CN106674899A - Composite material integrating flame retardance and heat conductivity and preparation method thereof - Google Patents

Composite material integrating flame retardance and heat conductivity and preparation method thereof Download PDF

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CN106674899A
CN106674899A CN201611193372.6A CN201611193372A CN106674899A CN 106674899 A CN106674899 A CN 106674899A CN 201611193372 A CN201611193372 A CN 201611193372A CN 106674899 A CN106674899 A CN 106674899A
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composite material
epoxy resin
flame
heat
graphene
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解孝林
冯跃战
周兴平
叶昀昇
陈超
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Huazhong University of Science and Technology
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/38—Boron-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2227—Oxides; Hydroxides of metals of aluminium
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/38—Boron-containing compounds
    • C08K2003/382—Boron-containing compounds and nitrogen
    • C08K2003/385—Binary compounds of nitrogen with boron
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2201/00—Properties
    • C08L2201/02—Flame or fire retardant/resistant

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Abstract

The invention discloses a composite material integrating flame retardance and heat conductivity and a preparation method thereof. The composite material is prepared from flame-retardant graphene, heat conductive filler and an epoxy resin base material and is an epoxy resin-based composite material of which the heat conductivity and the flame retardance are synergistically enhanced by the flame-retardant graphene and the heat conductive filler, wherein the flame-retardant graphene occupies 0.5 to 5 weight percent of the composite material; the heat conductive filler occupies 10 to 70 weight percent of the composite material; the flame-retardant graphene is at least one of reduced graphene oxide and organic flame retardant modified reduced graphene oxide. According to the composite material disclosed by the invention, by modifying the structure, the components, the dosage, the adding technology and the like of critical additives in a polymer-based heat conductive composite material, compared with the prior art, the problems that the mechanical performance, the heat performance and the processing fluidity of the polymer-based heat conductive composite material in which the additives are added are poor can be effectively solved.

Description

Composite material with flame retardance and thermal conductivity and preparation method thereof
Technical Field
The invention belongs to the technical field of manufacturing of polymer-based heat-conducting composite materials, and particularly relates to a composite material with flame retardance and heat conductivity and a preparation method thereof.
Background
The miniaturization and integration of electronic components has resulted in efficient and rapid heat dissipation as one of the imminent problems to be solved in the modern electronics industry. Polymer-based heat-conducting composite materials (PTC) have become a class of electronic packaging materials with wide application due to the characteristics of light weight, low price, easy processing and the like. However, PTC materials used in electronic packaging are often at risk of fire due to the flammable nature of the polymer material itself, coupled with the self-heating of the integrated circuit. Therefore, how to prevent the fire hazard of electronic products and improve the flame retardant property of the PTC material has important theoretical and practical significance.
The main method for industrially solving the problem of easy combustion of electronic packaging materials is to add a certain amount of flame retardant to improve the flame retardant property of the PTC material, for example, Yu and the like introduce metal hydroxide to be added into epoxy resin-based heat-conducting composite materials, so that the flame retardant property of the composite materials is improved and the heat conducting property of the materials is improved (Guan F, Zhang H, Yu Z, et. composites Part B,2016,98(1): 134-. However, the mechanical property, thermal property and processing fluidity of the PTC material are inevitably deteriorated due to the addition of excessive flame retardant, and the comprehensive properties of the PTC material cannot meet the requirements of high-end application fields.
Disclosure of Invention
In view of the above defects or improvement needs of the prior art, an object of the present invention is to provide a composite material with flame retardancy and thermal conductivity and a preparation method thereof, wherein the structure, composition, addition amount, addition process and the like of key additives in a polymer-based heat-conducting composite material are improved, so that compared with the prior art, the problem of poor mechanical properties, thermal properties and processing flowability of the polymer-based heat-conducting composite material added with a flame retardant can be effectively solved, and the composite material has high flame retardancy and high thermal conductivity, and is very suitable for high-end application of electronic packaging materials.
In order to achieve the above object, according to one aspect of the present invention, there is provided a composite material having both flame retardancy and thermal conductivity, comprising flame-retardant graphene, a thermal conductive filler, and an epoxy resin substrate, wherein the composite material is an epoxy resin-based composite material in which the thermal conductivity and the flame retardancy are synergistically enhanced by the flame-retardant graphene and the thermal conductive filler; wherein,
the flame-retardant graphene accounts for 0.5-5 wt% of the composite material, and the heat-conducting filler accounts for 10-70 wt% of the composite material;
preferably, the flame-retardant graphene is at least one of reduced graphene oxide and reduced graphene oxide modified by an organic flame retardant;
the heat-conducting filler is micron-sized heat-conducting filler.
As a further preferable aspect of the present invention, the aspect ratio of the flame retardant graphene is not less than 5000.
As a further preferable mode of the present invention, the micron-sized heat conductive filler is at least one of alpha-crystalline alumina and hexagonal boron nitride, and the particle size of the alpha-crystalline alumina is 1 to 50 μm;
the hexagonal boron nitride is of a lamellar structure, the length of each lamellar is 1-25 mu m, the thickness of each lamellar is 50-500 nm, and the length-diameter ratio of each hexagonal boron nitride is 10-100.
In a further preferred embodiment of the present invention, the epoxy resin is any one of a bisphenol a type epoxy resin and a bisphenol F type epoxy resin.
According to another aspect of the present invention, there is provided a method for preparing a composite material having both flame retardancy and thermal conductivity, comprising the steps of:
(a) adding flame-retardant graphene into the epoxy resin prepolymer, and then stirring and mixing to obtain a uniform epoxy resin prepolymer/graphene dispersion system; preferably, the flame-retardant graphene is at least one of reduced graphene oxide and reduced graphene oxide modified by an organic flame retardant;
(b) adding a heat-conducting filler into the epoxy resin prepolymer/graphene dispersion system obtained in the step (a), and then stirring and mixing uniformly to obtain an epoxy resin prepolymer/graphene/heat-conducting filler dispersion system; preferably, the heat-conducting filler is micron-sized heat-conducting filler;
(c) and (c) vacuumizing the epoxy resin prepolymer/graphene/heat-conducting filler dispersion system obtained in the step (b) to remove bubbles, adding a curing agent, and then heating to perform a curing reaction, thereby obtaining the composite material with flame retardance and heat conductivity.
As a further preferable mode of the present invention, in the step (a), the aspect ratio of the flame-retardant graphene is not less than 5000; the epoxy resin is any one of bisphenol A type epoxy resin and bisphenol F type epoxy resin.
As a further preferred aspect of the present invention, the reduced graphene oxide is chemically reduced graphene oxide; the modifier adopted by the reduced graphene oxide modified by the organic flame retardant is an organic flame retardant containing a phosphorus element, preferably an organic flame retardant containing both a nitrogen element and a phosphorus element, and preferably a polyamide flame retardant containing an amino group at the terminal.
As a further preferable mode of the present invention, in the step (b), the micron-sized heat conductive filler is at least one of alpha-crystalline alumina and hexagonal boron nitride, and a particle size of the alpha-crystalline alumina is 1 to 50 μm;
the hexagonal boron nitride is of a lamellar structure, the length of each lamellar is 1-25 mu m, the thickness of each lamellar is 50-500 nm, and the length-diameter ratio of each hexagonal boron nitride is 10-100.
In a further preferred aspect of the present invention, in the step (c), the curing agent is at least one of an imidazole-based curing agent, an acid anhydride-based curing agent, and an amino-based curing agent; the addition amount of the curing agent is 2-50 wt% of the epoxy resin prepolymer in the step (a).
As a further preferred aspect of the present invention, in the step (c), the temperature-raising curing reaction is a low-temperature curing reaction, and then a high-temperature curing reaction; the reaction temperature of the low-temperature curing reaction is 60-100 ℃, and the reaction temperature of the high-temperature curing reaction is 140-180 ℃.
Compared with the prior art, the technical scheme of the invention has the advantages that a small amount of reduced graphene oxide or flame-retardant modified reduced graphene oxide (for example, modified reduced graphene oxide obtained by taking an organic flame retardant containing phosphorus elements or nitrogen and phosphorus elements as a modifier) is taken as flame-retardant graphene and is introduced into the polymer-based heat-conducting composite material in situ, and the flame retardance and heat conductivity of the polymer-based heat-conducting composite material are improved by utilizing the synergistic effect of the reduced graphene oxide or the organic flame retardant modified reduced graphene oxide and the heat-conducting filler, and other performances of the composite material are not damaged, so that the polymer-based heat-conducting composite material with high flame retardance and high heat conductivity has good mechanical property, thermal property and processing flowability. The composite material with flame retardance and thermal conductivity has the characteristics of high thermal conductivity and high flame retardance, the thermal conductivity is 0.7-0.8W/mK, the limiting oxygen index reaches 28-29 vol%, the flame retardant grade is V-1, the maximum heat release rate in the combustion process is reduced by nearly 60%, the total heat release is reduced by nearly 40%, and an effective smoke suppression effect can be achieved. The synergistic effect between the flame-retardant graphene and the heat-conducting filler is mainly embodied in two aspects: 1, in the aspect of heat conduction, the addition of the graphene weakens the sedimentation effect of the micron filler in the curing process of the epoxy resin, enhances the interface effect of the heat-conducting filler and a matrix, reduces the interface thermal resistance and improves the heat-conducting property of the composite material; 2, the flame-retardant graphene has the function of promoting carbonization in the combustion process of the composite material, and is bonded with the formed carbonized layer together with the heat-conducting filler to form a firm and compact protective layer, so that the exchange of external heat oxygen and internal combustible degradation gas is blocked, further combustion is inhibited, and the flame-retardant effect is achieved.
The invention relates to a preparation method of a high-performance polymer-based graphene composite material, which is characterized in that reduced graphene oxide with flame-retardant efficacy, such as reduced graphene oxide and organic flame retardant modified reduced graphene oxide, is used as flame-retardant graphene, especially the organic flame retardant is used for modifying the graphene, and the compatibility of the graphene and a polymer matrix and the flame-retardant efficiency of the graphene are improved. In addition, the viscosity of the epoxy resin is increased due to the addition of the graphene with the extremely large specific surface area, the addition amount of the flame-retardant graphene and the filling amount of the heat-conducting filler are controlled, the structures and the compositions of the flame-retardant graphene and the heat-conducting filler are further optimized, the viscosity of the epoxy resin/heat-conducting filler/graphene mixture is reduced through the integral matching of various composition materials, the processability of the composite material is improved, and the prepared composite material has flame retardance and heat conductivity. According to the invention, 0.5-5 wt% of flame retardant modified graphene is introduced into the filled polymer matrix heat-conducting composite material (PTC), so that the purposes of simultaneously improving heat conduction and flame retardance are achieved, and in addition, the composite material also comprises 10-70 wt% of heat-conducting filler (such as micron-sized heat-conducting filler). Taking the added flame-retardant graphene as modified graphene obtained by modifying a polyamide flame retardant containing amino at the terminal as an example, the specific preparation steps of the composite material can be as follows: firstly, the poly-phosphoramide with the amino group at the tail end is used as a graphene modifier, then the modified graphene, the micron-sized heat-conducting filler and the epoxy resin are uniformly mixed, and the composite material with the heat-conducting and flame-retardant properties is obtained after a curing stage. According to the invention, the flame-retardant modified graphene has a synergistic heat conduction effect in the PTC material, the flame-retardant property of the PTC material can be enhanced, and the preparation process is simple.
Compared with the traditional flame retardant, the flame-retardant graphene has a unique two-dimensional layered structure, has excellent flame-retardant effect, and can be used as a traditional heat-conducting filler (such as Al) to improve the flame-retardant property of the heat-conducting composite material2O3BN, SiC, etc.) occurs.
The heat-conducting composite material provided by the invention has the following advantages:
1. the flame-retardant graphene with low filling amount (<5 wt%) can achieve ideal flame-retardant effect;
2. due to the high heat conduction nature of graphene and the synergistic effect between the added flame-retardant functionalized graphene and the heat-conducting filler, the heat-conducting composite material has excellent flame-retardant and heat-conducting properties, and also has good mechanical, thermal and processing properties. The preparation method of the high-flame-retardant heat-conducting composite material provided by the invention is simple, the graphene-based flame retardant is small in dosage, low in cost and great in industrial production potential.
Drawings
FIG. 1 is a scanning electron microscope picture of (a) micron alumina × 10000(b) micron boron nitride × 100000 used in the examples;
FIG. 2 shows EP/Al in comparative example 12O3-50 scanning electron microscopy of composite material (a)Mirror images (× 50000) and (b) top and bottom EDX spectra thereof;
FIG. 3 is EP/Al in example 52O3the/RGO-50 composite (a) scanning electron microscopy pictures (× 50000) and (b) top and bottom EDX spectra thereof;
FIG. 4 shows EP/Al in example 102O3the/FRGO-50 composite (a) scanning electron microscopy pictures (× 50000) and (b) top and bottom EDX spectra of the composite;
fig. 5 is a plot of cone calorimetry for the composites of comparative example 1, example 5, and example 10 (a) rate of heat release versus time, (b) total heat release versus time, and (c) total smoke versus time.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
In order to explore the enhancement effect of graphene and flame-retardant functionalized graphene on the heat conduction and flame retardance of the PTC material, the invention selects the commonly used electronic packaging material in the electronic industry, namely epoxy resin/Al2O3Composite material as base material, in which the epoxy resin is bisphenol F type, micron-sized α -Al2O3Is random shape, and has particle diameter of about 1 μm, as shown in FIG. 1 a; micron-sized hexagonal boron nitride, with a particle size of about 1 μm, is shown in FIG. 1 b.
The composite material with flame retardance and thermal conductivity (namely, the high-flame-retardance heat-conducting composite material) has high heat conduction and high flame retardance, and is an epoxy resin-based composite material with heat conduction and flame retardance reinforced by the cooperation of flame-retardant graphene and micron-sized heat-conducting filler, wherein the content of the flame-retardant graphene is 0.5-5 wt%; the filling amount of the micron-sized heat-conducting filler is 10-70 wt%.
The epoxy resin is any one of bisphenol A type epoxy resin and bisphenol F type epoxy resin; the flame-retardant graphene is one of reduced graphene and organic flame retardant modified graphene (wherein the organic flame retardant is an organic flame retardant containing phosphorus or nitrogen and phosphorus), and the surface length-diameter ratio of the graphene is not less than 5000; the micron-sized heat-conducting filler comprises one of alpha-crystal-form alumina or hexagonal boron nitride, wherein the alpha-crystal-form alumina can be in a random granular shape, and the size of the alpha-crystal-form alumina is 1-50 mu m; the hexagonal boron nitride is of a lamellar structure, the length of each lamellar is 1-25 mu m, the thickness of each lamellar is 50-500 nm, and the length-diameter ratio of each hexagonal boron nitride is 10-100.
The preparation method of the high-flame-retardant heat-conducting composite material comprises the following specific steps:
(a) adding flame-retardant graphene into the epoxy resin prepolymer, stirring and mixing to obtain a uniform epoxy resin prepolymer/graphene dispersion system;
(b) adding a micron-sized heat-conducting filler into the epoxy resin prepolymer/graphene dispersion system obtained in the step (a), stirring at a high speed (the rotating speed adopted by stirring can be 800-1500 rpm), and uniformly mixing to obtain a flame-retardant heat-conducting epoxy resin dispersion system;
(c) and (c) vacuumizing the flame-retardant heat-conducting epoxy resin dispersion system obtained in the step (b), removing bubbles, adding a curing agent, and heating for curing reaction to obtain the high-flame-retardant heat-conducting composite material.
In the above technical scheme, the flame-retardant graphene in the step (a) is one of reduced graphene oxide and reduced graphene oxide modified by an organic flame retardant; the surface length-diameter ratio of the graphene is not less than 5000; the epoxy resin is any one of bisphenol A type epoxy resin and bisphenol F type epoxy resin. The modifier in the organic flame retardant modified reduced graphene oxide is a polyamide flame retardant with an amino group at the tail end.
In the technical scheme, the micron-sized heat-conducting filler in the step (b) comprises one of alpha-crystal alumina or hexagonal boron nitride, wherein the alpha-crystal alumina is random in shape and 1-50 μm in size; the hexagonal boron nitride is of a lamellar structure, the length of each lamellar is 1-25 mu m, the thickness of each lamellar is 50-500 nm, and the length-diameter ratio of each hexagonal boron nitride is 10-100.
In the above technical scheme, the curing agent in the step (c) is one or two of imidazole curing agent, anhydride curing agent and amino curing agent; the proportion of the curing agent to the epoxy resin prepolymer is 2-50 wt%. The temperature-rising curing reaction comprises a low-temperature curing reaction and a high-temperature curing reaction, wherein the low-temperature curing reaction temperature is 60-100 ℃, and the high-temperature curing reaction temperature is 140-180 ℃.
The following is a detailed description of the analysis.
Comparative example 1
Graphene-free epoxy/Al2O3The composite material is prepared from bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-2O3Wherein the epoxy resin prepolymer comprises 94 wt% of the epoxy resin portion, the curing agent comprises 6 wt% of the epoxy resin portion, α -Al2O3The content accounts for 10, 20, 30, 40 and 50wt percent of the total composite material.
α -Al is dried by a high-temperature oven2O3Removing surface water absorption (100 ℃, 8h), weighing epoxy resin prepolymers with different proportions (shown in Table 1) and drying α -Al2O3The epoxy resin prepolymer and α -Al were mixed by mechanical stirring2O3The mixture is stirred at a high speed of 800-1500 rpm for 1h to prepare uniformly dispersed epoxy resin prepolymer/Al2O3Mixing; the obtained epoxy resin prepolymer/Al2O3Putting the mixture into a vacuum oven, continuously vacuumizing for 2h at 60 ℃,degree of vacuum<100Pa, removing gas introduced during stirring; then, a curing agent (2-ethyl-4-methylimidazole, EMI-2,4) was added dropwise, the curing agent accounting for 6 wt% of the epoxy resin portion, and the curing agent and the epoxy resin prepolymer/Al were mixed by using a planetary mixer2O3The mixture is evenly mixed, and finally the obtained blend is poured into a round steel mould (used as a heat conduction test sample) and a rectangular polytetrafluoroethylene mould (used as a flame-retardant sample) to be subjected to low-temperature curing at 60 ℃ for 2h, medium-temperature curing at 100 ℃ for 2h and high-temperature curing at 150 ℃ for 5h to finally obtain the epoxy resin/Al2O3Composite samples, for ease of writing, this type of composite is abbreviated EP/Al2O3。
In order to verify the dispersibility and the interface effect of the heat-conducting particles in the epoxy resin, the prepared EP/Al2O3The composite material is brittle under liquid nitrogen, and micron Al is observed by utilizing a Scanning Electron Microscope (SEM) after the section is sprayed with gold2O3The distribution is based on the interfacial adhesion with the substrate, and the results are shown in FIGS. 2a and 2b, Al2O3Dispersed uniformly in the local area, but Al was shown from the energy spectrum analysis (FIG. 2b)2O3Significant sedimentation occurs in the epoxy resin, resulting in the upper layer of the composite material Al2O3The content is low, and in addition, FIG. 2a shows Al2O3The interface between the filler and the epoxy resin is very weak, and obvious gaps exist between the filler and the matrix.
EP/Al at 10, 20, 30, 40, 50 wt% loading as measured according to ASTM-C111390 standard2O3The thermal conductivity of the composite material is respectively 0.2617, 0.3220, 0.3998, 0.4677 and 0.6182W/mK, which are respectively improved by 8.05%, 41.46%, 75.64%, 105.49% and 171.62% compared with pure epoxy resin (0.2276W/mK).
According to GB/T2495-2O3The composite was tested for oxygen index (LOI) and flame rating, and the LOI value of the composite increased from 25% to 28.8% compared to pure epoxy, however, the flame rating did not change. According to GB/T16172-2007 to EP/Al2O3The taper calorimetric test of the composite material shows that the EP/Al2O3The Heat Release Rate (HRR) of the composite throughout the combustion stage was less than that of the neat epoxy (FIG. 5a), with a Peak Heat Release Rate (PHRR) from 1137.6kW/m2Reduced to 802.7kW/m2The reduction amplitude is 29.4%; total heat release (THR, FIG. 5b) from 81.6MJ/m2Reduced to 56.3MJ/m2The reduction amplitude is 31.0%; total smoke generation (TSP, fig. 5c) from 62.4m2Reduced to 35.0m2The reduction was 43.9%, the above results indicate EP/Al2O3Compared with pure epoxy resin, the flame retardant property of the composite material is obviously improved.
Example 1
Containing 1 wt% Reduced Graphene Oxide (RGO), 10 wt% Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, hydrazine hydrate reduced graphene oxide and α -Al2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the reduced graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content of the composite material accounts for 10wt percent of the total mass of the composite material
Hydrazine hydrate Reduced Graphene Oxide (RGO) was first mixed into an epoxy prepolymer using a solution mixing method: 180mg of RGO (relative to epoxy resin) was dispersed ultrasonically (1h, 100W) into 100mL of acetone solution, then acetone solution (50mL) with 16.75g of epoxy resin prepolymer dissolved therein was introduced into the RGO dispersion according to the formulation in Table 1, and sonication was continued for 30min, followed by removal of acetone solvent using a rotary evaporator to give a premixed RGO/EP dispersion.
Then, according to comparative example 1, 2g of dried Al2O3Mechanically mixing the RGO/EP dispersion obtained as described above with high-speed stirring, placing the mixture in a vacuum oven, and continuously evacuating at 60 deg.C5h, vacuum degree<100Pa, removing gas introduced during stirring and residual acetone solvent; 1.07g of a curing agent (2-ethyl-4-methylimidazole, EMI-2,4) was then added dropwise, the curing agent accounting for 6 wt% of the epoxy resin portion, and the curing agent and epoxy resin prepolymer/Al were mixed using a planetary mixer2O3Mixing the mixture of the epoxy resin and the epoxy resin with the matrix oxide, pouring the obtained blend into a round steel mould (used as a heat conduction test sample) and a rectangular polytetrafluoroethylene mould (used as a flame-retardant sample), curing at a low temperature of 60 ℃ for 2h, at a medium temperature of 100 ℃ for 2h and at a high temperature of 150 ℃ for 5h to obtain the epoxy resin/Al2O3Sample of/RGO composite, for convenience of writing, the composite is abbreviated EP/Al2O3/RGO-10。
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-10 composite material is 0.2791, which is improved by 22.64 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, introduction of RGO vs. 10 wt% Al2O3The thermal conductivity of the filled composite material is improved by 6.6%, which shows that the addition of RGO is helpful for improving the thermal conductivity of the thermal conductive composite material.
Example 2
Containing 1 wt% Reduced Graphene Oxide (RGO), 20 wt% Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, hydrazine hydrate reduced graphene oxide and α -Al2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the reduced graphene accounts for 1 wt% of the epoxy resin part,α-Al2O3the content of the composite material accounts for 20wt percent of the total mass of the composite material
According to the method of example 1, the epoxy resin/Al is finally obtained after the raw materials of the composite material are mixed by solution, mechanically mixed and cured and formed by temperature programming according to the mixture ratio of the raw materials in the table 12O3Sample of/RGO composite, for convenience of writing, the composite is abbreviated EP/Al2O3/RGO-20。
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-20 composite material is 0.3402W/mK, which is improved by 49.47 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, incorporation of RGO vs 20 wt% Al2O3The thermal conductivity of the filled composite material is improved by 5.7%, which shows that the addition of RGO is helpful for improving the thermal conductivity of the thermal conductive composite material.
Example 3
Containing 1 wt% Reduced Graphene Oxide (RGO), 30 wt% Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, hydrazine hydrate reduced graphene oxide and α -Al2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the reduced graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content of the composite material accounts for 30 wt% of the total mass of the composite material.
According to the method of example 1, the composite material is prepared by mixing the raw materials according to the mixture ratio of Table 1, mechanically mixing, and curing at a programmed temperatureAfter the molding, the epoxy resin/Al is finally obtained2O3Sample of/RGO composite, for convenience of writing, the composite is abbreviated EP/Al2O3/RGO-30。
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-30 composite material is 0.4366W/mK, which is improved by 91.81 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, incorporation of RGO vs 30 wt% Al2O3The thermal conductivity of the filled composite material is improved by 9.2%, which shows that the addition of RGO is helpful for improving the thermal conductivity of the thermal conductive composite material.
Example 4
Containing 1 wt% Reduced Graphene Oxide (RGO), 40 wt% Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, hydrazine hydrate reduced graphene oxide and α -Al2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the reduced graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content accounts for 40 wt% of the total composite material mass.
According to the method of example 1, the epoxy resin/Al is finally obtained after the raw materials of the composite material are mixed by solution, mechanically mixed and cured and formed by temperature programming according to the mixture ratio of the raw materials in the table 12O3Sample of/RGO composite, for convenience of writing, the composite is abbreviated EP/Al2O3/RGO-40。
According to ASTM-C111390Quasi-measured EP/Al2O3The thermal conductivity coefficient of the/RGO-40 composite material is 0.5171W/mK, which is improved by 127.18 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, introduction of RGO vs 40 wt% Al2O3The thermal conductivity of the filled composite material is improved by 10.6%, which shows that the addition of RGO is helpful for improving the thermal conductivity of the thermal conductive composite material.
Example 5
Containing 1 wt% Reduced Graphene Oxide (RGO), 40 wt% Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, hydrazine hydrate reduced graphene oxide and α -Al2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the reduced graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content of the composite material accounts for 50 wt% of the total mass of the composite material.
According to the method of example 1, the epoxy resin/Al is finally obtained after the raw materials of the composite material are mixed by solution, mechanically mixed and cured and formed by temperature programming according to the mixture ratio of the raw materials in the table 12O3Sample of/RGO composite, for convenience of writing, the composite is abbreviated EP/Al2O3/RGO-50。
To verify Al2O3And the dispersibility of RGO in epoxy resin, the interfacial action and the synergistic action between the RGO and the epoxy resin, and the EP/Al prepared by the method2O3the/RGO-50 composite material is brittle-broken under liquid nitrogen, and micron Al is observed by using a Scanning Electron Microscope (SEM) after the section is sprayed with gold2O3RGO distribution and interfacial adhesion to the substrate, and Al are shown in FIGS. 3a and 3b2O3Is dispersed uniformly in local area, but Al is shown by energy spectrum analysis2O3The sedimentation effect in the epoxy resin is obviously inhibited due to the introduction of RGO, and Al on the upper surface and the lower surface of the obtained composite material2O3The distribution is substantially the same, which is advantageous for the improvement of the heat conductive property and the flame retardant property, and further, FIG. 3a shows Al2O3The interface between the filler and the epoxy resin is enhanced, and gaps between the filler and the matrix are basically eliminated.
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-50 composite material is 0.7226W/mK, which is improved by 217.50 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, introduction of RGO vs. 50 wt% Al2O3The thermal conductivity of the filled composite material is improved by 16.9%, which shows that the addition of RGO is helpful for improving the thermal conductivity of the thermal conductive composite material.
Respectively aiming at EP/Al according to GB/T2495-2O3The oxygen index (LOI) and fire rating of the/RGO-50 composite were tested, and the LOI value of the composite increased from 25% to 25.2% compared to pure epoxy, compared to EP/Al2O3Compared with the composite material, the introduction of RGO reduces the LOI value of the composite material, and the combustion grade is not changed. According to GB/T16172-2007 to EP/Al2O3The results of cone calorimetric tests carried out on the/RGO-50 composite material show that the EP/Al2O3The Heat Release Rate (HRR) of the/RGO-50 composite material is less than that of pure epoxy resin (FIG. 5a) throughout the combustion stage, with Peak Heat Release Rate (PHRR) from 1137.6kW/m2Reduced to 775.0kW/m2Decrease ofThe amplitude is 31.9%; total heat release (THR, FIG. 5b) from 81.6MJ/m2Reduced to 60.0MJ/m2The reduction amplitude is 26.5%; total smoke generation (TSP, fig. 5c) from 62.4m2Reduced to 38.5m2The reduction was 38.3%, the above results indicate EP/Al2O3The flame retardant performance of the/RGO composite material is compared with that of EP/Al2O3Further improvements in composite materials are obtained.
Example 6
Contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 10 wt% of Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the flame-retardant functionalized graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content of the composite material accounts for 10 wt% of the total mass of the composite material.
The polyphosphoric acid amide flame retardant PDMPD was synthesized according to the literature (Tai Q, Hu Y, Yuen R K K, et al. journal of materials chemistry.2011,21: 6621-: dissolving 0.01mol of 4, 4-diaminodiphenylmethane and 0.02mol of triethylamine in 20mL of distilled acetonitrile solution, slowly dropwise adding acetonitrile solution (10mL) in which 0.01mol of phenyl phosphorus dichloride is dissolved at room temperature for 1h, then heating to reflux temperature under the protection of argon, continuously stirring for reaction for 8h, then removing the solvent by rotary evaporation, then dissolving the obtained solid in dimethyl sulfoxide (50mL), filtering to remove triethylamine hydrochloride, then adding excessive deionized water (100mL) into the filtrate to precipitate a product, filtering to obtain a white precipitate, namely the synthesized polyphosphazene amide flame retardant PDMPD, and carrying out vacuum drying at 80 ℃ for 12h to obtain the product.
Grafting a flame retardant PDMPD to the surface of graphene by adopting a grafting to method: ultrasonically dispersing 1g of GO into 500mL of N, N-dimethylformamide for 1h, dissolving 2g of PDMPD into 50mL of DMF solvent, slowly dropwise adding a PDMPD solution into the GO solution at room temperature, heating to 80 ℃, reacting for 24h under the protection of reflux argon, then adding 5mL of hydrazine hydrate solution with the concentration of 85%, continuing to react for 4h, filtering and washing by using a 0.22 mu m polytetrafluoroethylene filter membrane after the reaction is stopped to obtain flame retardant modified graphene (FRGO), and freeze-drying to obtain a product for later use.
Contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 10 wt% of Al2O3The preparation steps of the epoxy group heat-conducting composite material are the same as those of the composite material in the embodiment 1, except that the reduced graphene oxide is replaced by the FRGO, the specific component ratio is shown in the table 1, and the epoxy resin/Al is finally obtained after solution mixing, mechanical mixing, temperature programmed curing and forming2O3Samples of/FRGO composite, for ease of writing, the composite is abbreviated EP/Al2O3/FRGO-10。
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-10 composite material is 0.2693W/mK, which is improved by 18.31 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite material, as shown in FIG. 4b, in comparison to EP/Al2O3Composite material, introduction of FRGO to 10 wt% Al2O3The thermal conductivity coefficient of the composite material with the filling amount is improved by 2.89%, which shows that the addition of the FRGO is beneficial to the improvement of the thermal conductivity of the thermal conductive composite material.
Example 7
Contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 20 wt% of Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy resin)Equivalent weight of 160-2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the flame-retardant functionalized graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content accounts for 20 wt% of the total composite material mass.
The flame retardant modified graphene (FRGO) method was the same as in example 6;
contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 20 wt% of Al2O3The preparation steps of the epoxy group heat-conducting composite material are the same as those of the composite material in the embodiment 1, except that the reduced graphene oxide is replaced by the FRGO, the specific component ratio is shown in the table 1, and the epoxy resin/Al is finally obtained after solution mixing, mechanical mixing, temperature programmed curing and forming2O3Samples of/FRGO composite, for ease of writing, the composite is abbreviated EP/Al2O3/FRGO-20。
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-20 composite material is 0.3348W/mK, which is improved by 47.11 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, introduction of FRGO to 20 wt% Al2O3The thermal conductivity coefficient of the composite material with the filling amount is improved by 3.98%, which shows that the addition of the FRGO is beneficial to the improvement of the thermal conductivity of the thermal conductive composite material.
Example 8
Contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 30 wt% of Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the flame-retardant functionalized graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content of the composite material accounts for 30 wt% of the total mass of the composite material.
The flame retardant modified graphene (FRGO) method was the same as in example 6;
contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 30 wt% of Al2O3The preparation steps of the epoxy group heat-conducting composite material are the same as those of the composite material in the embodiment 1, except that the reduced graphene oxide is replaced by the FRGO, the specific component ratio is shown in the table 1, and the epoxy resin/Al is finally obtained after solution mixing, mechanical mixing, temperature programmed curing and forming2O3Samples of/FRGO composite, for ease of writing, the composite is abbreviated EP/Al2O3/FRGO-30
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-30 composite material is 0.4225W/mK, which is improved by 85.63 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, introduction of FRGO to 30 wt% Al2O3The thermal conductivity coefficient of the composite material with the filling amount is improved by 5.69%, which shows that the addition of the FRGO is beneficial to the improvement of the thermal conductivity of the thermal conductive composite material.
Example 9
Contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 40 wt% of Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the flame-retardant functionalized graphene accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content accounts for 40 wt% of the total composite material mass.
The flame retardant modified graphene (FRGO) method was the same as in example 6;
contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 40 wt% of Al2O3The preparation steps of the epoxy group heat-conducting composite material are the same as those of the composite material in the embodiment 1, except that the reduced graphene oxide is replaced by the FRGO, the specific component ratio is shown in the table 1, and the epoxy resin/Al is finally obtained after solution mixing, mechanical mixing, temperature programmed curing and forming2O3Samples of/FRGO composite, for ease of writing, the composite is abbreviated EP/Al2O3/FRGO-40。
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-40 composite material is 0.5158W/mK, which is improved by 126.64 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite materials, in contrast to EP/Al2O3Composite material, introduction of FRGO to 40 wt% Al2O3The thermal conductivity coefficient of the composite material with the filling amount is improved by 10.29 percent, which shows that the addition of the FRGO is beneficial to the improvement of the thermal conductivity of the thermal conductive composite material.
Example 10
Contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 50 wt% of Al2O3The epoxy group heat-conducting composite material comprises bisphenol F epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-2O3Wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the FRGO accounts for 1 wt% of the epoxy resin part, and α -Al2O3The content of the composite material accounts for 50 wt% of the total mass of the composite material.
The flame retardant modified graphene (FRGO) method was the same as in example 6;
contains 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 50 wt% of Al2O3The preparation steps of the epoxy group heat-conducting composite material are the same as those of the composite material in the embodiment 1, except that the reduced graphene oxide is replaced by the FRGO, the specific component ratio is shown in the table 1, and the epoxy resin/Al is finally obtained after solution mixing, mechanical mixing, temperature programmed curing and forming2O3Samples of/FRGO composite, for ease of writing, the composite is abbreviated EP/Al2O3/FRGO-50。
To verify Al2O3And dispersion, interfacial action and synergy between FRGO in epoxy resin, EP/Al prepared by the method2O3Brittle fracture of/FRGO composite material under liquid nitrogen, and observation of micron Al by using Scanning Electron Microscope (SEM) after metal spraying on the section2O3Distribution of FRGO and interfacial adhesion with the substrate, the results are shown in FIGS. 4a and 4b, Al2O3Is dispersed uniformly in local area, but Al is shown by energy spectrum analysis2O3The sedimentation effect in the epoxy resin is obviously inhibited due to the introduction of FRGO, and Al on the upper surface and the lower surface of the obtained composite material2O3Are distributed substantially the sameIn favor of improvement of thermal conductivity and flame retardancy, and further, fig. 4a shows Al2O3The interface between the filler and the epoxy resin is enhanced, the gap between the filler and the matrix basically disappears, and the dispersibility of the FRGO in the matrix is superior to that of the RGO in the matrix.
EP/Al measured according to ASTM-C111390 Standard2O3The thermal conductivity coefficient of the/RGO-50 composite material is 0.6873W/mK, which is improved by 201.99 percent compared with that of pure epoxy resin (0.2276W/mK). Define (K) at the same timec1-Kc0)/Kc0Is graphene and Al2O3A synergistic enhancing effect between, wherein Kc1For EP/Al containing graphene2O3Composite material, Kc0Is EP/Al without graphene2O3Composite material, as shown in FIG. 4b, in comparison to EP/Al2O3Composite material, introduction of FRGO to 50 wt% Al2O3The thermal conductivity coefficient of the composite material with the filling amount is improved by 11.18%, which shows that the addition of the FRGO is beneficial to the improvement of the thermal conductivity of the thermal conductive composite material.
Respectively aiming at EP/Al according to GB/T2495-2O3The oxygen index (LOI) and combustion rating of the/FRGO-50 composite were tested, and the LOI value of the composite increased from 25% to 27.3% compared to pure epoxy, compared to EP/Al2O3Compared with the/RGO-50 composite material, the FRGO has higher flame retardant property, the combustion grade reaches V-1 grade, and no dripping phenomenon occurs in the combustion process. According to GB/T16172-2007 to EP/Al2O3the/FRGO-50 composite material is subjected to cone calorimetry test, and the result shows that EP/Al2O3The Heat Release Rate (HRR) of the/FRGO-50 composite material is less than that of pure epoxy resin (FIG. 5a), wherein the Peak Heat Release Rate (PHRR) is from 1137.6kW/m2Reduced to 533.5kW/m2The reduction amplitude is 53.1%; total heat release (THR, FIG. 5b) from 81.6MJ/m2Reduced to 51.2MJ/m2The reduction amplitude is 37.3%; total smoke generation (TSP, fig. 5c) from 62.4m2Reduced to 27.1m2The reduction was 56.6%, the above results indicate EP/Al2O3Compared with EP/Al, the flame retardant property of the/FRGO composite material2O3And EP/Al2O3the/RGO composite material is further improved.
Example 11
The epoxy-based heat-conducting composite material containing 1 wt% of Reduced Graphene Oxide (RGO) and 50 wt% of h-BN is prepared and comprises bisphenol F type epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, hydrazine hydrate Reduced Graphene (RGO) and h-BN, wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the RGO accounts for 1 wt% of the epoxy resin part, and the h-BN content accounts for 50 wt% of the total composite material.
Following example 1, hydrazine hydrate-Reduced Graphene Oxide (RGO) was first mixed into an epoxy prepolymer using a solution mixing method to give a pre-mixed epoxy prepolymer/RGO dispersion, in the proportions given in table 1.
Adding 40g of dried h-BN particles into the epoxy resin prepolymer/RGO dispersion system according to the mixture ratio shown in the table 1, and stirring at a high speed (800-1500 rpm) for 1h by using mechanical stirring to prepare an epoxy resin prepolymer/hBN/RGO mixture with uniform dispersion; putting the obtained epoxy resin prepolymer/h-BN/RGO mixture into a vacuum oven, continuously vacuumizing for 2h at the temperature of 60 ℃, wherein the vacuum degree is less than 100Pa, and removing gas introduced during stirring; then, 2.38g of curing agent (2-ethyl-4-methylimidazole, EMI-2,4) is dripped, the curing agent accounts for 6 wt% of the epoxy resin part, the curing agent and the epoxy resin prepolymer/h-BN/RGO mixture are uniformly mixed by using a star-shaped stirrer, and finally the obtained blend is poured into a round steel mold (used as a heat conduction test sample) and a rectangular polytetrafluoroethylene mold (used as a flame-retardant sample) and undergoes low-temperature curing at 60 ℃ for 2h, medium-temperature curing at 100 ℃ for 2h and high-temperature curing at 150 ℃ for 5h to finally obtain an epoxy resin/hBN/RGO composite material sample, wherein the composite material is abbreviated as EP/h-BN/RGO-50 for convenience of writing.
Example 12
The epoxy group heat-conducting composite material containing 1 wt% of organic flame retardant modified reduced graphene oxide (FRGO) and 50 wt% of h-BN is prepared, and comprises bisphenol F type epoxy resin prepolymer (type: YDF-170, epoxy equivalent 160-180), 2-ethyl-4-methylimidazole curing agent, polyphosphamide modified graphene (FRGO) and h-BN, wherein the epoxy resin prepolymer accounts for 94 wt% of the epoxy resin part, the curing agent accounts for 6 wt% of the epoxy resin part, the FRGO accounts for 1 wt% of the epoxy resin part, and the h-BN accounts for 50 wt% of the total composite material.
The flame retardant modified graphene (FRGO) method was the same as in example 6;
following example 1, the solutions were mixed in the proportions shown in Table 1 to obtain a pre-mixed epoxy prepolymer/FRGO dispersion.
Adding 40g of dried h-BN particles into the epoxy resin prepolymer/FRGO dispersion system according to the mixture ratio shown in the table 1, and stirring at a high speed (800-1500 rpm) for 1h by using mechanical stirring to prepare an epoxy resin prepolymer/h-BN/FRGO mixture with uniform dispersion; putting the obtained epoxy resin prepolymer/hBN/FRGO mixture into a vacuum oven, continuously vacuumizing for 2h at 60 ℃, wherein the vacuum degree is less than 100Pa, and removing gas introduced during stirring; then, 2.37g of curing agent (2-ethyl-4-methylimidazole, EMI-2,4) is dripped, the curing agent accounts for 6 wt% of the epoxy resin, a star stirrer is used for uniformly mixing the curing agent and the epoxy resin prepolymer/h-BN/FRGO mixture, finally, the obtained blend is poured into a round steel die (used as a heat conduction test sample) and a rectangular polytetrafluoroethylene die (used as a flame-retardant sample), and is subjected to low-temperature curing at 60 ℃ for 2h, medium-temperature curing at 100 ℃ for 2h and high-temperature curing at 150 ℃ for 5h to finally obtain an epoxy resin/h-BN composite material sample, and the composite material is abbreviated as EP/h-BN/FRGO-50 for convenience of writing.
TABLE 1 compounding ratio of each component of the composite
The curing agent in the invention can adopt the conventional epoxy resin curing agent in the prior art, such as imidazole curing agent, anhydride curing agent, amino curing agent and the like. The modified graphene is obtained by taking an organic flame retardant as a modifier, and the adopted modifier is a flame retardant containing phosphorus elements or nitrogen and phosphorus elements with active groups, such as a polyphosphazene flame retardant, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and derivatives thereof, a phosphazene flame retardant and the like; the modification method can refer to the existing graphene modification method (such as Bao C, Guo Y, Hu Y, et al. journal of materials Chemistry,2011,21, 13290; Liao S-H, Liu P-C, Chiang C-L, et al. Industrial & Engineering Chemistry Research,2012,51, 4573; Wang X, Xing W, Hu Y, et al. Polymer Chemistry,2014,5, 1145.).
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. The composite material with both flame retardance and thermal conductivity is characterized by comprising flame-retardant graphene, a heat-conducting filler and an epoxy resin substrate, wherein the composite material is an epoxy resin-based composite material with the heat conductivity and the flame retardance enhanced by the cooperation of the flame-retardant graphene and the heat-conducting filler; wherein,
the flame-retardant graphene accounts for 0.5-5 wt% of the composite material, and the heat-conducting filler accounts for 10-70 wt% of the composite material;
preferably, the flame-retardant graphene is at least one of reduced graphene oxide and reduced graphene oxide modified by an organic flame retardant;
the heat-conducting filler is micron-sized heat-conducting filler.
2. The composite material having both flame retardancy and thermal conductivity according to claim 1, wherein the flame retardant graphene has an aspect ratio of not less than 5000.
3. The composite material with flame retardancy and thermal conductivity as claimed in claim 1, wherein the micron-sized thermal conductive filler is at least one of alpha-crystalline alumina and hexagonal boron nitride, and the particle size of the alpha-crystalline alumina is 1 to 50 μm;
the hexagonal boron nitride is of a lamellar structure, the length of each lamellar is 1-25 mu m, the thickness of each lamellar is 50-500 nm, and the length-diameter ratio of each hexagonal boron nitride is 10-100.
4. The composite material having both flame retardancy and thermal conductivity according to claim 1, wherein the epoxy resin is any one of a bisphenol a type epoxy resin and a bisphenol F type epoxy resin.
5. A preparation method of a composite material with flame retardance and thermal conductivity is characterized by comprising the following steps:
(a) adding flame-retardant graphene into the epoxy resin prepolymer, and then stirring and mixing to obtain a uniform epoxy resin prepolymer/graphene dispersion system; preferably, the flame-retardant graphene is at least one of reduced graphene oxide and reduced graphene oxide modified by an organic flame retardant;
(b) adding a heat-conducting filler into the epoxy resin prepolymer/graphene dispersion system obtained in the step (a), and then stirring and mixing uniformly to obtain an epoxy resin prepolymer/graphene/heat-conducting filler dispersion system; preferably, the heat-conducting filler is micron-sized heat-conducting filler;
(c) and (c) vacuumizing the epoxy resin prepolymer/graphene/heat-conducting filler dispersion system obtained in the step (b) to remove bubbles, adding a curing agent, and then heating to perform a curing reaction, thereby obtaining the composite material with flame retardance and heat conductivity.
6. The method according to claim 5, wherein in the step (a), the aspect ratio of the flame-retardant graphene is not less than 5000; the epoxy resin is any one of bisphenol A type epoxy resin and bisphenol F type epoxy resin.
7. The method of claim 5, wherein the reduced graphene oxide is chemically reduced graphene oxide; the modifier adopted by the reduced graphene oxide modified by the organic flame retardant is an organic flame retardant containing a phosphorus element, preferably an organic flame retardant containing both a nitrogen element and a phosphorus element, and preferably a polyamide flame retardant containing an amino group at the terminal.
8. The method according to claim 5, wherein in the step (b), the micron-sized heat conductive filler is at least one of alpha-crystalline alumina and hexagonal boron nitride, and the particle size of the alpha-crystalline alumina is 1 to 50 μm;
the hexagonal boron nitride is of a lamellar structure, the length of each lamellar is 1-25 mu m, the thickness of each lamellar is 50-500 nm, and the length-diameter ratio of each hexagonal boron nitride is 10-100.
9. The method according to claim 5, wherein in the step (c), the curing agent is at least one of an imidazole curing agent, an acid anhydride curing agent and an amino curing agent; the addition amount of the curing agent is 2-50 wt% of the epoxy resin prepolymer in the step (a).
10. The method according to claim 5, wherein in the step (c), the temperature-raising curing reaction is performed by performing a low-temperature curing reaction and then performing a high-temperature curing reaction; the reaction temperature of the low-temperature curing reaction is 60-100 ℃, and the reaction temperature of the high-temperature curing reaction is 140-180 ℃.
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CN107216616A (en) * 2017-07-20 2017-09-29 江苏科技大学 High heat conduction waterproof mould material for bus duct and preparation method thereof
CN108109842A (en) * 2017-12-22 2018-06-01 黄山申格电子科技有限公司 A kind of aluminum hull noinductive capacitor production method
CN108192577A (en) * 2017-12-29 2018-06-22 中科院广州化学有限公司 A kind of fire-retardant graphene flexible membrane of high heat conduction and preparation method thereof
CN108659467A (en) * 2018-05-07 2018-10-16 武汉理工大学 The method of SiC/ graphene oxide compound modification of epoxy resin
CN109206848A (en) * 2017-06-30 2019-01-15 洛阳尖端技术研究院 A kind of epoxy prepreg and preparation method thereof
CN111117156A (en) * 2019-12-04 2020-05-08 沈阳化工大学 Preparation method of trimethyl isothiourea modified graphene oxide flame-retardant epoxy resin
WO2021079194A3 (en) * 2019-10-24 2021-06-03 Tianjin Laird Technologies Limited Dispensing systems and methods including online remixing of thermal management and/or emi mitigation materials
CN115368757A (en) * 2022-09-01 2022-11-22 安徽嘉阳新材料科技有限公司 Preparation process of high-strength high-barrier high-thermal-stability modified graphene powder

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Publication number Priority date Publication date Assignee Title
CN109206848A (en) * 2017-06-30 2019-01-15 洛阳尖端技术研究院 A kind of epoxy prepreg and preparation method thereof
CN107216616A (en) * 2017-07-20 2017-09-29 江苏科技大学 High heat conduction waterproof mould material for bus duct and preparation method thereof
CN108109842A (en) * 2017-12-22 2018-06-01 黄山申格电子科技有限公司 A kind of aluminum hull noinductive capacitor production method
CN108192577A (en) * 2017-12-29 2018-06-22 中科院广州化学有限公司 A kind of fire-retardant graphene flexible membrane of high heat conduction and preparation method thereof
CN108659467A (en) * 2018-05-07 2018-10-16 武汉理工大学 The method of SiC/ graphene oxide compound modification of epoxy resin
WO2021079194A3 (en) * 2019-10-24 2021-06-03 Tianjin Laird Technologies Limited Dispensing systems and methods including online remixing of thermal management and/or emi mitigation materials
CN111117156A (en) * 2019-12-04 2020-05-08 沈阳化工大学 Preparation method of trimethyl isothiourea modified graphene oxide flame-retardant epoxy resin
CN115368757A (en) * 2022-09-01 2022-11-22 安徽嘉阳新材料科技有限公司 Preparation process of high-strength high-barrier high-thermal-stability modified graphene powder

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Application publication date: 20170517