A high-toughness and heat-conductive PC composite material and its preparation method

Abstract

The present invention relates to the technical field of polymer composite materials, and discloses a high-toughness and heat-conducting PC composite material and a preparation method thereof. The PC composite material in the present invention comprises the following raw materials in parts by weight: 70-90 parts of PC resin, 8-12 parts of modified polyurethane elastomer, 5-10 parts of heat-conducting filler, 0.1-0.5 part of antioxidant, and 0.2-0.5 part of lubricant; the composite material uses PC resin as the matrix, and adding a modified polyurethane elastomer improves the mechanical properties of the matrix and endows the matrix with high toughness; adding a heat-conducting filler forms a heat-conducting network in the matrix, making the matrix have excellent heat-conducting performance; in addition, through the synergistic effect between the two, the toughness and flame retardancy of the matrix are also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, and particularly relates to a high-toughness and heat-conducting PC composite material and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) material is one of the five widely used engineering plastics. With its unique high light transmittance, high refractive index, high impact resistance, dimensional stability, and easy processing and molding characteristics, it has a wide range of applications in various industries such as optical materials, electronic appliances, automobile manufacturing, packaging building materials, etc. However, the PC material still has some disadvantages and needs to be modified.

[0003] During the processing of PC materials, its specific chain segment structure and entanglement degree determine its excellent comprehensive performance. However, due to polycarbonate having a high crack initiation energy and a low crack propagation energy, it results in poor notch sensitivity and easy stress cracking, being restricted in the application of high-toughness materials, and its performance needs to be further improved. In addition, although the PC material has certain heat conductivity and flame retardancy, with the improvement of actual application requirements, the heat conductivity and flame retardancy of the PC material itself can no longer meet the needs. Therefore, researchers need to develop a PC composite material with high toughness, good heat conductivity, and good flame retardancy to meet the actual needs. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a high-toughness and heat-conducting PC composite material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A high-toughness and heat-conducting PC composite material, comprising the following raw materials in parts by weight: 70 - 90 parts of PC resin, 8 - 12 parts of modified polyurethane elastomer, 5 - 10 parts of heat-conducting filler, 0.1 - 0.5 part of antioxidant, and 0.2 - 0.5 part of lubricant;

[0007] The heat-conducting filler is prepared by the following steps:

[0008] Step A1: Disperse γ-aminopropyltriethoxysilane in ethanol, heat to 60°C and stir for 30 min, then heat to 70 - 80°C, add silicon carbide and deionized water and stir and react for 3 - 5 h, centrifuge, wash, and dry to obtain amino-functionalized silicon carbide;

[0009] Step A2: Disperse 2,5-diaminophenol hydrochloride and triethylamine evenly in N,N-dimethylformamide, then add cyanuric chloride and amino-functionalized silicon carbide and ultrasonically treat for 30 min, then transfer to an autoclave and react at 120 - 140°C for 8 - 12 h, and then centrifuge, wash, and dry to obtain silicon carbide@COF;

[0010] Step A3: Graft maleic anhydride onto polypropylene and add silicon carbide@COF to acetone for uniform dispersion. Slowly add 4-dimethylaminopyridine acetone solution dropwise, then successively add triethylamine, 2-chloro-1-methylpyridinium iodide, and dichloromethane, and react for 12 - 18 h under nitrogen conditions. Then perform rotary evaporation, washing, and freeze-drying to obtain the thermal conductive filler;

[0011] Further, in step A1, the dosage ratio of γ-aminopropyltriethoxysilane, ethanol, silicon carbide, and deionized water is 1 - 2 mL: 100 mL: 3 - 6 g: 10 mL;

[0012] Further, in step A2, the dosage ratio of 2,5-diaminophenol hydrochloride, triethylamine, N,N-dimethylformamide, cyanuric chloride, and aminated silicon carbide is 0.1 - 0.2 mol: 15 mL: 200 mL: 0.05 - 0.1 mol: 0.5 - 1.2 g;

[0013] Further, in step A3, the dosage ratio of maleic anhydride-grafted polypropylene, silicon carbide@COF, acetone, 4-dimethylaminopyridine acetone solution, triethylamine, 2-chloro-1-methylpyridinium iodide, and dichloromethane is 0.05 - 0.2 mol: 1 - 3 g: 200 mL: 30 mL: 0.05 - 0.15 mol: 0.001 - 0.003 mol: 20 mL. The 4-dimethylaminopyridine acetone solution is prepared by mixing 4-dimethylaminopyridine and acetone in a dosage ratio of 0.001 - 0.002 mol: 30 mL.

[0014] The modified polyurethane elastomer is prepared by the following steps:

[0015] Step B1: Under nitrogen conditions, mix allylamine and 3,5-dihydroxybenzoic acid evenly, and heat to 180 - 200 °C for reaction for 3 - 5 h. Then raise the temperature to 220 °C for reaction for 2 - 3 h, and then lower the temperature to room temperature. Collect the intermediate product, and then add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and azobisisobutyronitrile to the intermediate product and stir evenly. Then raise the temperature to 70 - 80 °C for reaction for 8 - 12 h, and filter to obtain the phosphorus-containing product;

[0016] Step B2: Disperse the phosphorus-containing product in acetonitrile, then add β-alanine and mix evenly, and heat to 65 - 75 °C for reflux reaction for 18 - 24 h. Perform rotary evaporation and drying to obtain the end-amino chain extender;

[0017] Step B3: Polyethylene glycol ( M n=(1000) is dehydrated under vacuum at 120 - 140 °C for 1 - 3 h, argon is introduced, then the temperature is lowered to 70 - 90 °C, isophorone diisocyanate and dibutyltin dilaurate are added and reacted for 2 - 4 h, then toluene and an end - amino chain extender are added and stirred and reacted for 2 - 3 h to obtain a modified polyurethane elastomer;

[0018] Further, in step B1, the dosage ratio of allylamine, 3,5 - dihydroxybenzoic acid, 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide and azobisisobutyronitrile is 0.01 - 0.02 mol: 0.015 - 0.03 mol: 0.01 - 0.02 mol: 0.08 - 0.16 g;

[0019] Further, in step B2, the dosage ratio of the phosphorus - containing product, acetonitrile and β - alanine is 0.01 - 0.03 mol: 200 mL: 0.012 - 0.035 mol;

[0020] Further, in step B3, the dosage ratio of polyethylene glycol, isophorone diisocyanate, dibutyltin dilaurate, toluene and an end - amino chain extender is 0.1 mol: 0.15 - 0.25 mol: 0.001 - 0.005 mol: 30 - 50 mL: 0.01 - 0.03 mol.

[0021] A preparation method of a high - toughness and heat - conductive PC composite material comprises the following steps:

[0022] Step S1, weigh raw materials by weight parts, add PC resin, modified polyurethane elastomer, heat - conductive filler, antioxidant and lubricant into a high - speed mixer, and under the conditions of 60 - 100 °C and 800 - 1200 rpm, mix and process for 5 - 10 min to obtain a mixed material;

[0023] Step S2, transfer the mixed material to a twin - screw extruder, extrude and pelletize to obtain a high - toughness and heat - conductive PC composite material;

[0024] Further, the temperatures of each section in the twin - screw extruder are: section 1: 220 - 240 °C, section 2: 230 - 250 °C, section 3: 240 - 250 °C, section 4: 255 - 265 °C, section 5: 260 - 270 °C, section 6: 270 - 280 °C, the head temperature is 270 - 290 °C, and the screw speed is 100 - 300 rpm / min.

[0025] The beneficial effects of the present invention:

[0026] The PC composite material in the present invention uses PC resin as the matrix, adds a modified polyurethane elastomer to improve the mechanical properties of the matrix and endows the matrix with high toughness; adds a thermal conductive filler to form a thermal conductive network in the matrix, making the matrix have excellent thermal conductivity; in addition, through their synergistic effect, the toughness and flame retardancy of the matrix are also improved.

[0027] Among the thermal conductive fillers, first, γ-aminopropyltriethoxysilane is used to modify the surface of silicon carbide to synthesize amino-functionalized silicon carbide; then, the amino groups on the surface of silicon carbide react with the -Cl groups in COF to form silicon carbide@COF containing hydroxyl groups; finally, maleic anhydride grafted polypropylene is used to coat silicon carbide@COF to synthesize the thermal conductive filler. The introduction of the thermal conductive filler can improve the thermal conductivity, flame retardancy and mechanical properties of the matrix; among them, synergistic effects can occur between silicon carbide and COF to form a thermal conductive network in the matrix and thus improve the thermal conductivity of the matrix. This is because silicon carbide itself has excellent thermal conductivity, and after its surface is coated with COF, the periodic layered structure and pore structure of COF are used to further improve the thermal conductivity of silicon carbide. Moreover, silicon carbide@COF modified by maleic anhydride grafted polypropylene has excellent dispersibility in the matrix, further improving the thermal conductivity of the matrix; the maleic anhydride groups in the filler can undergo an esterification reaction with the terminal hydroxyl groups generated after heating of PC, thus forming chemical bonds, and the polypropylene chain segments on the surface of the filler will entangle with the molecular chains of the modified polyurethane elastomer. Therefore, the filler can improve the interfacial compatibility between the PC and polyurethane molecular chains through esterification reactions and molecular chain entanglements, which helps the transfer of stress at the interface, avoids stress concentration, inhibits crack propagation, and improves the mechanical properties of the matrix; in addition, synergistic effects can also occur among silicon carbide, COF and polypropylene to endow the matrix with certain flame retardancy.

[0028] In the modified polyurethane elastomer, first, an intermediate product is synthesized by using the amide reaction between the amino group in allylamine and the hydroxyl group in 3,5-dihydroxybenzoic acid. Then, the double bond structure in the intermediate product reacts with the active hydrogen in 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to synthesize a phosphorus-containing product. Next, the hydroxyl group in the phosphorus-containing product undergoes an esterification reaction with the carboxyl group in β-alanine to obtain an amino-terminated chain extender. Finally, using polyethylene glycol, isophorone diisocyanate, and the amino-terminated chain extender as raw materials and dibutyltin dilaurate as a catalyst, a modified polyurethane elastomer is synthesized. The addition of the modified polyurethane elastomer can utilize its excellent toughness to improve the toughness of the matrix, and at the same time, can also improve the flame retardancy of the matrix. Among them, the amino-terminated chain extender introduced into the modified polyurethane elastomer can endow the matrix with more excellent toughness compared with the traditional hydroxyl-terminated chain extender. This is because the amino-terminated chain extender can expand the molecular chain and increase the molecular weight in the polyurethane molecular chain, thereby significantly improving the mechanical properties of the polyurethane elastomer. The 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide introduced into the amino-terminated chain extender endows the polyurethane elastomer with excellent flame retardancy and can cooperate with the heat-conducting filler for flame retardancy, making the matrix have a certain flame retardancy. Detailed implementation manners

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention. Embodiment

[0030] The heat-conducting filler is prepared by the following steps:

[0031] Step A1: Disperse 1 mL of γ-aminopropyltriethoxysilane in 100 mL of ethanol, heat it to 60 °C and stir for 30 min, then heat it to 70 °C, add 3 g of silicon carbide and 10 mL of deionized water, stir and react for 3 h, and then centrifuge, wash, and dry to obtain amino-functionalized silicon carbide.

[0032] Step A2: Disperse 0.1 mol of 2,5-diaminophenol hydrochloride and 15 mL of triethylamine evenly in 200 mL of N,N-dimethylformamide, then add 0.05 mol of cyanuric chloride and 0.5 g of amino-functionalized silicon carbide, ultrasonically treat for 30 min, then transfer it to an autoclave, react at 120 °C for 8 h, and then centrifuge, wash, and dry to obtain silicon carbide@COF.

[0033] Step A3: Disperse 0.05 mol of maleic anhydride grafted polypropylene and 1 g of silicon carbide@COF in 200 mL of acetone evenly. Slowly add 30 mL of 4-dimethylaminopyridine acetone solution dropwise. Then, add 0.05 mol of triethylamine, 0.001 mol of 2-chloro-1-methylpyridinium iodide, and 20 mL of dichloromethane in sequence, and react for 12 h under nitrogen atmosphere. Rotate evaporate, wash, and freeze-dry to obtain the thermal conductive filler. The 4-dimethylaminopyridine acetone solution is prepared by mixing 4-dimethylaminopyridine and acetone in a dosage ratio of 0.001 mol:30 mL.

[0034] The modified polyurethane elastomer is prepared by the following steps:

[0035] Step B1: Under nitrogen atmosphere, mix 0.01 mol of allylamine and 0.015 mol of 3,5-dihydroxybenzoic acid evenly, and heat to 180 °C for reaction for 3 h. Then, raise the temperature to 220 °C for reaction for 2 h. Then, lower the temperature to room temperature, collect the intermediate product. Then, add 0.01 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.08 g of azobisisobutyronitrile to the intermediate product and stir evenly. Then, raise the temperature to 70 °C for reaction for 8 h, and filter to obtain the phosphorus-containing product;

[0036] Step B2: Disperse 0.01 mol of the phosphorus-containing product in 200 mL of acetonitrile, then add 0.012 mol of β-alanine and mix evenly, and heat to 65 °C for reflux reaction for 18 h. Rotate evaporate and dry to obtain the amino-terminated chain extender;

[0037] Step B3: Dehydrate 0.1 mol of polyethylene glycol ( M n =1000) under vacuum at 120 °C for 1 h, introduce argon, then lower the temperature to 70 °C, add 0.15 mol of isophorone diisocyanate and 0.001 mol of dibutyltin dilaurate and react for 2 h. Then, add 30 mL of toluene and 0.01 mol of the amino-terminated chain extender and stir for reaction for 2 h to obtain the modified polyurethane elastomer.

[0038] Example 2

[0039] The thermal conductive filler is prepared by the following steps:

[0040] Step A1: Disperse 1.5 mL of γ-aminopropyltriethoxysilane in 100 mL of ethanol, and heat to 60 °C and stir for 30 min. Then, raise the temperature to 75 °C, add 4.5 g of silicon carbide and 10 mL of deionized water and stir for reaction for 4 h. Centrifuge, wash, and dry to obtain the amino-functionalized silicon carbide;

[0041] Step A2: Disperse 0.15 mol of 2,5-diaminophenol hydrochloride and 15 mL of triethylamine evenly in 200 mL of N,N-dimethylformamide. Then add 0.075 mol of cyanuric chloride and 0.8 g of aminated silicon carbide, and perform ultrasonic treatment for 30 min. Then transfer it to an autoclave and react at 130 °C for 10 h. After centrifugation, washing, and drying, silicon carbide@COF is obtained.

[0042] Step A3: Disperse 0.1 mol of maleic anhydride-grafted polypropylene and 2 g of silicon carbide@COF evenly in 200 mL of acetone. Slowly dropwise add 30 mL of 4-dimethylaminopyridine acetone solution. Then sequentially add 0.1 mol of triethylamine, 0.002 mol of 2-chloro-1-methylpyridinium iodide, and 20 mL of dichloromethane, and react under nitrogen conditions for 15 h. Perform rotary evaporation, washing, and freeze-drying to obtain the thermal conductive filler. The 4-dimethylaminopyridine acetone solution is prepared by mixing 4-dimethylaminopyridine and acetone in a dosage ratio of 0.0015 mol:30 mL.

[0043] The modified polyurethane elastomer is prepared by the following steps:

[0044] Step B1: Under nitrogen conditions, mix 0.015 mol of allylamine and 0.02 mol of 3,5-dihydroxybenzoic acid evenly, and heat to 190 °C for reaction for 4 h. Then raise the temperature to 220 °C for reaction for 2.5 h. Then lower the temperature to room temperature, collect the intermediate product, and add 0.015 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.12 g of azobisisobutyronitrile to the intermediate product and stir evenly. Then raise the temperature to 75 °C for reaction for 10 h, and filter to obtain the phosphorus-containing product.

[0045] Step B2: Disperse 0.02 mol of the phosphorus-containing product in 200 mL of acetonitrile, add 0.022 mol of β-alanine and mix evenly, and heat to 70 °C for reflux reaction for 22 h. Perform rotary evaporation and drying to obtain the end-amino chain extender.

[0046] Step B3: Dehydrate 0.1 mol of polyethylene glycol ( M n = 1000) under vacuum at 130 °C for 2 h. Introduce argon, then lower the temperature to 80 °C, add 0.2 mol of isophorone diisocyanate and 0.003 mol of dibutyltin dilaurate and react for 3 h. Then add 40 mL of toluene and 0.02 mol of the end-amino chain extender and stir and react for 2.5 h to obtain the modified polyurethane elastomer.

[0047] Example 3

[0048] The thermal conductive filler is prepared by the following steps:

[0049] Step A1: Disperse 2 mL of γ-aminopropyltriethoxysilane in 100 mL of ethanol, heat it to 60 °C and stir for 30 min, then heat it to 80 °C, add 6 g of silicon carbide and 10 mL of deionized water, stir and react for 5 h, centrifuge, wash, and dry to obtain amino-functionalized silicon carbide;

[0050] Step A2: Disperse 0.2 mol of 2,5-diaminophenol hydrochloride and 15 mL of triethylamine evenly in 200 mL of N,N-dimethylformamide, then add 0.1 mol of cyanuric chloride and 1.2 g of amino-functionalized silicon carbide, ultrasonically treat for 30 min, then transfer to an autoclave, react at 140 °C for 12 h, and then centrifuge, wash, and dry to obtain silicon carbide@COF;

[0051] Step A3: Disperse 0.2 mol of maleic anhydride-grafted polypropylene and 3 g of silicon carbide@COF evenly in 200 mL of acetone, slowly dropwise add 30 mL of 4-dimethylaminopyridine acetone solution, then sequentially add 0.15 mol of triethylamine, 0.003 mol of 2-chloro-1-methylpyridinium iodide, and 20 mL of dichloromethane, and react under nitrogen conditions for 18 h, rotary evaporate, wash, and freeze-dry to obtain a thermal conductive filler. The 4-dimethylaminopyridine acetone solution is prepared by mixing 4-dimethylaminopyridine and acetone in a dosage ratio of 0.002 mol:30 mL.

[0052] The modified polyurethane elastomer is prepared by the following steps:

[0053] Step B1: Under nitrogen conditions, mix 0.02 mol of allylamine and 0.03 mol of 3,5-dihydroxybenzoic acid evenly, heat to 200 °C and react for 5 h, then heat to 220 °C and react for 3 h, then lower the temperature to room temperature, collect the intermediate product, and then add 0.02 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.16 g of azobisisobutyronitrile to the intermediate product, stir evenly, then heat to 80 °C and react for 12 h, filter to obtain a phosphorus-containing product;

[0054] Step B2: Disperse 0.03 mol of the phosphorus-containing product in 200 mL of acetonitrile, then add 0.035 mol of β-alanine, mix evenly, and heat to 75 °C for reflux reaction for 24 h, rotary evaporate and dry to obtain an end-amino chain extender;

[0055] Step B3: 0.1 mol of polyethylene glycol ( M n= 1000) was dehydrated under vacuum at 140 °C for 3 h, argon was introduced, then the temperature was lowered to 90 °C, 0.25 mol of isophorone diisocyanate and 0.005 mol of dibutyltin dilaurate were added and reacted for 4 h, then 50 mL of toluene and 0.03 mol of chain extender with terminal amino group were added and stirred and reacted for 3 h to obtain the modified polyurethane elastomer.

[0056] Example 4

[0057] A preparation method of a high-toughness and heat-conducting PC composite material comprises the following steps:

[0058] 70 parts of PC resin, 8 parts of the modified polyurethane elastomer prepared in Example 1, 5 parts of the heat-conducting filler prepared in Example 1, 0.1 part of antioxidant H161, and 0.2 part of zinc stearate;

[0059] Step S1, weigh the raw materials according to parts by weight, add the PC resin, the modified polyurethane elastomer prepared in Example 1, the heat-conducting filler prepared in Example 1, antioxidant H161 and zinc stearate into a high-speed mixer, and under the conditions of 60 °C and 800 rpm, perform mixing treatment for 5 min to obtain a mixed material;

[0060] Step S2, transfer the mixed material to a twin-screw extruder, extrude and pelletize to obtain the high-toughness and heat-conducting PC composite material. The temperatures of each section in the twin-screw extruder are: section 1: 220 °C, section 2: 230 °C, section 3: 240 °C, section 4: 255 °C, section 5: 260 °C, section 6: 270 °C, the head temperature is 270 °C, and the screw speed is 100 rpm / min.

[0061] Example 5

[0062] A preparation method of a high-toughness and heat-conducting PC composite material comprises the following steps:

[0063] 80 parts of PC resin, 10 parts of the modified polyurethane elastomer prepared in Example 2, 7 parts of the heat-conducting filler prepared in Example 2, 0.3 part of antioxidant H161, and 0.4 part of zinc stearate;

[0064] Step S1, weigh the raw materials according to parts by weight, add the PC resin, the modified polyurethane elastomer prepared in Example 2, the heat-conducting filler prepared in Example 2, antioxidant H161 and zinc stearate into a high-speed mixer, and under the conditions of 80 °C and 1000 rpm, perform mixing treatment for 8 min to obtain a mixed material;

[0065] Step S2, transfer the mixed material to a twin-screw extruder, extrude and pelletize to obtain the high-toughness and heat-conducting PC composite material. The temperatures of each section in the twin-screw extruder are: section 1: 230 °C, section 2: 240 °C, section 3: 245 °C, section 4: 260 °C, section 5: 265 °C, section 6: 275 °C, the head temperature is 280 °C, and the screw speed is 200 rpm / min.

[0066] Example 6

[0067] A preparation method of a high-toughness and heat-conducting PC composite material comprises the following steps:

[0068] 90 parts of PC resin, 12 parts of the modified polyurethane elastomer prepared in Example 3, 10 parts of the heat-conducting filler prepared in Example 3, 0.5 part of antioxidant H161, and 0.5 part of zinc stearate;

[0069] Step S1, weigh the raw materials according to parts by weight, add the PC resin, the modified polyurethane elastomer prepared in Example 3, the heat-conducting filler prepared in Example 3, antioxidant H161, and zinc stearate into a high-speed mixer, and perform mixing treatment at 100°C and 200 rpm for 10 min to obtain a mixed material;

[0070] Step S2, transfer the mixed material to a twin-screw extruder for extrusion granulation to obtain the high-toughness and heat-conducting PC composite material. The temperatures of each section in the twin-screw extruder are as follows: section 1: 240°C, section 2: 250°C, section 3: 250°C, section 4: 265°C, section 5: 270°C, section 6: 280°C, the head temperature is 290°C, and the screw speed is 300 rpm / min.

[0071] Comparative Example 1

[0072] This comparative example is a PC composite material. The difference from Example 6 is that silicon carbide is used to replace the heat-conducting filler prepared in Example 3, and the rest are the same.

[0073] Comparative Example 2

[0074] This comparative example is a PC composite material. The difference from Example 6 is that a commercially available polyurethane elastomer is used to replace the modified polyurethane elastomer prepared in Example 3, and the rest are the same.

[0075] The PC composite materials in Examples 4 - 6 and Comparative Examples 1 - 2 are respectively injection-molded according to the ISO standard. After the injection-molded specimens are stabilized for 48 h at 23°C and a relative humidity of 50%, performance tests are carried out:

[0076] The test results are shown in the following table:

[0077] Tensile strength (MPa) Notched impact strength (J / m) <![CDATA[Thermal conductivity (W / m -1 K -1 )]]> Flame retardant rating Test standard GB / T 1040.2-2006 GB / T 1843-2006 ISO 22007-3-2012 UL94 VTM Example 4 68.61 56.4 5.6 VTM-0 Example 5 71.24 57.8 5.8 VTM-0 Example 6 74.56 59.1 6.1 VTM-0 Comparative example 1 65.27 54.2 2.6 VTM-1 Comparative example 2 62.43 49.6 4.7 VTM-1

[0078] As can be seen from the above table, after the PC composite material prepared by the present invention is tested for mechanical properties, thermal conductivity, and flame retardancy, the tensile strength is in the range of 68.61 MPa - 74.56 MPa, the notched impact strength is in the range of 56.4 J / m - 59.1 J / m, and the thermal conductivity is in the range of 5.6 W / m -1 K -1 -6.1 W / m-1 K -1 The flame retardant grades are all VTM-0, indicating that the composite material has excellent toughness, thermal conductivity and flame retardant properties.

[0079] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-toughness thermally conductive PC composite material, characterized in that: The invention comprises the following raw materials in parts by weight: 70-90 parts of PC resin, 8-12 parts of modified polyurethane elastomer, 5-10 parts of thermal conductive filler, 0.1-0.5 parts of antioxidant, and 0.2-0.5 parts of lubricant; The thermally conductive filler is prepared by the following steps: Step A1, dispersing γ-aminopropyltriethoxysilane in ethanol, heating to 60°C and stirring for 30 minutes, then heating to 70-80°C, adding silicon carbide and deionized water, stirring for 3-5 hours, centrifuging, washing, and drying to obtain amino silicon carbide; Step A2, 2,5-diaminophenol hydrochloride and triethylamine are uniformly dispersed in N,N-dimethylformamide, and then cyanuric chloride and amino silicon carbide are added and ultrasonically treated for 30 minutes, and then transferred to an autoclave, reacted at 120-140° C. for 8-12 hours, and then centrifuged, washed, and dried to obtain silicon carbide@COF; Step A3, adding maleic anhydride grafted polypropylene and silicon carbide @COF into acetone and dispersing them evenly, slowly dropping 4-dimethylaminopyridine acetone solution, and then sequentially adding triethylamine, 2-chloro-1-methylpyridinium iodide and dichloromethane, and reacting under nitrogen for 12-18 hours, rotary evaporation, washing, and freeze drying to obtain a thermal conductive filler; The modified polyurethane elastomer is prepared by the following steps: Step B1, under nitrogen conditions, allylamine and 3,5-dihydroxybenzoic acid are mixed evenly, and heated to 180-200 ° C for reaction for 3-5h, and then heated to 220 ° C for reaction for 2-3h, and then the temperature is lowered to room temperature, the intermediate product is collected, and 9,10-dihydro-9-oxa-10-phosphophananthrene-10-oxa and azobisisobutyronitrile are added to the intermediate product and stirred evenly, and then the temperature is raised to 70-80 ° C for reaction for 8-12h, and filtered to obtain a phosphorus-containing product; Step B2, dispersing the phosphorus-containing product in acetonitrile, adding β-alanine and mixing evenly, heating to 65-75° C. and reflux reaction for 18-24 hours, rotary evaporation and drying to obtain an amino-terminated chain extender; Step B3, dehydrate polyethylene glycol in vacuo at 120-140°C for 1-3h, introduce argon, then cool to 70-90°C, add isophorone diisocyanate and dibutyltin dilaurate to react for 2-4h, then add toluene and amino-terminated chain extender and stir to react for 2-3h to obtain modified polyurethane elastomer.

2. The high-toughness thermally conductive PC composite material according to claim 1, characterized in that: In step A1, the usage ratio of γ-aminopropyltriethoxysilane, ethanol, silicon carbide and deionized water is 1-2 mL: 100 mL: 3-6 g: 10 mL.

3. The high-toughness thermally conductive PC composite material according to claim 1, characterized in that: In step A2, the usage ratio of 2,5-diaminophenol hydrochloride, triethylamine, N,N-dimethylformamide, cyanuric chloride and amino silicon carbide is 0.1-0.2 mol: 15 mL: 200 mL: 0.05-0.1 mol: 0.5-1.2 g.

4. The high-toughness thermally conductive PC composite material according to claim 1, characterized in that: In step A3, the amount ratio of maleic anhydride grafted polypropylene, silicon carbide @COF, acetone, 4-dimethylaminopyridine acetone solution, triethylamine, 2-chloro-1-methylpyridinium iodide and dichloromethane is 0.05-0.2 mol: 1-3 g: 200 mL: 30 mL: 0.05-0.15 mol: 0.001-0.003 mol: 20 mL, and the 4-dimethylaminopyridine acetone solution is prepared by mixing 4-dimethylaminopyridine and acetone in a dosage ratio of 0.001-0.002 mol: 30 mL.

5. The high-toughness thermally conductive PC composite material according to claim 1, characterized in that: In step B1, the usage ratio of allylamine, 3,5-dihydroxybenzoic acid, 9,10-dihydro-9-oxa-10-phosphophanol-10-oxa and azobisisobutyronitrile is 0.01-0.02 mol: 0.015-0.03 mol: 0.01-0.02 mol: 0.08-0.16 g.

6. The high-toughness thermally conductive PC composite material according to claim 1, characterized in that: The usage ratio of the phosphorus-containing product, acetonitrile and β-alanine in step B2 is 0.01-0.03 mol:200 mL:0.012-0.035 mol.

7. The high-toughness thermally conductive PC composite material according to claim 1, characterized in that: In step B3, the usage ratio of polyethylene glycol, isophorone diisocyanate, dibutyltin dilaurate, toluene and amino-terminated chain extender is 0.1 mol: 0.15-0.25 mol: 0.001-0.005 mol: 30-50 mL: 0.01-0.03 mol.

8. A method for preparing the high-toughness thermally conductive PC composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step S1, weighing raw materials by weight, adding PC resin, modified polyurethane elastomer, thermal conductive filler, antioxidant and lubricant into a high-speed mixer, mixing for 5-10 minutes at 60-100° C. and 800-1200 rpm to obtain a mixture; Step S2: transferring the mixed material to a twin-screw extruder, extruding and granulating, and obtaining a high-toughness thermally conductive PC composite material.

9. The method for preparing a high-toughness thermally conductive PC composite material according to claim 8, characterized in that: The temperature of each section in the twin-screw extruder is: section 1: 220-240°C, section 2 230-250°C, section 3: 240-250°C, section 4 255-265°C, section 5: 260-270°C, section 6: 270-280°C, the head temperature is 270-290°C, and the screw speed is 100-300rpm / min.