High-strength polymer composite material and preparation method thereof

Abstract

The invention discloses a high-strength polymer composite material and a preparation method thereof. The composite material is prepared from the following components in parts by mass: 70 to 83 parts of aliphatic nylon resin, 20 to 27 parts of fiber reinforced filler, 5 to 9 parts of red phosphorus, 2.5 to 5 parts of zinc borate, 4 to 6 parts of modified graphene and 2.5 to 6 parts of hydroxypropyl-beta-cyclodextrin. According to the composite material, the components are compounded, so that the mechanical property of the composite material is further improved on the basis of improving the flame retardance, and the technical problem that the mechanical property of the composite material is reduced due to the addition of a red phosphorus flame retardant is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composites, and particularly relates to a high-strength polymer composite and a preparation method thereof. Background Art

[0002] With the development of economy and the progress of technology, high-performance materials have received increasing attention. Polymer materials, also known as polymeric materials, have many excellent properties that traditional materials do not possess, such as chemical corrosion resistance, wear resistance, heat resistance, insulation, and good mechanical properties. They can replace traditional materials such as wood, steel, and metal in many fields and are widely used in the fields of automobiles, construction, and aerospace, gradually attracting the attention of researchers. To improve the limitations of single polymers and solve the problem that single materials cannot meet multiple properties simultaneously, researchers blend two or more fillers to create polymer materials with excellent properties.

[0003] Polyamide (PA), also known as nylon, is a general term for polymers with amide groups (-NHCO-) in the repeating units of the macromolecular main chain. It has high strength, good wear resistance, insulation, chemical stability, and good processing performance, and is widely used in the fields of electronics, mechanical parts, chemical engineering, automobiles, national defense, aerospace, etc. There are many types of polyamides, which can be divided into five categories according to the main chain structure: aliphatic polyamide, semi-aromatic polyamide, fully aromatic polyamide, heterocyclic aromatic polyamide, and alicyclic polyamide. As one of the five major engineering plastics (polyamide, polycarbonate, polyoxymethylene, polyphenylene ether, polybutylene terephthalate), polyamide is an important choice to replace metal materials such as steel, iron, and copper.

[0004] As an organic material, the flammability of polyamide is its obvious drawback. Polyamide has a fast burning speed and a high heat release rate in the flame, especially a large number of flaming droplets generated during combustion, which increases the risk of fire spread. The polyamides used industrially are divided into two types: reinforced and unreinforced, both of which are required to have a UL94-V0 rating. However, reinforced polyamide, especially fiber-reinforced polyamide, is more prone to combustion due to the fiber wick effect, which limits its application in the fields of electronics and transportation. Developing flame-retardant polyamides with excellent comprehensive properties is of great significance for expanding the application range of this engineering plastic and increasing its added value. Therefore, in recent years, many domestic and foreign research institutions and companies have invested a lot of manpower and material resources in the research on reducing the flammability of polyamide.

[0005] At present, additive flame retardants are mostly used in industrial flame-retardant polyamides. One type contains halogen, and the other is halogen-free. Although the former halogen-based flame retardants have relatively high flame retardancy efficiency, they often cause serious degradation of plastics during re-melting and mixing, which is not conducive to the recycling and utilization of plastics. More importantly, halogen-based flame retardants will generate more smoke, toxic, and corrosive gases during combustion, causing secondary pollution, which will cause great difficulties for both rescue work during a fire and post-disaster recovery work. For the other type of halogen-free flame retardants used in polyamides, they can reduce the smoke and corrosive gases generated during the thermal cracking or combustion of polyamides, which is environmentally friendly and is a development direction of flame retardants. However, the dosage of such flame retardants is often very high, thus seriously deteriorating the mechanical properties of polyamides, and there are also some problems with the processing performance of polyamides containing such flame retardants. With the continuous improvement of the requirements for material properties in the field of plastic applications and the high attention paid to environmental protection by people, it is further required that flame-retardant polyamides should have good flame retardancy and mechanical properties, and at the same time achieve environmental friendliness (halogen-free, non-toxic, etc.) during processing and use. Therefore, it is of great significance to study high-performance halogen-free flame-retardant polyamide composites. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a high-strength polymer composite material and its preparation method. Through the compounding of each component, the mechanical properties of the composite material are further improved on the basis of improving the flame retardancy, overcoming the technical problem of the decline in the mechanical properties of the composite material caused by the addition of red phosphorus flame retardant.

[0007] To achieve the above object, on the one hand, the present invention discloses a high-strength polymer composite material, which comprises the following components in parts by mass: 70-83 parts of aliphatic nylon resin, 20-27 parts of fiber-reinforced filler, 5-9 parts of red phosphorus, 2.5-5 parts of zinc borate, 4-6 parts of modified graphene, and 2.5-6 parts of hydroxypropyl-β-cyclodextrin.

[0008] Preferably, the high-strength polymer composite material comprises the following components in parts by mass: 75-83 parts of aliphatic nylon resin, 20-27 parts of fiber-reinforced filler, 5-9 parts of red phosphorus, 2.5-5 parts of zinc borate, 4-6 parts of modified graphene, and 2.5-5 parts of hydroxypropyl-β-cyclodextrin.

[0009] Preferably, the aliphatic nylon resin is one or more of nylon 6, nylon 46, nylon 56, nylon 66, nylon 610, nylon 1010, nylon 11, and nylon 12.

[0010] Preferably, the fiber-reinforced filler is one or more of glass fiber, carbon fiber, sisal fiber, aramid fiber, and ultra-high molecular weight polyethylene fiber.

[0011] Preferably, the modified graphene is graphene modified with an amino silane coupling agent.

[0012] Preferably, the preparation method of the graphene modified with an amino silane coupling agent is as follows: adding the amino silane coupling agent and graphene into a solvent, ultrasonically dispersing, then stirring and reacting at 55-70 °C for 1-2 hours, filtering, washing, and drying to obtain the graphene modified with an amino silane coupling agent; the mass ratio of the amino silane coupling agent to graphene is (0.2-1):1.

[0013] Preferably, the amino silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and N-cyclohexyl-γ-aminopropylmethyldimethoxysilane.

[0014] Preferably, the high-strength polymer composite further comprises 1-10 parts by mass of an auxiliary agent.

[0015] Preferably, the auxiliary agent is one or more of a flow modifier, a colorant, an antioxidant, a light stabilizer, a lubricant, a demolding agent, an antistatic agent, and a processing aid.

[0016] Preferably, the flow modifier is one or more of polyethylene glycol esters, polyol esters, lignite salts, and polyethylene waxes.

[0017] Preferably, the colorant is one or more of inorganic pigments, organic pigments, and dyes.

[0018] Preferably, the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 1098, or antioxidant DLTP.

[0019] Preferably, the lubricant is one or more of talc powder, stearates, ethylene acrylic acid copolymers, and montan ester lubricants.

[0020] Preferably, the light stabilizer is one or more of hindered amine light stabilizers, benzophenone light stabilizers, and benzotriazole light stabilizers.

[0021] Preferably, the demolding agent is one or more of paraffin wax, glycerin, petrolatum, silicone oil, and low molecular weight polyethylene.

[0022] Preferably, the antistatic agent comprises one or more of quaternary ammonium salts, sulfonates, and phosphates.

[0023] Preferably, the tensile strength is 151-165 MPa, the flexural strength is 189-208 MPa, and the notched impact strength is 7.7-9.6 kJ / m 2。

[0024] On the other hand, the present invention discloses a preparation method of the above-mentioned high-strength polymer composite material, which includes the following steps: (1) Mix aliphatic nylon resin, red phosphorus, zinc borate, modified graphene, and hydroxypropyl-β-cyclodextrin evenly to obtain a mixed material; (2) Add the mixed material obtained in step (1) into a twin-screw extruder from the main feeding port, and add the fiber-reinforced filler into the twin-screw extruder from the side feeding port, and melt and extrude and pelletize to obtain the high-strength polymer composite material.

[0025] Preferably, in step (2), the screw speed of the twin-screw extruder is 400-500 r / min, and the extrusion temperature is 260-300 °C.

[0026] Compared with the prior art, the advantages and positive effects of the present invention are as follows: A high-strength polymer composite material and its preparation method are provided. Through the preferred compounding of each component, the composite material ensures high flame retardancy performance while having high mechanical properties. Specifically: In order to improve the mechanical properties of the red phosphorus flame-retarded polyamide composite material, a specific amount of modified graphene and hydroxypropyl-β-cyclodextrin are added to the composite material. Both graphene and hydroxypropyl-β-cyclodextrin belong to excellent charring agents. Moreover, due to the nano-scale lamellar structure of graphene, it not only has higher mechanical properties, but also can form a hydrophobic barrier layer in the polymer matrix, effectively blocking the penetration of small molecules such as gases and liquids, improving the stability of the red phosphorus flame retardant, and preventing the deterioration of red phosphorus from damaging the mechanical properties of the composite material. Graphene containing amino groups can not only react with the active groups on the polyamide or form hydrogen bonds, but also form chemical bonds with the hydroxyl groups on hydroxypropyl-β-cyclodextrin, improving the density of the nylon composite material. The special cavity structure of hydroxypropyl-β-cyclodextrin can effectively lock the moisture inside the resin matrix, prevent its migration, be adsorbed by red phosphorus, resulting in the failure and deterioration of red phosphorus, and generating substances corrosive to the composite material. Hydrogen bond networks are also easily formed among nylon resin, amino-modified graphene, hydroxypropyl-β-cyclodextrin, and the hydroxyl groups on the surface of red phosphorus, improving the density of the composite material, preventing the intrusion of external moisture or gas, improving the stability of the red phosphorus flame retardant, and thus improving the mechanical strength of the composite material. Specific embodiments

[0027] Next, the present invention will be specifically described by way of exemplary embodiments. However, it should be understood that, without further recitation, the structures and features in one embodiment can also be beneficially combined into other embodiments. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred methods and materials described herein are for illustrative purposes only and do not limit the content of this application.

[0029] The experimental methods in the following examples are all conventional methods unless otherwise specified. The test materials used in the following examples are all obtained from commercial channels unless otherwise specified. Unless otherwise specified, the types of each component selected in each parallel example and comparative example are the same.

[0030] A high-strength polymer composite material comprises the following components in parts by mass: 70-83 parts of aliphatic nylon resin, 20-27 parts of fiber-reinforced filler, 5-9 parts of red phosphorus, 2.5-5 parts of zinc borate, 4-6 parts of modified graphene, and 2.5-6 parts of hydroxypropyl-β-cyclodextrin.

[0031] The preparation method of the above-mentioned high-strength polymer composite material comprises the following steps: (1) Mix the aliphatic nylon resin, red phosphorus, zinc borate, modified graphene, and hydroxypropyl-β-cyclodextrin evenly to prepare a mixed material; (2) Add the mixed material into a twin-screw extruder from the main feeding port, and add the fiber-reinforced filler into the twin-screw extruder from the side feeding port, and melt and extrude and pelletize to obtain a high-strength polymer composite material.

[0032] As a cheap and most widely used flame retardant, red phosphorus flame retardant mainly plays a flame retardant role in the solid phase. When the red phosphorus flame retardant comes into contact with fire, it melts and decomposes to produce viscous, glassy phosphoric acid, metaphosphoric acid and polyphosphoric acid. Among them, polyphosphoric acid is in the form of a viscous film, which can cover and wrap the polymer surface, isolating it from oxygen and flame in the air, thus playing a flame retardant role. In addition, due to the strong dehydrating property of phosphoric acid and polyphosphoric acid, a carbonized film is formed on the polymer surface to play a flame retardant role. However, compared with other phosphorus-containing flame retardants, red phosphorus flame retardant has the disadvantage of being ineffective due to moisture absorption during the processing process. Especially when the addition amount of red phosphorus flame retardant is large, it is extremely easy to react with components such as water and oxygen at high temperatures, generating corrosive gases and toxic substances, resulting in a reduction in the mechanical properties of the composite material. To improve the water resistance and thermal stability of red phosphorus flame retardant, the method of particle surface coating (i.e., microencapsulation) is generally used to improve its performance. There are reports on the microencapsulation of red phosphorus. Although its flame retardant performance has been improved to a certain extent, it still faces technical problems such as cumbersome coating processes, low effective content, and reduced mechanical properties.

[0033] In this embodiment, in order to improve the mechanical properties of the red phosphorus flame retardant polyamide composite material, a specific amount of modified graphene and hydroxypropyl-β-cyclodextrin are added. Due to the nano-scale sheet-like structure of graphene, compared with water-soluble graphene oxide, it not only has higher mechanical properties, can greatly improve the strength and modulus of the material even when the addition amount is very small, without increasing the density of the polymer material, but also can form a hydrophobic barrier layer in the polymer matrix, effectively blocking the penetration of small molecules such as gases and liquids, and improving the stability of the red phosphorus flame retardant. However, the dispersibility of pure graphene is poor. In order to improve its dispersion performance and promote the dispersion of hydroxypropyl-β-cyclodextrin, the present invention uses amino active groups to modify graphene to prepare graphene containing active amino groups. Graphene containing amino groups can not only react with the active groups on polyamide or form hydrogen bonds at high temperatures, but also form chemical bonds with the hydroxyl groups on hydroxypropyl-β-cyclodextrin, improving the density of the nylon composite material. Compared with ordinary types of cyclodextrin, hydroxypropyl-β-cyclodextrin has good water solubility, good compatibility with polar nylon resins, and is easy to absorb the moisture inside the composite material. Moreover, the outside of hydroxypropyl-β-cyclodextrin is covered with hydroxyl groups, having strong hydrophilicity; the inside is a cavity composed of various carbon-oxygen bonds. This special cavity structure can effectively lock the moisture inside the resin matrix, prevent its migration, and be adsorbed by red phosphorus, resulting in the failure of red phosphorus.

[0034] In addition, as a polar resin, nylon resin contains more amide groups, carboxyl groups and amino groups, which not only effectively improves the compatibility with amino-modified graphene, hydroxypropyl-β-cyclodextrin and red phosphorus, but also easily forms a wide range of hydrogen bond networks between the hydroxyl groups on the surfaces of nylon resin, amino-modified graphene, hydroxypropyl-β-cyclodextrin and red phosphorus, thereby improving the density of the composite material, preventing the intrusion of external moisture or gas, and improving the stability of the red phosphorus flame retardant.

[0035] This embodiment can not only improve the flame retardant properties of the composite material, but also improve its mechanical strength by precisely controlling the special dosage of components such as aliphatic nylon resin, fiber-reinforced filler, red phosphorus, zinc borate, modified graphene, and hydroxypropyl-β-cyclodextrin. As a flame retardant, generally speaking, as the red phosphorus component increases, the flame retardant effect increases, but when its dosage is too large, it is easy to cause the mechanical strength of the nylon composite material to decrease. Zinc borate, as a synergistic flame retardant of red phosphorus, not only improves the mechanical strength and flame retardant properties of the composite material, but also improves the stability of red phosphorus, preventing red phosphorus from precipitating during processing. In particular, hydroxypropyl-β-cyclodextrin, as an organic oligomer modifier, has an adsorption and dispersion effect that is not obvious when its addition amount is too small; when its dosage is too much, it itself will also face precipitation problems, which may affect the full dispersion of red phosphorus and graphene, which is not conducive to the improvement of mechanical properties and flame retardant effects of composite materials. More importantly, as a nanoscale filler, modified graphene is small in size and has more van der Waals forces between them. When it is used in excessive amounts, it is easy to cause mutual adsorption and agglomeration between graphenes, reducing its barrier effect.

[0036] Among them, the high-strength polymer composite material includes the following components in parts by mass: the high-strength polymer composite material includes the following components in parts by mass: 75-83 parts of aliphatic nylon resin, 20-27 parts of fiber-reinforced filler, 5-9 parts of red phosphorus, 2.5-5 parts of zinc borate, 4-6 parts of modified graphene, and 2.5-5 parts of hydroxypropyl-β-cyclodextrin.

[0037] Among them, the fiber-reinforced filler can be one or more of glass fiber, carbon fiber, sisal fiber, aramid fiber, and ultra-high molecular weight polyethylene fiber. Fiber fillers can greatly improve the mechanical properties of aliphatic nylon, but they can cause a "wick" effect, resulting in a decrease in the flame retardant properties of red phosphorus and nylon composites. The addition of amino-modified graphene and hydroxypropyl-β-cyclodextrin can form a cross-linked structure and reduce the "wick" effect of the fiber.

[0038] The aliphatic nylon resin is one or more of nylon 6, nylon 46, nylon 56, nylon 66, nylon 610, nylon 1010, nylon 11, and nylon 12. Aliphatic nylon has better processing performance than aromatic nylon, which is beneficial to the dispersion of active fillers such as amino-modified graphene and hydroxypropyl-β-cyclodextrin in the present invention.

[0039] Among them, the modified graphene is graphene modified with an amino silane coupling agent. Specifically, the amino silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and N-cyclohexyl-γ-aminopropylmethyldimethoxysilane. Due to the strong water solubility and hydrophilicity of graphene oxide, it cannot be used as a barrier protection agent for red phosphorus. By modifying graphene with amino active groups to prepare graphene containing active amino groups, the graphene containing amino groups can not only react with the active groups on polyamide or form hydrogen bonds, but also form chemical bonds with the hydroxyl groups on hydroxypropyl-β-cyclodextrin, improving the density of the nylon composite material.

[0040] Specifically, the preparation process of the amino silane coupling agent modified graphene is as follows: Add the amino silane coupling agent and graphene into a solvent, ultrasonically disperse, then stir and react at 55-70 °C for 1-2 hours, filter, wash, and dry to obtain it. Ultrasonication is beneficial to the dispersion of graphene, so as to better mix with the components of the nylon composite material. Further, the mass ratio of the amino silane coupling agent to graphene is (0.2-1):1.

[0041] Among them, in order to better meet the needs of material modification, the high-strength polymer composite material also includes 1-10 parts of filler. The filler can be one or more of a flow modifier, a colorant, an antioxidant, a light stabilizer, a lubricant, a demolding agent, an antistatic agent, and a processing aid, and can be added according to actual needs.

[0042] Specifically, the flow modifier can be at least one of polyethylene glycol esters, polyol esters, lignite salts, and polyethylene waxes; the colorant is at least one of inorganic pigments, organic pigments, and dyes; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 1098, or antioxidant DLTP; the lubricant is at least one of talc powder, stearate salts, ethylene acrylic acid copolymers, and montan ester lubricants; the light stabilizer is at least one of hindered amine light stabilizers, benzophenone light stabilizers, and benzotriazole light stabilizers; the demolding agent is at least one of paraffin wax, glycerin, petrolatum, silicone oil, and low molecular weight polyethylene; the antistatic agent includes at least one of quaternary ammonium salts, sulfonates, and phosphates.

[0043] Among them, the screw speed of the twin-screw extruder is 400-500 r / min, and the extrusion temperature is 260-300 °C.

[0044] Example 1 A high-strength polymer composite material, including the following components in parts by mass: 70 parts of aliphatic nylon resin, 20 parts of glass fiber, 5 parts of red phosphorus, 2.5 parts of zinc borate, 4 parts of modified graphene, 2.5 parts of hydroxypropyl-β-cyclodextrin, 1.2 parts of antioxidant, 2.5 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is talc powder; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, and then stir and react at 57 °C for 1.8 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.3:1, and the amino silane coupling agent is γ-aminopropyltriethoxysilane.

[0045] Example 2 A high-strength polymer composite material, comprising the following components in parts by mass: 82 parts of aliphatic nylon resin, 29 parts of glass fiber, 9 parts of red phosphorus, 5 parts of zinc borate, 6 parts of modified graphene, 4.5 parts of hydroxypropyl-β-cyclodextrin, 2.8 parts of antioxidant, 1.7 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is zinc stearate; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, and then stir and react at 63 °C for 1.4 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.8:1, and the amino silane coupling agent is selected from γ-aminopropyltrimethoxysilane.

[0046] Example 3 A high-strength polymer composite material, comprising the following components in parts by mass: 83 parts of aliphatic nylon resin, 22 parts of glass fiber, 8 parts of red phosphorus, 3 parts of zinc borate, 5.5 parts of modified graphene, 2.8 parts of hydroxypropyl-β-cyclodextrin, 2.6 parts of antioxidant, 1.7 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is barium stearate; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, and then stir and react at 66 °C for 1.5 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.6:1, and the amino silane coupling agent is selected from γ-aminopropyltriethoxysilane.

[0047] Example 4 A high-strength polymer composite material, comprising the following components in parts by mass: 75 parts of aliphatic nylon resin, 23 parts of glass fiber, 6.5 parts of red phosphorus, 3.3 parts of zinc borate, 4.5 parts of modified graphene, 3.2 parts of hydroxypropyl-β-cyclodextrin, 1.6 parts of antioxidant, 1.4 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is talc powder; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 60 °C for 1.7 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.4:1, and the amino silane coupling agent is selected from γ-aminopropyltriethoxysilane.

[0048] Example 5 A high-strength polymer composite material, comprising the following components in parts by mass: 80 parts of aliphatic nylon resin, 27 parts of glass fiber, 8 parts of red phosphorus, 4.5 parts of zinc borate, 5.6 parts of modified graphene, 4 parts of hydroxypropyl-β-cyclodextrin, 2.4 parts of antioxidant, 2.1 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is zinc stearate; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 64 °C for 1.4 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.7:1, and the amino silane coupling agent is selected from γ-aminopropyltrimethoxysilane.

[0049] Example 6 A high-strength polymer composite material, comprising the following components in parts by mass: 78 parts of aliphatic nylon resin, 26 parts of glass fiber, 7 parts of red phosphorus, 4 parts of zinc borate, 8 parts of modified graphene, 4.5 parts of hydroxypropyl-β-cyclodextrin, 2 parts of antioxidant, 2 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is talc powder; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 62 °C for 1.6 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.6:1, and the amino silane coupling agent is selected from γ-aminopropyltriethoxysilane.

[0050] Example 7 A high-strength polymer composite material, comprising the following components in parts by mass: 78 parts of aliphatic nylon resin, 26 parts of glass fiber, 7 parts of red phosphorus, 4 parts of zinc borate, 5.5 parts of modified graphene, 2 parts of hydroxypropyl-β-cyclodextrin, 2 parts of antioxidant, 2 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is talc powder; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 62 °C for 1.6 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.6:1, and the amino silane coupling agent is selected from γ-aminopropyltriethoxysilane.

[0051] Example 8 A high-strength polymer composite material, comprising the following components in parts by mass: 78 parts of aliphatic nylon resin, 26 parts of glass fiber, 7 parts of red phosphorus, 4 parts of zinc borate, 5.5 parts of modified graphene, 6 parts of hydroxypropyl-β-cyclodextrin, 2 parts of antioxidant, 2 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is talc powder; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 62 °C for 1.6 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.6:1, and the amino silane coupling agent is selected from γ-aminopropyltriethoxysilane.

[0052] Example 9 A high-strength polymer composite material, comprising the following components in parts by mass: 77 parts of aliphatic nylon resin, 26 parts of glass fiber, 7.3 parts of red phosphorus, 4.2 parts of zinc borate, 5.2 parts of modified graphene, 3.3 parts of hydroxypropyl-β-cyclodextrin, 2.4 parts of antioxidant, 2.1 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is zinc stearate; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 62 °C for 1.4 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.7:1, and the amino silane coupling agent is selected from γ-aminopropyltrimethoxysilane.

[0053] Example 10 A high-strength polymer composite material, comprising the following components in parts by mass: 78 parts of aliphatic nylon resin, 26 parts of glass fiber, 7 parts of red phosphorus, 4 parts of zinc borate, 5.5 parts of modified graphene, 4.5 parts of hydroxypropyl-β-cyclodextrin, 2 parts of antioxidant, 2 parts of lubricant; the aliphatic nylon resin is nylon 66; the antioxidant is antioxidant 1010; the lubricant is talc powder; Among them, the preparation process of the modified graphene is as follows: Add an amino silane coupling agent and graphene into a mixed solvent with a volume ratio of ethanol to deionized water of 1:1, ultrasonically disperse, then stir and react at 62 °C for 1.6 hours, filter, wash, and dry to obtain it; among them, the mass ratio of the amino silane coupling agent to graphene is 0.6:1, and the amino silane coupling agent is selected from γ-aminopropyltriethoxysilane.

[0054] Comparative Example 1 The difference between this comparative example and Example 10 is only that 0 part of modified graphene and 10 parts of hydroxypropyl-β-cyclodextrin are used.

[0055] Comparative Example 2 The difference between this comparative example and Example 10 is only that 10 parts of modified graphene and 0 part of hydroxypropyl-β-cyclodextrin are used.

[0056] Comparative Example 3 The difference between this comparative example and Example 10 is only that graphene oxide is used to replace the modified graphene.

[0057] Comparative Example 4 The difference between this comparative example and Example 10 is only that β-cyclodextrin is used to replace hydroxypropyl-β-cyclodextrin.

[0058] The specific preparation methods of the above examples and comparative examples include the following steps: (1) Mix the aliphatic nylon resin, red phosphorus, zinc borate, modified graphene, and hydroxypropyl-β-cyclodextrin evenly to prepare a mixed material; (2) Add the mixed material from the main feeding port into a twin-screw extruder, and add the fiber-reinforced filler from the side feeding port into the twin-screw extruder, and melt and extrude to granulate, thus obtaining a high-strength polymer composite material. The screw speed of the twin-screw extruder is 500 r / min, and the extrusion temperature is 272 °C.

[0059] Prepare samples of the high-strength polymer composite materials provided by the examples and comparative examples according to the test standards, and conduct performance tests on them. The test methods are as follows: (1) Tensile strength: Test according to ISO 527; (2) Flexural strength: Test according to ISO 178; (3) Notched impact strength: Test according to ISO 179; (4) Flame retardancy: Test according to UL94; (5)Degree of surface precipitation: visually observed; 1 represents no obvious precipitation, 2 represents a small amount of precipitation, 3 represents obvious precipitation, and 4 represents severe precipitation.

[0060] The performance test results are shown in Table 1 and Table 2.

[0061] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Tensile strength MPa 151 162 153 156 165 157 151 162 Flexural strength MPa 192 203 198 205 204 193 189 204 <![CDATA[Notched impact strength kJ / m 2 > 8.4 8.1 8.8 9.1 7.9 8.3 8.2 7.7 Flame retardant V-1 V-0 V-0 V-0 V-0 V-0 V-0 V-0 Precipitation 1 1 1 1 1 1 2 1 Table 2 Example 9 Example 10 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Tensile strength MPa 158 165 127 149 133 152 Flexural strength MPa 197 208 168 195 164 188 <![CDATA[Notched impact strength kJ / m 2 > 8.7 9.6 5.4 7.8 5.8 6.2 Flame retardant V-0 V-0 V-1 V-1 V-1 V-0 Precipitation 1 1 4 3 4 3 It can be seen from Table 1 and Table 2 that the present invention adds a specific amount of modified graphene and hydroxypropyl-β-cyclodextrin. Since graphene has a nano-scale lamellar structure, it not only has higher mechanical properties, but also can form a hydrophobic barrier layer in the polymer matrix, effectively blocking the penetration of small molecules such as gases and liquids, and improving the stability of the red phosphorus flame retardant.

[0062] The comparison results between Example 10 and Comparative Examples 1 and 2 show that graphene containing amino groups can not only react with the active groups on polyamide or form hydrogen bonds, but also form chemical bonds with the hydroxyl groups on hydroxypropyl-β-cyclodextrin, improving the density of the nylon composite. The special cavity structure of hydroxypropyl-β-cyclodextrin can effectively lock the moisture inside the resin matrix, prevent its migration and adsorption by red phosphorus, resulting in the failure of red phosphorus. Hydrogen bond networks are also easily formed between nylon resin, amino-modified graphene, hydroxypropyl-β-cyclodextrin, and the hydroxyl groups on the surface of red phosphorus, improving the density of the composite material, preventing the intrusion of external moisture or gas, improving the stability of the red phosphorus flame retardant, and thus improving the mechanical strength of the composite material.

[0063] The comparison results between Example 10 and Comparative Example 3 show that due to the strong water solubility and hydrophilicity of graphene oxide, it cannot be used as a barrier protector for red phosphorus. However, by modifying graphene with amino active groups to prepare graphene containing active amino groups, chemical bonds can be formed with the hydroxyl groups on hydroxypropyl-β-cyclodextrin, improving the density of the nylon composite and improving the precipitation problem.

[0064] The comparison results between Example 10 and Comparative Example 4 show that due to the poor hydrophilicity of β-cyclodextrin, it does not have the ability to store water and cannot form a shielding effect on red phosphorus.

[0065] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Accordingly, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-strength polymer composite material, characterized in that: The invention comprises the following components in parts by mass: 70-83 parts of aliphatic nylon resin, 20-27 parts of fiber-reinforced filler, 5-9 parts of red phosphorus, 2.5-5 parts of zinc borate, 4-6 parts of modified graphene and 2.5-6 parts of hydroxypropyl-β-cyclodextrin; the modified graphene is graphene modified by an aminosilane coupling agent; the preparation method of the aminosilane coupling agent modified graphene is as follows: adding the aminosilane coupling agent and graphene to a solvent, ultrasonically dispersing the mixture, stirring and reacting the mixture at 55-70°C for 1-2 hours, filtering, washing and drying the mixture to obtain the aminosilane coupling agent modified graphene; the mass ratio of the aminosilane coupling agent to the graphene is (0.2-1):

1.

2. The high-strength polymer composite material according to claim 1, characterized in that: The aliphatic nylon resin is one or more of nylon 6, nylon 46, nylon 56, nylon 66, nylon 610, nylon 1010, nylon 11, and nylon 12; the fiber-reinforced filler is one or more of glass fiber, carbon fiber, sisal fiber, aramid fiber, and ultra-high molecular weight polyethylene fiber.

3. The high-strength polymer composite material according to claim 1, characterized in that: The aminosilane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and N-cyclohexyl-γ-aminopropylmethyldimethoxysilane.

4. The high-strength polymer composite material according to claim 1, characterized in that: The high-strength polymer composite material further comprises 1-10 parts by mass of an auxiliary agent; the auxiliary agent is one or more of a flow modifier, a colorant, an antioxidant, a light stabilizer, a lubricant, a release agent, an antistatic agent, and a processing aid.

5. The high-strength polymer composite material according to claim 4, characterized in that: The flow modifier is one or more of polyethylene glycol ester, polyol ester, montanate, and polyethylene wax; the colorant is one or more of inorganic pigments, organic pigments, and dyes; the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 1098, or antioxidant DLTP; the lubricant is one or more of talc, stearate, ethylene acrylic acid copolymer, or montan ester lubricants; the light stabilizer is one or more of hindered amine light stabilizers, benzophenone light stabilizers, and benzotriazole light stabilizers; the release agent is one or more of paraffin, glycerin, vaseline, silicone oil, and low molecular weight polyethylene; the antistatic agent includes one or more of quaternary ammonium salts, sulfonates, and phosphates.

6. The high-strength polymer composite material according to claim 1, characterized in that: Tensile strength is 151~165MPa, flexural strength is 189~208MPa, notched impact strength is 7.7~9.6kJ / m 2 .

7. The method for preparing a high-strength polymer composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Evenly mixing aliphatic nylon resin, red phosphorus, zinc borate, modified graphene, and hydroxypropyl-β-cyclodextrin to prepare a mixed material; (2) The mixed material obtained in step (1) is fed into a twin-screw extruder from a main feed port, and a fiber-reinforced filler is fed into the twin-screw extruder from a side feed port, and the mixture is melt-extruded and granulated to obtain a high-strength polymer composite material.

8. The method for preparing a high-strength polymer composite material according to claim 7, characterized in that: In the step (2), the screw speed of the twin-screw extruder is 400-500 r / min, and the extrusion temperature is 260-300°C.