A modified glass fiber reinforced nylon resin composition and a method for preparing the same

Abstract

The application relates to the field of high polymer materials and discloses a modified glass fiber reinforced nylon resin composition and a preparation method thereof, which comprises the following components: a nylon resin, modified glass fibers and modified multi-walled carbon nanotubes; the modified glass fibers are prepared by grafting a modified silane coupling agent on the surface of the glass fibers; the modified silane coupling agent is prepared by grafting a modifier prepared by reacting a modified intermediate and a DOPO derivative with 3-chloropropyl triethoxysilane; the modified intermediate is prepared by reacting 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and diphenyldichlorosilane; the DOPO derivative is prepared by reacting p-aminobenzoic acid, hydroxybenzaldehyde and DOPO; and the modified multi-walled carbon nanotube is prepared by grafting an antioxidant component prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propyl acetate and ethylenediamine on the surface of acylchlorinated multi-walled carbon nanotubes; the prepared composition has excellent mechanical properties, flame-retardant properties, heat-oxygen aging resistance and ultraviolet resistance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a modified glass fiber reinforced nylon resin composition and its preparation method. Background Technology

[0002] Nylon resin refers to a general term for thermoplastic resins whose polymer backbone contains repeating amide groups. Common nylon resins include PA6, PA66, PA11, PA12, and PA6T, with PA6 and PA66 having the largest production volumes. As an ideal high-temperature resistant material, nylon resin has broad application prospects in electronics, electrical appliances, mechanical parts, home appliances, office equipment, and automobiles. However, conventional nylon resins have certain limitations, such as poor heat and oxygen aging resistance, poor dimensional stability, and low mechanical strength. These defects limit the application of nylon resins in more advanced fields.

[0003] To improve the strength of nylon resin, the commonly used reinforcement method is to add glass fiber. Glass fiber reinforced nylon resin has excellent mechanical properties, heat resistance, and chemical resistance, and is widely used in component housings, such as microphone housings for conference machines. However, nylon resin has a high viscosity after melting, making it difficult to fully impregnate glass fiber. Furthermore, the interfacial adhesion between glass fiber and nylon resin in composite materials is poor, limiting the performance and application of the composite material. In addition, with the development of technology, the high performance of glass fiber reinforced nylon resin is gradually becoming a priority. Glass fiber reinforced nylon resin should have good UV resistance and oxidation resistance to cope with environmental aging during long-term use of component housings. Moreover, to improve the durability and safety of products, fiber reinforced nylon resin needs to have even better mechanical properties and flame retardant properties for use in the manufacture of electronic and electrical appliances with higher flame retardant requirements. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a modified glass fiber reinforced nylon resin composition and its preparation method. By adding modified glass fiber and modified multi-walled carbon nanotubes, the composition is endowed with excellent mechanical properties, flame retardant properties, heat and oxygen aging resistance, and UV resistance.

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

[0006] A modified glass fiber reinforced nylon resin composition comprises the following components in parts by weight: 50-70 parts nylon resin, 10-15 parts modified glass fiber, 3-8 parts modified multi-walled carbon nanotubes, 0.5-1.5 parts lubricant, and 1-2 parts plasticizer.

[0007] The modified glass fiber is prepared by grafting a modified silane coupling agent onto the surface of the glass fiber; the modified silane coupling agent is prepared by reacting a modifier prepared by esterification of a modifier intermediate and a DOPO derivative with 3-chloropropyltriethoxysilane; the modifier intermediate is prepared by reacting two 2-(2,4-dihydroxyphenyl)-2H-benzotriazole molecules with diphenyldichlorosilane; the DOPO derivative is prepared by reacting p-aminobenzoic acid and hydroxybenzaldehyde with a Schiff base and then further reacting with DOPO.

[0008] The modified multi-walled carbon nanotubes are prepared by grafting antioxidant components onto the surface of acyl chloride multi-walled carbon nanotubes using a chemical reaction; the antioxidant components are prepared by grafting methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and ethylenediamine.

[0009] Preferably, the nylon resin is one of PA6 or PA66; the lubricant is one of polyethylene wax or oxidized polyethylene wax; and the plasticizer is one or more combinations of dimethyl phthalate, dioctyl phthalate, and diisodecyl phthalate.

[0010] Preferably, the method for preparing the modified glass fiber includes the following steps:

[0011] A. Take 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and triethylamine in a reactor, add diphenyl dichlorosilane and tetrahydrofuran, and stir the reaction at 70-85℃ for 4-6 hours. After the reaction is completed, filter, wash and dry to prepare the modifier intermediate.

[0012] B. Take p-aminobenzoic acid and p-hydroxybenzaldehyde in a reactor, add anhydrous ethanol, and stir the reaction at 55-70°C for 2-4 hours. Then, dissolve DOPO in anhydrous ethanol and add it to the reactor. Heat the reactor to 75-90°C and continue the reaction for 4-6 hours. After the reaction is completed, filter, wash and dry to prepare DOPO derivative.

[0013] C. Take DOPO derivative, 1-hydroxybenzotriazole and dimethyl sulfoxide in a reactor, add a mixed solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and dimethyl sulfoxide, then dissolve the modifier intermediate in dimethyl sulfoxide and add it to the reactor, stir and react at 80-95℃ for 8-12 hours. After the reaction is completed, filter, wash and dry to prepare the modifier.

[0014] D. Take the modifier and triethylamine into a reactor, add 3-chloropropyltriethoxysilane and tetrahydrofuran, and stir the reaction at 75-90℃ for 4-7h in a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to prepare the modified silane coupling agent.

[0015] E. Take glass fiber and sonicate it in acetone for 0.5-1h, then soak it for 2-3h to remove the slurry on the surface of the glass fiber, and wash it with deionized water to obtain pretreated glass fiber. Then, sonicate the pretreated glass fiber in a mixed solution of anhydrous ethanol and deionized water, add modified silane coupling agent, and stir the reaction at 60-85℃ for 3-5h. After the reaction is completed, filter, wash and dry to prepare modified glass fiber.

[0016] Preferably, in step A, the molar ratio of 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and diphenyldichlorosilane is 2 to 2.2:1.

[0017] Preferably, the molar ratio of p-aminobenzoic acid, p-hydroxybenzaldehyde, and DOPO in step B is 1:1:1 to 1.5.

[0018] Preferably, the molar ratio of DOPO derivative to modifier intermediate in step C is 2 to 2.2:1.

[0019] Preferably, the molar ratio of the modifier and 3-chloropropyltriethoxysilane in step D is 1:2 to 2.3.

[0020] Preferably, the method for preparing the modified multi-walled carbon nanotubes includes the following steps:

[0021] (1) Multi-walled carbon nanotubes were ultrasonically dispersed in a mixture of concentrated sulfuric acid and concentrated nitric acid, and then stirred at 50-60°C for 10-12 hours. After the reaction was completed, the mixture was filtered, washed and dried to prepare carboxylated multi-walled carbon nanotubes.

[0022] (2) 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was dispersed in methanol, and then ethylenediamine was added. The mixture was stirred at 40-60°C for 20-24 h. After the reaction was completed, the solvent was removed by rotary evaporation to prepare the antioxidant component.

[0023] (3) Carboxylated multi-walled carbon nanotubes were ultrasonically dispersed in N,N-dimethylacetamide, thionyl chloride was added and refluxed at 75-80℃ for 20-24h, then antioxidant components were added and refluxed at 110-125℃ for 42-48h. After the reaction was completed, the modified multi-walled carbon nanotubes were prepared by filtration, washing and drying.

[0024] Preferably, in step (2), the molar ratio of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to ethylenediamine is 1:1 to 2.5.

[0025] A method for preparing a modified glass fiber reinforced nylon resin composition includes the following steps: weighing each component according to the weight parts, mixing nylon resin, modified glass fiber, modified multi-walled carbon nanotubes, lubricant and plasticizer evenly to form a premix, and then melting and granulating the premix before injection molding to prepare the modified glass fiber reinforced nylon resin composition.

[0026] The beneficial effects of this invention are:

[0027] This invention utilizes a substitution reaction between two 2-(2,4-dihydroxyphenyl)-2H-benzotriazole molecules and the chlorine atoms at both ends of diphenyldichlorosilane to prepare a modifier intermediate. Simultaneously, this invention utilizes a Schiff base reaction between p-aminobenzoic acid and hydroxybenzaldehyde to generate a -N=CH bond, which then undergoes an addition reaction with the -PH bond in the DOPO structure to prepare a DOPO derivative with a hydroxyl group at one end and a carboxyl group at the other. Then, the carboxyl group in the DOPO derivative structure is esterified with the ungrafted hydroxyl group in the modifier intermediate structure to prepare a modified flame-retardant containing Si, P, and N elements. A modifier is first used, and then a modified silane coupling agent is prepared by reacting the modifier with 3-chloropropyltriethoxysilane through a substitution reaction. Finally, modified glass fibers are prepared by the condensation reaction between the silanol groups in the modified silane coupling agent and the hydroxyl groups on the surface of the glass fiber. This process firmly bonds the Si, P, and N-containing synergistic flame-retardant modifier to the glass fiber surface through chemical bonds. Simultaneously, benzotriazole groups with UV absorption are introduced onto the glass fiber surface through strong chemical bonds, preventing the long-term migration and leaching of flame-retardant and UV-resistant components, thus endowing the material with long-lasting flame-retardant and UV-resistant properties. Furthermore, the oleophilicity of the glass fiber surface is enhanced after modification with the silane coupling agent, promoting relatively uniform dispersion of the glass fiber in the resin matrix and strengthening the interfacial bonding between the glass fiber and the resin matrix, thereby effectively utilizing the comprehensive performance of the glass fiber.

[0028] This invention utilizes a grafting reaction between the ester group in the structure of the antioxidant methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and the amino group at one end of the ethylenediamine structure to prepare an aminated antioxidant component. Simultaneously, this invention utilizes thionyl chloride multi-walled carbon nanotubes (MWCNTs), and then grafts the acyl chloride groups in the MWCNTs structure with the amino groups in the antioxidant component to prepare modified MWCNTs. This allows the antioxidant component to be grafted onto the surface of the MWCNTs through strong chemical bonds. Furthermore, because the MWCNTs have a tubular structure, the antioxidant component can be slowly released, achieving a long-term antioxidant effect. At the same time, the grafting reaction facilitates the dispersion of MWCNTs in the resin matrix, to a certain extent avoiding performance defects caused by MWCNT aggregation. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1: A method for preparing modified glass fiber includes the following steps:

[0031] A. Take 4.5g of 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and 3mL of triethylamine into a reactor, add 2.5g of diphenyl dichlorosilane and 40mL of tetrahydrofuran, stir and react at 80℃ for 5h, and after the reaction is completed, filter, wash and dry to prepare the modifier intermediate;

[0032] B. Take 6.9g of p-aminobenzoic acid and 6.1g of p-hydroxybenzaldehyde into a reactor, add 50mL of anhydrous ethanol, and stir at 60℃ for 3h. Then take 10.9g of DOPO dissolved in 50mL of anhydrous ethanol and add it into the reactor. Heat to 85℃ and continue to react for 6h. After the reaction is completed, filter, wash and dry to prepare DOPO derivative.

[0033] C. Take 6.4g of DOPO derivative (Mr=457.4), 1.1g of 1-hydroxybenzotriazole and 50mL of dimethyl sulfoxide in a reactor, add a mixed solution of 2.7g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 20mL of dimethyl sulfoxide, then dissolve 4.4g of the modifier intermediate (Mr=634.6) in 20mL of dimethyl sulfoxide and add it to the reactor. Stir the reaction at 85℃ for 12h. After the reaction is completed, filter, wash and dry to prepare the modifier.

[0034] D. Take 9.1g of modifier (Mr=1513.4) and 2mL of triethylamine into a reactor, add 2.9g of 3-chloropropyltriethoxysilane and 50mL of tetrahydrofuran, and stir the reaction at 85℃ for 6h under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to prepare the modified silane coupling agent.

[0035] E. Take glass fiber and sonicate it in acetone for 1 hour, then soak it for 2 hours to remove the slurry on the surface of the glass fiber. Wash it with deionized water to obtain pretreated glass fiber. Then, sonicate 5g of pretreated glass fiber in a mixed solution of 135mL anhydrous ethanol and 15mL deionized water, add 2.7g of modified silane coupling agent, and stir the mixture at 80℃ for 4 hours. After the reaction is completed, filter, wash and dry to prepare modified glass fiber.

[0036] Example 2: A method for preparing modified multi-walled carbon nanotubes includes the following steps:

[0037] (1) Take 5g of multi-walled carbon nanotubes and ultrasonically disperse them in a mixture of 90mL concentrated sulfuric acid and 30mL concentrated nitric acid. Then, stir and react at 60℃ for 12h. After the reaction is completed, filter, wash and dry to prepare carboxylated multi-walled carbon nanotubes.

[0038] (2) Take 5g of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and disperse it in 50mL of methanol, then add 2.5mL of ethylenediamine, stir and react at 55℃ for 24h, and remove the solvent by rotary evaporation after the reaction is completed to prepare the antioxidant component;

[0039] (3) Take 5g of carboxylated multi-walled carbon nanotubes and ultrasonically disperse them in 120mL of N,N-dimethylacetamide. Add 50mL of thionyl chloride and reflux at 80℃ for 24h. Then add 3.7g of antioxidant component and reflux at 120℃ for 42h. After the reaction is completed, filter, wash and dry to prepare modified multi-walled carbon nanotubes.

[0040] Example 3: A modified glass fiber reinforced nylon resin composition, comprising the following components in parts by weight:

[0041] 52 parts of PA66 nylon resin, 11 parts of modified glass fiber prepared in Example 1, 3 parts of modified multi-walled carbon nanotubes prepared in Example 2, 0.6 parts of lubricant polyethylene wax, and 1 part of plasticizer dimethyl phthalate.

[0042] The preparation method of the above-mentioned modified glass fiber reinforced nylon resin composition includes the following steps:

[0043] Weigh each component according to the weight parts, mix the nylon resin, modified glass fiber, modified multi-walled carbon nanotubes, lubricant and plasticizer evenly to form a premix, then melt and granulate the premix and injection mold it to prepare a modified glass fiber reinforced nylon resin composition.

[0044] Example 4: A modified glass fiber reinforced nylon resin composition, comprising the following components in parts by weight:

[0045] 60 parts of PA66 nylon resin, 12 parts of modified glass fiber prepared in Example 1, 5 parts of modified multi-walled carbon nanotubes prepared in Example 2, 0.8 parts of oxidized polyethylene wax as lubricant, and 1.5 parts of dioctyl phthalate as plasticizer;

[0046] The preparation method of the above modified glass fiber reinforced nylon resin composition is the same as in Example 3.

[0047] Example 5: A modified glass fiber reinforced nylon resin composition, comprising the following components in parts by weight:

[0048] 68 parts of PA66 nylon resin, 14 parts of modified glass fiber prepared in Example 1, 7 parts of modified multi-walled carbon nanotubes prepared in Example 2, 1.2 parts of lubricant oxidized polyethylene wax, and 2 parts of plasticizer diisodecyl phthalate.

[0049] The preparation method of the above modified glass fiber reinforced nylon resin composition is the same as in Example 3.

[0050] Comparative Example 1: A method for preparing modified glass fiber includes the following steps:

[0051] A. Take 4.5g of 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and 3mL of triethylamine into a reactor, add 2.5g of diphenyl dichlorosilane and 40mL of tetrahydrofuran, stir and react at 80℃ for 5h, and after the reaction is completed, filter, wash and dry to prepare the modifier intermediate;

[0052] B. Take 3.8g of the modifier intermediate (Mr=634.6) and 2mL of triethylamine into a reactor, add 2.9g of 3-chloropropyltriethoxysilane and 50mL of tetrahydrofuran, and stir the reaction at 85℃ for 6h under a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to prepare the modified silane coupling agent.

[0053] C. Take glass fiber and sonicate it in acetone for 1 hour, then soak it for 2 hours to remove the slurry on the surface of the glass fiber. Wash it with deionized water to obtain pretreated glass fiber. Then, sonicate 5g of pretreated glass fiber in a mixed solution of 135mL anhydrous ethanol and 15mL deionized water, add 2.7g of modified silane coupling agent, and stir the mixture at 80℃ for 4 hours. After the reaction is completed, filter, wash and dry to prepare modified glass fiber.

[0054] Comparative Example 2: A modified glass fiber reinforced nylon resin composition, comprising the following components in parts by weight:

[0055] 68 parts of PA66 nylon resin, 14 parts of modified glass fiber prepared in Comparative Example 1, 7 parts of modified multi-walled carbon nanotubes prepared in Example 2, 1.2 parts of lubricant oxidized polyethylene wax, and 2 parts of plasticizer diisodecyl phthalate.

[0056] The preparation method of the above modified glass fiber reinforced nylon resin composition is the same as in Example 3.

[0057] Comparative Example 3: A modified glass fiber reinforced nylon resin composition comprising the following components in parts by weight:

[0058] 68 parts PA66 nylon resin, 14 parts glass fiber, 7 parts modified multi-walled carbon nanotubes prepared in Example 2, 1.2 parts lubricant oxidized polyethylene wax, and 2 parts plasticizer diisodecyl phthalate.

[0059] The preparation method of the above modified glass fiber reinforced nylon resin composition is the same as in Example 3.

[0060] Comparative Example 4: A modified glass fiber reinforced nylon resin composition, comprising the following components in parts by weight:

[0061] 68 parts of PA66 nylon resin, 14 parts of modified glass fiber prepared in Example 1, 7 parts of multi-walled carbon nanotubes, 1.2 parts of lubricant oxidized polyethylene wax, and 2 parts of plasticizer diisodecyl phthalate.

[0062] The preparation method of the above modified glass fiber reinforced nylon resin composition is the same as in Example 3.

[0063] Performance testing

[0064] The modified glass fiber reinforced nylon resin compositions prepared in Examples 3-5 and Comparative Examples 2-4 were subjected to performance testing:

[0065] (1) Flame retardant performance test: The limiting oxygen index test was adopted according to GB / T 2406.2-2009. The sample size was 100mm×6.5mm×3mm. The data results are shown in Table 1.

[0066] Table 1. Test results of flame retardant performance of the samples

[0067]

[0068] As can be seen from the data in Table 1, the compositions prepared in Examples 3-5 and Comparative Example 4 of this invention have high limiting oxygen indices and good flame retardant properties. In Comparative Example 2, the modified glass fiber was not grafted with DOPO derivatives, and in Comparative Example 3, the glass fiber was not modified. The measured flame retardant properties of Comparative Examples 2-3 were lower than those of Examples 3-5. However, the modified glass fiber structure added to the composition prepared in Comparative Example 2 contains the flame-retardant element silicon, therefore exhibiting stronger flame retardant properties than the composition prepared in Comparative Example 3.

[0069] (2) Mechanical property testing: The tensile properties of the samples were tested according to GB / T 1447-2005, with a tensile rate of 2 mm / min; the tensile strength change rate was tested after aging at 100℃ for 24 h and 48 h to evaluate the heat and oxygen aging resistance of the samples; the samples were placed in an aging chamber and aged under a 1000W mercury lamp for 10 h and 24 h, and the tensile strength change rate was tested to evaluate the UV aging resistance of the samples; the impact resistance of the samples was tested according to GB / T 1451-2005, with a notch size of R(0.3±0.05) mm. The data results are shown in Table 2.

[0070] Table 2 Results of mechanical property testing of the samples

[0071]

[0072] As can be seen from the data in Table 2, the compositions prepared in Examples 3-5 and Comparative Example 2 of this invention have high tensile strength and notched impact strength. They still have high tensile strength after aging at 100°C for 24h and 48h, and after UV aging for 10h and 24h, and have excellent resistance to heat-oxidative aging and UV aging. In Comparative Example 3, no glass fiber modification treatment was performed. The measured tensile strength and notched impact strength were lower than those of Examples 3-5. This was because the dispersibility and interfacial bonding ability of the glass fiber in the resin matrix were not improved. Furthermore, the change rate of tensile strength after UV aging for 10 h and 24 h was significantly different from that of Examples 3-5. This was because benzotriazole groups were not introduced into the glass fiber structure. In Comparative Example 4, no multi-walled carbon nanotubes were modified. The measured tensile strength and notched impact strength were slightly lower than those of Examples 3-5. This was possibly due to the agglomeration of multi-walled carbon nanotubes, which reduced mechanical properties. Furthermore, the change rate of tensile strength after aging at 100°C for 24 h and 48 h was significantly different from that of Examples 3-5. This was because antioxidant components were not grafted into the multi-walled carbon nanotube structure.

[0073] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0074] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A modified glass fiber reinforced nylon resin composition, characterized in that, It comprises the following components by weight: 50-70 parts nylon resin, 10-15 parts modified glass fiber, 3-8 parts modified multi-walled carbon nanotubes, 0.5-1.5 parts lubricant, and 1-2 parts plasticizer; The modified glass fiber is prepared by grafting a modified silane coupling agent onto the surface of the glass fiber; the modified silane coupling agent is prepared by reacting a modifier prepared by esterification of a modifier intermediate and a DOPO derivative with 3-chloropropyltriethoxysilane; the modifier intermediate is prepared by reacting two 2-(2,4-dihydroxyphenyl)-2H-benzotriazole molecules with diphenyldichlorosilane; the DOPO derivative is prepared by reacting p-aminobenzoic acid and hydroxybenzaldehyde with a Schiff base and then further reacting with DOPO. The modified multi-walled carbon nanotubes are prepared by grafting antioxidant components onto the surface of acyl chloride multi-walled carbon nanotubes using a chemical reaction; the antioxidant components are prepared by grafting methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and ethylenediamine.

2. The modified glass fiber reinforced nylon resin composition according to claim 1, characterized in that, The nylon resin is one of PA6 or PA66; the lubricant is one of polyethylene wax or oxidized polyethylene wax; the plasticizer is one or more of dimethyl phthalate, dioctyl phthalate, and diisodecyl phthalate.

3. The modified glass fiber reinforced nylon resin composition according to claim 1, characterized in that, The method for preparing the modified glass fiber includes the following steps: A. Take 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and triethylamine in a reactor, add diphenyl dichlorosilane and tetrahydrofuran, and stir the reaction at 70~85℃ for 4~6h. After the reaction is completed, filter, wash and dry to prepare the modifier intermediate. B. Take p-aminobenzoic acid and p-hydroxybenzaldehyde in a reactor, add anhydrous ethanol, and stir the reaction at 55~70℃ for 2~4h. Then, dissolve DOPO in anhydrous ethanol and add it to the reactor. Heat the reactor to 75~90℃ and continue the reaction for 4~6h. After the reaction is completed, filter, wash and dry to prepare DOPO derivative. C. Take DOPO derivative, 1-hydroxybenzotriazole and dimethyl sulfoxide in a reactor, add a mixed solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and dimethyl sulfoxide, then dissolve the modifier intermediate in dimethyl sulfoxide and add it to the reactor, stir and react at 80~95℃ for 8~12h, after the reaction is completed, filter, wash and dry to prepare the modifier; D. Take the modifier and triethylamine into a reactor, add 3-chloropropyltriethoxysilane and tetrahydrofuran, and stir the reaction at 75~90℃ for 4~7h in a nitrogen atmosphere. After the reaction is completed, filter, wash and dry to prepare the modified silane coupling agent. E. Take glass fiber and sonicate it in acetone for 0.5-1h, then soak it for 2-3h to remove the slurry on the surface of the glass fiber, and wash it with deionized water to obtain pretreated glass fiber. Then, sonicate the pretreated glass fiber in a mixed solution of anhydrous ethanol and deionized water, add modified silane coupling agent, and stir the reaction at 60-85℃ for 3-5h. After the reaction is completed, filter, wash and dry to prepare modified glass fiber.

4. The modified glass fiber reinforced nylon resin composition according to claim 3, characterized in that, In step A, the molar ratio of 2-(2,4-dihydroxyphenyl)-2H-benzotriazole and diphenyldichlorosilane is 2~2.2:

1.

5. The modified glass fiber reinforced nylon resin composition according to claim 3, characterized in that, In step B, the molar ratio of p-aminobenzoic acid, p-hydroxybenzaldehyde, and DOPO is 1:1:1~1.

5.

6. The modified glass fiber reinforced nylon resin composition according to claim 3, characterized in that, In step C, the molar ratio of DOPO derivative to modifier intermediate is 2~2.2:

1.

7. The modified glass fiber reinforced nylon resin composition according to claim 3, characterized in that, In step D, the molar ratio of the modifier to 3-chloropropyltriethoxysilane is 1:2~2.

3.

8. The modified glass fiber reinforced nylon resin composition according to claim 1, characterized in that, The method for preparing the modified multi-walled carbon nanotubes includes the following steps: (1) Multi-walled carbon nanotubes were ultrasonically dispersed in a mixture of concentrated sulfuric acid and concentrated nitric acid, and then stirred at 50-60°C for 10-12 hours. After the reaction was completed, the mixture was filtered, washed and dried to prepare carboxylated multi-walled carbon nanotubes. (2) 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was dispersed in methanol, and then ethylenediamine was added. The mixture was stirred at 40-60°C for 20-24 h. After the reaction was completed, the solvent was removed by rotary evaporation to prepare the antioxidant component. (3) Carboxylated multi-walled carbon nanotubes were ultrasonically dispersed in N,N-dimethylacetamide, thionyl chloride was added and refluxed at 75~80℃ for 20~24h, then antioxidant components were added and refluxed at 110~125℃ for 42~48h. After the reaction was completed, the modified multi-walled carbon nanotubes were prepared by filtration, washing and drying.

9. The modified glass fiber reinforced nylon resin composition according to claim 8, characterized in that, In step (2), the molar ratio of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate to ethylenediamine is 1:1~2.

5.

10. A method for preparing a modified glass fiber reinforced nylon resin composition according to any one of claims 1 to 9, characterized in that, Includes the following steps: Weigh each component according to the weight parts, mix the nylon resin, modified glass fiber, modified multi-walled carbon nanotubes, lubricant and plasticizer evenly to form a premix, then melt and granulate the premix and injection mold it to prepare a modified glass fiber reinforced nylon resin composition.

Images