Composite materials for coating-free one-time forming photovoltaic bracket bridge and their applications

Abstract

The present invention provides a composite material for coating-free, one-time-molded photovoltaic support bridges and its application, belonging to the technical field of composite material preparation for photovoltaic support bridges. The preparation process comprises the following steps: preparation of a toughened and modified tetrafluorophenyl epoxy resin blend; preparation of a trifluoromethyl group-containing polyimide; preparation of modified glass fiber; preparation of phosphorus-containing layered nickel silicate; preparation of modified phosphorus-containing layered nickel silicate; and preparation of the composite material. The present invention prepares a tetrafluorophenyl epoxy resin, which is toughened and modified using polypropylene glycol diglycidyl ether and polyethersulfone. The resulting composite material is then composited with modified glass fiber, glycidyloxypropyl polysilsesquioxane-modified phosphorus-containing layered nickel silicate, and other materials. The resulting composite material improves rigidity while maintaining toughness, resulting in more balanced mechanical properties for the composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation for photovoltaic support bridges, and in particular to composite materials for painting-free one-time molding of photovoltaic support bridges and applications thereof. Background Art

[0002] As the global energy transition accelerates toward renewable energy, solar photovoltaic power generation, with its outstanding advantages of cleanliness and sustainability, has become a key force in the energy sector, with installed capacity experiencing explosive growth. As a fundamental structural component in a photovoltaic power station, photovoltaic mounting bridges support photovoltaic modules and ensure safe and orderly electrical wiring. They play a crucial role in the stability, durability, and power generation efficiency of the entire photovoltaic system. Their performance is directly related to the full life cycle benefits of the photovoltaic power station.

[0003] Traditional photovoltaic brackets and bridges are mostly made of metal, with steel being the most common. Steel is widely available, and its initial mechanical strength can meet basic load-bearing requirements. However, its inherent weaknesses severely restrict its long-term and efficient application in the photovoltaic industry. On the one hand, metal is extremely susceptible to corrosion. In complex and changing outdoor climates, whether it's moisture in humid air, acidic rainfall in industrial areas, or erosion from salt-rich sea breezes in coastal areas, the steel surface quickly oxidizes and rusts, causing a drastic drop in structural strength. This not only significantly shortens the service life, but also creates a heavy burden for frequent maintenance and painting. Rust removal and painting require significant manpower, material, and financial resources every few years, resulting in high operational and maintenance costs. Furthermore, the painting process easily pollutes the surrounding environment, which is contrary to the concept of green energy development.

[0004] On the other hand, the high density of metal materials means they are considerable in weight, which increases vehicle fuel consumption and transport frequency during transportation, driving up transportation costs. On-site handling and installation require large lifting equipment, making construction more difficult, extending the construction period, and indirectly increasing the total project cost. Inconvenient installation can also lead to accumulated precision errors, affecting the overall layout of the photovoltaic array and reducing power generation efficiency. Furthermore, metal's excellent thermal conductivity becomes a disadvantage under intense sunlight. Heat absorbed and rapidly transferred to the connections of photovoltaic modules, forming localized hot spots, accelerating module aging, reducing photovoltaic conversion efficiency, and even causing serious failures such as module burnout, threatening the safe and stable operation of the power station.

[0005] With the advancement of materials science and technology, composite materials have gradually entered the field of view of photovoltaic equipment manufacturing. Although some composite materials currently in use or in the research and development stage are used to prepare paint-free disposable photovoltaic bracket bridges, they have attempted to overcome the problems of traditional metals such as frequent maintenance and painting and excessive weight, but they are still facing new difficulties. Conventional composite materials based on ordinary thermosetting resins have better corrosion resistance than metals, but they are brittle and have weak impact resistance after curing. They are easily cracked by the slightest external force collision or vibration, and cannot withstand the mechanical impact toughness required for photovoltaic bracket bridges in extreme weather conditions such as strong winds and hail.

[0006] Therefore, we proposed a composite material for painting-free one-time molding photovoltaic bracket bridge frame and its application that combines excellent mechanical properties, outstanding weather resistance and corrosion resistance, and high impact toughness. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the object of the present invention is to provide a composite material for a one-time molding photovoltaic bracket bridge frame without painting and its application.

[0008] A composite material for a one-time, paint-free photovoltaic bracket bridge, comprising 40-50 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 10-20 parts by weight of polybutylene terephthalate, 2-3 parts by weight of light calcium carbonate, 4-5 parts by weight of modified phosphorus-containing layered nickel silicate, 3-5 parts by weight of modified glass fiber, 1-2 parts by weight of an antioxidant, 0.5-1 parts by weight of an ultraviolet stabilizer, 1-2 parts by weight of a lubricant, and 5-8 parts by weight of a curing accelerator;

[0009] The preparation process of the composite material is as follows:

[0010] S1: Preparation of a toughened modified tetrafluorophenyl epoxy resin blend, wherein a tetrafluorophenyl epoxy resin is synthesized using 2,3,5,6-tetrafluorophenylenediol, epichlorohydrin, sodium hydroxide, and tetramethylammonium bromide as raw materials, and then the tetrafluorophenyl epoxy resin is modified with polypropylene glycol diglycidyl ether and polyethersulfone to obtain a toughened modified tetrafluorophenyl epoxy resin blend;

[0011] S2: Preparation of a trifluoromethyl group-containing polyimide, comprising reacting hydroquinone and 2-chloro-5-nitrotrifluorotoluene as raw materials to obtain an intermediate product I, reducing the intermediate product I with iron powder, and then adding ammonium hydroxide to prepare an intermediate product II, and finally reacting the intermediate product II with 4,4'-biphenyl ether dianhydride, triethylamine, and acetic anhydride to prepare a trifluoromethyl group-containing polyimide;

[0012] S3: Preparation of modified glass fiber, wherein the glass fiber is modified with dopamine and then modified with polyimide containing trifluoromethyl groups to obtain modified glass fiber;

[0013] S4: Preparation of phosphorus-containing layered nickel silicate: mixing a silane coupling agent KH560, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and triphenylphosphine to obtain an intermediate, and reacting the intermediate with nickel chloride hexahydrate to obtain phosphorus-containing layered nickel silicate;

[0014] S5: Preparation of modified phosphorus-containing layered nickel silicate, modifying the phosphorus-containing layered nickel silicate with glycidyloxypropyl polysilsesquioxane to obtain modified phosphorus-containing layered nickel silicate;

[0015] S6: Preparation of composite materials: mixing various raw materials, melting and blending, extruding, and granulating to obtain finished granules, which are composite materials.

[0016] Furthermore, step S1 of preparing the toughened modified tetrafluorophenyl epoxy resin blend specifically comprises the following steps:

[0017] S1.1: 1-2 parts by weight of 2,3,5,6-tetrafluorophenylenediol, 2-3 parts by weight of epichlorohydrin, and 0.5-1 part by weight of sodium hydroxide were mechanically stirred at room temperature for 20-30 minutes, followed by the addition of 0.05-0.1 parts by weight of tetramethylammonium bromide, and the mixture was reacted at 67-70°C for 2-3 hours. After the reaction was completed, the mixture was cooled to room temperature and washed with deionized water until the pH of the aqueous phase was neutral to obtain a tetrafluorophenyl epoxy resin;

[0018] S1.2: Place 80-100 parts by weight of tetrafluorophenyl epoxy resin in an oil bath at 150-180°C and stir continuously at 200-300 rpm for 10-12 hours to obtain a transparent liquid. Then, add 30-35 parts by weight of 4,4'-diaminodiphenyl sulfone and stir continuously at 200-300 rpm until the 4,4'-diaminodiphenyl sulfone is completely dissolved to obtain a mixture.

[0019] S1.3: Then, 20-25 parts by weight of polypropylene glycol diglycidyl ether and 10-12 parts by weight of polyethersulfone are added to the mixture and blended using a high-speed homogenizer. After the mixture is evenly mixed, it is placed in a vacuum oven preheated to 70-80°C for 20-30 minutes for degassing to obtain a toughened modified tetrafluorophenyl epoxy resin blend.

[0020] Furthermore, step S2 of preparing the polyimide containing trifluoromethyl groups specifically comprises the following steps:

[0021] S2.1: Add 2-3 parts by weight of hydroquinone and 3-5 parts by weight of 2-chloro-5-nitrobenzotrifluoride to 300-400 parts by weight of N,N-dimethylacetamide solution, stir and mix at room temperature for 20-30 minutes, then add 1-2 parts by weight of anhydrous potassium carbonate, stir and mix, and heat at 200-300 rpm and 130-135°C for 4-5 hours to obtain a reaction system. Pour the reaction system into 500-800 parts by weight of deionized water to obtain a precipitate. Rinse the precipitate again with deionized water 2-3 times and then dry in vacuo to obtain intermediate product I.

[0022] S2.2: After mixing the intermediate product I with 10-20 parts by weight of iron powder, 30-40 parts by weight of ethanol are added, and the mixture is stirred at 200-300 r / min. Then, 10-12 parts by weight of a 20-30 wt% hydrochloric acid solution are added. The mixture is stirred under reflux for 2-3 hours. Within 20-30 minutes of reflux, 8-10 parts by weight of an 8-10 wt% ammonium hydroxide solution is added. After the reaction is completed, a precipitate is obtained, which is vacuum filtered and dried to obtain intermediate product II;

[0023] S2.3: Mix 2-3 parts by weight of intermediate product II, 1-2 parts by weight of 4,4'-biphenyl ether dianhydride and 200-300 parts by weight of N,N-dimethylacetamide, stir at 500-600 r / min for 4-5 hours, then add 2-3 parts by weight of triethylamine and 1-2 parts by weight of acetic anhydride, and then heat at 120-130°C for 8-10 hours. After the reaction is completed, stop heating, filter, and then wash the precipitate with ethanol 2-3 times. Place the washed precipitate in an oven and dry it to obtain a polyimide containing a trifluoromethyl group.

[0024] Furthermore, step S3 of preparing the modified glass fiber specifically includes the following steps:

[0025] S3.1: Immerse the glass fiber in acetone and ultrasonically clean it 2-3 times, each time for 20-30 minutes. Rinse the cleaned glass fiber again with distilled water 2-3 times and then dry it in an oven to obtain the cleaned glass fiber.

[0026] S3.2: Prepare a 2-3 g / L dopamine solution using dopamine hydrochloride and distilled water. Add Tris to adjust the pH. Measure the pH using a pH meter until the pH reaches 8.5 to obtain the dopamine solution.

[0027] S3.3: Soak the cleaned glass fiber in 20-30 parts by weight of dopamine solution and stir under magnetic stirring for 4-5 hours. Then, add 15-20 parts by weight of polyimide containing trifluoromethyl group and stir and react at 30-32°C for 8-10 hours. Wash the reacted glass fiber with deionized water 2-3 times and then dry it to obtain modified glass fiber.

[0028] Furthermore, step S4 of preparing phosphorus-containing layered nickel silicate specifically includes the following steps:

[0029] S4.1: Under nitrogen, mix 4-5 parts by weight of silane coupling agent KH560, 3-4 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 0.3-0.5 parts by weight of triphenylphosphine. The mixture is reacted at 130-140°C for 7-8 hours. The resulting solid is then dried at 70-80°C to constant weight to obtain an intermediate.

[0030] S4.2: Add 2-3 parts by weight of the intermediate and 0.9-1.2 parts by weight of nickel chloride hexahydrate to 100-120 parts by weight of methanol, stir at 200-300 r / min for 20-30 min to obtain a mixed solution, add the mixed solution to 200-230 parts by weight of a 0.05 mol / L aqueous sodium hydroxide solution, react at room temperature for 3-4 days, then centrifuge, wash and dry to obtain phosphorus-containing layered nickel silicate.

[0031] Furthermore, step S5 of preparing the modified phosphorus-containing layered nickel silicate specifically includes the following steps:

[0032] S5.1: Add 3-5 parts by weight of phosphorus-containing layered nickel silicate to 10-12 parts by weight of N,N-dimethylformamide, then stir at 200-300 rpm for 20-30 minutes, and ultrasonically disperse for 20-30 minutes to obtain a suspension. Add 1-2 parts by weight of glycidyloxypropyl polysilsesquioxane to the suspension, and continue ultrasonically stirring for 20-30 minutes to obtain a mixed solution.

[0033] S5.2: Transfer the mixed solution to a reactor and react it under a nitrogen atmosphere at 120-150°C for 10-12 hours. After the reaction, cool the reaction product to room temperature, and then centrifuge, wash, and dry it to obtain modified phosphorus-containing layered nickel silicate.

[0034] Furthermore, step S6 of preparing the composite material specifically includes the following steps:

[0035] S6.1: Premix 40-50 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 10-20 parts by weight of polybutylene terephthalate, 1-2 parts by weight of an antioxidant, 0.5-1 parts by weight of an ultraviolet stabilizer UV-328, 1-2 parts by weight of zinc stearate, and 5-8 parts by weight of a curing accelerator DMP-30 in a blender at 200-300 rpm for 3-5 minutes at 70-90°C to obtain a mixed resin;

[0036] S6.2: Slowly add 2-3 parts by weight of light calcium carbonate and 4-5 parts by weight of modified phosphorus-containing layered nickel silicate to the mixed resin, stir at 800-1000 r / min for 8-12 minutes, and then feed 3-5 parts by weight of modified glass fiber into a twin-screw extruder at a uniform speed through a special side feeding device. The screw speed is 250-350 rpm and the temperature is controlled at 230-280°C. After melt blending, extrusion, and granulation, the finished pellets are obtained, which is the composite material.

[0037] Furthermore, the antioxidant in step S6.1 is antioxidant 1010.

[0038] Application of any of the composite materials described in the invention in a one-time-molded photovoltaic bracket bridge frame without painting.

[0039] Compared with the prior art, the present invention has at least the following beneficial effects:

[0040] 1. The present invention prepares tetrafluorophenyl epoxy resin and introduces tetrafluorophenyl group. Due to the CF bond, unique electronic effect and rich intermolecular force of tetrafluorophenyl group, tetrafluorophenyl epoxy resin exhibits excellent thermomechanical properties, thermal stability and hydrophobicity. The fluorine element in tetrafluorophenyl epoxy resin has strong electronegativity, which makes the molecular chain have low surface energy and high chemical stability, so that the composite material has good tolerance to chemical media such as acid, alkali and salt, and can maintain good performance in harsh chemical environment. In addition, polypropylene glycol diglycidyl ether and polyether sulfone are used for toughening modification. The glycidyl ether groups at both ends of polypropylene glycol diglycidyl ether can react with tetrafluoroethylene to form a new type of epoxy resin. The epoxy groups in the phenyl epoxy resin undergo a ring-opening reaction to form a cross-linked network, and the polypropylene glycol diglycidyl ether has a flexible polyether chain segment, which can form a flexible phase in the tetrafluorophenyl epoxy resin, absorb and dissipate external energy, and prevent the expansion of cracks, thereby significantly improving the impact resistance of the composite material. Polyethersulfone is a thermoplastic resin and is incompatible with thermosetting epoxy resin. As the curing reaction proceeds, the molecular weight of the epoxy resin continues to increase, and the polyethersulfone will gradually precipitate and exist in the form of a second phase. When the composite material yields and cracks under external force, the polyethersulfone particles will connect the cracks in the form of bridges to prevent further propagation of the cracks, thereby improving the toughness of the composite material.

[0041] 2. The present invention forms a polydopamine coating by polymerizing dopamine on the surface of glass fiber, and then uses a polyimide containing a trifluoromethyl group to modify it. The polydopamine coating formed by the polymerization of dopamine on the surface of glass fiber has rich active functional groups. These functional groups can react chemically with the polyimide containing a trifluoromethyl group to build a strong chemical bond connection. The molecular structure of the polyimide containing a trifluoromethyl group has both rigidity and a certain degree of flexibility. Its rigid part can form a certain mutual support with the rigid structure of the epoxy resin. At the same time, the flexible chain segment helps to alleviate the steric hindrance caused by the collision of the rigid structure, allowing the polyimide molecules containing the trifluoromethyl group to be more flexible. The modified glass fiber can be well interspersed between the epoxy resin molecules, so that the modified glass fiber can be evenly dispersed between the epoxy resin molecules. When the composite material is subjected to tensile load, the modified glass fiber is like a strong pillar, working with the epoxy resin to bear the external force together, thereby significantly improving the tensile strength and modulus of the composite material, making it have a stronger load-bearing capacity, and the interaction between the polydopamine wrapping layer and the polyimide containing trifluoromethyl groups can effectively absorb and dissipate impact energy; at the same time, the stable interface bonding can ensure that the modified glass fiber will not be easily peeled off from the matrix when subjected to impact, which greatly improves the impact resistance of the composite material and makes it show stronger toughness and stability when facing sudden impact.

[0042] 3. The present invention adopts glycidyloxypropyl polysilsesquioxane to modify phosphorus-containing layered nickel silicate. Phosphorus-containing layered nickel silicate itself contains phosphorus. Phosphorus can form phosphoric acid substances at high temperatures. These substances can form a dense protective film on the material surface, isolate oxygen, prevent the further spread of flames, and play a role in gas phase flame retardancy. At the same time, the structure of the layered nickel silicate can hinder the transfer of heat to a certain extent, slow down the thermal decomposition rate of the material, and enhance the flame retardant effect from the solid phase level. The layered nickel silicate contains a PH group that can undergo a ring-opening reaction with the epoxy bond in the glycidyloxypropyl polysilsesquioxane to achieve modification. The glycidyloxypropyl polysilsesquioxane contains a reactive epoxy group that can be well combined with the epoxy resin matrix. Its silicon-oxygen skeleton structure has high thermal stability. At high temperatures, it is not only difficult to burn itself, but also can further promote the protective film formed by the phosphorus-containing layered nickel silicate to be more dense and stable. The synergistic effect of the two greatly improves the flame retardant properties of the composite material. Although the phosphorus-containing layered nickel silicate is relatively rigid, the flexible silicon-oxygen chain segments of glycidyloxypropyl polysilsesquioxane can alleviate stress concentration to a certain extent and absorb impact energy. When the composite material is impacted by external force, these flexible segments can deform to prevent the rapid expansion of cracks, thereby improving the rigidity while taking into account the toughness of the material, making the mechanical properties of the composite material more balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, further serve to explain the principles of the invention and to enable one skilled in the art to make and use the invention.

[0044] Figure 1 This is a process flow chart of the composite material process for the paint-free one-time molding of photovoltaic bracket bridge frames used in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The composite material for a coating-free, one-time molded photovoltaic support bridge provided by the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are optimal and preferred embodiments, and those skilled in the art may employ alternative implementations for known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0046] Infrared and NMR data:

[0047] Tetrafluorophenyl epoxy resin:

[0048] FTIR (KBr, cm -1 ):3300-3600(-OH),1286(CF),and903(epoxygroup). 1 HNMR (400MHz, CDCl3, ppm) δ4.70(qt,2H),3.83(dd,1H),3.47(dd,1H),3.17(ddt,1H),2.81(dd,1H),2.63(dd,1H). 13 CNMR(101MHz, CDCl3, ppm)*δ146.25,143.86,116.31,71.45,60.33,50.55,44.08.

[0049] Reaction process and structure of polyimide containing trifluoromethyl group:

[0050]

[0051] Phosphorus-containing layered nickel silicate structure:

[0052]

[0053] Example 1

[0054] Preparation process of composite materials for one-time molding of photovoltaic bracket bridge without painting, such as Figure 1 As shown, the following steps are included:

[0055] S1: Preparation of toughened modified tetrafluorophenyl epoxy resin blends

[0056] S1.1: 1 part by weight of 2,3,5,6-tetrafluorophenylenediol, 2 parts by weight of epichlorohydrin, and 0.5 parts by weight of sodium hydroxide were mechanically stirred at room temperature for 20 minutes, followed by the addition of 0.05 parts by weight of tetramethylammonium bromide and the reaction at 67°C for 2 hours. After the reaction was complete, the mixture was cooled to room temperature and washed with deionized water until the pH of the aqueous phase was neutral to obtain a tetrafluorophenyl epoxy resin;

[0057] S1.2: Place 80 parts by weight of tetrafluorophenyl epoxy resin in an oil bath at 150°C and stir continuously at 200 rpm for 10 h to obtain a transparent liquid. Then, add 30 parts by weight of 4,4'-diaminodiphenyl sulfone and stir continuously at 200 rpm until the 4,4'-diaminodiphenyl sulfone is completely dissolved to obtain a mixture.

[0058] S1.3: 20 parts by weight of polypropylene glycol diglycidyl ether and 10 parts by weight of polyethersulfone were then added to the mixture and blended using a high-speed homogenizer. After uniform mixing, the mixture was placed in a vacuum oven preheated to 70°C for 20 minutes for degassing to obtain a toughened modified tetrafluorophenyl epoxy resin blend;

[0059] S2: Preparation of polyimide containing trifluoromethyl groups

[0060] S2.1: 2 parts by weight of hydroquinone and 3 parts by weight of 2-chloro-5-nitrobenzotrifluoride were added to 300 parts by weight of N,N-dimethylacetamide solution, and the mixture was stirred at room temperature for 20 minutes. Then, 1 part by weight of anhydrous potassium carbonate was added, and the mixture was stirred and heated at 200 rpm and 130°C for 4 hours to obtain a reaction system. The reaction system was poured into 500 parts by weight of deionized water to obtain a precipitate. The precipitate was rinsed again twice with deionized water and then dried in vacuo to obtain intermediate product I.

[0061] S2.2: The intermediate product I was mixed with 10 parts by weight of iron powder, and 30 parts by weight of ethanol was added. The mixture was stirred at 200 r / min, and then 10 parts by weight of a 20 wt% hydrochloric acid solution was added. The mixture was stirred under reflux for 2 h. Within 20 min of reflux, 8 parts by weight of an 8 wt% ammonium hydroxide solution was added. After the reaction was completed, a precipitate was obtained. The precipitate was vacuum filtered and dried to obtain an intermediate product II.

[0062] S2.3: 2 parts by weight of intermediate product II, 1 part by weight of 4,4'-biphenyl ether dianhydride, and 200 parts by weight of N,N-dimethylacetamide were mixed and stirred at 500 r / min for 4 h. 2 parts by weight of triethylamine and 1 part by weight of acetic anhydride were then added. The mixture was then heated at 120°C for 8 h. After the reaction was completed, heating was stopped, the mixture was filtered, and the precipitate was washed twice with ethanol. The washed precipitate was dried in an oven to obtain a polyimide containing a trifluoromethyl group.

[0063] S3: Preparation of modified glass fiber

[0064] S3.1: Immerse the glass fiber in acetone and ultrasonically clean it twice, each time for 20 minutes. Rinse the cleaned glass fiber again with distilled water twice and then dry it in an oven to obtain the cleaned glass fiber.

[0065] S3.2: Prepare a 2 g / L dopamine solution using dopamine hydrochloride and distilled water. Add Tris to adjust the pH. Measure the pH using a pH meter until the pH reaches 8.5 to obtain the dopamine solution.

[0066] S3.3: Immersing the cleaned glass fiber in 20 parts by weight of a dopamine solution and stirring under magnetic stirring for 4 hours, then adding 15 parts by weight of a trifluoromethyl group-containing polyimide and stirring at 30°C for 8 hours. The reacted glass fiber is washed twice with deionized water and then dried to obtain a modified glass fiber.

[0067] S4: Preparation of phosphorus-containing layered nickel silicate

[0068] S4.1: Under nitrogen, 4 parts by weight of silane coupling agent KH560, 3 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 0.3 parts by weight of triphenylphosphine were mixed and reacted at 130°C for 7 hours. The resulting solid was then dried at 70°C to constant weight to obtain an intermediate.

[0069] S4.2: 2 parts by weight of the intermediate and 0.9 parts by weight of nickel chloride hexahydrate are added to 100 parts by weight of methanol, and stirred at 200 rpm for 20 minutes to obtain a mixed solution. The mixed solution is added to 200 parts by weight of a 0.05 mol / L aqueous sodium hydroxide solution, and the mixture is reacted at room temperature for 3 days. The mixture is then centrifuged, washed, and dried to obtain phosphorus-containing layered nickel silicate.

[0070] S5: Preparation of modified phosphorus-containing layered nickel silicate

[0071] S5.1: 3 parts by weight of phosphorus-containing layered nickel silicate were added to 10 parts by weight of N,N-dimethylformamide, followed by stirring at 200 rpm for 20 minutes and ultrasonic dispersion for 20 minutes to obtain a suspension. 1 part by weight of glycidyloxypropyl polysilsesquioxane was added to the suspension, and ultrasonic stirring was continued for 20 minutes to obtain a mixed solution.

[0072] S5.2: The mixed solution was transferred to a reactor and reacted under a nitrogen atmosphere at 120°C for 10 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged, washed, and dried to obtain a modified phosphorus-containing layered nickel silicate.

[0073] S6: Preparation of composite materials

[0074] S6.1: Premix 40 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 10 parts by weight of polybutylene terephthalate, 1 part by weight of antioxidant 1010, 0.5 parts by weight of UV stabilizer UV-328, 1 part by weight of zinc stearate, and 5 parts by weight of curing accelerator DMP-30 in a blender at 200 rpm for 3 minutes at 70°C to obtain a mixed resin;

[0075] S6.2: Slowly add 2 parts by weight of light calcium carbonate and 4 parts by weight of modified phosphorus-containing layered nickel silicate to the mixed resin, stir at 800 r / min for 8 minutes, and then feed 3 parts by weight of modified glass fiber into a twin-screw extruder at a uniform speed through a special side feeding device. The screw speed is 250 rpm and the temperature is controlled at 230°C. After melt blending, extrusion and granulation, the finished pellets are obtained, which is the composite material.

[0076] Example 2

[0077] Preparation process of composite materials for one-time molding of photovoltaic bracket bridge without painting, such as Figure 1 As shown, the following steps are included:

[0078] S1: Preparation of toughened modified tetrafluorophenyl epoxy resin blends

[0079] S1.1: 2 parts by weight of 2,3,5,6-tetrafluorophenylenediol, 3 parts by weight of epichlorohydrin, and 1 part by weight of sodium hydroxide were mechanically stirred at room temperature for 20 minutes, followed by the addition of 0.1 parts by weight of tetramethylammonium bromide and the reaction at 67°C for 2 hours. After the reaction was complete, the mixture was cooled to room temperature and washed with deionized water until the pH of the aqueous phase was neutral to obtain a tetrafluorophenyl epoxy resin;

[0080] S1.2: Place 100 parts by weight of tetrafluorophenyl epoxy resin in an oil bath at 150°C and stir continuously at 200 rpm for 10 h to obtain a transparent liquid. Then, add 35 parts by weight of 4,4'-diaminodiphenyl sulfone and stir continuously at 200 rpm until the 4,4'-diaminodiphenyl sulfone is completely dissolved to obtain a mixture.

[0081] S1.3: 25 parts by weight of polypropylene glycol diglycidyl ether and 12 parts by weight of polyethersulfone were then added to the mixture and blended using a high-speed homogenizer. After uniform mixing, the mixture was placed in a vacuum oven preheated to 70°C for 20 minutes for degassing to obtain a toughened modified tetrafluorophenyl epoxy resin blend;

[0082] S2: Preparation of polyimide containing trifluoromethyl groups

[0083] S2.1: 3 parts by weight of hydroquinone and 5 parts by weight of 2-chloro-5-nitrobenzotrifluoride were added to 400 parts by weight of N,N-dimethylacetamide solution, and the mixture was stirred at room temperature for 20 minutes. 2 parts by weight of anhydrous potassium carbonate was then added, and the mixture was stirred and heated at 200 rpm and 130°C for 4 hours to obtain a reaction system. The reaction system was poured into 800 parts by weight of deionized water to obtain a precipitate. The precipitate was rinsed again twice with deionized water and then dried in vacuo to obtain intermediate product I.

[0084] S2.2: The intermediate product I was mixed with 20 parts by weight of iron powder, and 40 parts by weight of ethanol was added. The mixture was stirred at 200 r / min, and then 12 parts by weight of a 30 wt% hydrochloric acid solution was added. The mixture was stirred under reflux for 2 h. Within 20 min of reflux, 10 parts by weight of a 10 wt% ammonium hydroxide solution was added. After the reaction was completed, a precipitate was obtained. The precipitate was vacuum filtered and dried to obtain the intermediate product II.

[0085] S2.3: 3 parts by weight of intermediate product II, 2 parts by weight of 4,4'-biphenyl ether dianhydride, and 300 parts by weight of N,N-dimethylacetamide were mixed and stirred at 500 r / min for 4 h. 3 parts by weight of triethylamine and 2 parts by weight of acetic anhydride were then added. The mixture was then heated at 120°C for 8 h. After the reaction was completed, heating was stopped, the mixture was filtered, and the precipitate was washed twice with ethanol. The washed precipitate was dried in an oven to obtain a polyimide containing a trifluoromethyl group.

[0086] S3: Preparation of modified glass fiber

[0087] S3.1: Immerse the glass fiber in acetone and ultrasonically clean it twice, each time for 20 minutes. Rinse the cleaned glass fiber again with distilled water twice and then dry it in an oven to obtain the cleaned glass fiber.

[0088] S3.2: Prepare a 3 g / L dopamine solution using dopamine hydrochloride and distilled water. Add Tris to adjust the pH. Measure the pH using a pH meter until the pH reaches 8.5 to obtain the dopamine solution.

[0089] S3.3: Soaking the cleaned glass fiber in 30 parts by weight of a dopamine solution and stirring under magnetic stirring for 4 hours, then adding 20 parts by weight of a trifluoromethyl group-containing polyimide and stirring at 30°C for 8 hours. The reacted glass fiber is washed twice with deionized water and then dried to obtain a modified glass fiber.

[0090] S4: Preparation of phosphorus-containing layered nickel silicate

[0091] S4.1: Under nitrogen, 5 parts by weight of silane coupling agent KH560, 4 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 0.5 parts by weight of triphenylphosphine were mixed and reacted at 130°C for 7 hours. The resulting solid was then dried at 70°C to constant weight to obtain an intermediate.

[0092] S4.2: 3 parts by weight of the intermediate and 1.2 parts by weight of nickel chloride hexahydrate were added to 120 parts by weight of methanol, and stirred at 200 rpm for 20 min to obtain a mixed solution. The mixed solution was added to 230 parts by weight of a 0.05 mol / L aqueous sodium hydroxide solution, and the mixture was reacted at room temperature for 3 days. The mixture was then centrifuged, washed, and dried to obtain phosphorus-containing layered nickel silicate.

[0093] S5: Preparation of modified phosphorus-containing layered nickel silicate

[0094] S5.1: 5 parts by weight of phosphorus-containing layered nickel silicate were added to 12 parts by weight of N,N-dimethylformamide, followed by stirring at 200 rpm for 20 minutes and ultrasonic dispersion for 20 minutes to obtain a suspension. 2 parts by weight of glycidyloxypropyl polysilsesquioxane were added to the suspension, and ultrasonic stirring was continued for 20 minutes to obtain a mixed solution.

[0095] S5.2: The mixed solution was transferred to a reactor and reacted under a nitrogen atmosphere at 120°C for 10 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged, washed, and dried to obtain a modified phosphorus-containing layered nickel silicate.

[0096] S6: Preparation of composite materials

[0097] S6.1: Premix 50 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 20 parts by weight of polybutylene terephthalate, 2 parts by weight of antioxidant 1010, 1 part by weight of UV stabilizer UV-328, 2 parts by weight of zinc stearate, and 8 parts by weight of curing accelerator DMP-30 in a blender at 200 rpm for 3 minutes at 70°C to obtain a mixed resin;

[0098] S6.2: Slowly add 3 parts by weight of light calcium carbonate and 5 parts by weight of modified phosphorus-containing layered nickel silicate to the mixed resin, stir at 800 r / min for 8 minutes, and then feed 5 parts by weight of modified glass fiber into a twin-screw extruder at a uniform speed through a special side feeding device. The screw speed is 250 rpm and the temperature is controlled at 230°C. After melt blending, extrusion and granulation, the finished pellets are obtained, which is the composite material.

[0099] Example 3

[0100] Preparation process of composite materials for one-time molding of photovoltaic bracket bridge without painting, such as Figure 1 As shown, the following steps are included:

[0101] S1: Preparation of toughened modified tetrafluorophenyl epoxy resin blends

[0102] S1.1: 1 part by weight of 2,3,5,6-tetrafluorophenylenediol, 2 parts by weight of epichlorohydrin, and 0.5 parts by weight of sodium hydroxide were mechanically stirred at room temperature for 30 minutes, followed by the addition of 0.05 parts by weight of tetramethylammonium bromide and the reaction at 70°C for 3 hours. After the reaction was complete, the mixture was cooled to room temperature and washed with deionized water until the pH of the aqueous phase was neutral to obtain a tetrafluorophenyl epoxy resin;

[0103] S1.2: Place 80 parts by weight of tetrafluorophenyl epoxy resin in an oil bath at 180°C and stir continuously at 300 rpm for 12 h to obtain a transparent liquid. Then, add 30 parts by weight of 4,4'-diaminodiphenyl sulfone and stir continuously at 300 rpm until the 4,4'-diaminodiphenyl sulfone is completely dissolved to obtain a mixture.

[0104] S1.3: 20 parts by weight of polypropylene glycol diglycidyl ether and 10 parts by weight of polyethersulfone were then added to the mixture and blended using a high-speed homogenizer. After uniform mixing, the mixture was placed in a vacuum oven preheated to 80°C for 30 minutes for degassing to obtain a toughened modified tetrafluorophenyl epoxy resin blend;

[0105] S2: Preparation of polyimide containing trifluoromethyl groups

[0106] S2.1: 2 parts by weight of hydroquinone and 3 parts by weight of 2-chloro-5-nitrobenzotrifluoride were added to 300 parts by weight of N,N-dimethylacetamide solution, and the mixture was stirred at room temperature for 30 minutes. Then, 1 part by weight of anhydrous potassium carbonate was added, and the mixture was stirred and heated at 300 rpm and 135°C for 5 hours to obtain a reaction system. The reaction system was poured into 500 parts by weight of deionized water to obtain a precipitate. The precipitate was rinsed again with deionized water three times and then dried in vacuo to obtain intermediate product I.

[0107] S2.2: The intermediate product I was mixed with 10 parts by weight of iron powder, and 30 parts by weight of ethanol was added. The mixture was stirred at 300 r / min, and then 10 parts by weight of a 20 wt% hydrochloric acid solution was added. The mixture was stirred under reflux for 3 h. Within 30 min of reflux, 8 parts by weight of an 8 wt% ammonium hydroxide solution was added. After the reaction was completed, a precipitate was obtained. The precipitate was vacuum filtered and dried to obtain an intermediate product II.

[0108] S2.3: 2 parts by weight of intermediate product II, 1 part by weight of 4,4'-biphenyl ether dianhydride, and 200 parts by weight of N,N-dimethylacetamide were mixed and stirred at 600 r / min for 5 h. 2 parts by weight of triethylamine and 1 part by weight of acetic anhydride were then added. The mixture was then heated at 130°C for 10 h. After the reaction was completed, heating was stopped, the mixture was filtered, and the precipitate was washed three times with ethanol. The washed precipitate was dried in an oven to obtain a polyimide containing a trifluoromethyl group.

[0109] S3: Preparation of modified glass fiber

[0110] S3.1: Immerse the glass fiber in acetone and ultrasonically clean it three times, each time for 30 minutes. Rinse the cleaned glass fiber again three times with distilled water and dry it in an oven to obtain cleaned glass fiber.

[0111] S3.2: Prepare a 2 g / L dopamine solution using dopamine hydrochloride and distilled water. Add Tris to adjust the pH. Measure the pH using a pH meter until the pH reaches 8.5 to obtain the dopamine solution.

[0112] S3.3: Soaking the cleaned glass fiber in 20 parts by weight of a dopamine solution and stirring under magnetic stirring for 5 hours, then adding 15 parts by weight of a trifluoromethyl group-containing polyimide and stirring the solution at 32°C for 10 hours. The reacted glass fiber is washed three times with deionized water and then dried to obtain a modified glass fiber.

[0113] S4: Preparation of phosphorus-containing layered nickel silicate

[0114] S4.1: Under nitrogen, 4 parts by weight of silane coupling agent KH560, 3 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 0.3 parts by weight of triphenylphosphine were mixed and reacted at 140°C for 8 hours. The resulting solid was then dried at 80°C to constant weight to obtain an intermediate.

[0115] S4.2: 2 parts by weight of the intermediate and 0.9 parts by weight of nickel chloride hexahydrate are added to 100 parts by weight of methanol, and stirred at 300 rpm for 30 min to obtain a mixed solution. The mixed solution is added to 200 parts by weight of a 0.05 mol / L aqueous sodium hydroxide solution, and the mixture is reacted at room temperature for 4 days. The mixture is then centrifuged, washed, and dried to obtain phosphorus-containing layered nickel silicate.

[0116] S5: Preparation of modified phosphorus-containing layered nickel silicate

[0117] S5.1: 3 parts by weight of phosphorus-containing layered nickel silicate were added to 10 parts by weight of N,N-dimethylformamide, followed by stirring at 300 rpm for 30 minutes and ultrasonic dispersion for 30 minutes to obtain a suspension. 1 part by weight of glycidyloxypropyl polysilsesquioxane was added to the suspension, and ultrasonic stirring was continued for 30 minutes to obtain a mixed solution.

[0118] S5.2: The mixed solution was transferred to a reactor and reacted under a nitrogen atmosphere at 150°C for 12 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged, washed, and dried to obtain a modified phosphorus-containing layered nickel silicate.

[0119] S6: Preparation of composite materials

[0120] S6.1: Premix 40 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 10 parts by weight of polybutylene terephthalate, 1 part by weight of antioxidant 1010, 0.5 parts by weight of UV stabilizer UV-328, 1 part by weight of zinc stearate, and 5 parts by weight of curing accelerator DMP-30 in a blender at 300 rpm for 5 minutes at 90°C to obtain a mixed resin;

[0121] S6.2: Slowly add 2 parts by weight of light calcium carbonate and 4 parts by weight of modified phosphorus-containing layered nickel silicate to the mixed resin, stir at 1000 r / min for 12 minutes, and then feed 3 parts by weight of modified glass fiber into a twin-screw extruder at a uniform speed through a special side feeding device. The screw speed is 350 rpm and the temperature is controlled at 280°C. After melt blending, extrusion and granulation, the finished pellets are obtained, which is the composite material.

[0122] Comparative Example 1

[0123] Compared with Example 1, Comparative Example 1 is different in that, in Comparative Example 1, polypropylene glycol diglycidyl ether in step S1.3 is removed, and the remaining steps remain unchanged to prepare the composite material, which is recorded as Comparative Example 1.

[0124] Comparative Example 2

[0125] Compared with Example 1, Comparative Example 2 is different in that the polyethersulfone in step S1.3 is removed from Comparative Example 1, and the composite material is prepared with the remaining steps unchanged, which is recorded as Comparative Example 2.

[0126] Comparative Example 3

[0127] Compared with Example 1, Comparative Example 3 is different in that the trifluoromethyl group-containing polyimide in steps S2 and S3.3 is removed, and the remaining steps remain unchanged to prepare the composite material, which is recorded as Comparative Example 3.

[0128] Comparative Example 4

[0129] Compared with Example 1, the difference of Comparative Example 4 is that step S5 is removed in Comparative Example 4, and the modified phosphorus-containing layered nickel silicate in S6.2 is replaced with phosphorus-containing layered nickel silicate. The remaining steps remain unchanged to prepare the composite material, which is recorded as Comparative Example 4.

[0130] Comparative Example 5

[0131] Compared with Example 1, the difference of Comparative Example 5 is that step S1.1 is removed in Comparative Example 5, the tetrafluorophenyl epoxy resin in S1.2 is replaced by epoxy resin, and the other steps remain unchanged to prepare the composite material, which is recorded as Comparative Example 5.

[0132] Comparative Example 6

[0133] Compared with Example 1, the difference of Comparative Example 6 is that Comparative Example 6 removes steps S4 and S5, replaces the modified phosphorus-containing layered nickel silicate in S6.2 with glycidyl ether oxypropyl polysilsesquioxane, and prepares a composite material without changing the other steps, which is recorded as Comparative Example 6.

[0134] The composite materials prepared in Examples 1-3 and Comparative Examples 1-6 were used to prepare disposable photovoltaic bracket bridge samples by injection molding or extrusion process and set aside.

[0135] The photovoltaic bracket bridge samples prepared in Examples 1-3 were tested for corrosion resistance, flexural strength, tensile strength, impact strength and flame retardancy:

[0136] The flexural strength is measured according to GB / T1449-2005, the tensile strength is tested according to GB / T1447-2005, the impact strength is measured according to GB / T1843-2008, and the flame retardancy is measured according to GB / T2408-2021.

[0137] The measurement results are shown in Table 1.

[0138] Table 1. Performance measurement results of Examples 1-3

[0139]

[0140] It can be seen from the data in Table 1 that the composite material prepared by the present invention has excellent mechanical properties and toughness, and can achieve good flame retardant effect.

[0141] Corrosion resistance: 5 specimens were prepared for each test object, and the contact angles were tested. Then, the specimens were immersed in distilled water, 2% sulfuric acid solution, 2% sodium hydroxide solution, 10% sulfuric acid solution, and 10% sodium hydroxide solution for 7 days. After being taken out, the contact angles were tested again. The test values ​​before immersion were subtracted from the test values ​​after immersion, and the obtained difference values ​​were recorded. The degree of corrosion was judged based on the recorded phase difference values. The larger the phase difference value, the greater the change in contact angle before and after immersion, the more serious the corrosion, and the worse the corrosion resistance of the corresponding specimen.

[0142] The corrosion resistance test was performed on Examples 1-3 and Comparative Example 5.

[0143] Please refer to Table 2 for the test results.

[0144] Table 2. Corrosion resistance test results of Examples 1-3

[0145]

[0146] It can be seen from the data in Table 2 that the composite material prepared by the present invention has excellent corrosion resistance.

[0147] It can be seen from the data of Comparative Example 5 that the composite material prepared by using tetrafluorophenyl epoxy resin has good tolerance to chemical media such as acid and alkali, and can improve the corrosion resistance of the composite material.

[0148] The data of Example 1 was used to measure the impact strength of Comparative Examples 1-4. The results are shown in Table 3.

[0149] Table 3. Impact strength test results of Comparative Examples 1-4

[0150] <![CDATA[Impact strength kJ / m 2 > Example 1 39.4 Comparative Example 1 25.4 Comparative Example 2 28.5 Comparative Example 3 24.3 Comparative Example 4 30.1

[0151] It can be seen from the data in Table 3 that the data of Comparative Example 1 and Comparative Example 2 are both smaller than those in Example, indicating that the effect of toughening and modifying the tetrafluorophenyl epoxy resin with a single component of polypropylene glycol diglycidyl ether or polyether sulfone is not as good as the effect of synergistic toughening modification with polypropylene glycol diglycidyl ether and polyether sulfone, indicating that the interaction between polypropylene glycol diglycidyl ether and polyether sulfone for toughening modification significantly improves the toughness of the composite material.

[0152] From the data of Comparative Example 3, it can be seen that the impact strength has decreased, indicating that the glass fiber modified with trifluoromethyl polyimide can improve the impact resistance of the composite material, making it exhibit stronger toughness and stability when facing sudden impact.

[0153] It can be seen from the data of Comparative Example 4 that the presence of glycidyloxypropyl polysilsesquioxane can improve the impact resistance of the composite material.

[0154] The data of Example 1 was continued to be used, and the flame retardancy of Comparative Examples 4 and 6 was measured.

[0155] The measurement results are shown in Table 4.

[0156] Table 4. Flame retardancy test results of Comparative Examples 4 and 6

[0157] UL-94 rating Example 1 V-0 Comparative Example 4 V-1 Comparative Example 7 V-2

[0158] From the data in Table 4, it can be seen that the flame retardancy of Comparative Examples 4 and 7 is poorer than that of the embodiment, indicating that the synergistic effect of glycidyloxypropyl polysilsesquioxane and phosphorus-containing layered nickel silicate greatly improves the flame retardancy of the composite material.

[0159] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A composite material for a one-time, paint-free photovoltaic bracket bridge, characterized in that: The composite material comprises 40-50 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 10-20 parts by weight of polybutylene terephthalate, 2-3 parts by weight of light calcium carbonate, 4-5 parts by weight of modified phosphorus-containing layered nickel silicate, 3-5 parts by weight of modified glass fiber, 1-2 parts by weight of an antioxidant, 0.5-1 parts by weight of an ultraviolet stabilizer, 1-2 parts by weight of a lubricant, and 5-8 parts by weight of a curing accelerator; The preparation process of the composite material is as follows: S1: Preparation of a toughened modified tetrafluorophenyl epoxy resin blend, wherein a tetrafluorophenyl epoxy resin is synthesized using 2,3,5,6-tetrafluorophenylenediol, epichlorohydrin, sodium hydroxide, and tetramethylammonium bromide as raw materials, and then the tetrafluorophenyl epoxy resin is modified with polypropylene glycol diglycidyl ether and polyethersulfone to obtain a toughened modified tetrafluorophenyl epoxy resin blend; S2: Preparation of a trifluoromethyl group-containing polyimide, comprising reacting hydroquinone and 2-chloro-5-nitrotrifluorotoluene as raw materials to obtain an intermediate product I, reducing the intermediate product I with iron powder, and then adding ammonium hydroxide to prepare an intermediate product II, and finally reacting the intermediate product II with 4,4'-biphenyl ether dianhydride, triethylamine, and acetic anhydride to prepare a trifluoromethyl group-containing polyimide; S3: Preparation of modified glass fiber, wherein the glass fiber is modified with dopamine and then modified with polyimide containing trifluoromethyl groups to obtain modified glass fiber; S4: Preparation of phosphorus-containing layered nickel silicate: mixing a silane coupling agent KH560, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and triphenylphosphine to obtain an intermediate, and reacting the intermediate with nickel chloride hexahydrate to obtain phosphorus-containing layered nickel silicate; S5: Preparation of modified phosphorus-containing layered nickel silicate, modifying the phosphorus-containing layered nickel silicate with glycidyloxypropyl polysilsesquioxane to obtain modified phosphorus-containing layered nickel silicate; S6: Preparation of composite materials: mixing various raw materials, melting and blending, extruding, and granulating to obtain finished granules, which are composite materials.

2. The composite material for coating-free one-time forming photovoltaic bracket bridge according to claim 1, characterized in that: Step S1: Preparation of a toughened and modified tetrafluorophenyl epoxy resin blend, specifically comprising the following steps: S1.1: 1-2 parts by weight of 2,3,5,6-tetrafluorophenylenediol, 2-3 parts by weight of epichlorohydrin, and 0.5-1 part by weight of sodium hydroxide were mechanically stirred at room temperature for 20-30 minutes, followed by the addition of 0.05-0.1 parts by weight of tetramethylammonium bromide, and the mixture was reacted at 67-70°C for 2-3 hours. After the reaction was completed, the mixture was cooled to room temperature and washed with deionized water until the pH of the aqueous phase was neutral to obtain a tetrafluorophenyl epoxy resin; S1.2: Place 80-100 parts by weight of tetrafluorophenyl epoxy resin in an oil bath at 150-180°C and stir continuously at 200-300 rpm for 10-12 hours to obtain a transparent liquid. Then, add 30-35 parts by weight of 4,4'-diaminodiphenyl sulfone and stir continuously at 200-300 rpm until the 4,4'-diaminodiphenyl sulfone is completely dissolved to obtain a mixture. S1.3: Then, 20-25 parts by weight of polypropylene glycol diglycidyl ether and 10-12 parts by weight of polyethersulfone are added to the mixture and blended using a high-speed homogenizer. After the mixture is evenly mixed, it is placed in a vacuum oven preheated to 70-80°C for 20-30 minutes for degassing to obtain a toughened modified tetrafluorophenyl epoxy resin blend.

3. The composite material for coating-free one-time forming photovoltaic bracket bridge according to claim 2, characterized in that: Step S2: Preparation of polyimide containing trifluoromethyl group, specifically comprising the following steps: S2.1: Add 2-3 parts by weight of hydroquinone and 3-5 parts by weight of 2-chloro-5-nitrotrifluorotoluene to 300-400 parts by weight of N,N-dimethylacetamide solution, stir and mix at room temperature for 20-30 minutes, then add 1-2 parts by weight of anhydrous potassium carbonate, stir and mix, and heat at 200-300 r / min and 130-135°C for 4-5 hours to obtain a reaction system, pour the reaction system into 500-800 parts by weight of deionized water to obtain a precipitate, rinse the precipitate again with deionized water for 2-3 times, and then vacuum dry. Air drying to obtain intermediate product I; S2.2: After mixing the above intermediate product I with 10-20 parts by weight of iron powder, 30-40 parts by weight of ethanol are added, and the mixture is stirred at 200-300 r / min. Then, 10-12 parts by weight of 20-30wt% hydrochloric acid solution are added, and the mixture is stirred under condensation reflux for 2-3 hours. Within 20-30 minutes of condensation reflux, 8-10 parts by weight of 8-10wt% ammonium hydroxide solution are added. After the reaction is completed, a precipitate is obtained, which is vacuum filtered and dried to obtain intermediate product II; S2.3: Mix 2-3 parts by weight of intermediate product II, 1-2 parts by weight of 4,4'-biphenyl ether dianhydride and 200-300 parts by weight of N,N-dimethylacetamide, stir at 500-600 r / min for 4-5 hours, then add 2-3 parts by weight of triethylamine and 1-2 parts by weight of acetic anhydride, and then heat at 120-130°C for 8-10 hours. After the reaction is completed, stop heating, filter, and then wash the precipitate with ethanol 2-3 times. Place the washed precipitate in an oven and dry it to obtain a polyimide containing a trifluoromethyl group.

4. The composite material for coating-free one-time forming photovoltaic bracket bridge according to claim 3, characterized in that: Step S3: Preparation of modified glass fiber, specifically comprising the following steps: S3.1: Immerse the glass fiber in acetone and ultrasonically clean it 2-3 times, each time for 20-30 minutes. Rinse the cleaned glass fiber again with distilled water 2-3 times and then dry it in an oven to obtain the cleaned glass fiber. S3.2: Prepare a 2-3 g / L dopamine solution using dopamine hydrochloride and distilled water. Add Tris to adjust the pH. Measure the pH using a pH meter until the pH reaches 8.5 to obtain the dopamine solution. S3.3: Soak the cleaned glass fiber in 20-30 parts by weight of dopamine solution and stir under magnetic stirring for 4-5 hours. Then, add 15-20 parts by weight of polyimide containing trifluoromethyl group and stir and react at 30-32°C for 8-10 hours. Wash the reacted glass fiber with deionized water 2-3 times and then dry it to obtain modified glass fiber.

5. The composite material for coating-free one-time forming photovoltaic bracket bridge according to claim 4, characterized in that: Step S4: Preparation of phosphorus-containing layered nickel silicate, specifically comprising the following steps: S4.1: Under nitrogen, mix 4-5 parts by weight of silane coupling agent KH560, 3-4 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 0.3-0.5 parts by weight of triphenylphosphine. The mixture is reacted at 130-140°C for 7-8 hours. The resulting solid is then dried at 70-80°C to constant weight to obtain an intermediate. S4.2: Add 2-3 parts by weight of the intermediate and 0.9-1.2 parts by weight of nickel chloride hexahydrate to 100-120 parts by weight of methanol, stir at 200-300 r / min for 20-30 min to obtain a mixed solution, add the mixed solution to 200-230 parts by weight of a 0.05 mol / L aqueous sodium hydroxide solution, react at room temperature for 3-4 days, then centrifuge, wash and dry to obtain phosphorus-containing layered nickel silicate.

6. The composite material for coating-free one-time forming photovoltaic bracket bridge according to claim 5, characterized in that: Step S5 is the preparation of modified phosphorus-containing layered nickel silicate, specifically comprising the following steps: S5.1: Add 3-5 parts by weight of phosphorus-containing layered nickel silicate to 10-12 parts by weight of N,N-dimethylformamide, then stir at 200-300 rpm for 20-30 minutes, and ultrasonically disperse for 20-30 minutes to obtain a suspension. Add 1-2 parts by weight of glycidyloxypropyl polysilsesquioxane to the suspension, and continue ultrasonically stirring for 20-30 minutes to obtain a mixed solution. S5.2: Transfer the mixed solution to a reactor and react it under a nitrogen atmosphere at 120-150°C for 10-12 hours. After the reaction, cool the reaction product to room temperature, and then centrifuge, wash, and dry it to obtain modified phosphorus-containing layered nickel silicate.

7. The composite material for painting-free one-time forming photovoltaic bracket bridge according to claim 6, characterized in that: Step S6: Preparation of the composite material, specifically comprising the following steps: S6.1: Premix 40-50 parts by weight of a toughened modified tetrafluorophenyl epoxy resin blend, 10-20 parts by weight of polybutylene terephthalate, 1-2 parts by weight of an antioxidant, 0.5-1 parts by weight of an ultraviolet stabilizer UV-328, 1-2 parts by weight of zinc stearate, and 5-8 parts by weight of a curing accelerator DMP-30 in a blender at 200-300 rpm for 3-5 minutes at 70-90°C to obtain a mixed resin; S6.2: Slowly add 2-3 parts by weight of light calcium carbonate and 4-5 parts by weight of modified phosphorus-containing layered nickel silicate to the mixed resin, stir at 800-1000 r / min for 8-12 minutes, and then feed 3-5 parts by weight of modified glass fiber into a twin-screw extruder at a uniform speed through a special side feeding device. The screw speed is 250-350 rpm and the temperature is controlled at 230-280°C. After melt blending, extrusion, and granulation, the finished pellets are obtained, which is the composite material.

8. The composite material for coating-free one-time forming photovoltaic bracket bridge according to claim 7, characterized in that: The antioxidant in step S6.1 is antioxidant 1010.

9. Use of the composite material according to any one of claims 1 to 8 in a one-time molding photovoltaic bracket bridge frame without painting.

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