

[0011] In one specific embodiment, the amount of oxidizing agent used in step S3 is 4.2-4.8 times the molar amount of product B.

[0012] In one specific embodiment, the preparation of the hydrophobic aromatic hydrocarbon epoxy chain extender comprises the following steps: S1. Dry pyrogallol is dissolved in anhydrous toluene under nitrogen; dry (3,3,3-trifluoropropyl) dichloromethylsilane is added; slowly drop amine catalyst, stir at 60-80 ℃ for 10-16 hours; cool, filter, concentrate the filtrate to obtain product E; S2. Dissolve product E in anhydrous dichloromethane, ice bath; add m-chloroperbenzoic acid in batches; stir at room temperature for 12-24 hours; wash with 10% sodium bicarbonate solution, dry and concentrate the organic phase, and purify by column chromatography to obtain a hydrophobic aromatic hydrocarbon epoxy chain extender.

[0013] In a specific embodiment, the amount of pyrogallol in the S1 step is 2.05-2.1 times the molar amount of (3,3,3-trifluoropropyl) dichloromethylsilane; the amine catalyst is N,N-diisopropylethylamine or triethylamine, and the amount is 2.1-2.5 times the molar amount of (3,3,3-trifluoropropyl) dichloromethylsilane.

[0014] In a specific embodiment, the amount of m-chloroperbenzoic acid in the S2 step is 2.1-2.4 times the molar amount of product E.

[0015] Another object of the present application is to protect the use of the polyamide glass fiber composite foaming material in the water chamber of a radiator.

[0016] The present application also discloses a preparation method of the polyamide glass fiber composite foaming material, comprising the following steps: 1) The nylon 66 resin and the foaming agent carrier resin are dried in a vacuum drying oven at 100-120 ℃ for 4-8 hours in advance; 2) The foaming agent carrier resin, foaming agent and nucleating agent are mixed and added to a twin-screw extruder, and then melt extruded, water-cooled, cut into particles and dried under the conditions of a rotation speed of 200-300 rpm and a temperature of 100-130 ℃ to prepare a foaming agent master batch; 3) The nylon 66 resin, epoxy chain extender, lubricant, heat stabilizer and antioxidant are uniformly mixed and added to a twin-screw extruder, and then melt extruded, water-cooled, cut into particles and dried under the conditions of a rotation speed of 250-350 rpm and a temperature of 180-260 ℃ to prepare a nylon 66 resin particle; 4) The nylon 66 resin particles and the foaming agent master batch are physically mixed and then dried at 80-100 ℃ for 2-4 hours; the mixture is added into the barrel of a micro-foaming injection molding machine preheated to 250-270 ℃, a back pressure of 4-10 MPa is set, and the mixture is uniformly melted for 1-2 minutes to obtain a mixed melt; the mixed melt is injected into a mold cavity preheated to 80-100 ℃ at an injection pressure of 80-100 MPa and an injection speed of 100-120 m / s, the pressure is quickly released, and the material is cooled for 15-30 seconds, annealed in an oven at 60-80 ℃ for 1-3 hours, and then a polyamide glass fiber composite foaming material is prepared.

[0017] Advantages

[0018] The application provides a polyamide glass fiber composite foaming material and application thereof to a radiator water chamber. The polyamide glass fiber composite foaming material is prepared by mixing and melting a foaming agent master batch prepared by melt extrusion of a foaming agent carrier resin, a foaming agent and a nucleating agent, and nylon 66 resin particles prepared by melt extrusion of nylon 66 resin, chopped glass fibers, an epoxy type chain extender, a lubricant, a heat stabilizer and an antioxidant, and continuous extrusion foaming. The chopped glass fibers and the epoxy type chain extender synergistically enhance the high strength and impact resistance of the material. The rigid biphenyl and π-π stacking effect of the hydrophobic aromatic hydrocarbon epoxy type chain extender can enhance the intermolecular interaction of the melt and increase the rigidity of the molecular chain. The long-chain aliphatic hydrocarbon epoxy type chain extender has multifunctionality to increase the crosslinking degree and flexible long-chain entanglement to increase the viscosity, thereby improving the melt strength, supporting the growth of the cells, preparing a foaming material with lower density, more compact cells and smaller cell diameter, and realizing lightweight. Meanwhile, the cells can endow the material with toughness, effectively disperse external force, improve the impact strength, reduce the maximum impact strength, and thereby realize shock absorption and prevent crack propagation. In addition, the hydrophobic F atom introduced in the hydrophobic aromatic hydrocarbon epoxy type chain extender effectively reduces the water absorption rate, inhibits the water absorption and expansion of the material, and prolongs the service life. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Synthetic path of the long-chain aliphatic hydrocarbon epoxy type chain extender and the hydrophobic aromatic hydrocarbon epoxy type chain extender; Figure 2 Nuclear magnetic resonance hydrogen spectrum of the long-chain aliphatic hydrocarbon epoxy type chain extender; Figure 3 Nuclear magnetic resonance hydrogen spectrum of the hydrophobic aromatic hydrocarbon epoxy type chain extender. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0021] In the embodiments, the experimental methods used are conventional methods, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0022] The raw materials used in the examples and comparative examples are described as follows: Tetrakis(dimethylsiloxyl)silane: 96%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Phosphorus pentachloride (PCl5): 98%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Amine catalyst 1 (TEA): triethylamine, 99%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Amine catalyst 2: N,N-diisopropylethylamine (DIPEA), 99%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Oleic alcohol: 80-85%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Oxidant: meta-chloroperoxybenzoic acid (mCPBA), 75%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Santalene: 97%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; (3,3,3-trifluoropropyl)dichloromethylsilane: 98%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Nylon 66 resin (PA66): item N861767, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Reinforcing material: alkali-free chopped glass fiber (GF), brand ECS11-4.5-560A, purchased from China Jushi; Nucleating agent: talc powder, 58%, 5 μm, purchased from Forsman Technology (Beijing) Co., Ltd.; Lubricant: polyethylene wax, item P903665, Mn 2000-3000, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Foaming agent carrier resin: polypropylene grafted maleic anhydride, item P478291, Mn 3900, grafting rate 8-10 wt%, purchased from Shanghai Aldrich Biochemical Technology Co., Ltd.; Thermal stabilizer: cuprous iodide, reagent grade, ≥99%, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.; Antioxidants: Antioxidant 1010 and antioxidant 168, mass ratio 1:1, commercially available; Foaming agent 1: azodicarbonamide, 99%, commercially available; Foaming agent 2: p-toluenesulfonylurea, 96%, commercially available; Foaming agent 3: sodium bicarbonate, ≥99%, commercially available; Long-chain aliphatic hydrocarbon epoxy chain extender: self-made, the preparation method is as follows: S1. Under the condition of nitrogen, phosphorus pentachloride (4.05 mole equivalents) was dissolved in anhydrous dichloromethane, and an ice bath was used; tetra(dimethylsiloxane) silane (1 mole equivalent) was added dropwise, and the reaction was carried out at room temperature for 8 hours; after the reaction was completed, it was distilled under reduced pressure and purified by column chromatography to obtain product A, with a yield of 96%; S2. Under the condition of nitrogen, dry oleyl alcohol (4.1 mole equivalents) and triethylamine (4.3 mole equivalents) were dissolved in anhydrous dichloromethane and stirred for 10 minutes; a solution of product A (1 mole equivalent) dissolved in a small amount of anhydrous dichloromethane was added dropwise within 30 minutes, and the temperature was lowered to below 0 ℃ and stirred for 2 hours; after the reaction was completed by stirring at room temperature for 7 hours, it was filtered, the filtrate was concentrated, and column chromatography was used for purification to obtain product B, with a yield of 95.2%.

[0023] S3. Product B (1 mole equivalent) was dissolved in anhydrous dichloromethane, and an ice bath was used to lower the temperature to 0 ℃; m-chloroperoxybenzoic acid (mCPBA) (4.5 mole equivalents) was added in batches; after stirring at room temperature for 16 hours, the reaction was completed; it was washed with a 10% sodium bicarbonate solution, the organic phase was taken and dried and concentrated, and column chromatography was used for purification to obtain the long-chain aliphatic hydrocarbon epoxy chain extender, with a yield of 90%.

[0024] Hydrophobic aromatic hydrocarbon epoxy chain extender: self-made, the preparation method is as follows: S1. Under the condition of nitrogen, dry santalone (2.05 mole equivalents) was dissolved in anhydrous toluene and stirred until dissolved; dry (3,3,3-trifluoropropyl) dichloromethylsilane (1 mole equivalent) was added; N,N-diisopropyl ethylamine (2.3 mole equivalents) was slowly added dropwise, and the temperature was raised to 70 ℃ and stirred for 15 hours; after cooling, filtering, and concentrating the filtrate, product E was obtained, with a yield of 84%; S2. Product E (1 mole equivalent) was dissolved in anhydrous dichloromethane, and an ice bath was used to lower the temperature to 0 ℃; m-chloroperoxybenzoic acid (mCPBA) (2.2 mole equivalents) was added in batches; after stirring at room temperature for 18 hours, the reaction was completed; it was washed with a 10% sodium bicarbonate solution, the organic phase was taken and dried and concentrated, and column chromatography was used for purification to obtain the hydrophobic aromatic hydrocarbon epoxy chain extender, with a yield of 81%.

[0025] Short-chain aliphatic hydrocarbon epoxy chain extender: self-made, the preparation method is similar to that of the long-chain aliphatic hydrocarbon epoxy chain extender, except that the oleyl alcohol in step S2 is replaced by 2-butenol; Aromatic hydrocarbon epoxy chain extender: self-made. The preparation method is different from that of hydrophobic aromatic hydrocarbon epoxy chain extender in that (3,3,3-trifluoropropyl)dichloromethylsilane in step S1 is replaced with 2,2-dichloropropane.

[0026] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0027] Examples and Comparative Examples A polyamide-glass fiber composite foam material, the weight parts of which are shown in Table 1, is prepared by the following method: 1) Place the nylon 66 resin and foaming agent carrier resin in a vacuum drying oven at 110 ℃ for 6 hours in advance to dry the water content to less than 200 ppm; 2) Mix the foaming agent carrier resin, foaming agent, and nucleating agent, add them to a twin-screw extruder, melt extrude at 200 rpm and 120 ℃, cool with water, pelletize, and dry to obtain foaming agent masterbatch; 3) Nylon 66 resin, epoxy chain extender, lubricant, heat stabilizer and antioxidant are mixed evenly and added to a twin-screw extruder for melt chain extension at 300 rpm and 240 ℃. Glass fibers are chopped at the side feed port, extruded, water-cooled, pelletized and dried to obtain nylon 66 resin granules. 4) Physically mix nylon 66 resin granules and foaming agent masterbatch, and then dry them at 100 ℃ for 3 hours; add the mixture to the barrel of a micro-foaming injection molding machine preheated to 260 ℃, set the back pressure to 6 MPa, and melt and mix for 1.5 minutes to obtain a mixed melt; inject the mixed melt into the mold cavity preheated to 100 ℃ at an injection pressure of 95 MPa and an injection speed of 110 m / s, quickly depressurize, cool for 20 s, and anneal in an 80 ℃ oven for 2 hours to obtain polyamide glass fiber composite foam material.

[0028] Table 1. Polyamide-glass fiber composite foam materials (parts by weight)

[0029] The polyamide-glass fiber composite foam material prepared in the examples and comparative examples was subjected to the following performance tests, and the results are shown in the attached figures and Table 2, respectively.

[0030] 1. Proton NMR Spectroscopy: The synthesized long-chain aliphatic hydrocarbon epoxy chain extender and hydrophobic aromatic hydrocarbon epoxy chain extender samples were dissolved in deuterated dimethyl sulfoxide to prepare a 1.0 wt% solution. The NMR spectra of the samples were measured by a proton NMR spectrometer at 400 MHz. The results are shown below. Figure 2 , Figure 3As shown, the integral number is consistent with the number of hydrogen atoms in both the long-chain aliphatic hydrocarbon epoxy chain extender and the hydrophobic aromatic hydrocarbon epoxy chain extender, and the chemical shift is consistent with its chemical environment, indicating that the target product has been synthesized.

[0031] 2. Tensile strength: Tested according to ASTM C297 standard, the polyamide fiberglass composite foam material was cut into circular cross-sections, ensuring a cross-sectional area ≥ 625 mm². 2 The tensile strength was tested using a universal testing machine.

[0032] 3. Compression strength: Tested according to GB / T 8813-2020 standard. A regular square prism with a diameter of 100 mm*100 mm and a thickness of 50 mm was prepared. The compression strength was tested using a universal testing machine at 23 ℃ and 50%RH. The compression speed was set to 10 mm / min and the compression ratio was 50%.

[0033] 4. Apparent density: Tested according to GB / T 6343-2009 standard, the volume of the cut sample is not less than 100 cm³. 3 A regular cube.

[0034] 5. Cell size test: The SEM images of the samples were analyzed using Image-Pro Plus 7.0 graphics analysis software, and the average cell diameter and cell density were calculated using statistical methods.

[0035] 6. Closed-cell rate: Tested according to GB / T 10799 2008 standard. The sample is a cube with a length of 25 mm, a width of 25 mm, and a height of 25 mm.

[0036] 7. Water absorption rate: Tested according to GB / T 8810-2005 standard. The sample size is 15 cm long × 15 cm wide × 7.5 cm thick. The constant temperature water bath temperature is 23±2 ℃ and the soaking time is 96 hours.

[0037] 8. Notched Impact Strength: Tested according to ISO 179-1 standard. Select a sample with a V-notch that is flat, free of bubbles, cracks, impurities, and burrs, and has no imperfections at the edges. Impact the notch with a pendulum with an impact energy of 25 J. Record the impact energy W (J) when the sample continues to swing to its maximum height after complete fracture. Calculate the notched impact strength a using the following formula. kU (kJ / m 2 ): b: width of the sample notch (m); h: remaining thickness of the sample notch (m).

[0038] 9. Impact Absorption Test: The maximum impact force of the sample after absorbing energy is tested using a drop hammer impact tester in accordance with GB / T 11548-1989 standard. The sample size is 100 mm long × 100 mm wide × 10 mm thick, the drop hammer mass is 1 kg, the impact height is 1 m, and the temperature is 120 ℃.

[0039] Table 2 Performance test results of polyamide-glass fiber composite foam material

[0040] As can be seen from Table 2, a high-strength and impact-resistant polyamide-glass fiber composite foam material was prepared by introducing short-cut glass fibers and epoxy chain extenders.

[0041] Comparative examples and comparative studies show that by introducing hydrophobic aromatic hydrocarbon epoxy chain extenders, the rigidity of the molecular chains is improved by enhancing the intermolecular interactions of the melt through rigid biphenyls and π-π stacking effects. Conversely, by introducing long-chain aliphatic hydrocarbon epoxy chain extenders, the degree of crosslinking is increased through multifunctionality, and flexible long-chain entanglement is achieved to increase viscosity, thereby improving melt strength and supporting cell growth. This results in the preparation of foamed materials with lower density, denser cells, and smaller cell diameters, achieving lightweighting. Simultaneously, the cells impart toughness to the material, effectively dispersing external forces, improving impact resistance, and reducing maximum impact force, thus achieving shock absorption and preventing crack propagation.

[0042] Furthermore, as shown in the comparative examples and Comparative Example 2, the introduction of hydrophobic F atoms into the hydrophobic aromatic hydrocarbon epoxy chain extender reduces water absorption, inhibits material swelling due to water absorption, and extends service life. In Comparative Example 1, the aliphatic hydrocarbon epoxy chain extender has a shorter chain length and weaker chain entanglement, resulting in poor melt strength. This is unfavorable for cell growth, and bubbles may rupture or merge, leading to a larger average cell radius and a lower closed-cell rate, thereby increasing water absorption.

[0043] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A polyamide-glass fiber composite foam material, characterized in that, By weight, it includes the following components: 46-75.45 parts of nylon 66 resin, 20-40 parts of chopped glass fiber, 1-4 parts of epoxy chain extender, 0.5-1 part of lubricant, 0.1-1 part of heat stabilizer, 0.05-1.3 parts of antioxidant, and 2.2-7.3 parts of foaming agent masterbatch; The epoxy chain extender comprises 0.3-2 parts of a long-chain aliphatic hydrocarbon epoxy chain extender and 0.7-2.7 parts of a hydrophobic aromatic hydrocarbon epoxy chain extender; the long-chain aliphatic hydrocarbon epoxy chain extender is obtained by modifying oleyl alcohol with chlorotetra(dimethylsiloxane)silane and then epoxidizing it with double bonds, and the hydrophobic aromatic hydrocarbon epoxy chain extender is obtained by modifying styrax with (3,3,3-trifluoropropyl)dichloromethylsilane and then epoxidizing it with double bonds, with the structural formulas shown in Formula 1 and Formula 2 respectively: Formula 1; Formula 2.

2. The polyamide-glass fiber composite foam material as described in claim 1, characterized in that, The foaming agent masterbatch comprises 1.4-3.75 parts of foaming agent carrier resin, 0.6-1.25 parts of foaming agent, and 0.1-2 parts of nucleating agent; the lubricant is one or a combination of polyethylene wax and calcium stearate; the heat stabilizer is cuprous iodide; the antioxidant is antioxidant 1010 and / or antioxidant 168; the foaming agent carrier resin is polypropylene grafted with maleic anhydride; the foaming agent is any two or three combinations of azodicarbonamide, p-toluenesulfonamide, and sodium bicarbonate; and the nucleating agent is one or a combination of talc, calcium carbonate, and kaolin.

3. The polyamide-glass fiber composite foam material as described in claim 1, characterized in that, The preparation of the long-chain aliphatic hydrocarbon epoxy chain extender includes the following steps: S1. Under nitrogen atmosphere, phosphorus pentachloride was dissolved in anhydrous dichloromethane in an ice bath; tetra(dimethylsiloxane)silane was added dropwise, and the reaction was carried out at room temperature for 8-10 hours; product A was obtained by vacuum distillation and column chromatography. S2. Under nitrogen atmosphere, dry oleic alcohol and amine catalysts are dissolved in anhydrous dichloromethane; product A solution dissolved in a small amount of anhydrous dichloromethane is added dropwise over 30 minutes, the temperature is lowered to below 0 °C and stirred for 1.5-3 hours; stirred at room temperature for 5-8 hours, filtered, concentrated, and purified by column chromatography to obtain product B; S3. Dissolve product B in anhydrous dichloromethane in an ice bath; add oxidant in batches; stir at room temperature for 10-18 hours; wash with 10% sodium bicarbonate solution, take the organic phase for drying and concentration, and purify by column chromatography to obtain long-chain aliphatic hydrocarbon epoxy chain extender.

4. The polyamide-glass fiber composite foam material as described in claim 3, characterized in that, In step S1, the amount of phosphorus pentachloride used is 4.05-4.1 times the molar amount of tetra(dimethylsiloxane)silane; in step S2, the amount of oleyl alcohol used is 4.05-4.1 times the molar amount of product A; the amine catalyst is triethylamine, and the amount used is 4.1-4.5 times the molar amount of product A; in step S3, the oxidant is m-chloroperoxybenzoic acid, and the amount used is 4.2-4.8 times the molar amount of product B.

5. The polyamide-glass fiber composite foam material as described in claim 1, characterized in that, The preparation of the hydrophobic aromatic epoxy chain extender includes the following steps: S1. Under nitrogen atmosphere, dry arsenic trioxide was dissolved in anhydrous toluene; dry (3,3,3-trifluoropropyl)dichloromethylsilane was added; an amine catalyst was slowly added dropwise, and the mixture was stirred at 60-80 °C for 10-16 hours; the mixture was cooled, filtered, and the filtrate was concentrated to obtain product E; S2. Dissolve product E in anhydrous dichloromethane in an ice bath; add m-chloroperoxybenzoic acid in batches; stir at room temperature for 12-24 hours; wash with 10% sodium bicarbonate solution, take the organic phase for drying and concentration, and purify by column chromatography to obtain hydrophobic aromatic hydrocarbon epoxy chain extender.

6. The polyamide-glass fiber composite foam material as described in claim 5, characterized in that, In step S1, the amount of styrax is 2.05-2.1 times the molar amount of (3,3,3-trifluoropropyl)dichloromethylsilane; the amine catalyst is N,N-diisopropylethylamine or triethylamine, and the amount is 2.1-2.5 times the molar amount of (3,3,3-trifluoropropyl)dichloromethylsilane; in step S2, the amount of m-chloroperoxybenzoic acid is 2.1-2.4 times the molar amount of product E.

7. A method for preparing a polyamide-glass fiber composite foam material as described in claims 1-6, characterized in that, Includes the following steps: 1) Place the nylon 66 resin and foaming agent carrier resin in a vacuum drying oven at 100-120 ℃ for 4-8 hours beforehand; 2) Mix the foaming agent carrier resin, foaming agent, and nucleating agent, add them to a twin-screw extruder, melt extrude at 200-300 rpm and 100-130 ℃, water cool, pelletize, and dry to obtain foaming agent masterbatch; 3) Mix Nylon 66 resin, epoxy chain extender, lubricant, heat stabilizer and antioxidant evenly, add to twin screw extruder and melt extend chain at 250-350 rpm and 180-260 ℃, add short glass fiber at the side feed port, extrude, water cool, pelletize and dry to obtain Nylon 66 resin granules; 4) Physically mix nylon 66 resin granules and foaming agent masterbatch, and then dry them at 80-100 ℃ for 2-4 hours; add the mixture to the barrel of a micro-foaming injection molding machine preheated to 250-270 ℃, set the back pressure to 4-10 MPa, and melt and mix for 1-2 minutes to obtain a mixed melt; inject the mixed melt into the mold cavity preheated to 80-100 ℃ at an injection pressure of 80-100 MPa and an injection speed of 100-120 m / s, quickly depressurize, cool for 15-30 s, and anneal in an oven at 60-80 ℃ for 1-3 hours to obtain polyamide glass fiber composite foam material.

8. The application of a polyamide-glass fiber composite foam material as described in any one of claims 1 to 6 in a radiator water chamber.

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