A nanofiber-containing polymer composite and a method for preparing the same

Abstract

The application discloses a kind of polymer composite materials containing nanofiber and preparation method thereof, by weight parts, including the following raw materials: polypropylene 90-100 parts, nylon 6 10-15 parts, modified flame retardant 13-16 parts, modified carbon nanotube 4-7 parts, compatible agent 3-5 parts, antioxidant 0.5-0.8 parts, lubricant 0.3-0.5 parts.The composite material is blended with polypropylene and nylon 6, and the modified flame retardant and modified carbon nanotube prepared by the method are added, and the auxiliary agent such as compatible agent is synergized, which effectively overcomes the defects of existing polypropylene material, such as easy degradation, flammable, traditional flame retardant and antioxidant easy migration failure, realizes efficient flame retardation and excellent weather resistance and aging resistance performance (especially ultraviolet aging resistance performance), while maintaining and improving the mechanical properties of the material, solves the problem that the prior art is difficult to consider multiple performances, and widens the application range of polypropylene composite material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a high polymer composite material containing nanofibers and a preparation method thereof. BACKGROUND

[0002] With the development of science and technology and the improvement of people's living standards, people's demand for various materials gradually increases, and various plastic products gradually enter people's field of vision. Plastic is a high molecular compound polymerized by monomers as raw materials through polycondensation or condensation polymerization. It is mainly composed of synthetic resins and various additives. Among numerous high molecular materials, polypropylene has become one of the preferred materials in plastic production due to its good chemical stability, low density, good electrical insulation, odorless and non-toxic characteristics, and is widely used in household appliances, packaging, medical treatment, automobiles and other fields.

[0003] However, the tertiary carbon-hydrogen bond exists in its molecular structure, which makes it prone to free radical reaction under the action of ultraviolet light, oxygen and heat, resulting in molecular chain rupture and oxidative degradation. This degradation directly manifests as a decrease in tensile strength and elongation at break of the material. Moreover, polypropylene is a flammable material that can quickly ignite when exposed to open flames or high temperatures, which can easily cause fires and pose a significant safety hazard. In addition, polypropylene produces a large amount of heat, smoke and toxic gases during combustion, which not only threatens human life and property safety, but also has a serious impact on the environment. Therefore, polypropylene plastic still has certain deficiencies in practical application.

[0004] In order to improve the flame retardant performance, DOPO-based flame retardant is currently used as a flame retardant. However, this substance has a low flame retardant efficiency due to its molecular structure. At the same time, the compatibility of DOPO-based flame retardant with non-polar polymers such as polyolefins is poor, which can easily cause agglomeration and migration to the surface of the material, further reducing the flame retardant performance, and also affecting the interfacial performance between the polymer matrix and accelerating the aging of the material, resulting in performance degradation and shortened service life. The antioxidant technology for polypropylene aging also has deficiencies. These antioxidants are prone to volatilization loss during high-temperature processing, and the long-term anti-aging effect is not ideal. Due to poor compatibility with polymers, they are prone to migration and precipitation, affecting the appearance and long-term stability of the material.

[0005] Chinese patent application CN110903548A discloses a kind of polypropylene glass fiber composite material, the polypropylene glass fiber composite material is by polypropylene master batch, glass fiber, polypropylene fiber, coupling agent and maleic anhydride graft polypropylene composite, its mass percentage is as follows: polypropylene master batch 40%-42%, glass fiber 36%-38%, polypropylene fiber 10%-12%, coupling agent 2%-4% and maleic anhydride graft polypropylene 6%-10%, wherein, the polypropylene master batch includes T30S and EPS30R, the mass ratio of T30S and EPS30R in the polypropylene master batch is 1:1, the polypropylene glass fiber composite material is formed by double screw extrusion.The invention can improve the mechanical properties and heat resistance of polypropylene glass fiber composite material, so that its modulus is not less than wood formwork, its product is not easy to deform and bend, and the production cost can be reduced, but the patent cannot significantly improve the flame retardant performance and ultraviolet aging resistance of polypropylene material.Chinese patent application CN118421011A discloses a kind of fiber reinforced flame-retardant polypropylene composite material and its preparation method and application.The fiber reinforced flame-retardant polypropylene composite material includes the following components by weight fraction: polypropylene 4-30 parts, flame retardant 10-30 parts, flame retardant synergist 3-10 parts, modifier 5-20 parts, compatibilizer 3-8 parts, glass fiber 35-50 parts.The invention can improve the wetting effect of glass fiber, avoid obvious appearance defects of the material, avoid the decline of the flame retardant efficiency of the material, and effectively improve the interlaminar shear strength of the material after laying, so that the composite material has the advantages of light weight, high strength, good appearance, high flame retardant efficiency and good mechanical properties, but the patent does not improve the ultraviolet aging resistance of polypropylene.

[0006] Therefore, how to realize efficient flame retardation and excellent aging resistance while maintaining or improving the original excellent mechanical properties of high polymer composite material as much as possible, and avoiding the negative effects caused by the addition of additives, is a key problem to be solved in the field of high polymer material modification. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a kind of high polymer composite material containing nanofiber and its preparation method.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0009] A kind of high polymer composite material containing nanofiber, by weight parts, includes the following raw materials:

[0010] Polypropylene 90-100 parts, nylon 6 10-15 parts, modified flame retardant 13-16 parts, modified carbon nanotube 4-7 parts, compatibilizer 3-5 parts, antioxidant 0.5-0.8 parts, lubricant 0.3-0.5 parts.

[0011] Preferably, a kind of nanofiber-containing polymer composite material includes the following raw materials by weight parts: polypropylene 95-100 parts, nylon 6 10-13 parts, modified flame retardant 13-18 parts, modified carbon nanotube 4-6 parts, compatibilizer 3-4 parts, antioxidant 0.5-0.7 parts, lubricant 0.4-0.5 parts.

[0012] In the present application, polypropylene and nylon are used as base materials, and modified flame retardant and modified carbon nanotube prepared by a specific method are added, and compatibilizer, antioxidant and lubricant are also added, so that the composite material can maintain good processing performance while comprehensively improving flame retardant performance, mechanical properties and weather resistance and aging resistance.

[0013] Preferably, the preparation method of the modified flame retardant is as follows:

[0014] S1, ammonium polyphosphate is added to anhydrous ethanol, then sodium dodecyl sulfate is added, and after stirring uniformly, ammonium polyphosphate suspension is obtained; then, under stirring, titania sol is added dropwise to the ammonium polyphosphate suspension, and after the dropwise addition is completed, stirring reaction is carried out, and after the reaction is completed, aging is carried out, followed by filtration, washing and drying to obtain composite ammonium polyphosphate;

[0015] S2, the composite ammonium polyphosphate in step S1 is added to an ethanol aqueous solution, then γ-glycidoxypropyltrimethoxysilane is added, and constant temperature reaction is carried out, and after the reaction is completed, filtration, washing and drying are carried out to obtain silane-modified ammonium polyphosphate;

[0016] S3, the silane-modified ammonium polyphosphate in step S2 is added to butanone, then 2,2,6,6-tetramethyl-4-piperidinol and triethylamine are added, and ring-opening reaction is carried out, and after the reaction is completed, filtration, washing and drying are carried out to obtain a modified flame retardant.

[0017] Preferably, in step S1, the mass ratio of ammonium polyphosphate, sodium dodecyl sulfate and anhydrous ethanol is 80-90:2-3:1000, the mass ratio of the ammonium polyphosphate suspension and titania sol is 1000:200-300, the temperature of the stirring reaction is 30-40℃, the time is 2-4h, the temperature of the aging is 20-25℃, and the time is 12-16h; the preparation method of the titania sol is as follows: 15-20g tetrabutyl titanate is added to 200-300g anhydrous ethanol, then 1.5-2g deionized water is added dropwise, and stirring is carried out at 500-800r / min for 1-2h.

[0018] In the present application, sodium dodecyl sulfate is used as a dispersing agent to uniformly coat the titanium dioxide sol on the surface of ammonium polyphosphate in anhydrous ethanol medium to form a core-shell composite ammonium polyphosphate, which not only protects ammonium polyphosphate by using the ultraviolet shielding and potential flame-retardant synergistic effect of TiO2, but also provides abundant hydroxyl active sites on the surface thereof.

[0019] Preferably, in step S2, the mass ratio of the composite ammonium polyphosphate and the γ-glycidoxypropyltrimethoxysilane is 90-100:8-11, and the temperature of the constant-temperature reaction is 60-70℃, and the time is 2-3h.

[0020] In the present application, the epoxy groups are successfully introduced by the reaction of γ-glycidoxypropyltrimethoxysilane and the TiO2 layer on the surface of the composite ammonium polyphosphate, which provides active sites for the subsequent reaction.

[0021] Preferably, in step S3, the mass ratio of the silane-modified ammonium polyphosphate, 2,2,6,6-tetramethyl-4-piperidinol and triethylamine is 90-100:5.5-7.5:2-3, and the temperature of the ring-opening reaction is 60-70℃, and the time is 3-4h.

[0022] In the present application, the ring-opening reaction of the epoxy groups and the alcohol hydroxyl groups of 2,2,6,6-tetramethyl-4-piperidinol introduces 2,2,6,6-tetramethyl-4-piperidinol to the surface of the flame retardant particles in a covalent bond manner, effectively avoiding its migration and volatile loss in the polymer matrix, and ensuring the long-term effectiveness of the anti-aging effect. The application of the modified flame retardant in the composite material not only efficiently plays the intumescent flame-retardant effect of ammonium polyphosphate, but also enhances the flame-retardant effect by promoting charring, heat and oxygen insulation, etc. due to the introduction of TiO2, and significantly improves the weather resistance and service life of the composite material due to the effective capture of the free radicals generated by the degradation of the polymer under the action of light and heat by the grafted 2,2,6,6-tetramethyl-4-piperidinol.

[0023] Preferably, the preparation method of the modified carbon nanotube is as follows:

[0024] The carbon nanotube is immersed in concentrated nitric acid for treatment, and the pretreated carbon nanotube is obtained after the treatment; then the pretreated carbon nanotube is added into an ethanol aqueous solution, followed by adding γ-glycidoxypropyltrimethoxysilane, and stirring reaction is performed, and after completion, filtration, washing and drying are performed to obtain epoxy carbon nanotubes; the epoxy carbon nanotubes are added into toluene, followed by adding 2-(2-hydroxy-5-phenylmethyl) benzotriazole and triethylamine, and heating reaction is performed, and after completion of the reaction, filtration, washing and drying are performed to obtain the modified carbon nanotube.

[0025] Preferably, the temperature of the impregnation treatment is 40-50 DEG C, and the time is 1-2h; the mass ratio of the pretreated carbon nanotubes and the gamma-glycidoxypropyltrimethoxysilane is 50-60:4-7, the temperature of the stirring reaction is 60-70 DEG C, and the time is 2-3h; the mass ratio of the epoxy carbon nanotubes, 2-(2-hydroxy-5-phenylmethyl) benzotriazole and triethylamine is 50-60:4-7:1-2, and the temperature of the heating reaction is 70-80 DEG C, and the time is 2-3h.

[0026] In the present application, the carbon nanotubes are impregnated with concentrated nitric acid to introduce carboxyl, hydroxyl and other oxygen-containing functional groups on the surface of the carbon nanotubes; subsequently, the oxygen-containing functional groups are reacted with gamma-glycidoxypropyltrimethoxysilane to covalently bond the epoxy groups to the surface of the carbon nanotubes; finally, the epoxy groups are reacted with the phenolic hydroxyl groups of 2-(2-hydroxy-5-phenylmethyl) benzotriazole to successfully graft the 2-(2-hydroxy-5-phenylmethyl) benzotriazole molecules to the surface of the carbon nanotubes, thereby realizing the double functionalization of the surface of the carbon nanotubes. The 2-(2-hydroxy-5-phenylmethyl) benzotriazole is fixed on the carbon nanotubes by covalent bonds, thereby avoiding its migration and precipitation and improving the persistence and efficiency of the ultraviolet absorption of the composite material; the modified carbon nanotubes can effectively enhance the mechanical indexes such as the tensile strength and the bending strength of the composite material by virtue of their excellent mechanical properties; on the other hand, the grafted 2-(2-hydroxy-5-phenylmethyl) benzotriazole endows the carbon nanotubes with excellent ultraviolet absorption capacity, thereby protecting the polymer matrix from ultraviolet degradation and further improving the weather resistance of the material.

[0027] The present application also protects a preparation method of the polymer composite material containing the nanofibers as described above, which comprises the following steps:

[0028] The raw materials are weighed according to the formula, added into a high-speed mixer, uniformly mixed, and then extruded and granulated by a double-screw extruder, so that the polymer composite material containing the nanofibers is obtained.

[0029] Preferably, the rotation speed of the mixing is 700-900r / min, and the time is 5-10min; the temperature of the extrusion is 230-250 DEG C.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] (1) The polymer composite material containing nanofibers provided by the application effectively overcomes the defects of existing polypropylene materials, such as easy degradation, flammability, easy migration of traditional flame retardants and antioxidants, and the like, realizes efficient flame retardation and excellent weather resistance and anti-aging performance (especially ultraviolet aging resistance), maintains and improves the mechanical properties of the material, solves the problem that the prior art is difficult to balance multiple performances, and widens the application range of the polypropylene composite material.

[0032] (2) The polymer composite material containing nanofibers provided by the application is added with a modified flame retardant, the ammonium polyphosphate is sequentially coated with titanium dioxide, the epoxy group is introduced by means of gamma-glycidoxypropyltrimethoxysilane, and the 2,2,6,6-tetramethyl-4-piperidinol ring-opening reaction is performed to graft and fix the tetramethylpiperidyl group, so that the flame retardant is endowed with multiple functions, the modification method not only improves the thermal stability of APP through the TiO2 layer and possibly produces flame retardant synergism, but more importantly, the 2,2,6,6-tetramethyl-4-piperidinol component is firmly anchored on the surface of the flame retardant particles in the form of a covalent bond, which effectively solves the problems of poor compatibility, easy volatilization loss at high temperature and easy migration and precipitation during long-term use of the traditional ultraviolet aging-resistant agent in polypropylene, and ensures the long-term effectiveness and stability of the anti-aging effect; meanwhile, the modified flame retardant has more excellent flame retardant efficiency and compatibility with the polymer matrix through a specific preparation method, avoids the performance degradation and early aging of the composite material caused by the migration of the auxiliary agent, and endows the composite material with excellent flame retardancy and long-lasting aging resistance.

[0033] (3) The polymer composite material containing nanofibers provided by the application is added with modified carbon nanotubes prepared by the method of pretreatment with concentrated nitric acid, grafting of an epoxy group and 2-(2-hydroxy-5-benzyl) benzotriazole ring-opening grafting fixation; the method enables 2-(2-hydroxy-5-benzyl) benzotriazole to be stably grafted on the surface of the carbon nanotube in the form of a covalent bond, fundamentally solves the defects of easy migration, easy volatilization and poor resistance to extraction of the traditional small-molecule ultraviolet absorber, and ensures the persistent ultraviolet protection performance of the ultraviolet absorber in the composite material; meanwhile, the carbon nanotube itself is an excellent nanofiller, and the surface functionalization improves the dispersibility and interfacial compatibility of the carbon nanotube in the polymer matrix, effectively plays the nanometer reinforcing role of the carbon nanotube, and significantly improves the mechanical strength of the composite material; and the introduction of the modified carbon nanotube not only strengthens the mechanical skeleton of the material, but also endows the material with excellent and long-acting ultraviolet aging resistance.

[0034] (4) The polymer composite material containing nanofibers provided by the application has the following advantages: the modified flame retardant and the modified carbon nanotube can play a significant synergistic reinforcing effect in the polymer matrix; in terms of flame retardation, the modified ammonium polyphosphate as the main intumescent flame retardant forms an intumescent carbon layer during combustion, and the modified carbon nanotube can enhance the structural strength and compactness of the intumescent carbon layer due to its good thermal stability and network structure, effectively preventing molten dripping and further preventing the transmission of heat and combustible gas; in terms of weather resistance and aging resistance, the TiO2 on the surface of the modified flame retardant has the physical shielding function and the 2,2,6,6-tetramethyl-4-piperidyl group has the chemical free radical capturing function, which are combined with the ultraviolet absorption function of the benzotriazole group on the surface of the modified carbon nanotube, so that the ultraviolet resistance of the composite material is synergistically improved, and the effect is much better than that of a single additive; the existence of the surface functional groups of the two modified fillers can promote the uniform dispersion and interfacial compatibility of the fillers in the matrix through the interaction with the compatible agent and the polymer matrix, thereby positively affecting the mechanical properties of the composite material. DETAILED DESCRIPTION

[0035] The technical solutions of the application will be described clearly and completely below in combination with the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0036] Unless otherwise specified, the chemical reagents and materials in the application are purchased through market channels or synthesized from raw materials purchased through market channels.

[0037] The brand of the polypropylene is Sinopec PPH-T03; the brand of the nylon 6 is Balin Petrochemical BL3280H; the carbon nanotube is a multi-walled carbon nanotube with a diameter of 20-30 nm and a length of 5-10 μm; the polymerization degree of the ammonium polyphosphate is greater than 1000. Example 1

[0038] A polymer composite material containing nanofibers comprises the following raw materials in parts by weight:

[0039] Polypropylene 95 parts, nylon 6 13 parts, modified flame retardant 15 parts, modified carbon nanotube 6 parts, maleic anhydride grafted polypropylene 4 parts, antioxidant 1010 0.7 parts, silicone master batch 0.4 parts.

[0040] The preparation method of the modified flame retardant is as follows:

[0041] S1, 85 g of ammonium polyphosphate was added into 1000 g of absolute ethanol, then 2.5 g of sodium dodecyl sulfate was added, and after stirring uniformly, a suspension of ammonium polyphosphate was obtained; then 250 g of titanium dioxide sol was added dropwise into 1000 g of the suspension of ammonium polyphosphate under stirring, after the dropwise addition was completed, the reaction was stirred at 35℃ for 3 h, after the reaction was completed, aging was carried out at 23℃ for 14 h, then filtration, washing and drying were carried out, to obtain a composite ammonium polyphosphate; the preparation method of the titanium dioxide sol is as follows: 18 g of tetrabutyl titanate was added into 250 g of absolute ethanol, then 1.8 g of deionized water was added dropwise, and stirring was carried out at 700 r / min for 1.5 h, to obtain the titanium dioxide sol;

[0042] S2, 95 g of the composite ammonium polyphosphate in step S1 was added into 1200 g of an ethanol aqueous solution (the mass ratio of ethanol to water was 3:1), then 10 g of γ-glycidoxypropyltrimethoxysilane was added, and reaction was carried out at 65℃ for 2.5 h, after the reaction was completed, filtration, washing and drying were carried out, to obtain silane-modified ammonium polyphosphate;

[0043] S3, 95 g of the silane-modified ammonium polyphosphate in step S2 was added into 1200 g of butanone, then 6.5 g of 2,2,6,6-tetramethyl-4-piperidinol and 2.5 g of triethylamine were added, and reaction was carried out at 65℃ for 3.5 h, after the reaction was completed, filtration, washing and drying were carried out, to obtain a modified flame retardant.

[0044] The preparation method of the modified carbon nanotube is as follows:

[0045] 70 g of carbon nanotubes was added into 900 g of concentrated nitric acid (mass fraction 70%), and immersion treatment was carried out at 45℃ for 1.5 h, to obtain pretreated carbon nanotubes; then 55 g of the pretreated carbon nanotubes was added into 800 g of an ethanol aqueous solution (the mass ratio of ethanol to water was 3:1), then 6 g of γ-glycidoxypropyltrimethoxysilane was added, and reaction was carried out at 65℃ for 2.5 h, after the reaction was completed, filtration, washing and drying were carried out, to obtain epoxy carbon nanotubes; 55 g of the epoxy carbon nanotubes was added into 800 mL of toluene, then 6 g of 2-(2-hydroxy-5-benzyl) benzotriazole and 1.5 g of triethylamine were added, and reaction was carried out at 75℃ for 2.5 h, after the reaction was completed, filtration, washing and drying were carried out, to obtain modified carbon nanotubes.

[0046] A preparation method of a polymer composite material containing nanofibers, comprising the following steps:

[0047] The raw materials were weighed according to the formula, added into a high-speed mixer, and mixed at a speed of 800 r / min for 8 min, and then granulated by extrusion at a temperature of 240℃, to obtain the polymer composite material containing nanofibers. Example 2

[0048] A nanofiber-containing polymer composite includes the following raw materials in parts by weight:

[0049] Polypropylene 90 parts, nylon 6 10 parts, modified flame retardant 13 parts, modified carbon nanotube 4 parts, maleic anhydride grafted polypropylene 3 parts, antioxidant 1010 0.5 parts, silicone master batch 0.3 parts.

[0050] The preparation method of the modified flame retardant is as follows:

[0051] S1, 80g of ammonium polyphosphate is added to 1000g of anhydrous ethanol, then 2g of sodium dodecyl sulfate is added, and after stirring uniformly, a ammonium polyphosphate suspension is obtained; then 200g of titanium dioxide sol is added dropwise to 1000g of the ammonium polyphosphate suspension under stirring, and after the dropwise addition is completed, the reaction is stirred at 30℃ for 4h, and after the reaction is completed, it is aged at 20℃ for 16h, then filtered, washed and dried to obtain a composite ammonium polyphosphate; the preparation method of the titanium dioxide sol is as follows: 15g of tetrabutyl titanate is added to 200g of anhydrous ethanol, then 1.5g of deionized water is added dropwise, and stirred at 500r / min for 2h to obtain the titanium dioxide sol;

[0052] S2, 90g of the composite ammonium polyphosphate in step S1 is added to 1200g of an ethanol aqueous solution (the mass ratio of ethanol to water is 3:1), then 8g of γ-glycidoxypropyltrimethoxysilane is added, and the reaction is carried out at 60℃ for 3h, and after the reaction is completed, it is filtered, washed and dried to obtain silane-modified ammonium polyphosphate;

[0053] S3, 90g of the silane-modified ammonium polyphosphate in step S2 is added to 1200g of butanone, then 5.5g of 2,2,6,6-tetramethyl-4-piperidinol and 2g of triethylamine are added, and the reaction is carried out at 60℃ for 4h, and after the reaction is completed, it is filtered, washed and dried to obtain a modified flame retardant.

[0054] The preparation method of the modified carbon nanotube is as follows:

[0055] 70g of carbon nanotubes is added to 900g of concentrated nitric acid (mass fraction 70%), and immersed and treated at 40℃ for 2h to obtain pretreated carbon nanotubes; then 50g of the pretreated carbon nanotubes is added to 800g of an ethanol aqueous solution (the mass ratio of ethanol to water is 3:1), then 4g of γ-glycidoxypropyltrimethoxysilane is added, and the reaction is carried out at 60℃ for 3h, and after the reaction is completed, it is filtered, washed and dried to obtain epoxy carbon nanotubes; 50g of the epoxy carbon nanotubes is added to 800mL of toluene, then 4g of 2-(2-hydroxy-5-phenylmethyl)benzotriazole and 1g of triethylamine are added, and the reaction is carried out at 70℃ for 3h, and after the reaction is completed, it is filtered, washed and dried to obtain modified carbon nanotubes.

[0056] A preparation method of a nanofiber-containing polymer composite material, comprising the following steps:

[0057] The raw materials are weighed according to the formula, and then added into a high-speed mixer, and mixed at a speed of 700 r / min for 10 min. After uniform mixing, the mixture is granulated by extrusion at a temperature of 240 DEG C to obtain the nanofiber-containing polymer composite material. Example 3

[0058] A nanofiber-containing polymer composite material, comprising the following raw materials in parts by weight:

[0059] 100 parts of polypropylene, 15 parts of nylon 6, 16 parts of modified flame retardant, 7 parts of modified carbon nanotube, 5 parts of maleic anhydride grafted polypropylene, 0.8 parts of antioxidant 1010, and 0.5 parts of silicone master batch.

[0060] The preparation method of the modified flame retardant is as follows:

[0061] S1, 90g of ammonium polyphosphate is added to 1000g of anhydrous ethanol, followed by adding 3g of sodium dodecyl sulfate, and stirring uniformly to obtain an ammonium polyphosphate suspension; then 300g of titanium dioxide sol is added dropwise to 1000g of the ammonium polyphosphate suspension under stirring, and after the dropwise addition is completed, the reaction is stirred at 40 DEG C for 2h, and after the reaction is completed, the reaction is aged at 25 DEG C for 12h, followed by filtration, washing, and drying to obtain a composite ammonium polyphosphate; the preparation method of the titanium dioxide sol is as follows: 20g of tetrabutyl titanate is added to 300g of anhydrous ethanol, followed by dropwise addition of 2g of deionized water, and stirring at 800r / min for 1h to obtain;

[0062] S2, 100g of the composite ammonium polyphosphate in step S1 is added to 1200g of an ethanol-water solution (the mass ratio of ethanol to water is 3:1), followed by adding 11g of γ-glycidyl ether propyltrimethoxysilane, and reacting at 70 DEG C for 2h, and after the reaction is completed, the reaction is filtered, washed, and dried to obtain silane-modified ammonium polyphosphate;

[0063] S3, 100g of the silane-modified ammonium polyphosphate in step S2 is added to 1200g of butanone, followed by adding 7.5g of 2,2,6,6-tetramethyl-4-piperidinol and 3g of triethylamine, and reacting at 70 DEG C for 3h, and after the reaction is completed, the reaction is filtered, washed, and dried to obtain a modified flame retardant.

[0064] The preparation method of the modified carbon nanotube is as follows:

[0065] 70 g carbon nanotubes were added to 900 g concentrated nitric acid (mass fraction 70%) and immersed at 50°C for 1 h to obtain pretreated carbon nanotubes; then 60 g of the pretreated carbon nanotubes were added to 800 g of an ethanol aqueous solution (mass ratio of ethanol to water 3:1), followed by the addition of 7 g of γ-glycidoxypropyltrimethoxysilane, and stirring and reaction at 70°C for 2 h; after completion, filtration, washing, and drying, epoxy carbon nanotubes were obtained; 60 g of the epoxy carbon nanotubes were added to 800 mL of toluene, followed by the addition of 7 g of 2-(2-hydroxy-5-phenylmethyl)benzotriazole and 2 g of triethylamine, and reaction at 80°C for 2 h; after completion, filtration, washing, and drying, modified carbon nanotubes were obtained.

[0066] A preparation method of a nanofiber-containing polymer composite material, comprising the following steps:

[0067] The raw materials are weighed according to the formula, added to a high-speed mixer, mixed at a speed of 900 r / min for 5 min, and then granulated by extrusion at a temperature of 240°C to obtain the nanofiber-containing polymer composite material. Comparative Example 1

[0068] A nanofiber-containing polymer composite material, comprising the following raw materials by weight:

[0069] Polypropylene 95 parts, nylon 6 13 parts, modified flame retardant 15 parts, modified carbon nanotubes 6 parts, maleic anhydride grafted polypropylene 4 parts, antioxidant 1010 0.7 parts, silicone master batch 0.4 parts.

[0070] The preparation method of the modified flame retardant is as follows:

[0071] S1, 85 g of ammonium polyphosphate was added to 1000 g of anhydrous ethanol, followed by the addition of 2.5 g of sodium dodecyl sulfate, and stirring to obtain an ammonium polyphosphate suspension; then 250 g of titanium dioxide sol was added dropwise to the 1000 g of ammonium polyphosphate suspension under stirring, and stirred at 35°C for 3 h after the addition was completed; after the reaction was completed, it was aged at 23°C for 14 h, and then filtered, washed, and dried to obtain a composite ammonium polyphosphate; the preparation method of the titanium dioxide sol is as follows: 18 g of tetrabutyl titanate was added to 250 g of anhydrous ethanol, followed by the dropwise addition of 1.8 g of deionized water, and stirring at 700 r / min for 1.5 h to obtain the titanium dioxide sol;

[0072] S2, 95 g of the composite ammonium polyphosphate in step S1 was added to 1200 g of an ethanol aqueous solution (mass ratio of ethanol to water 3:1), followed by the addition of 10 g of γ-glycidoxypropyltrimethoxysilane, and constant-temperature reaction at 65°C for 2.5 h; after the reaction was completed, it was filtered, washed, and dried to obtain a modified flame retardant.

[0073] The preparation method of the modified carbon nanotube is as follows:

[0074] 70g carbon nanotubes were added to 900g concentrated nitric acid (mass fraction 70%) and immersed at 45℃ for 1.5h to obtain pretreated carbon nanotubes. Then 55g of the pretreated carbon nanotubes were added to 800g of an ethanol aqueous solution (mass ratio of ethanol to water 3:1), followed by the addition of 6g of γ-glycidoxypropyltrimethoxysilane. The mixture was stirred at 65℃ for 2.5h, and then filtered, washed and dried to obtain epoxy carbon nanotubes. Then 55g of the epoxy carbon nanotubes were added to 800mL of toluene, followed by the addition of 6g of 2-(2-hydroxy-5-phenylmethyl)benzotriazole and 1.5g of triethylamine. The mixture was reacted at 75℃ for 2.5h, and then filtered, washed and dried to obtain the modified carbon nanotubes.

[0075] A preparation method of a polymer composite containing nanofibers, comprising the following steps:

[0076] The raw materials are weighed according to the formula, added to a high-speed mixer, mixed at a speed of 800r / min for 8min, and then granulated by extrusion at a temperature of 240℃ to obtain the polymer composite containing nanofibers.

[0077] Compared with Example 1, the comparative example does not introduce 2,2,6,6-tetramethyl-4-piperidinol on the flame retardant. Comparative Example 2

[0078] A polymer composite containing nanofibers, comprising the following raw materials by weight:

[0079] Polypropylene 95 parts, nylon 6 13 parts, modified flame retardant 15 parts, modified carbon nanotube 6 parts, maleic anhydride grafted polypropylene 4 parts, antioxidant 1010 0.7 parts, silicone master batch 0.4 parts.

[0080] The preparation method of the modified flame retardant is as follows:

[0081] S1, 85g of ammonium polyphosphate was added to 1000g of anhydrous ethanol, followed by the addition of 2.5g of sodium dodecyl sulfate. After stirring, a suspension of ammonium polyphosphate was obtained. Then 250g of titanium dioxide sol was added dropwise to the suspension under stirring. After the addition was completed, the mixture was stirred at 35℃ for 3h, and then aged at 23℃ for 14h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a composite ammonium polyphosphate. The preparation method of the titanium dioxide sol is as follows: 18g of tetrabutyl titanate was added to 250g of anhydrous ethanol, followed by the dropwise addition of 1.8g of deionized water. The mixture was stirred at 700r / min for 1.5h to obtain the titanium dioxide sol.

[0082] S2, 95 g of the compound polyammonium phosphate in step S1 is added into 1200 g of an ethanol aqueous solution (the mass ratio of ethanol to water is 3:1), then 10 g of γ-glycidoxypropyltrimethoxysilane is added, and reaction is carried out at 65℃ for 2.5 h. After the reaction is completed, filtration, washing and drying are carried out to obtain silane-modified polyammonium phosphate;

[0083] S3, 95 g of the silane-modified polyammonium phosphate in step S2 is added into 1200 g of butanone, then 6.5 g of 2,2,6,6-tetramethyl-4-piperidinol and 2.5 g of triethylamine are added, and reaction is carried out at 65℃ for 3.5 h. After the reaction is completed, filtration, washing and drying are carried out to obtain the modified flame retardant.

[0084] The preparation method of the modified carbon nanotube is as follows:

[0085] 70 g of carbon nanotubes is added into 900 g of concentrated nitric acid (mass fraction 70%) and immersed and treated at 45℃ for 1.5 h to obtain pretreated carbon nanotubes. Then 55 g of the pretreated carbon nanotubes is added into 800 g of an ethanol aqueous solution (the mass ratio of ethanol to water is 3:1), then 6 g of γ-glycidoxypropyltrimethoxysilane is added, and reaction is carried out at 65℃ for 2.5 h. After the reaction is completed, filtration, washing and drying are carried out to obtain the modified carbon nanotube.

[0086] A preparation method of a polymer composite containing nanofibers, comprising the following steps:

[0087] The raw materials are weighed according to the formula, added into a high-speed mixer, mixed at a speed of 800 r / min for 8 min, and then extruded and granulated at a temperature of 240℃ to obtain the polymer composite containing nanofibers.

[0088] Compared with Example 1, the comparative example does not introduce 2-(2-hydroxy-5-phenyl) benzotriazole on the carbon nanotube. Comparative Example 3

[0089] A polymer composite containing nanofibers, comprising the following raw materials by weight:

[0090] Polypropylene 95 parts, nylon 6 13 parts, modified flame retardant 15 parts, modified carbon nanotube 6 parts, maleic anhydride grafted polypropylene 4 parts, antioxidant 1010 0.7 parts, silicone master batch 0.4 parts.

[0091] The preparation method of the modified flame retardant is as follows:

[0092] S1, 85 g of ammonium polyphosphate was added into 1000 g of anhydrous ethanol, then 2.5 g of sodium dodecyl sulfate was added, and after stirring uniformly, a ammonium polyphosphate suspension was obtained; then 250 g of titanium dioxide sol was added dropwise into 1000 g of the ammonium polyphosphate suspension under stirring, after the dropwise addition was completed, the reaction was stirred at 35℃ for 3 h, after the reaction was completed, the product was aged at 23℃ for 14 h, then filtered, washed and dried to obtain a composite ammonium polyphosphate; the preparation method of the titanium dioxide sol is as follows: 18 g of tetrabutyl titanate was added into 250 g of anhydrous ethanol, then 1.8 g of deionized water was added dropwise, and after stirring at 700 r / min for 1.5 h, the titanium dioxide sol was obtained;

[0093] S2, 95 g of the composite ammonium polyphosphate in step S1 was mixed with 6.5 g of 2,2,6,6-tetramethyl-4-piperidinol to obtain a modified flame retardant.

[0094] The preparation method of the modified carbon nanotube is as follows:

[0095] 70 g of carbon nanotubes was added into 900 g of concentrated nitric acid (mass fraction 70%) and immersed at 45℃ for 1.5 h to obtain pretreated carbon nanotubes; then 55 g of the pretreated carbon nanotubes was mixed with 6 g of 2-(2-hydroxy-5-phenyl) benzotriazole to obtain modified carbon nanotubes.

[0096] A preparation method of a polymer composite material containing nanofibers, comprising the following steps:

[0097] The raw materials were weighed according to the formula, added into a high-speed mixer, and mixed at a speed of 800 r / min for 8 min, then granulated by extrusion at a temperature of 240℃ to obtain the polymer composite material containing nanofibers.

[0098] Compared with Example 1, the modified flame retardant of the present comparative example was prepared by physically blending the composite ammonium polyphosphate with 2,2,6,6-tetramethyl-4-piperidinol; and the modified carbon nanotube was prepared by physically blending the pretreated carbon nanotube with 2-(2-hydroxy-5-phenyl) benzotriazole. Comparative Example 4

[0099] A polymer composite material containing nanofibers, comprising the following raw materials by weight:

[0100] Polypropylene 95 parts, nylon 6 13 parts, modified flame retardant 21 parts, maleic anhydride grafted polypropylene 4 parts, antioxidant 101 0.7 parts, silicone master batch 0.4 parts.

[0101] The preparation method of the modified flame retardant is as follows:

[0102] S1, 85 g of ammonium polyphosphate is added to 1000 g of anhydrous ethanol, then 2.5 g of sodium dodecyl sulfate is added, and after stirring uniformly, an ammonium polyphosphate suspension is obtained; then 250 g of titanium dioxide sol is added dropwise to 1000 g of the ammonium polyphosphate suspension under stirring, after the dropwise addition is completed, stirring is carried out at 35°C for 3 h, after the reaction is completed, aging is carried out at 23°C for 14 h, then filtration, washing and drying are carried out, to obtain a composite ammonium polyphosphate; the preparation method of the titanium dioxide sol is as follows: 18 g of tetrabutyl titanate is added to 250 g of anhydrous ethanol, then 1.8 g of deionized water is added dropwise, and stirring is carried out at 700 r / min for 1.5 h, to obtain the titanium dioxide sol;

[0103] S2, 95 g of the composite ammonium polyphosphate in step S1 is added to 1200 g of an ethanol aqueous solution (the mass ratio of ethanol to water is 3:1), then 10 g of γ-glycidoxypropyltrimethoxysilane is added, and constant temperature reaction is carried out at 65°C for 2.5 h, after the reaction is completed, filtration, washing and drying are carried out, to obtain silane-modified ammonium polyphosphate;

[0104] S3, 95 g of the silane-modified ammonium polyphosphate in step S2 is added to 1200 g of butanone, then 6.5 g of 2,2,6,6-tetramethyl-4-piperidinol and 2.5 g of triethylamine are added, and reaction is carried out at 65°C for 3.5 h, after the reaction is completed, filtration, washing and drying are carried out, to obtain a modified flame retardant.

[0105] A preparation method of a polymer composite material containing nanofibers, comprising the following steps:

[0106] The raw materials are weighed according to the formula, added to a high-speed mixer, mixed at a speed of 800 r / min for 8 min, uniformly mixed, and then extruded and granulated by a double-screw extruder at a temperature of 240°C, to obtain the polymer composite material containing nanofibers.

[0107] Compared with Example 1, the modified carbon nanotubes are not added in the present comparative example.

[0108] The polymer composite materials prepared in Examples 1-3 and Comparative Examples 1-4 are injection molded into sample bars, and performance tests are carried out, wherein the tensile strength and elongation at break are tested according to the standard GB / T 1040.2-2022 “Determination of the tensile properties of plastics Part 2: test conditions for moulded and extruded plastics”, the sample bar has a size of 180 mm x 10 mm x 4 mm, and the tensile speed is 10 mm / min; the limiting oxygen index is tested according to GB / T 2406.2-2009, the sample bar is prepared in the size of type I, and the ignition method is A; the ultraviolet aging resistance is tested according to the standard GB / T 16422.3-2022 “Plastics Laboratory light source exposure test method Part 3: fluorescent ultraviolet lamp”, and the aging conditions are: ultraviolet intensity 210 W / m 2The tensile strength and elongation at break retention of the sample after aging were tested, and the results are shown in Table 1.

[0109] Table 1

[0110] Tensile strength (MPa) Elongation at break (%) Limiting oxygen index (%) Tensile strength retention rate (%) Elongation at break retention rate (%) Example 1 40.3 127 35.3 92.1 90.4 Example 2 37.9 136 34.1 90.6 87.5 Example 3 39.2 114 34.5 91.7 89.2 Comparative Example 1 36.1 105 34.6 80.3 77.1 Comparative Example 2 35.7 102 34.9 82.5 79.3 Comparative Example 3 33.8 97 35.1 86.4 83.8 Comparative Example 4 32.6 84 29.7 83.2 80.6

[0111] As shown in Table 1, the polymer composite material containing nanofiber prepared by the application has good mechanical properties, flame retardant properties and ultraviolet aging resistance, and has good application prospect.

[0112] The above is a further detailed description of the application in combination with specific implementation examples, and cannot be considered as limiting the specific implementation of the application to these descriptions. For ordinary skilled persons in the technical field to which the application belongs, any modification, equivalent replacement and improvement within the concept and principle of the application should be considered as falling within the protection scope of the application.

[0113] Those skilled in the art will readily understand that the above description is only of the preferred embodiments of the application and is not intended to limit the application, and any modification, equivalent replacement and improvement within the concept and principle of the application should be included in the protection scope of the application.

Claims

1. A nanofiber-containing polymer composite, characterized by, By weight parts, including the following raw materials: Polypropylene 90-100 parts, nylon 6 10-15 parts, modified flame retardant 13-16 parts, modified carbon nanotube 4-7 parts, compatibilizer 3-5 parts, antioxidant 0.5-0.8 parts, lubricant 0.3-0.5 parts; The preparation method of the modified flame retardant is as follows: S1, ammonium polyphosphate is added to anhydrous ethanol, then sodium dodecyl sulfate is added, and the mixture is stirred uniformly to obtain an ammonium polyphosphate suspension; then, under stirring, titanium dioxide sol is added dropwise to the ammonium polyphosphate suspension, and after the addition is completed, stirring reaction is carried out, and after the reaction is completed, aging is carried out, followed by filtration, washing, and drying to obtain a composite ammonium polyphosphate; S2, the composite ammonium polyphosphate is added to an ethanol aqueous solution, then γ-glycidoxypropyltrimethoxysilane is added, and constant temperature reaction is carried out to obtain silane modified ammonium polyphosphate; S3, the silane modified ammonium polyphosphate is added to butanone, then 2,2,6,6-tetramethyl-4-piperidinol and triethylamine are added, and ring-opening reaction is carried out to obtain a modified flame retardant; The preparation method of the modified carbon nanotube is as follows: The carbon nanotube is immersed in concentrated nitric acid for treatment, and pretreated carbon nanotube is obtained after the treatment is completed; then the pretreated carbon nanotube is added to an ethanol aqueous solution, followed by the addition of γ-glycidoxypropyltrimethoxysilane, and stirring reaction is carried out to obtain epoxy carbon nanotube; the epoxy carbon nanotube is added to toluene, followed by the addition of 2-(2-hydroxy-5-phenyl) benzotriazole and triethylamine, and heating reaction is carried out to obtain modified carbon nanotube.

2. The nanofiber-containing polymer composite of claim 1, wherein By weight parts, including the following raw materials: polypropylene 95-100 parts, nylon 6 10-13 parts, modified flame retardant 13-16 parts, modified carbon nanotube 4-6 parts, compatibilizer 3-4 parts, antioxidant 0.5-0.7 parts, lubricant 0.4-0.5 parts; the compatibilizer is maleic anhydride grafted polypropylene, the antioxidant is one or more of antioxidant 168, antioxidant 1010, and antioxidant 1098; and the lubricant is silicone master granules.

3. The nanofiber-containing polymer composite of claim 1, wherein In step S1, the mass ratio of the ammonium polyphosphate, sodium dodecyl sulfate, and anhydrous ethanol is 80-90:2-3:1000, the mass ratio of the ammonium polyphosphate suspension and titanium dioxide sol is 1000:200-300, the temperature of the stirring reaction is 30-40℃, the time is 2-4h, the temperature of the aging is 20-25℃, and the time is 12-16h; the preparation method of the titanium dioxide sol is as follows: 15-20g tetrabutyl titanate is added to 200-300g anhydrous ethanol, followed by the dropwise addition of 1.5-2g deionized water, and stirring is carried out at 500-800r / min for 1-2h.

4. The nanofiber-containing polymer composite of claim 1, wherein In step S2, the mass ratio of the composite ammonium polyphosphate and γ-glycidoxypropyltrimethoxysilane is 90-100:8-11, and the temperature of the constant temperature reaction is 60-70℃, and the time is 2-3h.

5. The nanofiber-containing polymer composite of claim 1, wherein The mass ratio of the silane modified ammonium polyphosphate, 2,2,6,6-tetramethyl-4-piperidinol and triethylamine in step S3 is 90-100:5.5-7.5:2-3, the temperature of the ring-opening reaction is 60-70 DEG C, and the time is 3-4h.

6. The nanofiber-containing polymer composite of claim 1, wherein In the preparation process of the modified carbon nanotube, the temperature of the impregnation treatment is 40-50 DEG C, and the time is 1-2h; the mass ratio of the pretreated carbon nanotube and gamma-glycidoxypropyltrimethoxysilane is 50-60:4-7, the temperature of the stirring reaction is 60-70 DEG C, and the time is 2-3h; the mass ratio of the epoxy group carbon nanotube, 2-(2-hydroxy-5-benzyl) benzotriazole and triethylamine is 50-60:4-7:1-2, and the temperature of the heating reaction is 70-80 DEG C, and the time is 2-3h.

7. A method for preparing the nanofiber-containing polymer composite according to any one of claims 1 to 6, characterized by, The method comprises the following steps: The raw materials are weighed according to the formula, added into a high-speed mixer, uniformly mixed, and then granulated by double-screw extrusion to obtain the polymer composite material containing nanofibers.

8. The production method according to claim 7, characterized by, The rotating speed of the mixer is 700-900r / min, and the time is 5-10min; the temperature of the extrusion is 230-250 DEG C.