A low linear expansion coefficient, high heat stability impact-resistant PC-ABS composite material and preparation method thereof

Abstract

The present invention provides a method for preparing an impact-resistant PC-ABS composite material with a low coefficient of linear expansion and high thermal stability, comprising the following steps: S1. A modified electrospun fiber membrane and maleic anhydride-grafted ABS are added to a solvent, the temperature is raised for reaction and maintained, then cooled to room temperature, and then ultrasonic and radiation treatments are carried out to obtain composite particles, wherein the electrospun fiber membrane is a modified polyimide fiber membrane; S2. The ABS resin particles and PC resin particles are fully dried, weighed according to the mass ratio of ABS:PC of 50-70:20-35, and the composite particles prepared in step S1 with a resin matrix mass fraction of 3-6.5 wt% are weighed; S3. The weighed ABS and PC are mixed evenly, heated to a molten state, and then the composite particles are added to the molten resin, and after double-screw extrusion, wire drawing and cooling granulation are carried out to obtain the filled PC-ABS resin alloy material. The PC-ABS composite material prepared by the present invention solves the thermal stability and impact resistance of traditional alloy materials.

Description

Technical Field

[0001] The present invention relates to the field of polymer material preparation, and particularly relates to a low linear expansion coefficient, high heat stability impact-resistant PC-ABS composite material and a preparation method thereof. Background Art

[0002] Composite materials play an increasingly important role in current industrial production. Among them, polymer matrix composite materials have the characteristics of light weight, high strength, easy processing, etc., and are widely used in practice. Especially in the field of heavy equipment manufacturing, with the implementation of the sustainable development strategy, the requirements for material selection are becoming more and more stringent. The most direct way to reduce the structural weight of products is to use high-performance composite materials to replace traditional metal alloy materials. In the past, single polymer resin materials could not meet the increasingly severe performance requirements. However, these two polymer resin materials, PC and ABS, have similar main chain structures and similar solubility parameters, which provides a theoretical basis for the preparation of polymer resin alloy materials.

[0003] PC / ABS is an alloy prepared by mixing polycarbonate and acrylonitrile-butadiene-styrene. Because of its excellent weather resistance, impact resistance, chemical stability and other advantages, it is often used in automotive decoration, furniture accessories, etc. With the continuous improvement of people's requirements for various performance of plastic alloys, improving the processing performance and service performance of PC / ABS has gradually become the focus of attention. Usually, researchers use methods such as chemical grafting or filler melt blending to improve the thermal stability, mechanical strength, etc. of PC / ABS. By filling polymer polymers with materials such as fillers, new composite materials with good application value can be obtained. However, the compatibility between different polymer resins and the interfacial adhesion between fillers and organic substances are important factors affecting the performance of composite materials, and the thermal stability and mechanical properties of current PC / ABS materials need to be improved. Summary of the Invention

[0004] Technical problems to be solved: The purpose of the present invention is to provide a low linear expansion coefficient, high heat stability impact-resistant PC-ABS composite material and a preparation method thereof, which improve the compatibility of ABS / PC resin and fillers in actual production, and improve the thermal stability and impact resistance.

[0005] Technical solution: A low linear expansion coefficient, high heat stability impact-resistant PC-ABS composite material and a preparation method thereof, including the following steps:

[0006] S1. Add the modified electrospun fiber membrane and maleic anhydride grafted ABS into a solvent, raise the temperature for reaction and keep warm, then cool down to room temperature, and then perform ultrasonic and radiation treatment to obtain composite particles, wherein the electrospun fiber membrane is a modified polyimide fiber membrane;

[0007] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 50 - 70:20 - 35, and also weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 3 - 6.5 wt%.

[0008] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles into the molten resin, and after double - screw extrusion, draw and cool to granulate to obtain the filled PC - ABS resin alloy material.

[0009] Preferably, in step S1, the temperature for the temperature - rising reaction is 120 - 140 °C, the heat - preservation time is 2 - 4 h, the radiation dose is 0.3 - 0.5 kGy / h, and the radiation time is 3 - 7 h.

[0010] Preferably, in step S3, the screw speed of the double - screw extruder is 120 - 160 r / min

[0011] Preferably, in step S3, the temperatures of each zone of the screw extruder are respectively: zone 1 is 220 - 230 °C, zone 2 is 230 - 240 °C, zone 3 is 240 - 245 °C, zone 4 is 245 - 250 °C, zone 5 is 250 - 260 °C, zone 6 is 250 - 260 °C, zone 7 is 245 - 255 °C, and the head is 240 - 250 °C.

[0012] Preferably, the preparation method of the modified polyimide fiber membrane includes the following steps:

[0013] S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches, control the solid content to be 10 - 15 wt%, and continue to react in an ice bath to obtain a light - yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution, and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.2 - 0.5 mm, and the porosity of the electrospun membrane is 90 - 95%;

[0014] S12. Cut the electrospun membrane prepared in step S11 to an area of 1.5 - 2.5 cm 2 in size, and then heat the electrospun membrane at different temperature gradients to obtain a polyimide fiber membrane;

[0015] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix and stir evenly. Then add the polyimide fiber membrane prepared in step S12 into it, stir and then perform suction filtration to disperse the fiber membrane. Place the suction - filtered polyimide fiber membrane in ethanol for aging, and after aging, perform supercritical drying to obtain a porous silica - modified polyimide fiber membrane;

[0016] S14. After drying the polyimide fiber membrane modified with porous silica prepared in step S13, it is added to xylene, and then KH560 is added, and the reaction is carried out at 120 - 140 °C to generate a silane-modified polyimide fiber membrane.

[0017] Preferably, in step S11, the mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.05 - 1.12, the temperature of the ice bath is -5 to 5 °C, and the reaction time of the ice bath is 2 - 5 h.

[0018] Preferably, in step S12, the temperature gradient is a thermal reaction at 50 °C for 0.5 - 1.5 h, a thermal reaction at 120 °C for 0.5 - 1.5 h, and finally a thermal reaction at 280 °C for 2.5 - 4 h.

[0019] Preferably, in step S13, the molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 0.8 - 1:6.7 - 8:4.5 - 5.5×10 -5 :2.6 - 3.5×10 -3 :4 - 5.

[0020] Beneficial effects: The low linear expansion coefficient, high thermal stability impact-resistant PC-ABS composite material and its preparation method of the present invention have the following advantages:

[0021] 1. In the present invention, a polyimide fiber membrane with a certain thickness and porosity is first prepared, and it is cut to a certain area size. In order to enable the fiber membrane to be fully mixed and dispersed evenly with PC / ABS, a layer of porous silica is attached to the surface of the prepared polyimide fiber membrane, and at the same time, the polyimide fiber membrane modified with porous silica is secondarily modified with a silane coupling agent, so that the fiber membrane and PC / ABS have good compatibility;

[0022] 2. In the present invention, porous silica is selected to modify the surface of the polyimide film instead of other porous materials because silica has good thermal stability;

[0023] 3. In the present invention, an electrospun fiber membrane is used, and combined with a porous silica gel attached to the surface of the fiber membrane, and the whole is used as a reinforcing material because the electrospun fiber membrane has a very high porosity, and the macromolecular chain segments can penetrate the fiber membrane, thereby improving the interfacial bonding ability between the fiber membrane and the alloy and improving the mechanical properties of the alloy material. Specific embodiments

[0024] The present invention will be further described below in conjunction with embodiments. The following embodiments are explanations of the present invention and the present invention is not limited to the following embodiments:

[0025] Example 1

[0026] A low linear expansion coefficient, high thermal stability impact-resistant PC-ABS composite material and its preparation method, comprising the following steps:

[0027] S1. Add the modified electrospun fiber membrane and maleic anhydride grafted ABS into a solvent. The mass ratio of the modified electrospun fiber membrane to maleic anhydride grafted ABS is 1:1. After heating the reaction and keeping it warm for 2 h, the temperature of the heating reaction is 140 °C. Cool down to room temperature, then perform ultrasonic and radiation treatment. The radiation dose is 0.3 kGy / h and the radiation time is 7 h to obtain composite particles, where the electrospun fiber membrane is a modified polyimide fiber membrane;

[0028] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC of 70:35, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 6.5 wt%;

[0029] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles into the molten resin. After double-screw extrusion, draw and cool to granulate to obtain the filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 160 r / min, and the temperatures of each zone of the screw extruder are 220 °C in zone 1, 230 °C in zone 2, 240 °C in zone 3, 245 °C in zone 4, 250 °C in zone 5, 250 °C in zone 6, 245 °C in zone 7, and 240 °C at the die head;

[0030] Among them, the preparation method of the modified polyimide fiber membrane comprises the following steps:

[0031] S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.05. Control the solid content to be 15 wt%, and continue the reaction under the ice bath. The temperature of the ice bath is -5 °C, and the reaction time of the ice bath is 5 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.2 mm, and the porosity of the electrospun membrane is 92.5%;

[0032] S12. Cut the electrospun membrane prepared in step S11 into an electrospun membrane with an area of 1.5 cm 2 in size, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is a thermal reaction at 50 °C for 1.5 h, a thermal reaction at 120 °C for 0.5 h, and finally a thermal reaction at 280 °C for 4 h to obtain a polyimide fiber membrane;

[0033] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix well by stirring. Then add the polyimide fiber membrane prepared in step S12 into it. After stirring, perform suction filtration to disperse the fiber membrane. Place the suction-filtered polyimide fiber membrane in ethanol for aging. After aging, perform supercritical drying to obtain a polyimide fiber membrane modified with porous silica. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 0.8:6.7:4.5×10 -5 :2.6×10 -3 :4;

[0034] S14. After drying the polyimide fiber membrane modified with porous silica prepared in step S13, add it into xylene, then add KH560 and react at 120 °C to produce a silane-modified polyimide fiber membrane.

[0035] Example 2

[0036] A low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material and its preparation method, comprising the following steps:

[0037] S1. Add the modified electrospun fiber membrane and maleic anhydride-grafted ABS into a solvent. The mass ratio of the modified electrospun fiber membrane to maleic anhydride-grafted ABS is 1:1. After heating the reaction and holding for 4 h, the temperature of the heating reaction is 120 °C. Cool down to room temperature, then perform ultrasonic and radiation treatment. The radiation dose is 0.5 kGy / h and the radiation time is 3 h to obtain composite particles, wherein the electrospun fiber membrane is a modified polyimide fiber membrane;

[0038] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 50:20, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 3 wt%;

[0039] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles into the molten resin. After double-screw extrusion, draw and cool to granulate to obtain a filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 120 r / min, and the temperatures of each zone of the screw extruder are 230 °C in zone 1, 240 °C in zone 2, 245 °C in zone 3, 250 °C in zone 4, 260 °C in zone 5, 260 °C in zone 6, 255 °C in zone 7, and 250 °C at the head;

[0040] Among them, the preparation method of the modified polyimide fiber membrane comprises the following steps:

[0041] S11. Add 4,4'-diaminodiphenyl ether to N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.12. Control the solid content to be 10 wt%. Continue the reaction under the ice bath. The temperature of the ice bath is 5 °C, and the reaction time under the ice bath is 2 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.5 mm, and the porosity of the electrospun membrane is 91.6%;

[0042] S12. Cut the electrospun membrane prepared in step S11 into an electrospun membrane with an area of 2.5 cm 2 in size, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is a thermal reaction at 50 °C for 0.5 h, a thermal reaction at 120 °C for 1.5 h, and finally a thermal reaction at 280 °C for 2.5 h to obtain a polyimide fiber membrane;

[0043] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix and stir evenly. Then add the polyimide fiber membrane prepared in step S12 into it. After stirring, perform suction filtration to disperse the fiber membrane. Place the suction-filtered polyimide fiber membrane in ethanol for aging. After aging, perform supercritical drying to obtain a polyimide fiber membrane modified with porous silica. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 1:8:5.5×10 -5 :3.5×10 -3 :5;

[0044] S14. After drying the polyimide fiber membrane modified with porous silica prepared in step S13, add it to xylene, and then add KH560 and react at 140 °C to generate a silane-modified polyimide fiber membrane.

[0045] Example 3

[0046] A low coefficient of linear expansion and high thermal stability impact-resistant PC-ABS composite material and its preparation method, including the following steps:

[0047] S1. Add the modified electrospun fiber membrane and maleic anhydride-grafted ABS to a solvent. The mass ratio of the modified electrospun fiber membrane to maleic anhydride-grafted ABS is 1:1. Raise the temperature for reaction and keep it warm for 4 h. The temperature of the temperature-raising reaction is 135 °C. Cool down to room temperature, and then perform ultrasonic and radiation treatment. The radiation dose is 0.4 kGy / h, and the radiation time is 5 h to obtain composite particles, where the electrospun fiber membrane is a modified polyimide fiber membrane;

[0048] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 65:30, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 4.8 wt%.

[0049] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles to the molten resin, and after double-screw extrusion, draw and cool to granulate to obtain the filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 150 r / min, and the temperatures of each zone of the screw extruder are 230 °C in zone 1, 240 °C in zone 2, 245 °C in zone 3, 250 °C in zone 4, 260 °C in zone 5, 260 °C in zone 6, 255 °C in zone 7, and 240 °C at the die head;

[0050] Among them, the preparation method of the modified polyimide fiber membrane includes the following steps:

[0051] S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.08, control the solid content to be 12 wt%, continue to react under the ice bath, the temperature of the ice bath is 5 °C, and the reaction time of the ice bath is 3 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.3 mm, and the porosity of the electrospun membrane is 92.2%;

[0052] S12. Cut the electrospun membrane prepared in step S11 to an area of 1.6 cm 2 sized electrospun membrane, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is to conduct a thermal reaction at 50 °C for 1 h, a thermal reaction at 120 °C for 0.5 h, and finally a thermal reaction at 280 °C for 3 h to obtain a polyimide fiber membrane;

[0053] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix and stir evenly. Then add the polyimide fiber membrane prepared in step S12, stir and then perform suction filtration to disperse the fiber membrane. Place the suction-filtered polyimide fiber membrane in ethanol for aging, and perform supercritical drying after aging to obtain a porous silica-modified polyimide fiber membrane. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 1:7.5:5.5×10 -5 :3.2×10 -3 :5;

[0054] S14. After drying the polyimide fiber membrane modified with porous silica prepared in step S13, add it to xylene, then add KH560, and react at 120 °C to produce a silane-modified polyimide fiber membrane.

[0055] Example 4

[0056] A low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material and its preparation method, including the following steps:

[0057] S1. Add the modified electrospun fiber membrane and maleic anhydride-grafted ABS to a solvent. The mass ratio of the modified electrospun fiber membrane to maleic anhydride-grafted ABS is 1:1. After heating the reaction and maintaining the temperature for 4 h, the temperature of the heating reaction is 125 °C. Then cool to room temperature, and then perform ultrasonic and radiation treatment. The radiation dose is 0.5 kGy / h, and the radiation time is 6 h to obtain composite particles, where the electrospun fiber membrane is a modified polyimide fiber membrane;

[0058] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC of 55:25, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 5.5 wt%;

[0059] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles to the molten resin, and after double-screw extrusion, draw and cool to granulate to obtain the filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 140 r / min, and the temperatures of each zone of the screw extruder are 220 °C in zone 1, 230 °C in zone 2, 240 °C in zone 3, 245 °C in zone 4, 260 °C in zone 5, 250 °C in zone 6, 245 °C in zone 7, and 240 °C at the die head;

[0060] Among them, the preparation method of the modified polyimide fiber membrane includes the following steps:

[0061] S11. Add 4,4'-diaminodiphenyl ether, and then add N,N'-dimethylformamide. After stirring in an ice bath, then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.11. Control the solid content to be 14 wt%, and continue to react in an ice bath. The temperature of the ice bath is -5 °C, and the reaction time in the ice bath is 4 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution, and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.4 mm, and the porosity of the electrospun membrane is 93.8%;

[0062] S12. Cut the electrospun membrane prepared in step S11 to an area of 2.0 cm 2Electrospun membranes of a certain size were then heated at different temperature gradients, with a thermal reaction at 50 °C for 1.5 h, a thermal reaction at 120 °C for 1 h, and finally a thermal reaction at 280 °C for 3.5 h to obtain polyimide fiber membranes;

[0063] S13. Ethanol and tetraethyl orthosilicate were mixed, and then oxalic acid was added for hydrolysis. After complete hydrolysis, ammonia water was added and mixed and stirred evenly. Then, the polyimide fiber membrane prepared in step S12 was added thereto. After stirring, suction filtration was carried out to disperse the fiber membrane. The suction-filtered polyimide fiber membrane was aged in ethanol and then subjected to supercritical drying to obtain a polyimide fiber membrane modified with porous silica. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water was 0.8:7:4.5×10 -5 :2.8×10 -3 :4;

[0064] S14. The porous silica-modified polyimide fiber membrane prepared in step S13 was dried and then added to xylene, and then KH560 was added, and reacted at 140 °C to form a silane-modified polyimide fiber membrane.

[0065] Example 5

[0066] A low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material and its preparation method, including the following steps:

[0067] S1. The modified electrospun fiber membrane and maleic anhydride-grafted ABS were added to a solvent. The mass ratio of the modified electrospun fiber membrane to maleic anhydride-grafted ABS was 1:1. After heating and reacting and holding for 3.5 h, the temperature of the heating reaction was 130 °C, and then cooled to room temperature. Then, ultrasonic and radiation treatment was carried out. The radiation dose was 0.4 kGy / h, and the radiation time was 5 h to obtain composite particles, where the electrospun fiber membrane was a modified polyimide fiber membrane;

[0068] S2. The ABS resin particles and PC resin particles were fully dried, weighed according to the mass ratio of ABS:PC of 60:28, and the composite particles prepared in step S1 with a resin matrix mass fraction of 5 wt% were weighed;

[0069] S3. The weighed ABS and PC were mixed evenly, heated to a molten state, and then the composite particles were added to the molten resin. After being extruded by a twin-screw extruder and drawn and cooled to form pellets, a filled PC-ABS resin alloy material was obtained. Among them, the screw speed of the twin-screw extruder was 140 - 150 r / min, and the temperatures of each zone of the screw extruder were 220 °C in zone 1, 230 °C in zone 2, 240 °C in zone 3, 250 °C in zone 4, 255 °C in zone 5, 255 °C in zone 6, 245 °C in zone 7, and 240 °C at the die head;

[0070] Among them, the preparation method of the modified polyimide fiber membrane includes the following steps:

[0071] S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.1. Control the solid content to be 12 wt%. Continue to react under the ice bath. The temperature of the ice bath is 0 °C, and the reaction time of the ice bath is 4 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution, and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.3 mm, and the porosity of the electrospun membrane is 94.5%;

[0072] S12. Cut the electrospun membrane prepared in step S11 to an area of 1.7 cm 2 sized electrospun membrane, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is a thermal reaction at 50 °C for 1 h, a thermal reaction at 120 °C for 1 h, and finally a thermal reaction at 280 °C for 3 h to obtain a polyimide fiber membrane;

[0073] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix and stir evenly. Then add the polyimide fiber membrane prepared in step S12 into it. After stirring, perform suction filtration to disperse the fiber membrane. Place the suction-filtered polyimide fiber membrane in ethanol for aging, and perform supercritical drying after aging to obtain a polyimide fiber membrane modified with porous silica. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 0.8:7:5×10 -5 :3×10 -3 :4.5;

[0074] S14. Dry the polyimide fiber membrane modified with porous silica prepared in step S13, add it to xylene, and then add KH560 and react at 130 °C to generate a silane-modified polyimide fiber membrane.

[0075] Comparative Example 1

[0076] A PC-ABS composite material and its preparation method include the following steps:

[0077] S1. Add the electrospun fiber membrane and maleic anhydride-grafted ABS into a solvent. The mass ratio of the electrospun fiber membrane to maleic anhydride-grafted ABS is 1:1. After heating and reacting and holding for 4 h, the temperature of the heating reaction is 125 °C. Cool to room temperature, and then perform ultrasonic and radiation treatment. The radiation dose is 0.5 kGy / h, and the radiation time is 6 h to obtain composite particles, where the electrospun fiber membrane is a polyimide fiber membrane;

[0078] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 55:25, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 5.5 wt%.

[0079] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles into the molten resin, and after double-screw extrusion, draw, cool, and pelletize to obtain the filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 140 r / min, and the temperatures of each zone of the screw extruder are 220 °C in zone 1, 230 °C in zone 2, 240 °C in zone 3, 245 °C in zone 4, 260 °C in zone 5, 250 °C in zone 6, 245 °C in zone 7, and 240 °C at the die head.

[0080] Among them, the preparation method of the modified polyimide fiber membrane includes the following steps:

[0081] S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.11, control the solid content to be 14 wt%, continue the reaction under the ice bath, the temperature of the ice bath is -5 °C, and the reaction time of the ice bath is 4 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.4 mm, and the porosity of the electrospun membrane is 93.8%.

[0082] S12. Cut the electrospun membrane prepared in step S11 into an electrospun membrane with an area of 2.0 cm 2 in size, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is to conduct a thermal reaction at 50 °C for 1.5 h, at 120 °C for 1 h, and finally at 280 °C for 3.5 h to obtain a polyimide fiber membrane.

[0083] Comparative Example 2

[0084] A PC-ABS composite material and its preparation method include the following steps:

[0085] S1. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 60:28, and weigh the silane-modified polyimide fiber membrane particles with a resin matrix mass fraction of 5 wt%.

[0086] S2. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the silane-modified polyimide fiber membrane particles to the molten resin. After double-screw extrusion, draw and cool to granulate to obtain the filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 140 - 150 r / min, and the temperatures of each zone of the screw extruder are 220 °C in zone 1, 230 °C in zone 2, 240 °C in zone 3, 250 °C in zone 4, 255 °C in zone 5, 255 °C in zone 6, 245 °C in zone 7, and 240 °C at the die head;

[0087] Among them, the preparation method of the modified polyimide fiber membrane particles includes the following steps:

[0088] S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.1. Control the solid content to be 12 wt%, and continue to react under the ice bath. The temperature of the ice bath is 0 °C, and the reaction time of the ice bath is 4 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution, and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.3 mm, and the porosity of the electrospun membrane is 94.5%;

[0089] S12. Cut the electrospun membrane prepared in step S11 to an area of 1.7 cm 2 sized electrospun membrane, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is a thermal reaction at 50 °C for 1 h, a thermal reaction at 120 °C for 1 h, and finally a thermal reaction at 280 °C for 3 h to obtain a polyimide fiber membrane;

[0090] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix and stir evenly. Then add the polyimide fiber membrane prepared in step S12 into it. After stirring, perform suction filtration to disperse the fiber membrane. Place the suction-filtered polyimide fiber membrane in ethanol for aging, and perform supercritical drying after aging to obtain a porous silica-modified polyimide fiber membrane. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 0.8:7:5×10 -5 :3×10 -3 :4.5;

[0091] S14. Dry the porous silica-modified polyimide fiber membrane prepared in step S13, add it to xylene, and then add KH560. React at 130 °C to generate a silane-modified polyimide fiber membrane.

[0092] Comparative Example 3

[0093] A low linear expansion coefficient, high thermal stability impact-resistant PC-ABS composite material and a preparation method thereof, comprising the following steps:

[0094] S1. Add the modified electrospun fiber membrane and ABS into a solvent. The mass ratio of the modified electrospun fiber membrane to ABS is 1:1. After heating and reacting and keeping warm for 3.5 h, the temperature of the heating reaction is 130 °C. Then cool down to room temperature, and then perform ultrasonic and radiation treatment. The radiation dose is 0.4 kGy / h and the radiation time is 5 h to obtain composite particles, wherein the electrospun fiber membrane is a modified polyimide fiber membrane;

[0095] S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 60:28, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 5 wt%;

[0096] S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles into the molten resin, and after double-screw extrusion, draw and cool to granulate to obtain the filled PC-ABS resin alloy material. Among them, the screw speed of the double-screw extruder is 140 - 150 r / min, and the temperatures of each zone of the screw extruder are 220 °C in the first zone, 230 °C in the second zone, 240 °C in the third zone, 250 °C in the fourth zone, 255 °C in the fifth zone, 255 °C in the sixth zone, 245 °C in the seventh zone, and 240 °C at the head;

[0097] Among them, the preparation method of the modified polyimide fiber membrane comprises the following steps:

[0098] S11. Add 4,4'-diaminodiphenyl ether, and then add N,N'-dimethylformamide. After stirring in an ice bath, then add pyromellitic dianhydride in batches. The mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.1. Control the solid content to be 12 wt%, and continue to react in the ice bath. The temperature of the ice bath is 0 °C, and the reaction time in the ice bath is 4 h to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.3 mm, and the porosity of the electrospun membrane is 94.5%;

[0099] S12. Cut the electrospun membrane prepared in step S11 into an electrospun membrane with an area of 1.7 cm 2 in size, and then heat the electrospun membrane at different temperature gradients. The temperature gradient is to perform a thermal reaction at 50 °C for 1 h, a thermal reaction at 120 °C for 1 h, and finally a thermal reaction at 280 °C for 3 h to obtain a polyimide fiber membrane;

[0100] S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix well by stirring. Then add the polyimide fiber membrane prepared in step S12 into it. After stirring, perform suction filtration to disperse the fiber membrane. Place the suction-filtered polyimide fiber membrane in ethanol for aging. After aging, perform supercritical drying to obtain a polyimide fiber membrane modified with porous silica. The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water is 0.8:7:5×10 -5 :3×10 -3 :4.5.

[0101] Performance test: Conducted in accordance with GB / T 1043.1-2008. The bottom radius of the Type A notch prepared on the specimen bar is 0.25 ± 0.05 mm; perform thermal analysis using a thermal analyzer and record the initial temperature of thermal decomposition; use ISO11359-2-2004 to test the linear thermal expansion coefficient. The specific test results are shown in the following table.

[0102] <![CDATA[Coefficient of linear expansion (10 -5 / °C)]]> Initial decomposition temperature (°C) <![CDATA[Impact toughness (kJ / m 2 ).]]> Example 1 3.3 384 36.5 Example 2 3.4 385 37.1 Example 3 3.2 385 36.6 Example 4 3.2 389 37.0 Example 5 3.3 388 36.8 Comparative Example 1 4.2 365 34.5 Comparative Example 2 3.8 374 32.2 Comparative Example 3 3.6 377 33.3

[0103] As can be seen from the above table, the modification of silica and the surface modification of the final fiber membrane, etc. all have an impact on the performance of the PC / ABS alloy material.

[0104] Obviously, the above embodiments are merely examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or alterations derived therefrom are still within the protection scope of this invention.

Claims

1. A preparation method of an impact-resistant PC-ABS composite material with a low linear expansion coefficient and high thermal stability, characterized in that, It includes the following steps: S1. Add the modified electrospun fiber membrane and maleic anhydride grafted ABS into a solvent, raise the temperature for reaction and keep it warm, then cool it down to room temperature, and then perform ultrasonic and radiation treatment to obtain composite particles, where the electrospun fiber membrane is a modified polyimide fiber membrane; S2. Thoroughly dry the ABS resin particles and PC resin particles, weigh them according to the mass ratio of ABS:PC being 50 - 70:20 - 35, and weigh the composite particles prepared in step S1 with a resin matrix mass fraction of 3 - 6.5 wt%; S3. Mix the weighed ABS and PC evenly, heat them to a molten state, then add the composite particles into the molten resin, and after double - screw extrusion, draw and cool to granulate to obtain the filled PC - ABS resin alloy material; Among them, the preparation method of the modified polyimide fiber membrane includes the following steps: S11. Add 4,4'-diaminodiphenyl ether, then add N,N'-dimethylformamide, stir in an ice bath, and then add pyromellitic dianhydride in batches, control the solid content to be 10 - 15 wt%, and continue the reaction under ice bath to obtain a light yellow viscous polyamic acid solution. Use the polyamic acid solution as the spinning solution, and prepare an electrospun membrane by electrospinning. The thickness of the electrospun membrane is 0.2 - 0.5 mm, and the porosity of the electrospun membrane is 90 - 95%; S12. Cut the electrospun membrane prepared in step S11 into an electrospun membrane with an area of 1.5 - 2.5 cm 2 in size, and then heat the electrospun membrane at different temperature gradients to obtain a polyimide fiber membrane; S13. Mix ethanol and tetraethyl orthosilicate, then add oxalic acid for hydrolysis. After complete hydrolysis, add ammonia water and mix and stir evenly. Then add the polyimide fiber membrane prepared in step S12 into it, stir and then perform suction filtration to disperse the fiber membrane. Place the suction - filtered polyimide fiber membrane in ethanol for aging, and perform supercritical drying after aging to obtain a porous silica - modified polyimide fiber membrane; S14. Dry the porous silica - modified polyimide fiber membrane prepared in step S13 and add it into xylene, then add KH560, and react at 120 - 140 °C to generate a silane - modified polyimide fiber membrane.

2. The preparation method of the low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material according to claim 1, wherein: In step S1, the temperature for the temperature - raising reaction is 120 - 140 °C, the heat - preservation time is 2 - 4 h, the radiation dose is 0.3 - 0.5 kGy / h, and the radiation time is 3 - 7 h.

3. The preparation method of the low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material according to claim 1, characterized in that: In step S3, the screw speed of the double - screw extruder is 120~160 r / min.

4. The preparation method of the low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material according to claim 1, characterized in that: In step S3, the temperatures of each zone of the screw extruder are 220 - 230 °C for zone 1, 230 - 240 °C for zone 2, 240 - 245 °C for zone 3, 245 - 250 °C for zone 4, 250 - 260 °C for zone 5, 250 - 260 °C for zone 6, 245 - 255 °C for zone 7, and 240 - 250 °C for the die head.

5. The preparation method of the low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material according to claim 1, characterized in that: In step S11, the mass ratio of 4,4'-diaminodiphenyl ether to pyromellitic dianhydride is 1:1.05 - 1.12, the temperature of the ice bath is - 5~5 °C, and the ice - bath reaction time is 2 - 5 h.

6. The preparation method of the low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material according to claim 1, characterized in that: In step S12, the temperature gradient is a thermal reaction at 50 °C for 0.5 - 1.5 h, a thermal reaction at 120 °C for 0.5 - 1.5 h, and finally a thermal reaction at 280 °C for 2.5 - 4 h.

7. The preparation method of the low linear expansion coefficient and high thermal stability impact-resistant PC-ABS composite material according to claim 1, characterized in that: The molar ratio of tetraethyl orthosilicate / ethanol / oxalic acid / ammonia / water in the step S13 is 0.8-1:6.7-8:4.5-5.5×10 -5 :2.6-3.5×10 -3 :4-5.