阅读说明：本技术 一种双模碳纤维及其制备方法和在pc/abs合金材料中的应用 (Dual-mode carbon fiber, preparation method thereof and application thereof in PC/ABS alloy material ) 是由 刘春艳 王慧珊 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种双模碳纤维及其制备方法和在PC/ABS合金材料中的应用,这种双模碳纤维,其组分和含量如下：纳米级碳纤维5-100g；微米级碳纤维20-100g；混合酸10-500ml；硫酸10-500ml；丙酮50-500ml；高锰酸钾5-500g；马来酸10-500ml。利用纳米级碳纤维具有增强增韧作用,微米级碳纤维网络对于聚合物导热特性具有显著增强的特点,首次实现其有效复合,使聚合物兼具两者特性。即在高温条件下,羧基化处理的纳米级碳纤维,其羧基处于活性状态,与羟基化的微米级碳纤维可以实现部分酯化。同时由于微米级碳纤维的石墨化结构,极易吸附纳米级碳纤维颗粒,以范德华力相互作用,形成表面与边缘束缚的微米-纳米级双模结构碳纤维。(The invention discloses a double-mode carbon fiber, a preparation method thereof and application thereof in PC/ABS alloy materials, wherein the double-mode carbon fiber comprises the following components in percentage by weight: 5-100g of nano carbon fiber; 20-100g of micron-sized carbon fibers; 10-500ml of mixed acid; 10-500ml of sulfuric acid; 50-500ml of acetone; 5-500g of potassium permanganate; 10-500ml of maleic acid. The nanometer carbon fiber has the reinforcing and toughening functions, and the micron carbon fiber network has the characteristic of obviously reinforcing the heat conducting property of the polymer, so that the polymer has the characteristics of the nanometer carbon fiber and the micron carbon fiber for the first time. Namely, under the condition of high temperature, carboxyl of the carboxylated nano-scale carbon fiber is in an active state, and partial esterification can be realized with the hydroxylated micro-scale carbon fiber. Meanwhile, due to the graphitized structure of the micron-scale carbon fiber, the nano-scale carbon fiber particles are easily adsorbed, and the micron-scale and nano-scale double-mode structure carbon fiber with the bound surface and edge is formed under the interaction of Van der Waals force.)

1. A bimodal carbon fiber characterized by: comprises the following components in percentage by weight:

2. the bimodal carbon fiber as claimed in claim 1, wherein: the length of the nano-scale carbon fiber is 80-200 nm; the length of the micron-sized carbon fiber is 5-20 μm.

3. The bimodal carbon fiber as claimed in claim 1, wherein: in the mixed acid, concentrated sulfuric acid accounts for 1-50% by mass; 1-50% of nitric acid and 1-40% of hydrochloric acid.

4. The bimodal carbon fiber as claimed in claim 1, wherein: the sulfuric acid is 5-40% by mass.

5. A process for preparing the bimodal carbon fiber as claimed in any one of claims 1 to 4, characterized in that: the method comprises the following steps:

(1) performing surface carboxylation treatment on the nano-scale carbon fiber: weighing 5-100g of nano-scale carbon fiber, immersing the nano-scale carbon fiber into 10-1000ml of mixed acid solution, carrying out ultrasonic treatment for 5-500kHz for 5-50h, then putting the nano-scale carbon fiber into a 100-plus 200 ℃ oil bath pot for reaction for 2-4h, then carrying out centrifugal cleaning, carrying out freeze drying after cleaning at the rotation number of 1000-plus 10000rap, and using the nano-scale carbon fiber for subsequent dual-mode assembly;

(2) meanwhile, carrying out hydroxylation treatment on the micron-sized carbon fibers: dissolving 20-100g of micron-sized carbon fiber in an acetone solution, soaking the mixture for 5-10h by ultrasonic at 5-500kHz, volatilizing the acetone, dissolving the acetone again in 10-500ml of a mixed solution of sulfuric acid and maleic acid, dropwise adding 0.5g/ml of a potassium permanganate solution, putting the mixture into an oil bath kettle at 50-70 ℃ for reaction for 2-4h, and then carrying out centrifugal cleaning with the rotation number of 1000 plus 10000 rap;

(3) the cleaned sample can be directly dissolved in acetone solution without freeze drying, and the carboxylated nano-scale carbon fiber is added for ultrasonic treatment for 4-8h at the high temperature of 100-; finally, volatilizing the acetone to obtain the target sample.

6. A high-toughness, flame-retardant, good heat-dissipating PC/ABS composite comprising the bimodal carbon fiber of any of claims 1-4, characterized in that: the composite material comprises the following raw materials in percentage by weight:

7. the PC/ABS composite material of claim 6, wherein: the PC is bisphenol A type aromatic polycarbonate and has the weight-average molecular weight of 60000g/mol of 2000-one.

8. The PC/ABS composite material of claim 6, wherein: the ABS contains 10-40% of styrene, 5-30% of acrylonitrile and 5-30% of butadiene.

9. The PC/ABS composite material of claim 6, wherein: the halogen-free flame retardant auxiliary agent is an environment-friendly phosphorus, nitrogen, silicon, metal oxide and the like, and comprises any one or more than two of red phosphorus (P), resorcinol bis (diphenyl phosphate) (RDP), bisphenol A bis (diphenyl phosphate) (BDP), ammonium polyphosphate (APP), aluminum phosphinate (AHP), 1-oxo-4-hydroxymethyl-1-phospha-2, 6, 7-trioxabicyclo [2, 2, 2] octane (PEPA), triphenyl phosphate, tricresyl phosphate or tris (2, 6-dimethylphenyl) phosphine, brominated aromatic phosphate and phosphorus oxide. (ii) a

The silane coupling agent is any one or the combination of at least two of gamma-aminopropyltriethoxysilane KH550, gamma-glycidoxypropyltrimethoxysilane KH560, gamma-methacryloxypropyltrimethoxysilane KH570, N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane KH792, gamma-glycidoxypropyltriethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane, N-aminoethyl-gamma-aminopropyltriethoxysilane, gamma-aminopropylmethyldiethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyltriethoxysilane and aniline methyltrimethoxysilane.

10. The method for preparing the PC/ABS composite material according to claim 6, wherein the method comprises the following steps: the method comprises the following steps:

(1) weighing the raw materials according to a formula;

(2) drying the dual-mode assembled carbon fiber, PC and ABS raw materials at the temperature of 80-120 ℃, then placing the raw materials in a high-speed mixing machine according to the proportion for mixing for 5-15min, then adding the mixture into a double-screw extruder for melt blending, wherein the extrusion temperature is 230-280 ℃, the screw rotation speed is 350-1000 r/min, and the retention time is 1-3 min; and cooling, drying and granulating after extrusion to obtain the PC/ABS composite material with high toughness, flame retardance and good heat dissipation.

Technical Field

The invention relates to a plastic material, in particular to a dual-mode carbon fiber, a preparation method thereof and application thereof in a PC/ABS alloy material, belonging to the technical field of high polymer materials.

Background

Polycarbonate/styrene-acrylonitrile-butadiene copolymer (PC/ABS) is a widely used polymer alloy material. Polycarbonate (PC) has the advantages of high toughness, good dimensional stability, chemical resistance, low water absorption, good dielectric property and the like, and can be widely used in the fields of electronic appliances, automobiles, machinery and the like. However, Polycarbonate (PC) has the defects of poor processing flowability, easy stress cracking of a notch, easy scratching of the surface and the like, and the defects of PC are completely compensated by compounding and adding styrene-acrylonitrile-butadiene (ABS). The styrene-acrylonitrile-butadiene (ABS) has the advantages of good fluidity, low melting temperature, strong flow forming capability and the like, and the two-phase blending can realize the preparation of alloy materials with high impact, high heat resistance, good forming processing, difficult degradation, water absorption and other excellent performances. Therefore, the material can be used as an ideal material for manufacturing electronic communication equipment, automobile interior and exterior trimming parts, household appliance shells and the like.

At present, the polymer composite material which is expected to have high strength, high toughness, good flame retardant property, good processing flowability and good heat dissipation and is expected to be developed for high-end notebooks, smart phones and the like in the 5G market is used for manufacturing plastic parts and shell parts in the notebooks, can resist high-strength drawing force, has high strength and toughness, is well welded with a metal shell, can obviously reduce the whole weight of the notebooks and enables the notebooks to be lighter and thinner.

Based on the method, the modified PC/ABS alloy is designed and researched, the dual-mode assembled carbon fiber filler is added to increase the strength and toughness, enhance the flame retardance and improve the heat dissipation performance, and the requirements of the electronic and electric appliance market are greatly met. Meanwhile, the high-performance air conditioner has wide application in parts such as automobile heat-dissipation air outlets, air conditioner panels, oil tank covers and the like.

The existing commercial notebook computer plastic products are generally manufactured by modifying polycarbonate/styrene-acrylonitrile-butadiene (PC/ABS) alloy polymers, and fillers such as inorganic mineral powder and glass fibers are generally added, for example, patent CN201010541575.6 discloses that the hardness modifiers such as PMMA-ultrahigh molecular weight siloxane and the like are compounded with composite fillers such as mica glass fibers to improve the hardness and scratch resistance. Patent CN201410705041.0 uses high-performance inorganic mineral powder and secondary blending to improve the modulus, strength and heat resistance of the alloy. However, the addition of the inorganic filler does not cause the impact reduction of the PC/ABS alloy material and the weakening of the processing fluidity, and meanwhile, the uneven mixing of the flame retardant, the matrix and the filler causes the heat dissipation and the unstable flame retardance of the material.

Disclosure of Invention

The invention aims to provide a double-mode carbon fiber, a preparation method thereof and application thereof in PC/ABS alloy materials; by adding the dual-mode carbon fiber reinforced filler (nano-micron grade co-assembly), the strength, toughness and processing fluidity of the alloy are obviously enhanced, and meanwhile, a heat conduction network is constructed, so that effective heat dissipation is realized, the problem of poor heat dissipation of plastic parts is greatly improved, and the dual-mode carbon fiber reinforced filler can be widely applied to internal parts of commercial notebooks.

The purpose of the invention is realized by the following technical scheme:

a bimodal carbon fiber having the following composition and content:

in the above-described double-mode carbon fiber,

the length of the nano-scale carbon fiber is 80-200 nm.

The length of the micron-sized carbon fiber is 5-20 μ M, and the micron-sized carbon fiber is selected from Nippon Dongli brands M50J, M60J, T30, T300, T1000G and the like.

In the mixed acid, concentrated sulfuric acid accounts for 1-50% by mass; 1-50% of nitric acid and 1-40% of hydrochloric acid.

The sulfuric acid is 5-40% by mass.

The acetone, potassium permanganate and maleic acid are all analytically pure.

The preparation method of the double-mold carbon fiber comprises the following steps:

(1) performing surface carboxylation treatment on the nano-scale carbon fiber: weighing 5-100g of nano-scale carbon fiber, immersing the nano-scale carbon fiber into 10-1000ml of mixed acid solution, carrying out ultrasonic (5-500kHz) treatment for 5-50h, then placing the nano-scale carbon fiber into a 100-plus 200 ℃ oil bath pot for reaction for 2-4h, then carrying out centrifugal cleaning (the revolution is 1000-plus 10000rap), and carrying out freeze drying after cleaning for subsequent dual-mode assembly;

(2) meanwhile, carrying out hydroxylation treatment on the micron-sized carbon fibers: dissolving 20-100g micron-sized carbon fibers in an acetone solution, soaking for 5-10h by ultrasonic (5-500kHz), volatilizing the acetone, dissolving the acetone again in a mixed solution (10-500ml) of sulfuric acid (30%) and maleic acid, dropwise adding 0.5g/ml potassium permanganate solution, reacting for 2-4h in an oil bath kettle at 50-70 ℃, and then carrying out centrifugal cleaning (the revolution is 1000) for 10000 rap).

(3) The cleaned sample can be directly dissolved in acetone (50-200) solution without freeze drying, and the carboxylated nano-scale carbon fiber is added for ultrasonic treatment at high temperature (100-; finally, volatilizing the acetone to obtain the target sample.

The raw materials of PC, ABS and the double-mold construction carbon fiber are respectively placed in an oven at 100 ℃ for drying and used for subsequent extrusion experiments.

The principle of the dual-mode assembly is that carboxyl of the carboxylated nano-scale carbon fiber treated in the first step is in an active state under a high temperature condition, partial esterification can be realized with the hydroxylated micro-scale carbon fiber, and meanwhile, due to the graphitized structure of the carbon fiber, partial nano-scale carbon fiber can be adsorbed on the carbon fiber, and the micro-nano-scale dual-mode structure carbon fiber with the bound surface and edge is formed through van der Waals force interaction. The introduction of ultrasonic treatment enables the carbon fibers to be effectively dispersed in the solution, and the carbon fibers can exert the volume exclusion effect thereof based on the effective regulation and control of the content of the carbon fibers, thereby greatly avoiding the occurrence of agglomeration.

In the process, the carboxyl functional group is grafted on the surface of the nano-scale carbon fiber by using an oxidation method, and the micro-scale carbon fiber structure is only subjected to hydroxylation treatment, so that the original network structure is not affected, and the original electric and heat conducting characteristics can be maintained after the re-combination.

A high-toughness, flame-retardant and good-heat-dissipation PC/ABS composite material containing the double-mode carbon fiber comprises the following raw materials in percentage by weight:

in the above-mentioned PC/ABS composite material,

the PC is bisphenol A type aromatic polycarbonate and has an average molecular weight of 60000g/mol of 2000-.

The ABS contains 10-40% of styrene, 5-30% of acrylonitrile and 5-30% of butadiene.

The halogen-free flame retardant auxiliary agent is compounded by one or more than two of environment-friendly phosphorus series, nitrogen series, silicon series, metal oxide and the like.

The silane coupling agent is any one or the combination of at least two of aminosilane KH550, epoxy silane KH560 and methacryloxy functional silane KH 570.

A preparation method of a material of double-mold assembled carbon fiber modified PC/ABS comprises the following steps:

(2) weighing the raw materials according to a formula;

(2) drying the dual-mode assembled carbon fiber, PC and ABS raw materials at the temperature of 80-120 ℃, then placing the raw materials in a high-speed mixing machine according to the proportion for mixing for 5-10min, then adding the mixture into a double-screw extruder for melt blending, wherein the extrusion temperature is 230-280 ℃, the screw rotation speed is 350-1000 r/min, and the retention time is 1-3 min; and cooling, drying and granulating after extrusion to obtain the PC/ABS composite material with high toughness, flame retardance and good heat dissipation.

The principle and the beneficial effects of the technical scheme of the invention are as follows:

1) the nanometer carbon fiber has the reinforcing and toughening functions, and the micron carbon fiber network has the characteristic of obviously reinforcing the electric and heat conducting characteristics of the polymer, so that the polymer has the characteristics of both the reinforcing and toughening functions. Namely, under the condition of high temperature, carboxyl of the carboxylated nano-scale carbon fiber is in an active state, and partial esterification can be realized with the hydroxylated micro-scale carbon fiber. Meanwhile, due to the graphitized structure of the micron-scale carbon fiber, the nano-scale carbon fiber particles are easily adsorbed, and the micron-scale and nano-scale double-mode structure carbon fiber with the bound surface and edge is formed under the interaction of Van der Waals force.

2) In the surface treatment process of the carbon fiber, the carboxyl functional group is grafted on the surface of the nano-scale carbon fiber by an oxidation method, and the micro-scale carbon fiber structure is only subjected to hydroxylation treatment, so that the original network structure is not affected, and the original electric and heat conducting characteristics can be effectively maintained after the re-combination.

3) The carboxyl groups grafted on the surface of the carbon fiber constructed in the double mode cannot be completely esterified, and can further react with the matrix PC/ABS, so that the double-mode carbon fiber forms a continuous and uniform network structure in the matrix, the toughness is maintained, and the heat dissipation characteristic of a finished product is obviously improved.

Detailed Description

The technical features of the present invention will be further described with reference to the following embodiments.

In the invention, the adopted raw materials are as follows: PC (bisphenol A type aromatic polycarbonate, average molecular weight 2000-60000 g/mol); ABS (styrene content 10-40%, acrylonitrile content 5-30%, butadiene content 5-30%).

For comparison, the nano-scale carbon fiber and the micro-scale carbon fiber are added separately for experiments. Firstly, nano-scale carbon fibers are mixed with PC and ABS raw materials and auxiliary agents, the raw materials and the auxiliary agents are uniformly mixed for 5-10min by a high-speed mixer according to the proportion of an embodiment, and then the mixture is added into a double-screw extruder for melt blending, wherein the preferable arrangement is that the temperature of a first zone is 250 ℃, the temperature of a second zone is 260 ℃, the temperature of a third zone is 270 ℃, the temperature of a fourth zone is 270 ℃, the temperature of a fifth zone is 270 ℃, the temperature of a sixth zone is 270 ℃, the temperature of a seventh zone is 270 ℃, the temperature of an eighth zone is 270 ℃, the temperature of a ninth zone is 270 ℃, the temperature of a tenth zone is 270 ℃, the temperature of an eleventh zone is 265 ℃, the. And cooling, drying and granulating after extrusion to obtain the nano carbon fiber modified PC/ABS material.

In addition, the micron-sized carbon fibers are mixed with PC, ABS raw materials and auxiliary agents, uniformly mixed for 5-10min by a high-speed mixer according to the proportion of an embodiment, and then added into a double-screw extruder for melt blending, wherein the preferable arrangement is that the temperature of a first zone is 250 ℃, the temperature of a second zone is 260 ℃, the temperature of a third zone is 270 ℃, the temperature of a fourth zone is 270 ℃, the temperature of a fifth zone is 270 ℃, the temperature of a sixth zone is 270 ℃, the temperature of a seventh zone is 270 ℃, the temperature of an eighth zone is 270 ℃, the temperature of a ninth zone is 270 ℃, the temperature of a tenth zone is 270 ℃, the temperature of an eleventh zone is 265 ℃, the rotation speed of a screw is 550 revolutions per. And cooling, drying and granulating after extrusion to obtain the micron-sized carbon fiber modified PC/ABS material.

And finally, preparing the material of the double-mold assembled carbon fiber modified PC/ABS. Drying the double-mode assembled carbon fiber, PC and ABS raw materials at 110 ℃, mixing for 5-10min by using a high-speed mixer according to the proportion of an embodiment, adding the mixture into a double-screw extruder for melt blending, and preferably setting the first-zone temperature to be 260 ℃, the second-zone temperature to be 270 ℃, the third-zone temperature to be 280 ℃, the fourth-zone temperature to be 280 ℃, the fifth-zone temperature to be 280 ℃, the sixth-zone temperature to be 280 ℃, the seventh-zone temperature to be 280 ℃, the eighth-zone temperature to be 280 ℃, the ninth-zone temperature to be 280 ℃, the eleventh-zone temperature to be 275 ℃, the screw rotating speed to be 500 revolutions per minute, and the retention time to be 2 minutes. And extruding, cooling, drying and granulating to obtain the PC/ABS composite material with high toughness, flame retardance and good heat dissipation.

All the materials are subjected to functional tests such as mechanical property and heat conduction.

Table 1: formulations and test results of comparative examples 1-7 of the present invention.

As can be seen from the data in Table 1, the strength of the single addition of the nano-scale carbon fiber is increased from 2600 to 5500MPa, the toughness is reduced, and the lowest toughness is 70kJ/m²Reduced to 48kJ/m²The heat conductivity coefficient is not improved at all basically, so that an effective heat conduction path cannot be formed by simple nanoscale addition, and the heat dissipation requirement cannot be realized. The single addition of the micron-sized carbon fiber can effectively improve the thermal conductivity, and the in-plane thermal conductivity coefficient is improved from 1.0W/(m.K) to 2.0W/(m.K) of the original polymer, but the dispersibility of the filler and the mutual interaction between the filler and the matrixThe effect has larger influence on the physical property of the material, the toughness is lower and more, and the rigidity is not obviously improved.

Table 2: formulations and test results for inventive examples 1-13.

As can be seen from the formulations and test data of table 2: the addition of the double-mold assembled carbon fiber effectively embodies the advantages of two fillers. Along with the gradual increase of the addition amount, the overall physical property is obviously improved, but agglomeration occurs at 15 percent, so that the overall physical property is reduced. The addition amount of 10 percent is optimized, under the condition of the optimal addition proportion, the preparation of the carbon fiber reinforced PC/ABS composite material with good physical property, flame retardance and heat dissipation property is realized by regulating and controlling the flame retardant, the toughening agent and the silane coupling agent, and the notch impact of the ISO simple beam can reach 65kJ/m²The flexural modulus is 6920MPa, the in-plane thermal conductivity coefficient can reach 7.0W/(m.K), which is obviously higher than that of PC/ABS polymer, and the material of the invention can be widely applied to the manufacturing of notebooks.

The applicant states that the invention is illustrated by the above examples to the compounded halogen-free flame-retardant engineering resin of the invention, the preparation method and the application thereof, but the invention is not limited to the above examples, that is, the invention is not meant to be implemented only by relying on the above examples. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.