Nano silicon carbide / polypropylene composite material and production process thereof

Abstract

The invention relates to the field of materials, in particular to a nano silicon carbide / polypropylene composite material and a production process thereof, the polypropylene composite material is prepared by taking polypropylene resin, modified nano silicon carbide and a macromolecular flame retardant as main raw materials and talcum powder, an antioxidant 1010 and dioctyl phthalate as auxiliary materials through melt blending and extrusion granulation. In the adding process, the nano silicon carbide is modified, so that the nano silicon carbide has high toughness, rigidity and other mechanical properties, ammonium polyphosphate in the macromolecular flame retardant is combusted and decomposed to generate acidic substances, sorbitol is catalyzed to be dehydrated, a carbon layer is formed, and the flame retardant property is shown; the nano silicon carbide / polypropylene composite material prepared by the invention has excellent flame retardance and mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of materials, in particular to a kind of nano silicon carbide / polypropylene composite material and its production process. BACKGROUND

[0002] Polypropylene is a widely used thermoplastic synthetic resin, with chemical resistance, electrical insulation, good processing performance and cost advantage, plays an important role in many fields such as automobile industry, household appliances, electronics, packaging, building materials and furniture. However, polypropylene itself has some performance defects, which limits its further application. For example, its mechanical strength is low, and it is easy to deform or even damage when subjected to large external force. These shortcomings make polypropylene unable to meet the demand in some structural material application scenarios with strict requirements on material performance. To improve the performance of polypropylene, researchers have carried out a lot of modification research work. Among them, one of the research hotspots in recent years is to fill and blend nano particles to modify polypropylene. This method has a certain degree of improvement on the crystallization performance, aging resistance and toughening and strengthening of polypropylene composite material. Among the many optional blending fillers, nano silicon carbide is attracting attention due to its unique advantages. Nano silicon carbide has high hardness, high wear resistance, good self-lubricity, and it also has high thermal conductivity, low thermal expansion coefficient and high temperature strength, etc. It has stable chemical properties and can resist oxidation at high temperature.

[0003] However, when nano silicon carbide is applied to polypropylene modification, there are many challenges. On the one hand, nano silicon carbide is prone to fracture under impact or alternating stress, and it is difficult to be used alone as a structural material. On the other hand, traditional nano silicon carbide / polypropylene composite material often has deficiencies in flame retardant performance. In some application scenarios with strict requirements on fire safety, such as electronic and electrical equipment shell, automobile interior materials, etc., if the material has poor flame retardant performance, it will bring great safety hazards in case of fire.

[0004] Therefore, it is a key problem to be solved in the current material field to develop a nano silicon carbide / polypropylene composite material that significantly improves the flame retardant performance of the composite material and has reinforcement and toughening. SUMMARY

[0005] The present application relates to the field of materials, in particular to a kind of nano silicon carbide / polypropylene composite material and its production process.

[0006] The object of the present application can be achieved by the following technical solutions: A kind of nanometer silicon carbide / polypropylene composite material, according to weight fraction, it includes the following components: 50-70 parts of polypropylene resin, 5-8 parts of modified nanometer silicon carbide, 5-8 parts of macromolecular flame retardant, 2-3 parts of talcum powder, 1-2 parts of antioxidant 1010, 0.5-1 part of dioctyl phthalate.

[0007] Further, the preparation method of the macromolecular flame retardant includes the following steps: Step A: ethanol and deionized water are added to the reactor, heated to 90-95 DEG C, stirring for 30-40 min, adding ammonium polyphosphate and 4-aminobenzaldehyde, temperature control 60-65 DEG C, stirring reaction 4-5 h, after reaction is completed, cooling to room temperature, filtering, and preparing macromolecular flame retardant intermediate; Step B: macromolecular flame retardant intermediate is added to deionized water, catalyst and sorbitol are added, heated to 60-70 DEG C, reaction 5-6 h, 30-40% sodium carbonate aqueous solution is added to adjust PH value, reduced pressure concentration, and the product is dried in an oven to prepare macromolecular flame retardant.

[0008] Further, in step A, the volume ratio of the ethanol and deionized water is 1:0.05-0.08.

[0009] Further, in step B, the catalyst is p-toluenesulfonic acid.

[0010] Further, in step B, the PH value is adjusted to 7.0-7.5.

[0011] By the above technical solution, the ammonium ion in ammonium polyphosphate and the amino group in 4-aminobenzaldehyde are prepared into flame retardant intermediate by cation exchange method, and the aldehyde group in the flame retardant intermediate and the hydroxyl group in sorbitol are prepared into macromolecular flame retardant by acetal reaction under the action of catalyst.

[0012] Further, the preparation method of the modified nanometer silicon carbide includes the following steps: Step I: nanometer silicon carbide is added to benzene, ultrasonic dispersion is carried out for 5-10 min, it is transferred to a ball mill jar, aminosulfonyl chloride and corundum ball are added, the ball mill jar is placed in a planetary ball mill, ball milling is carried out for 2-3 h, centrifugation is carried out, and drying is carried out in a drying box to prepare nanometer silicon carbide intermediate; Step II: nanometer silicon carbide intermediate is weighed and placed in 20 ml of ether, 1,3-di-4-piperidinyl propane is added at a controlled temperature, and an alkali catalyst is added, after addition, the temperature is controlled at 0-1 DEG C, stirring reaction is carried out for 4-5 h, after reaction is completed, reduced pressure concentration is carried out, and drying is carried out to prepare modified nanometer silicon carbide.

[0013] Further, the drying box drying temperature is 70-75 DEG C.

[0014] Further, the temperature control temperature is-5-0 DEG C.

[0015] Further, the base catalyst is triethylamine or pyridine.

[0016] By the above technical solution, the silicon hydroxyl in the nanometer silicon carbide and the amino in the sulfamoyl chloride are condensed under the action of the corundum ball grinding to obtain the nanometer silicon carbide intermediate; the acyl chloride in the nanometer silicon carbide intermediate reacts with the secondary amine in the 1,3-di-4-piperidyl propane under the action of the catalyst to obtain the modified nanometer silicon carbide.

[0017] A preparation process of a nanometer silicon carbide / polypropylene composite material, comprising the following steps: Step one: polypropylene resin, modified nanometer silicon carbide, macromolecular flame retardant, dioctyl phthalate, talcum powder and antioxidant 1010 are placed in a mixing kettle, and are stirred uniformly to obtain a premix; Step two: the premix is placed in a double-screw extruder, the rotating speed of the extruder is set to 400-500 r / min, and the melt temperature is 190-200 DEG C to perform melt extrusion granulation to obtain the nanometer silicon carbide / polypropylene composite material.

[0018] The beneficial effects of the present application are: (1) When the material is heated, the ammonium polyphosphate decomposes to release acidic intermediates such as phosphoric acid and polyphosphoric acid. These acidic substances act as dehydration catalysts. Sorbitol contains a large number of hydroxyl groups, which rapidly dehydrate under acidic conditions to form unsaturated double bonds, which then crosslink and polymerize to form a dense carbon layer. The carbon layer has a porous structure and a very low thermal conductivity, effectively preventing heat from transferring to the interior of the material. At the same time, the carbon layer physically separates oxygen from the internal combustible material, cutting off the fuel supply for combustion, thus exhibiting strong flame retardant properties. Finally, through melt blending with polypropylene and modified nanometer silicon carbide, the nitrogen element in the modified nanometer silicon carbide and the phosphoric acid element in the macromolecular flame retardant synergistically retard flame, resulting in the polypropylene material prepared by the present application having excellent flame retardant properties.

[0019] (2) Nanometer silicon carbide itself has rigidity and weak breaking resistance, and is prone to breaking under external force. The modified nanometer silicon carbide prepared by the present application exhibits strong mechanical properties through chemical grafting of a rigid heterocyclic structure, and finally melt extrusion granulation with polypropylene, resulting in the prepared polypropylene composite material having high mechanical properties and flame retardancy.

[0020] Of course, implementing any product of the present application does not necessarily require achieving all the advantages described above. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0022] Embodiment 1, a production process of a nano silicon carbide / polypropylene composite material, comprising the following steps: Step one: according to the weight fraction, 50 parts of polypropylene resin, 5 parts of modified nano silicon carbide, 5 parts of macromolecular flame retardant, 0.5 parts of dioctyl phthalate, 2 parts of talc, 1 part of antioxidant 1010 are placed in a mixer, stirred uniformly, and a premix is prepared; Step two: the premix is placed in a twin-screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190 DEG C for melting extrusion granulation to prepare a nano silicon carbide / polypropylene composite material.

[0023] The preparation method of the macromolecular flame retardant comprises the following steps: Step A: 100 ml of ethanol and 5 ml of deionized water are added to a reactor, heated to 90 DEG C, stirred for 40 min, 10 g of ammonium polyphosphate and 5 g of 4-aminobenzaldehyde are added, the temperature is controlled at 65 DEG C, and stirring is carried out for 5 h. After the reaction is completed, it is cooled to room temperature, filtered, and a macromolecular flame retardant intermediate is prepared; Step B: 5 g of the macromolecular flame retardant intermediate is added to 80 ml of deionized water, 4.5 g of p-toluenesulfonic acid and 2.5 g of sorbitol are added, the temperature is raised to 70 DEG C, and the reaction is carried out for 6 h. A 30% sodium carbonate aqueous solution is added to adjust the pH to 7.5, and the product is dried in an oven after being concentrated under reduced pressure to prepare a macromolecular flame retardant.

[0024] The preparation method of the modified nano silicon carbide comprises the following steps: Step I: 5 g of nano silicon carbide is added to 50 ml of benzene, ultrasonic dispersion is carried out for 10 min, it is transferred to a ball mill tank, 1 g of aminosulfonyl chloride and 3 g of corundum balls are added, the ball mill tank is placed in a planetary ball mill, ball milling is carried out for 3 h, centrifugation is carried out, and drying is carried out in a 75 DEG C drying box to prepare a nano silicon carbide intermediate; Step II: 3 g of the nano silicon carbide intermediate is weighed and placed in 20 ml of diethyl ether, the temperature is controlled at-5 DEG C, 1.5 g of 1,3-di-4-piperidinyl propane is added, 0.5 g of triethylamine is added, after the addition is completed, the temperature is controlled at 0 DEG C, stirring is carried out for 5 h, after the reaction is completed, it is concentrated under reduced pressure, and drying is carried out to prepare modified nano silicon carbide.

[0025] Embodiment 2, a production process of a nano silicon carbide / polypropylene composite material, comprising the following steps: Step one: according to the weight fraction, 58 parts of polypropylene resin, 7 parts of modified nano silicon carbide, 7 parts of macromolecular flame retardant, 1 part of dioctyl phthalate, 3 parts of talc, 2 parts of antioxidant 1010 are placed in the mixing auxiliary, stirred uniformly, and the premix is prepared; Step two: the premix is placed in a double screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190℃ for melting extrusion granulation to prepare nano silicon carbide / polypropylene composite material.

[0026] The preparation method of the macromolecular flame retardant and the modified nano silicon carbide is the same as that of example 1.

[0027] Example 3, a production process of nano silicon carbide / polypropylene composite material, comprising the following steps: Step one: according to the weight fraction, 58 parts of polypropylene resin, 7 parts of modified nano silicon carbide, 7 parts of macromolecular flame retardant, 1 part of dioctyl phthalate, 3 parts of talc, 2 parts of antioxidant 1010 are placed in the mixing auxiliary, stirred uniformly, and the premix is prepared; Step two: the premix is placed in a double screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190℃ for melting extrusion granulation to prepare nano silicon carbide / polypropylene composite material.

[0028] The preparation method of the macromolecular flame retardant and the modified nano silicon carbide is the same as that of example 1.

[0029] Comparative example 1, a production process of nano silicon carbide / polypropylene composite material, comprising the following steps: Step one: according to the weight fraction, 58 parts of polypropylene resin, 7 parts of modified nano silicon carbide, 1 part of dioctyl phthalate, 3 parts of talc, 2 parts of antioxidant 1010 are placed in the mixing auxiliary, stirred uniformly, and the premix is prepared; Step two: the premix is placed in a double screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190℃ for melting extrusion granulation to prepare nano silicon carbide / polypropylene composite material.

[0030] The preparation method of the modified nano silicon carbide is the same as that of example 1.

[0031] Comparative example 2, a production process of nano silicon carbide / polypropylene composite material, comprising the following steps: Step one: according to the weight fraction, 58 parts of polypropylene resin, 7 parts of macromolecular flame retardant, 1 part of dioctyl phthalate, 3 parts of talc, 2 parts of antioxidant 1010 are placed in the mixing auxiliary, stirred uniformly, and the premix is prepared; Step two: the premix is placed in a twin-screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190℃ for melt extrusion granulation to prepare the nano-silicon carbide / polypropylene composite material.

[0032] The preparation method of the macromolecular flame retardant is the same as that in Example 1.

[0033] Comparative Example 3, a production process of a nano-silicon carbide / polypropylene composite material, comprising the following steps: Step one: 58 parts of polypropylene resin, 7 parts of nano-silicon carbide, 7 parts of macromolecular flame retardant, 1 part of dioctyl phthalate, 3 parts of talc, and 2 parts of antioxidant 1010 are placed in a mixer, stirred uniformly, and a premix is prepared; Step two: the premix is placed in a twin-screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190℃ for melt extrusion granulation to prepare the nano-silicon carbide / polypropylene composite material.

[0034] The preparation method of the macromolecular flame retardant is the same as that in Example 1.

[0035] The nano-silicon carbide is purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., and the product number is S799162.

[0036] Comparative Example 4, a production process of a nano-silicon carbide / polypropylene composite material, comprising the following steps: Step one: 58 parts of polypropylene resin, 1 part of dioctyl phthalate, 3 parts of talc, and 2 parts of antioxidant 1010 are placed in a mixer, stirred uniformly, and a premix is prepared; Step two: the premix is placed in a twin-screw extruder, the rotating speed of the extruder is set to 400 r / min, and the melting temperature is 190℃ for melt extrusion granulation to prepare the nano-silicon carbide / polypropylene composite material.

[0037] Test Example, the polypropylene nano-material prepared in Examples 1-3 and Comparative Examples 1-4 of the present application is made into a sample conforming to the test specification, the tensile strength of the sample is tested according to GB / T 1040.1-2018; the impact strength of the sample is tested according to GB / T 1843-2008; The flame retardant performance of the sample is tested according to GB / T2406.2-2009.

[0038]

[0039] It can be known from the experimental data that the rigidity and toughness of the polypropylene composite prepared by adding the modified nano silicon carbide are strong, the rigidity and toughness of the polypropylene composite prepared by adding the nano silicon carbide are general, the rigidity and toughness of the polypropylene composite prepared by not adding the modified nano silicon carbide and the nano silicon carbide are poor, the flame-retardant performance of the polypropylene composite prepared by adding the macromolecular flame retardant is excellent, and the flame-retardant performance of the polypropylene composite prepared by not adding the macromolecular flame retardant is poor. Therefore, the modified nano silicon carbide prepared by the application has strong mechanical properties, and the macromolecular flame retardant prepared by the application has excellent flame-retardant performance.

[0040] The above is only an example and description of the concept of the application, and those skilled in the art can make various modifications or supplements or replace with similar ways, as long as the concept of the application is not deviated or beyond the scope defined by the claims.

Claims

1. A nanosized silicon carbide / polypropylene composite, characterized in that According to the weight parts, including the following components: 50-70 parts of polypropylene resin, 5-8 parts of modified nano silicon carbide, 5-8 parts of macromolecular flame retardant, 2-3 parts of talcum powder, 1-2 parts of antioxidant 1010, 0.5-1 part of dioctyl phthalate.

2. The nanosized silicon carbide / polypropylene composite according to claim 1, characterized in that The preparation method of the macromolecular flame retardant comprises the following steps: Step A: ethanol and deionized water are added to a reactor, heated to 90-95 DEG C, stirred for 30-40 min, ammonium polyphosphate and 4-amino benzaldehyde are added, the temperature is controlled at 60-65 DEG C, and stirring is carried out for 4-5 h; after the reaction is completed, it is cooled to room temperature, filtered, and a macromolecular flame retardant intermediate is prepared; Step B: the macromolecular flame retardant intermediate is added to deionized water, a catalyst and sorbitol are added, the temperature is raised to 60-70 DEG C, and reaction is carried out for 5-6 h; 30-40% sodium carbonate aqueous solution is added to adjust the pH value, vacuum concentration is carried out, and the product is dried in an oven to prepare a macromolecular flame retardant.

3. The nanosized silicon carbide / polypropylene composite according to claim 2, characterized in that In step A, the volume ratio of the ethanol and deionized water is 1:0.05-0.

08.

4. The nanosized silicon carbide / polypropylene composite according to claim 2, characterized in that In step B, the catalyst is p-toluenesulfonic acid.

5. The nanosized silicon carbide / polypropylene composite according to claim 2, characterized in that In step B, the pH value is adjusted to 7.0-7.

5.

6. The nanosized silicon carbide / polypropylene composite according to claim 1, characterized in that The preparation method of the modified nano silicon carbide comprises the following steps: Step I: nano silicon carbide is added to benzene, ultrasonic dispersion is carried out for 5-10 min, it is transferred to a ball mill tank, amino sulfuryl chloride and corundum balls are added, the ball mill tank is placed in a planetary ball mill, ball milling is carried out for 2-3 h, centrifugation is carried out, and drying is carried out in a drying box to prepare a nano silicon carbide intermediate; Step II: the nano silicon carbide intermediate is weighed and placed in diethyl ether, 1,3-di-4-piperidinyl propane is added at a controlled temperature, an alkali catalyst is added, after addition is completed, the temperature is kept at 0-1 DEG C, stirring is carried out for 4-5 h, after the reaction is completed, vacuum concentration is carried out, and drying is carried out to prepare modified nano silicon carbide.

7. The nanosized silicon carbide / polypropylene composite according to claim 6, characterized in that In step I, the drying box drying temperature is 70-75 DEG C.

8. The nanosized silicon carbide / polypropylene composite according to claim 6, characterized in that In step II, the controlled temperature is -5-0 DEG C.

9. The nanosized silicon carbide / polypropylene composite according to claim 6, characterized in that In step II, the alkali catalyst is triethylamine or pyridine.

10. A process for preparing the nanosized silicon carbide / polypropylene composite of claim 1, characterized by, The following steps are included: Step one: polypropylene resin, modified nano silicon carbide, macromolecular flame retardant, dioctyl phthalate, talcum powder, and antioxidant 1010 are placed in a mixing kettle, stirring is carried out uniformly, and a premix is prepared; Step two: the premix is placed in a twin-screw extruder, the rotation speed of the extruder is set to 400-500 r / min, and the melting temperature is 190-200 DEG C for melt extrusion granulation to prepare a nano silicon carbide / polypropylene composite material.

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