High-wear-resistance halogen-free fireproof composite material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses a high-wear-resistance halogen-free fireproof composite material and a preparation method thereof. The high-wear-resistance halogen-free fireproof composite material comprises the following raw materials in parts by weight: 40-60 parts of PA9T, 6-10 parts of a modified flame retardant, 8-12 parts of carbon fibers, 0.5-1 part of an antioxidant, 1-3 parts of wear-resistant powder, 1-2 parts of a compatilizer and 1-3 parts of modified lignin. According to the modified flame retardant disclosed by the invention, the material is endowed with halogen-free, environment-friendly and flame-retardant characteristics through the synergistic effect of phosphorus-nitrogen-boron elements; the modified lignin is hydrophobically modified, so that the compatibility with nylon is improved, the modified lignin has excellent wear resistance and mechanical property, and the service life of the material is prolonged.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a high wear-resistant halogen-free fireproof composite material and its preparation method. Background Technology

[0002] With the development of industrial automation and new energy equipment, the service environment of materials is becoming increasingly stringent, requiring a balance between wear resistance and fire resistance. Components in fields such as mechanical transmission operate under complex conditions. Traditional rubbers have short wear resistance and poor flame retardancy, while halogenated flame-retardant plastics release toxins upon combustion, and their surface hardness and wear resistance are insufficient to meet the demands of heavy-duty friction. Among numerous engineering nylon materials, PA9T (poly(p-phenylene azelonyl)diamine), as a typical representative of semi-aromatic nylons, has become a preferred material due to its unique molecular structure design, balancing adaptability to harsh working conditions with ease of processing. Compared with traditional general-purpose nylons and other aromatic nylons, PA9T exhibits superior heat resistance, better processing compatibility, and significant low water absorption. The balanced combination of rigid benzene rings and flexible methylene chains in its molecular chain gives PA9T both high strength and high toughness, while its good crystal regularity creates a wear-resistant microstructure. In current research, achieving a synergistic improvement in flame retardancy and wear resistance remains a core challenge. The addition of certain flame retardants can reduce the crystallinity and interfacial bonding of the material, leading to a decrease in wear resistance; conversely, high-content wear-resistant fillers may interfere with the dispersion of flame retardants and the effectiveness of their flame-retardant mechanisms. Therefore, developing composite materials that combine excellent fire safety with long-term wear resistance has become a key support for safety upgrades in high-end equipment manufacturing, rail transportation, and other fields.

[0003] Patent application CN201210128140.8 discloses an antibacterial flame-retardant nylon composite material, using tetrabromobisphenol A as a flame retardant to improve the flame-retardant performance of the nylon composite material. However, long-term exposure to halogenated flame retardants poses health risks and can decompose in the environment to produce toxic derivatives, leading to restrictions on their use in many regions. Patent application CN201210411329.8 discloses a composite environmentally friendly flame retardant for nylon 6 and flame-retardant plastics for nylon 6. It uses a mixture of flame retardants such as dimethyl trimethylsilyl methylphosphonate, melamine cyanurate, and antimony trioxide to obtain a composite environmentally friendly flame retardant that can improve the flame-retardant performance of nylon 6. However, multi-component compound flame retardants not only increase preparation costs but also require higher addition amounts, potentially reducing the mechanical properties of nylon materials. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a high wear-resistant, halogen-free fire-retardant composite material and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A high wear-resistant halogen-free fireproof composite material comprises the following raw materials in parts by weight: 40-60 parts PA9T, 6-10 parts modified flame retardant, 8-12 parts carbon fiber, 0.5-1 part antioxidant, 1-3 parts wear-resistant powder, 1-2 parts compatibilizer, and 1-3 parts modified lignin.

[0007] The carbon fiber is short-cut carbon fiber with a diameter of 0.4-0.9 micrometers;

[0008] The antioxidant is one of antioxidant 1010, antioxidant 1076, and antioxidant 168;

[0009] The wear-resistant powder is one of nano-silica, alumina, and calcium carbonate;

[0010] The compatibilizer is maleic anhydride-grafted polyethylene.

[0011] The modified flame retardant is prepared by the following steps:

[0012] Step A1: Mix pentaerythritol and phosphorus oxychloride, stir at 60°C for 1.5 h under nitrogen protection, raise the temperature to 105°C and reflux for 10 h. After the reaction is completed, distill under reduced pressure and dry under vacuum to obtain intermediate product 1.

[0013] Furthermore, the ratio of pentaerythritol to phosphorus oxychloride is 0.8-1 mol: 4-5 mol;

[0014] In step A1, pentaerythritol and phosphorus oxychloride undergo a phosphorylation reaction. The introduced phosphoryl group provides the reaction conditions for the subsequent phosphorylation reaction. The resulting phosphorus-containing structure decomposes when heated and burned. The phosphorus-oxygen double bond and phosphorus-oxygen carbon bond break to produce phosphorus-containing compounds such as phosphate esters, phosphoric acid, and polyphosphoric acid. These compounds exhibit a liquid, viscous, glassy state at high temperatures and can coat the burning surface of the material, thereby isolating energy and oxygen exchange.

[0015] Step A2: Mix intermediate product 1 with N,N-dimethylformamide, place it in an oil bath, heat to 80°C, stir for 10 min, add 3,5-diamino-1,2,4-triazole, react for 6 h, after the reaction is completed, filter under reduced pressure, wash, and dry under vacuum to obtain intermediate product 2.

[0016] Furthermore, the ratio of intermediate 1, N,N-dimethylformamide and 3,5-diamino-1,2,4-triazole is 0.5-0.7 mol: 150-200 mL: 0.95-1.35 mol;

[0017] In step A2, intermediate 1 and 3,5-diamino-1,2,4-triazole undergo a phosphorylation reaction, introducing an amino group into the system and providing reaction conditions for the subsequent Schiff base reaction. The introduced triazole structure is a five-membered nitrogen heterocyclic compound with a high nitrogen content. When heated, it decomposes to generate a flame-retardant gas, which can dilute the concentration of gaseous combustibles and oxygen, quench active free radicals, and achieve the purpose of gas-phase flame retardancy.

[0018] Step A3: Mix 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol, stir, heat to 80°C under nitrogen protection, reflux for 2 hours, filter, wash and vacuum dry to obtain modified flame retardant;

[0019] Furthermore, the ratio of 4-formylphenylboronic acid, intermediate 2, and anhydrous ethanol is 0.2-0.4 mol: 0.1-0.2 mol: 150-200 mL;

[0020] In step A3, 4-formylphenylboronic acid and intermediate product 2 undergo a Schiff base reaction. When heated, the boric acid groups undergo dehydration and cross-linking to form a boron-oxygen hexacyclic cross-linked network structure. As the temperature increases further, it continues to decompose and eventually forms a boron-oxygen glass layer with strong heat resistance and oxidation resistance, which covers the surface of the material to prevent the escape of combustible gases and volatiles and the transfer of combustion heat. It works synergistically with nitrogen and phosphorus flame retardants to further enhance the flame retardant properties of the system.

[0021] The modified lignin is prepared by the following steps:

[0022] Step B1: Add 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran to the polymerization tube. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted at 70°C for 20 h to obtain the adamantane derivative.

[0023] Furthermore, the ratio of 1-adamantanecarboxylic acid, 1,2-epoxydodecane, and tetrahydrofuran is 0.3-0.5 mol: 0.3-0.5 mol: 100-150 mL;

[0024] In step B1, 1-adamantane carboxylic acid and 1,2-epoxydodecane undergo a ring-opening reaction, introducing hydroxyl groups into the system and providing reaction conditions for subsequent ring-opening reactions. Adamantane is a highly symmetrical three-membered cyclic aliphatic hydrocarbon composed of three chair-shaped cyclohexanes. The unique structure of this substance endows it with high hydrophobicity and mechanical stability. Introducing it into the polymer system can improve the hydrophobicity and wear resistance of the system and extend its service life. In addition, the introduced long-chain alkyl groups can interact with the material surface, improving its hydrophobic properties by reducing surface energy or forming a hydrophobic layer.

[0025] Step B2: Mix the adamantane derivative and epichlorohydrin, heat to 90°C, add tetramethylammonium bromide, heat to 100°C and react for 6 hours, then cool to room temperature, add 3wt% sodium hydroxide aqueous solution, stir for 1 hour, wash with deionized water, separate, and distill under reduced pressure to obtain the epi-adamantane derivative.

[0026] Furthermore, the ratio of adamantane derivative, epichlorohydrin, tetramethylammonium bromide, sodium hydroxide aqueous solution, and deionized water is 0.1-0.3 mol: 0.5-1.5 mol: 2-6 mmol: 4.5-13.5 mL: 100 mL;

[0027] In step B2, the adamantane derivative and epichlorohydrin first undergo a ring-opening reaction, and then the nucleophilicity is enhanced by the use of a base, resulting in intramolecular substitution and reconstruction of the epoxy ring, which provides the reaction conditions for subsequent grafting of lignin.

[0028] Step B3: Mix enzymatically hydrolyzed lignin with N,N-dimethylformamide, heat to 100°C, then add an epoxy adamantane derivative and 1,8-diazabicyclo[5.4.0]undec-7-ene, stir and react under a nitrogen atmosphere for 24 h, cool to room temperature, add acetic acid dropwise and stir for 5 min, then add it dropwise into methanol under stirring to precipitate, wash twice with methanol, then wash twice with deionized water, freeze dry to obtain modified lignin;

[0029] Furthermore, the ratio of enzymatic hydrolysis of lignin, N,N-dimethylformamide, adamantane derivative, 1,8-diazabicyclo[5.4.0]undec-7-ene, acetic acid, methanol, and deionized water is 10g:50-60mL:0.03-0.04mol:0.003-0.004mol:12-14mL:400mL:300mL;

[0030] In step B3, enzymatic hydrolysis of lignin and the grafting reaction of the adamantane derivative hydrophobically modify the lignin, improving the compatibility between lignin and nylon. At the same time, the hydrophobic lignin easily forms a transfer film on the friction surface during the friction process. The transfer film has a lubricating effect and reduces the friction coefficient of the system. In addition, lignin can improve the crystallinity of the nylon matrix, thereby increasing its strength and reducing wear during the friction process.

[0031] A method for preparing a high wear-resistant, halogen-free fire-retardant composite material includes the following steps:

[0032] Step S1: Weigh the raw materials according to the weight proportions, dry PA9T in a dehumidifying dryer at 100℃ for 7 hours, and control the moisture content to be less than 0.03% for later use;

[0033] Step S2: PA9T, modified lignin, compatibilizer and antioxidant are added to the extruder through the main feed port, carbon fiber is added to the extruder through the first side feed port, and modified flame retardant and wear-resistant powder are added to the extruder through the second side feed port. The mixture is melt-blended at 280-350℃, cooled, air-dried and granulated to obtain a high wear-resistant halogen-free fireproof composite material.

[0034] The beneficial effects of this invention are:

[0035] The high-wear-resistant, halogen-free fire-retardant composite material of this invention can be widely used in production fields with stringent requirements for fire resistance and wear resistance, such as electronic and electrical appliance housings, automotive parts, building materials, and machinery equipment. The modified flame retardant, through the synergistic effect of phosphorus, nitrogen, and boron elements, endows the material with halogen-free, environmentally friendly, and flame-retardant properties, achieving a highly efficient fire-retardant effect while ensuring both safety and environmental friendliness. Hydrophobic modification of lignin significantly improves its interfacial bonding with the nylon matrix, solving the performance dispersion problem caused by insufficient compatibility in composite materials and endowing the material with excellent wear resistance, effectively reducing wear rate under friction conditions and significantly extending product lifespan. Compared with existing technologies, the composite material prepared by this invention possesses multiple core advantages, including halogen-free environmental protection, high flame retardancy, high wear resistance, and good compatibility. Its comprehensive performance is significantly superior to traditional products, and it has broad market application prospects.

[0036] The modified flame retardant of this invention first undergoes a phosphorylation reaction between pentaerythritol and phosphorus oxychloride. The resulting phosphorus-containing structure decomposes upon heating and combustion, breaking the phosphorus-oxygen double bonds and phosphorus-oxygen carbon bonds to produce phosphorus-containing compounds such as phosphate esters, phosphoric acid, and polyphosphoric acid. These compounds exhibit a liquid, viscous, glassy state at high temperatures, which can coat the burning surface of the material, thereby isolating energy and oxygen exchange. Subsequently, it undergoes a phosphorylation reaction with 3,5-diamino-1,2,4-triazole. The triazole structure is a five-membered nitrogen heterocyclic compound with a high nitrogen content. Upon heating, it decomposes to generate a flame-retardant gas, which can dilute the concentration of gaseous combustibles and oxygen, quench active free radicals, and achieve the purpose of gas-phase flame retardancy. Finally, using the Schiff base reaction, the introduced boric acid groups undergo dehydration and cross-linking upon heating, forming a boron-oxygen hexacyclic cross-linked network structure. As the temperature further increases, it continues to decompose, eventually forming a boron-oxygen-containing glass layer with strong heat resistance and oxidation resistance, covering the surface of the material. This prevents the escape of combustible gases and volatiles, as well as the transfer of combustion heat. In synergy with nitrogen and phosphorus flame retardants, it further enhances the flame retardant performance of the system.

[0037] The modified lignin of this invention first undergoes a ring-opening reaction with 1-adamantanecarboxylic acid and 1,2-epoxydodecane. Adamantane is a highly symmetrical three-membered cyclic aliphatic hydrocarbon composed of three chair-shaped cyclohexanes. This unique structure endows it with high hydrophobicity and mechanical stability. Introducing it into a polymer system can improve the system's hydrophobicity and wear resistance, extending its service life. Furthermore, the introduced long-chain alkyl groups can interact with the material surface, improving its hydrophobic properties by reducing surface energy or forming a hydrophobic layer. Next, it reacts with epichlorohydrin to introduce epoxy groups. Finally, it undergoes a grafting reaction with enzymatically hydrolyzed lignin to hydrophobically modify the lignin, improving its compatibility with nylon. Simultaneously, the hydrophobic lignin easily forms a transfer film on the friction surface during friction, which has a lubricating effect, reducing the system's coefficient of friction. In addition, lignin can improve the crystallinity of the nylon matrix, thereby increasing its strength and reducing wear during friction. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1: The modified flame retardant was prepared by the following steps:

[0040] Step A1: Mix pentaerythritol and phosphorus oxychloride, stir at 60°C for 1.5 h under nitrogen protection, raise the temperature to 105°C and reflux for 10 h. After the reaction is completed, distill under reduced pressure and dry under vacuum to obtain intermediate product 1. The ratio of pentaerythritol to phosphorus oxychloride is 0.8 mol: 4 mol.

[0041] Step A2: Mix intermediate product 1 and N,N-dimethylformamide, place them in an oil bath, heat to 80°C, stir for 10 min, add 3,5-diamino-1,2,4-triazole, react for 6 h, after the reaction is complete, filter under reduced pressure, wash, and dry under vacuum to obtain intermediate product 2. The ratio of intermediate product 1, N,N-dimethylformamide and 3,5-diamino-1,2,4-triazole is 0.5 mol: 150 mL: 0.95 mol.

[0042] Step A3: Mix 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol, stir, and under nitrogen protection, heat to 80℃ and reflux for 2 hours. After the reaction is completed, filter, wash and vacuum dry to obtain the modified flame retardant. The ratio of 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol is 0.2mol:0.1mol:150mL.

[0043] Modified lignin is prepared by the following steps:

[0044] Step B1: Add 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran to the polymerization tube. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted at 70℃ for 20 h to obtain the adamantane derivative. The ratio of 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran is 0.3 mol: 0.3 mol: 100 mL.

[0045] Step B2: Mix the adamantane derivative and epichlorohydrin, heat to 90°C, add tetramethylammonium bromide, heat to 100°C and react for 6 hours, then cool to room temperature, add 3wt% sodium hydroxide aqueous solution, stir for 1 hour, wash with deionized water, separate, and distill under reduced pressure to obtain the epi-adamantane derivative. The ratio of adamantane derivative, epichlorohydrin, tetramethylammonium bromide, sodium hydroxide aqueous solution and deionized water is 0.1 mol: 0.5 mol: 2 mmol: 4.5 mL: 100 mL.

[0046] Step B3: Mix enzymatically hydrolyzed lignin and N,N-dimethylformamide, heat to 100℃, then add epoxide adamantane derivative and 1,8-diazabicyclo[5.4.0]undec-7-ene, stir and react for 24 h under a nitrogen atmosphere, cool to room temperature, add acetic acid dropwise and stir for 5 min, then add it dropwise to methanol to precipitate, wash twice with methanol, then wash twice with deionized water, freeze dry to obtain modified lignin. The ratio of enzymatically hydrolyzed lignin, N,N-dimethylformamide, epoxide adamantane derivative, 1,8-diazabicyclo[5.4.0]undec-7-ene, acetic acid, methanol and deionized water is 10 g: 50 mL: 0.03 mol: 0.003 mol: 12 mL: 400 mL: 300 mL.

[0047] Example 2: The modified flame retardant was prepared by the following steps:

[0048] Step A1: Mix pentaerythritol and phosphorus oxychloride, stir at 60°C for 1.5 h under nitrogen protection, raise the temperature to 105°C and reflux for 10 h. After the reaction is completed, distill under reduced pressure and dry under vacuum to obtain intermediate product 1. The ratio of pentaerythritol to phosphorus oxychloride is 0.9 mol: 4.5 mol.

[0049] Step A2: Mix intermediate product 1 and N,N-dimethylformamide, place them in an oil bath, heat to 80°C, stir for 10 min, add 3,5-diamino-1,2,4-triazole, react for 6 h, after the reaction is complete, filter under reduced pressure, wash, and dry under vacuum to obtain intermediate product 2. The ratio of intermediate product 1, N,N-dimethylformamide and 3,5-diamino-1,2,4-triazole is 0.6 mol: 175 mL: 1.15 mol.

[0050] Step A3: Mix 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol, stir, and under nitrogen protection, heat to 80°C and reflux for 2 hours. After the reaction is complete, filter, wash and vacuum dry to obtain the modified flame retardant. The ratio of 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol is 0.3 mol: 0.15 mol: 175 mL.

[0051] Modified lignin is prepared by the following steps:

[0052] Step B1: Add 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran to the polymerization tube. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted at 70℃ for 20h to obtain the adamantane derivative. The ratio of 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran is 0.4mol:0.4mol:125mL.

[0053] Step B2: Mix the adamantane derivative and epichlorohydrin, heat to 90°C, add tetramethylammonium bromide, heat to 100°C and react for 6 hours, then cool to room temperature, add 3wt% sodium hydroxide aqueous solution, stir for 1 hour, wash with deionized water, separate, and distill under reduced pressure to obtain the epi-adamantane derivative. The ratio of adamantane derivative, epichlorohydrin, tetramethylammonium bromide, sodium hydroxide aqueous solution and deionized water is 0.2mol:1mol:4mmol:9mL:100mL.

[0054] Step B3: Mix enzymatically hydrolyzed lignin and N,N-dimethylformamide, heat to 100℃, then add epoxide adamantane derivative and 1,8-diazabicyclo[5.4.0]undec-7-ene, stir and react for 24 h under a nitrogen atmosphere, cool to room temperature, add acetic acid dropwise and stir for 5 min, then add it dropwise to methanol to precipitate, wash twice with methanol, then wash twice with deionized water, freeze dry to obtain modified lignin. The ratio of enzymatically hydrolyzed lignin, N,N-dimethylformamide, epoxide adamantane derivative, 1,8-diazabicyclo[5.4.0]undec-7-ene, acetic acid, methanol and deionized water is 10 g: 55 mL: 0.035 mol: 0.0035 mol: 13 mL: 400 mL: 300 mL.

[0055] Example 3: The modified flame retardant was prepared by the following steps:

[0056] Step A1: Mix pentaerythritol and phosphorus oxychloride, stir at 60°C for 1.5 h under nitrogen protection, raise the temperature to 105°C and reflux for 10 h. After the reaction is completed, distill under reduced pressure and dry under vacuum to obtain intermediate product 1. The ratio of pentaerythritol to phosphorus oxychloride is 1 mol: 5 mol.

[0057] Step A2: Mix intermediate product 1 and N,N-dimethylformamide, place them in an oil bath, heat to 80°C, stir for 10 min, add 3,5-diamino-1,2,4-triazole, react for 6 h, after the reaction is complete, filter under reduced pressure, wash, and dry under vacuum to obtain intermediate product 2. The ratio of intermediate product 1, N,N-dimethylformamide and 3,5-diamino-1,2,4-triazole is 0.7 mol: 200 mL: 1.35 mol.

[0058] Step A3: Mix 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol, stir, and under nitrogen protection, heat to 80°C and reflux for 2 hours. After the reaction is complete, filter, wash and vacuum dry to obtain the modified flame retardant. The ratio of 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol is 0.4 mol: 0.2 mol: 200 mL.

[0059] Modified lignin is prepared by the following steps:

[0060] Step B1: Add 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran to the polymerization tube. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted at 70℃ for 20h to obtain the adamantane derivative. The ratio of 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran is 0.5mol:0.5mol:150mL.

[0061] Step B2: Mix the adamantane derivative and epichlorohydrin, heat to 90°C, add tetramethylammonium bromide, heat to 100°C and react for 6 hours, then cool to room temperature, add 3wt% sodium hydroxide aqueous solution, stir for 1 hour, wash with deionized water, separate, and distill under reduced pressure to obtain the epi-adamantane derivative. The ratio of adamantane derivative, epichlorohydrin, tetramethylammonium bromide, sodium hydroxide aqueous solution and deionized water is 0.3mol:1.5mol:6mmol:13.5mL:100mL.

[0062] Step B3: Mix enzymatically hydrolyzed lignin and N,N-dimethylformamide, heat to 100℃, then add epoxide adamantane derivative and 1,8-diazabicyclo[5.4.0]undec-7-ene, stir under nitrogen atmosphere for 24 h, cool to room temperature, add acetic acid dropwise and stir for 5 min, then add it dropwise to methanol to precipitate, wash twice with methanol, then wash twice with deionized water, freeze dry to obtain modified lignin. The ratio of enzymatically hydrolyzed lignin, N,N-dimethylformamide, epoxide adamantane derivative, 1,8-diazabicyclo[5.4.0]undec-7-ene, acetic acid, methanol and deionized water is 10 g: 60 mL: 0.04 mol: 0.004 mol: 14 mL: 400 mL: 300 mL.

[0063] Example 4: A method for preparing a high wear-resistant halogen-free fire-retardant composite material, comprising the following steps:

[0064] 40 parts of PA9T, 6 parts of the modified flame retardant prepared in Example 1, 8 parts of carbon fiber, 0.5 parts of antioxidant 1010, 1 part of nano silica, 1 part of maleic anhydride grafted polyethylene, and 1 part of the modified lignin prepared in Example 1.

[0065] Step S1: Weigh the raw materials according to the weight proportions, dry PA9T in a dehumidifying dryer at 100℃ for 7 hours, and control the moisture content to be less than 0.03% for later use;

[0066] Step S2: PA9T, modified lignin prepared in Example 1, maleic anhydride grafted polyethylene and antioxidant 1010 are added to the extruder through the main feed port, carbon fiber is added to the extruder through the first side feed port, and modified flame retardant and nano silica prepared in Example 1 are added to the extruder through the second side feed port. The mixture is melt-blended at 280°C, cooled, air-dried and granulated to obtain a high wear-resistant halogen-free fireproof composite material.

[0067] Example 5: A method for preparing a high wear-resistant halogen-free fire-retardant composite material, comprising the following steps:

[0068] 50 parts of PA9T, 8 parts of the modified flame retardant prepared in Example 2, 10 parts of carbon fiber, 1 part of antioxidant 1076, 2 parts of alumina, 1.5 parts of maleic anhydride-grafted polyethylene, and 2 parts of modified lignin prepared in Example 2.

[0069] Step S1: Weigh the raw materials according to the weight proportions, dry PA9T in a dehumidifying dryer at 100℃ for 7 hours, and control the moisture content to be less than 0.03% for later use;

[0070] Step S2: PA9T, modified lignin prepared in Example 2, maleic anhydride grafted polyethylene and antioxidant 1076 are added to the extruder through the main feed port, carbon fiber is added to the extruder through the first side feed port, and modified flame retardant and alumina prepared in Example 1 are added to the extruder through the second side feed port. The mixture is melt-blended at 310°C, cooled, air-dried and granulated to obtain a high wear-resistant halogen-free fireproof composite material.

[0071] Example 6: A method for preparing a high wear-resistant halogen-free fire-retardant composite material, comprising the following steps:

[0072] 60 parts of PA9T, 10 parts of the modified flame retardant prepared in Example 3, 12 parts of carbon fiber, 1 part of antioxidant 168, 3 parts of calcium carbonate, 2 parts of maleic anhydride-grafted polyethylene, and 3 parts of the modified lignin prepared in Example 3.

[0073] Step S1: Weigh the raw materials according to the weight proportions, dry PA9T in a dehumidifying dryer at 100℃ for 7 hours, and control the moisture content to be less than 0.03% for later use;

[0074] Step S2: PA9T, modified lignin prepared in Example 3, maleic anhydride grafted polyethylene and antioxidant 168 are added to the extruder through the main feed port. Carbon fiber is added to the extruder through the first side feed port. Modified flame retardant and calcium carbonate prepared in Example 3 are added to the extruder through the second side feed port. The mixture is melt-blended at 350°C, cooled, air-dried and granulated to obtain a high wear-resistant halogen-free fireproof composite material.

[0075] Comparative Example 1: This comparative example is a composite material. The difference between this example and Example 6 is that melamine borate is used instead of the modified flame retardant prepared in Example 3. All other aspects are the same.

[0076] Comparative Example 2: This comparative example is a composite material. The difference between this example and Example 6 is that lignin is used instead of the modified lignin prepared in Example 3. All other aspects are the same.

[0077] Comparative Example 3: This comparative example is a composite material. The difference between this example and Example 6 is that melamine borate is used instead of the modified flame retardant prepared in Example 3, and lignin is used instead of the modified lignin prepared in Example 3. All other aspects are the same.

[0078] The materials prepared in Examples 4-6 and Comparative Examples 1-3 were subjected to performance tests:

[0079] Tensile properties: tested according to ASTM D-638;

[0080] Bending performance: tested according to ASTM D-790;

[0081] Impact strength: tested according to ASTM D-256;

[0082] Flame retardancy: tested according to UL94 vertical burning test, with a sample size of 100×10×1mm;

[0083] Dynamic friction coefficient: Tested according to ASTM G133, with a sample size of 5×5×4mm, a surface normal pressure of 10N, and a speed of 12.5cm / s.

[0084] The test results are shown in Table 1:

[0085] Table 1: Performance Test Results

[0086]

[0087] As shown in Table 1, the high wear-resistant halogen-free fire-retardant composite material prepared by this invention possesses excellent mechanical and flame-retardant properties. The flame-retardant rating of the materials prepared in the examples is V-0. Comparing Example 6 and Comparative Example 1, it can be seen that the modified flame retardant of this invention can effectively improve the flame-retardant rating and flame-retardant stability of the nylon matrix, while having no significant negative impact on its mechanical properties, achieving a synergistic balance between flame-retardant modification and the mechanical properties of the matrix. Comparing Example 6 and Comparative Example 2, the modified lignin prepared by this invention improves the mechanical and wear-resistant properties of the system and reduces the coefficient of dynamic friction. This indicates that the composite material prepared by this invention possesses multiple characteristics of being halogen-free and environmentally friendly, highly flame-retardant, and highly wear-resistant, and has broad application prospects.

[0088] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. A high wear-resistant, halogen-free fire-retardant composite material, characterized in that, The raw materials include the following parts by weight: PA9T 40-60 parts, modified flame retardant 6-10 parts, carbon fiber 8-12 parts, antioxidant 0.5-1 part, wear-resistant powder 1-3 parts, compatibilizer 1-2 parts, and modified lignin 1-3 parts. The modified flame retardant is prepared by the following steps: Step A1: Mix pentaerythritol and phosphorus oxychloride, stir at 60°C for 1.5 h under nitrogen protection, raise the temperature to 105°C and reflux for 10 h. After the reaction is completed, distill under reduced pressure and dry under vacuum to obtain intermediate product 1. Step A2: Mix intermediate product 1 with N,N-dimethylformamide, place it in an oil bath, heat to 80°C, stir for 10 min, add 3,5-diamino-1,2,4-triazole, react for 6 h, after the reaction is completed, filter under reduced pressure, wash, and dry under vacuum to obtain intermediate product 2. Step A3: Mix 4-formylphenylboronic acid, intermediate product 2 and anhydrous ethanol, stir, heat to 80°C under nitrogen protection, reflux for 2 hours, filter, wash and vacuum dry to obtain modified flame retardant.

2. The high wear-resistant halogen-free fireproof composite material according to claim 1, characterized in that, In step A1, the ratio of pentaerythritol to phosphorus oxychloride is 0.8-1 mol: 4-5 mol.

3. The high wear-resistant halogen-free fireproof composite material according to claim 1, characterized in that, In step A2, the ratio of intermediate 1, N,N-dimethylformamide and 3,5-diamino-1,2,4-triazole is 0.5-0.7 mol: 150-200 mL: 0.95-1.35 mol.

4. The high wear-resistant halogen-free fireproof composite material according to claim 1, characterized in that, In step A3, the ratio of 4-formylphenylboronic acid, intermediate product 2, and anhydrous ethanol is 0.2-0.4 mol: 0.1-0.2 mol: 150-200 mL.

5. The high wear-resistant halogen-free fireproof composite material according to claim 1, characterized in that, The modified lignin is prepared by the following steps: Step B1: Add 1-adamantane carboxylic acid, 1,2-epoxydodecane and tetrahydrofuran to the polymerization tube. After three cycles of liquid nitrogen freezing-vacuuming-nitrogen purging-thawing, the polymerization tube is sealed and reacted at 70°C for 20 h to obtain the adamantane derivative. Step B2: Mix the adamantane derivative and epichlorohydrin, heat to 90°C, add tetramethylammonium bromide, heat to 100°C and react for 6 hours, then cool to room temperature, add 3wt% sodium hydroxide aqueous solution, stir for 1 hour, wash with deionized water, separate, and distill under reduced pressure to obtain the epi-adamantane derivative. Step B3: Mix enzymatically hydrolyzed lignin with N,N-dimethylformamide and heat to 100°C. Then add an epoxy adamantane derivative and 1,8-diazabicyclo[5.4.0]undec-7-ene. Stir the reaction under a nitrogen atmosphere for 24 hours, cool to room temperature, add acetic acid dropwise and stir for 5 minutes. While stirring, add the lignin dropwise into methanol to precipitate it. Wash the lignin twice with methanol and twice with deionized water. Freeze-dry to obtain modified lignin.

6. The high wear-resistant halogen-free fireproof composite material according to claim 5, characterized in that, In step B1, the ratio of 1-adamantanecarboxylic acid, 1,2-epoxydodecane, and tetrahydrofuran is 0.3-0.5 mol: 0.3-0.5 mol: 100-150 mL.

7. The high wear-resistant halogen-free fireproof composite material according to claim 5, characterized in that, In step B2, the ratio of adamantane derivative, epichlorohydrin, tetramethylammonium bromide, sodium hydroxide aqueous solution, and deionized water is 0.1-0.3 mol: 0.5-1.5 mol: 2-6 mmol: 4.5-13.5 mL: 100 mL.

8. The high wear-resistant halogen-free fireproof composite material according to claim 5, characterized in that, In step B3, the ratio of enzymatic hydrolysis of lignin, N,N-dimethylformamide, adamantane derivative, 1,8-diazabicyclo[5.4.0]undec-7-ene, acetic acid, methanol, and deionized water is 10g:50-60mL:0.03-0.04mol:0.003-0.004mol:12-14mL:400mL:300mL.

9. The high wear-resistant halogen-free fireproof composite material according to claim 1, characterized in that, The carbon fiber is short-cut carbon fiber with a diameter of 0.4-0.9 micrometers. The antioxidant is one of antioxidant 1010, antioxidant 1076, and antioxidant 168. The wear-resistant powder is one of nano-silica, alumina, and calcium carbonate. The compatibilizer is maleic anhydride-grafted polyethylene.

10. A method for preparing a high wear-resistant, halogen-free fire-retardant composite material according to any one of claims 1-9, characterized in that, The high wear-resistant, halogen-free fire-retardant composite material is prepared by the following steps: Step S1: Weigh the raw materials according to the weight proportions, dry PA9T in a dehumidifying dryer at 100℃ for 7 hours, and control the moisture content to be less than 0.03% for later use; Step S2: PA9T, modified lignin, compatibilizer and antioxidant are added to the extruder through the main feed port, carbon fiber is added to the extruder through the first side feed port, and modified flame retardant and wear-resistant powder are added to the extruder through the second side feed port. The mixture is melt-blended at 280-350℃, cooled, air-dried and granulated to obtain a high wear-resistant halogen-free fireproof composite material.

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