CN112029273A - Conductive nylon master batch with graphene-carbon nanotube composite structure and preparation method thereof - Google Patents
Conductive nylon master batch with graphene-carbon nanotube composite structure and preparation method thereof Download PDFInfo
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Abstract
The invention provides a conductive nylon master batch with a graphene-carbon nanotube composite structure, which takes nylon as a carrier, and carbon nanotubes and graphene are connected in a chemical bonding manner after being grafted and modified to form the composite structure and are loaded on the nylon carrier. The conductive nylon master batch provided by the invention is prepared by the steps of firstly carrying out surface grafting treatment on the carbon nano tube and the graphene, then carrying out ring-opening reaction on an amino group grafted on the surface of the carbon nano tube and a glycidyl ether oxygen group grafted on the surface of the graphene, and chemically combining the graphene and the carbon nano tube. The carbon nanotube-graphene composite structure can be well dispersed in a polymer, and simultaneously, graphene and the carbon nanotube can be fully lapped, so that the synergistic effect of the graphene and the carbon nanotube can be exerted, and a conductive network can be efficiently constructed. The master batch can be blended with various polymers, so that the conductive filler in the prepared composite material is uniformly distributed, and the conductivity is obviously improved. The amount of carbon nano tube/graphene used can be greatly reduced.
Description
Technical Field
The application relates to the field of functional polymer composite materials, in particular to a conductive nylon conductive master batch with a graphene-carbon nanotube composite structure and a preparation method thereof.
Background
The graphene and the carbon nano tube are typical nano carbon materials, the graphene and the carbon nano tube have special surface effect, small size effect, quantum size effect and macroscopic quantum tunneling effect due to the structural characteristics of the graphene and the carbon nano tube, and the material compounded by the graphene and the carbon nano tube can also show unique mechanical, thermal, magnetic, electrical and optical properties. The compounding of polymers with carbon nanotubes and graphene as fillers has been one of the hot researches in the direction of functional polymer composites in recent years, which can change the polymer materials from insulators to semiconductors. Theoretically, the use of carbon nanotubes or graphene to improve the conductivity of polymeric materials requires the construction of a perfect conductive network in the polymer, namely: and filling a sufficient amount of graphene or carbon nanotubes in the polymer to ensure that the graphene or carbon nanotubes can be mutually overlapped to form an integral conductive path in the polymer. Experiments prove that when the adding amount of the carbon nano tube and the graphene is small, the overall conductivity of the polymer material is not changed remarkably, and when a certain amount of the carbon nano tube or the graphene is added, a small amount of the carbon nano tube or the graphene is added, the conductivity of the composite material is improved by several orders of magnitude, and an exponential relationship is presented.
From the perspective of industrial application, the carbon nanotubes and graphene are expensive, and the addition of a large amount of them inevitably increases the material cost. The key to improving the conductivity of polymer materials is to build a conductive network inside the polymer. Therefore, a more efficient conductive network is constructed in the material, and the total consumption of the carbon nanotubes and the graphene can be reduced, so that the overall cost of the high-conductivity polymer composite material is reduced.
CN105885401A discloses a graphene carbon nanotube bio-based nylon ternary composite material, which is prepared by modifying the surface of a carbon nanotube/graphene to improve the solubility thereof in an organic solvent, then respectively connecting with diamine and diacid, and finally synthesizing the graphene carbon nanotube nylon ternary composite material by in-situ polymerization. However, the patent method has the problems that the combination synergistic effect between the graphene and the carbon nanotube is insufficient, the preparation method is difficult to realize industrially, and the like.
CN108117743A discloses a carbon nanotube modified highly conductive nylon composite material, wherein the modified carbon nanotube material is prepared by mixing carbon nanotubes and graphene, calcining, ultrasonically dispersing, adding cobalt chloride hexahydrate, nickel dichloride hexahydrate and sodium borohydride solution, dropwise separating, and washing. The method is a simple mechanical mixing method of the carbon nano tube and the graphene, still has the problems of blending compatibility and overlarge addition amount, is high in preparation cost, and is not a production method convenient for industrialization.
CN106183316A discloses a flexible conductive composite fabric, and its preparation and application, in which a layer of carbon nanotube film is immersed in graphene suspension, taken out and dried to obtain a carbon nanotube/graphene composite film; growing a polyaniline nanowire array on the surface of the carbon nanotube/graphene composite membrane in situ to obtain the carbon nanotube/graphene/polyaniline composite membrane; and then adhering electrodes at two ends of the composite film, coating matrix fabrics on the upper and lower surfaces of the composite film through an adhesive, and curing to obtain the composite film. The patent also fails to solve the defect of large addition amount of carbon nanotubes and graphene.
Disclosure of Invention
In order to reduce the using amount of graphene/carbon nano tubes and achieve the aim of efficiently constructing a conductive network structure in a polymer, the invention designs a method for preparing a conductive filler by firstly carrying out grafting treatment on the surfaces of the carbon nano tubes and graphene, then carrying out ring-opening reaction on an amino group grafted on the surface of the carbon nano tube and a glycidyl ether oxygen group grafted on the surface of the graphene, and chemically combining the graphene and the carbon nano tubes. The conductive filler of the chemically combined graphene and the carbon nano tube prepared by the method is subjected to graft modification by the silane coupling agent, and has a microstructure in which the graphene and the carbon nano tube are tightly and chemically combined, so that the graphene and the carbon nano tube can be fully lapped while being well dispersed in a polymer, the synergistic effect of the graphene and the carbon nano tube can be exerted, and a conductive network can be efficiently constructed.
In addition, in the process of preparing the polymer composite material, the conductive filler component and the polymer are mixed for a long time, and meanwhile, the specific modifier is added, so that the improvement of the dispersibility of the conductive filler is completed in the mixing process, and the method is the existing scheme for improving the comprehensive performance of the polymer composite material; however, long-term mixing can also lead to polymer degradation, and the graphene and carbon nanotube structures are destroyed, so that the improvement of the overall performance of the composite material is very limited. Aiming at the problem, the invention designs a method for continuously preparing nylon master batch with a graphene-carbon nano tube chemical bonding structure by convection flocculation of modified graphene slurry and a nylon formic acid solution. The method avoids the use of high-temperature and high-shear mixing equipment, and realizes the preparation of the polymer high-efficiency conductive master batch by utilizing the phenomenon that the nylon formic acid solution is flocculated when meeting methanol. The nylon master batch with the graphene-carbon nanotube chemical bonding structure prepared by the invention is used as a raw material, and is mixed with a polymer to obtain the plastic composite material with antistatic and even conductive characteristics, and the whole addition amount of the conductive filler is less than that of the graphene or the carbon nanotube which is used alone or is less than that of the graphene or the carbon nanotube which is simply mixed for use.
The invention provides a conductive nylon master batch with a graphene-carbon nanotube composite structure, which takes nylon as a carrier, and carbon nanotubes and graphene are connected in a chemical bonding manner after being grafted and modified to form the composite structure and are loaded on the nylon carrier.
Further, the total loading amount of the carbon nano tube and the graphene is 5-50%, and the mass ratio of the carbon nano tube to the graphene is 1-5: 1-5. Preferably, the total loading amount of the carbon nanotubes and the graphene is 10-30%, and the mass ratio of the carbon nanotubes to the graphene is 1-2: 1-2.
Further, the carbon nanotube and graphene are subjected to graft modification by (i) reacting and graft modifying the acidified carbon nanotube and polyether surfactant and silane coupling agent with amino group, and (ii) reacting and graft modifying the acidified graphene and polyether surfactant and silane coupling agent with glycidyl ether group; the chemical bonding connection is a reaction between amino groups on the carbon nanotubes subjected to the grafting modification and epoxy groups on the graphene subjected to the grafting modification.
The hydrolyzed amino silane coupling agent and the glycidyl ether oxygen silane coupling agent can react with hydroxyl or carboxyl on the surfaces of the acidified carbon nano tube and the acidified graphene by utilizing the silicon hydroxyl group at the tail end of the hydrolyzed amino silane coupling agent to form chemical combination, so that a layer of silane coupling agent is grafted on the surfaces of the carbon nano tube and the graphene, and the dispersibility of the carbon nano tube and the graphene in the polymer can be effectively improved through grafting modification. More importantly, the amino group exposed outside the carbon nanotube has the ability to undergo a ring-opening reaction with the glycidyl ether oxygen group exposed outside the graphene, and the reaction between the amino group and the glycidyl ether oxygen group can promote chemical bonding between the graphene and the carbon nanotube, so that the carbon nanotube and the graphene are tightly bonded. The polyether surfactant can form hydrogen bond action with hydroxyl on the surfaces of the graphene and the carbon nano tube by utilizing a polyether structure of the polyether surfactant, so that the graphene and the carbon nano tube are coated and modified, and the graphene and the carbon nano tube are easy to disperse in a nylon carrier quickly. In addition, the polyether surfactant can form a coating structure with the silane coupling agent, so that the hydrolysis degree of the silane coupling agent in the next hydrolysis process is controlled, and the coupling agent is prevented from being obviously self-polymerized after being hydrolyzed.
Further, the chemical structure of the polyether surfactant is shown as formula (I), the chemical structure of the silane coupling agent with amino group is shown as formula (II), and the chemical structure of the silane coupling agent with glycidyl ether group is shown as formula (III):
CH3(CH2)m(OCH2CH2)nOH
(Ⅰ)
NH2-(CH2)p-Si-X3
(Ⅱ)
wherein m has a value of between 1 and 20, preferably between 5 and 10; n has a value of between 2 and 10, preferably between 3 and 8; p has a value between 2 and 8; q has a value of between 2 and 8, preferably between 3 and 5; x represents an alkoxy group of C1-C6, such as methoxy, ethoxy, propoxy or butoxy.
Preferably, the polyether surfactant is CH3(CH2)10(OCH2CH2)4OH, the silane coupling agent with the glycidyl ether group is
The silane coupling agent with amino is NH2-(CH2)3-Si-(OCH3)3。
The nylon of the present invention is not particularly limited, and may be an amide material known in the art, such as nylon 6, nylon 66, nylon 56, nylon 610.
The carbon nano tube and the graphene are loaded on a nylon carrier and are obtained by carrying out convection flocculation on turbid liquid obtained by chemically bonding the carbon nano tube and the graphene and a formic acid solution of nylon.
Preferably, the solvent of the suspension after the carbon nanotube-graphene chemical bonding is methanol, and the total mass concentration of the carbon nanotube and the graphene is 0.5-20 wt%, preferably 0.8-15 wt%; the mass concentration of the nylon in the formic acid solution of the nylon is 5-20 wt%, preferably 5-15 wt%.
And the convection flocculation is carried out by mixing the carbon nano tube-graphene turbid liquid and the formic acid solution of nylon according to the flow velocity of 1: 0.5-5, and rapidly intersecting the two feed liquids according to opposite flow directions. Preferably, the flow rates of the carbon nanotube-graphene suspension and the formic acid solution of nylon are 1: 0.6-4.
In the convection flocculation process, the chemically bonded carbon nanotube-graphene suspended in the methanol is uniformly mixed into the nylon formic acid solution under the flowing action of the liquid flow, the separation phenomenon of formic acid can occur after the nylon formic acid solution meets the methanol, and the graphene and the carbon nanotube package dispersed in the nylon formic acid solution and chemically bonded are carried out while the formic acid is separated out, so that the nylon coated mixture with the carbon nanotube-graphene chemical bonding structure is formed. The two liquid flows are converged and then fall into a product container with the lower end, and a certain liquid flow impact effect is achieved, so that the nylon formic acid solution can be more fully contacted with methanol, and the precipitation of nylon is further accelerated. Because the surfaces of the chemically combined graphene and carbon nano tubes are coated and grafted with a certain amount of organic modifier, and the graphene-carbon nano tube suspension liquid flow and the nylon formic acid solution liquid flow are uniformly and stably mixed in the mixing process, the chemically combined graphene-carbon nano tubes can be effectively and uniformly dispersed in nylon, and the formic acid can enable the nylon coated graphene-carbon nano tubes to be rapidly separated out, so that the uniformly dispersed state of the chemically combined graphene-carbon nano tubes in a nylon carrier is kept until master batches are formed, and finally, the conductive carbon material in the polymer master batches with the chemical combination structure of the graphene-carbon nano tubes can be uniformly dispersed. In addition, the preparation process of the master batch is realized through continuous flow, so that the stable and continuous production of the master batch can be realized without introducing a huge reaction container.
The second purpose of the invention is to provide a preparation method of the conductive nylon master batch with the carbon nanotube-graphene composite structure, which comprises the following steps: (1) respectively carrying out acidification treatment on the carbon nano tube and the graphene; (2) respectively carrying out grafting modification on the carbon nano tube and the graphene after the acidification treatment, and reacting with each other to obtain a chemically bonded carbon nano tube-graphene suspension; (3) and (3) carrying out convection flocculation on the chemically bonded carbon nanotube-graphene turbid liquid and the nylon formic acid solution, carrying out centrifugal separation, and drying to obtain the conductive nylon master batch with the carbon nanotube-graphene composite structure.
Preferably, the step (1) of the acidification treatment is to add the carbon nanotubes and the graphene into a mixed acid of concentrated nitric acid and concentrated sulfuric acid, centrifuge, take a bottom layer suspension, wash the bottom layer suspension to be weakly alkaline or neutral, and dry the bottom layer suspension.
Further, the mass ratio of the concentrated nitric acid to the concentrated sulfuric acid is 1: 2-3. The concentration of nitric acid is more than 60 wt%, and the concentration of sulfuric acid is more than 90 wt%. The amount of the acid used is not particularly limited, and the carbon nanotube and the graphene can be sufficiently impregnated with the acid. In one embodiment of the present invention, the amount of the acid is 150 times the mass of the carbon nanotube or graphene. The acidification treatment is to add mixed acid and then to ultrasonically vibrate for 2 to 8 hours at the frequency of 15 to 40 kHz.
In one embodiment of the present invention, the centrifugation is to centrifuge the acidified carbon nanotube and graphene slurry for 10 minutes at 4000 r/min using a centrifuge, respectively, so as to separate the mixed solution into layers. Separating the black carbon nano tube and the graphene turbid liquid at the bottom layer; and in the water washing step, the pH value is repeatedly washed by using clean water to 6-7, and then the obtained product is dried to constant weight in a vacuum oven at the temperature of 60-80 ℃ to obtain the acidified carbon nano tube and the acidified graphene. And refining the supernatant liquor after centrifugal separation to remove impurities, and then reusing the supernatant liquor.
Through acidification treatment, hydroxyl (-OH) and carboxyl (-COOH) groups appear on the surfaces of the carbon nano tube and the graphene, and a structural basis is provided for surface grafting modification treatment of the carbon nano tube and the graphene.
Preferably, the grafting modification in step (2) is to prepare the mixed reagents (i) and (ii) separately:
mixing reagent (i): alcohol-water solution of polyether surfactant and amino silane coupling agent;
mixing reagent (ii): polyether surfactant and alcohol-water solution of silane coupling agent with glycidyl ether group;
and (3) putting the carbon nano tube and the graphene which are subjected to the acidification treatment into a mixed reagent (i) and a mixed reagent (ii), and fully reacting to respectively obtain the grafted and modified carbon nano tube and the graphene.
Further, in the mixed reagent (i), the total concentration of the polyether surfactant and the aminosilane coupling agent is 15-45 wt%, preferably 25-35 wt%; the mass ratio of the polyether surfactant to the amino silane coupling agent is 2-5: 5-8; in the mixed reagent (ii), the total concentration of the polyether surfactant and the silane coupling agent with the glycidyl ether group is 15-45 wt%, preferably 25-35 wt%; the mass ratio of the polyether surfactant to the silane coupling agent with the glycidyl ether group is 2-5: 5-8.
The solvent in the mixed reagents (i) and (ii) is an aqueous solution of an alcohol, wherein the concentration of the alcohol is 70-95 wt%, and the alcohol is selected from at least one of methanol, ethanol and propanol, and is preferably methanol.
In one embodiment of the present invention, the mixed reagents (i) and (ii) are prepared such that the respective materials are fed and then hydrolyzed for 2 to 8 hours by ultrasonic oscillation at 15 to 30kHz while stirring at a speed of 800-.
Further, in the graft modification, the mixed reagents (i) and (ii) are heated to 50-70 ℃ and then acidified carbon nanotubes and acidified graphene are added, wherein the amount of the acidified carbon nanotubes and acidified graphene added is 1-5 wt%, preferably 2-3 wt% of the mixed reagent (i) or (ii). After mixing, stirring at the speed of 500-2000rpm and simultaneously matching 30-60kHz ultrasonic oscillation to ensure that the mixed solution is in a flowing state, and modifying for 1-6 hours under the condition of keeping the temperature and the stirring speed stable.
In the step (2), the reaction of the grafted and modified carbon nanotube and graphene means that a mixed reagent (i) and a mixed reagent (ii) are mixed according to a mass ratio of 1-2:1-2, and are centrifugally separated, wherein a black carbon nanotube-graphene mixed suspension is formed at the bottom layer.
The centrifugal separation is not particularly limited so long as it can be separated into layers. In one embodiment of the invention, the mixture is stirred at the speed of 1000-.
Preferably, after obtaining bottom suspension by centrifugal separation, after filtering and washing by methanol, adding methanol to prepare slurry with the total content of graphene and carbon nano tubes of 0.5-20 wt%, and preferably adding methanol to prepare slurry with the total content of graphene and carbon nano tubes of 0.8-15 wt%.
Preferably, the convection flocculation in the step (3) is to rapidly intersect the carbon nanotube-graphene mixed suspension and the nylon formic acid solution at opposite flow rates in a certain proportion.
In the nylon formic acid solution, the mass concentration of nylon is 5-20 wt%, preferably 10-15 wt%.
Mixing a carbon nanotube-graphene turbid liquid and a formic acid solution of nylon at a flow rate of 1: 0.5-5, preferably 1: 0.6-4.
In one embodiment of the present invention, the nylon formic acid solution is prepared by: the formic acid is heated to 50-80 ℃, the nylon particles are added, the temperature is kept constant, and the mixture is stirred at the speed of 500-2500rpm until the particles completely disappear and the liquid is completely transparent, so as to prepare the nylon formic acid solution.
The technical meaning of said nylons is that of the resins known in the art, being polyamides obtained by ring-opening polymerization of lactams or by condensation polymerization of diacids and diamines, such as nylon 6, nylon 66, nylon 610, nylon 56.
In one embodiment of the present invention, the graphene-carbon nanotube mixed slurry and the nylon formic acid solution are stirred at a speed of 300-1000rpm, respectively, to keep the feed liquid uniformly dispersed.
The lower end of the container for containing the graphene-carbon nanotube mixed slurry and the nylon formic acid solution is provided with a discharge hole, and the outflow speed of the liquid can be stably controlled. And (2) enabling the discharge ports of the containers for containing the graphene-carbon nanotube mixed slurry and the nylon formic acid solution to be close to ensure that the liquid in the two containers can be intersected before entering the containing container in the process of flowing out and falling, simultaneously opening the discharge ports of the two containers, and respectively adjusting the flow rates of the liquid outlets of the two containers according to the designed loading capacity of the graphene-carbon nanotube in the master batch and the ratio.
After preparing enough nylon master batch with the graphene-carbon nano tube chemical bonding structure, closing discharge ports of the two containers at the same time, placing the product in the container at the lower end into a centrifugal machine for centrifugal separation, collecting the precipitate at the lower part, and drying in vacuum to be heavy, thereby obtaining the nylon master batch with the graphene-carbon nano tube chemical bonding structure.
The main components of the upper layer solution after centrifugal separation are formic acid, methanol and a small amount of mixed modifier, and the formic acid and the methanol are recovered by a distillation method and are reused.
The invention designs a method for preparing a conductive master batch with a chemically combined graphene and carbon nanotube structure, which is mainly realized by three main steps of grafting modification treatment of carbon nanotubes and graphene in a liquid phase, reaction of modified carbon nanotubes and modified graphene, and convection flocculation of graphene-carbon nanotube turbid liquid and a nylon formic acid solution. The preparation of the conductive master batch can ensure that a relatively perfect conductive network is formed under the condition that the total consumption of the conductive filler is less; meanwhile, the conductive filler can be uniformly dispersed in the polymer material in a short time, and the damage to the structure and the performance of the material in the mixing processing process is reduced. Experiments show that the use of the master batch is helpful for reducing the consumption of the conductive filler in the polymer composite material with specific conductive grade and improving the overall performance of the material.
The third objective of the present invention is to provide a polymer composition, which includes the conductive nylon masterbatch with the carbon nanotube-graphene composite structure and a polymer, wherein the amount of the conductive nylon masterbatch with the carbon nanotube-graphene composite structure is 0.3 wt% to 8 wt%, preferably 0.5 wt% to 2 wt%, of the polymer composition, based on the total mass of the carbon nanotube-graphene.
The polymer is one or more of conventional high molecular materials in the field, such as polyolefins, polyesters, polyamides, polyolefin derivatives and polymers containing polyolefin block structures. A certain amount of the conductive nylon master batch with the carbon nano tube-graphene composite structure, which is prepared by the invention, is added into a conventional high molecular polymer, and after the initial mechanical mixing, the conductive nylon master batch is added into polymer processing equipment which can provide a shearing action, such as an open mill, an internal mixer or a screw extruder, and the polymer composite material with improved conductivity and mechanical property is prepared by melt blending.
In addition to the above components, various other auxiliary additives commonly used in the polymer composite processing field are also used in the preparation process of the present invention. Experiments prove that the load capacity of graphene and carbon nanotubes in the nylon master batch with the graphene-carbon nanotube chemical bonding structure prepared by the invention is accurate and controllable, and the chemically bonded graphene-carbon nanotube filler is uniformly dispersed. The polymer composite material prepared by using the master batch can obviously improve the conductivity of the polymer composite material, and meanwhile, the mechanical property of the composite material can be improved to a certain extent.
Drawings
Fig. 1 is a Scanning Electron Microscope (SEM) photograph of a nylon master batch having a graphene-carbon nanotube chemical bonding structure prepared according to the preparation method described in example 1.
Detailed Description
For further understanding of the present invention, the following description will be made of preferred embodiments of the preparation and application of the nylon masterbatch with the chemical bonding structure of graphene-carbon nanotube in accordance with the present invention with reference to the examples, but it should be understood that these descriptions are only for illustrating the features and advantages of the present invention in more detail, and do not limit the claims of the present invention in any way.
The mass concentration of the concentrated nitric acid used in the invention is 65%, and the mass concentration of the concentrated sulfuric acid is 98 wt%.
The graphene is B-type conductive graphene provided by Beijing Qing Dajian optical science and technology development Limited company in cooperative units, and the carbon nano tube is a multi-wall carbon nano tube sold in the market.
The loading amount of the carbon nanotube-graphene in the conductive master batch is calculated by a Thermal Gravimetric Analyzer (TGA) at 800 ℃ for the firing allowance.
Example 1:
taking two 1000ml beakers, respectively preparing 400g of mixed concentrated acid with nitric acid and sulfuric acid in a ratio of 1:3, respectively adding 5 g of commercially available graphite and 5 g of carbon nano tubes, placing the two beakers into an ultrasonic water tank, adjusting the temperature of the water tank to 65 ℃, carrying out ultrasonic oscillation for 4 hours at a frequency of 25KHz, then carrying out centrifugal separation on the two obtained mixed slurry for 10 minutes by using a centrifugal machine under a condition of 4000 r/min, and respectively layering the two mixed slurry to separate out black graphene turbid liquid and black carbon nano tube turbid liquid at the bottom layer. And respectively and repeatedly washing the two turbid liquids by using clear water to enable the pH value of the two turbid liquids to reach 6, and drying the two turbid liquids to constant weight at 70 ℃ by using a vacuum oven to obtain 4.8 g of acidified graphene and 4.8 g of acidified carbon nano tubes.
Another 500ml beaker was charged with 24 g of aliphatic vinyl ether (A), 56 g of aminopropyltriethoxysilane (B) in the first beaker and 56 g of glycidyloxypropyltrimethoxysilane (C) in the second beaker. Both beakers were stirred at 45 ℃ and 500rpm for 0.5 hour to obtain two mixed modifiers. And then taking two 2000ml beakers, respectively adding 360 g of methanol and 40 g of water, dropwise adding formic acid to adjust the pH value of the solution to 5, respectively adding 200 g of each of the two mixed modifiers into the two beakers, then placing the two beakers into an ultrasonic water tank, adjusting the temperature of the water tank to be 60 ℃, setting the frequency of ultrasonic oscillation to be 20Hz, simultaneously stirring the mixed solution in the two beakers by using a stirring paddle at the speed of 500rpm, keeping the temperature in the beakers stable, and obtaining mixed hydrolysate which is respectively a graphene modified solution and a carbon nanotube modified solution after 3 hours.
NH2-(CH2)3-Si-(OC2H5)3
(B)
Adjusting the frequency of ultrasonic oscillation to 30Hz, adjusting the temperature to 60 ℃, adding the obtained 4.8 g of acidified carbon nano tube into the carbon nano tube modified solution at one time, adjusting the stirring speed to 1000rpm, adding the obtained 4.8 g of acidified graphene into the graphite modified solution at one time, adjusting the stirring speed to 1500rpm, and modifying for 3 hours under the condition of keeping the temperature of two beakers and the stirring speed stable. And (3) pouring the modified graphene slurry and the carbon nanotube slurry into a 3000ml beaker, then placing the beaker into an ultrasonic water tank, adjusting the temperature of the water tank to 80 ℃, setting the frequency of ultrasonic oscillation to 40Hz, stirring at 1500rpm by using a stirring paddle, keeping the temperature in the beaker stable, and obtaining the chemically-combined graphene-carbon nanotube slurry after 4 hours. And then transferring the slurry into a centrifuge, setting the rotation speed of the centrifuge to be 4000 r/min, carrying out centrifugal separation for 10 min to stratify the mixed solution, separating out the carbon nano tube/graphene mixed suspension at the bottom layer, carrying out suction filtration and washing for 3 times by using methanol, adding methanol, and adjusting the total content of the carbon nano tube and the graphene to be 0.95 wt%.
A10 wt% polycaprolactam solution was prepared by adding 900 g of formic acid to a 2000ml beaker, adjusting the formic acid temperature to 60 ℃ using a water bath, placing 100 g of polycaprolactam (nylon 6) particles, holding the temperature constant, and stirring at 1000rpm until the polycaprolactam particles completely disappeared and the liquid was completely clear.
Respectively putting the methanol turbid liquid of the carbon nano tube and the graphene and the polycaprolactam formic acid solution into a glass kettle with a discharge hole at the bottom. And respectively starting stirring devices arranged in the two kettles, stirring the methanol suspension of the carbon nano tube and the graphene at the speed of 600rpm, and stirring the polycaprolactam formic acid solution at the speed of 400 rpm. The discharge gate position of two cauldron is adjusted, makes it be close to, is enough to guarantee that liquid flows out in two containers whereabouts in-process can intersect as early as possible, takes a 10000 ml's container to put under two cauldron discharge gate positions. And simultaneously opening the discharge ports of the two containers, and adjusting to ensure that the quality of the liquid flowing out of the two containers in unit time is the same. Keeping the outflow liquid flow of the two kettles stable, and closing the discharge holes of the two kettles simultaneously after finishing the outflow of the materials in the two kettles. Putting a product in a beaker with the lower end of 5000ml into a centrifuge, performing centrifugal separation for 5 minutes under the condition of 2000 r/min, collecting a precipitate at the lower part, drying to constant weight at 80 ℃ by using a vacuum oven to obtain about 109 g of nylon master batch with a graphene-carbon nanotube chemical bonding structure, measuring the total loading capacity of the carbon nanotube-graphene by using a thermal weight loss method, and calculating to obtain the total loading capacity of the carbon nanotube and the graphene to be 10.2%. By observing the master batch by using a Transmission Electron Microscope (TEM), the graphene and the carbon nano tube are uniformly dispersed in the master batch, which is directly related to the modification treatment of the filler and the convection method, as shown in figure 1.
Example 2:
taking two 3000ml beakers, respectively preparing 1000g of mixed concentrated acid with nitric acid and sulfuric acid being 1:3, adding 50 g of graphene into one beaker, adding 50 g of carbon nano tubes into the other beaker, placing the beakers into an ultrasonic water tank, adjusting the temperature of the water tank to be 70 ℃, carrying out ultrasonic oscillation for 8 hours at the frequency of 40KHz, respectively using a centrifuge to centrifugally separate the two obtained mixed slurry for 10 minutes under the condition of 4000 r/min, and layering the mixed slurry to separate out black graphene suspension and black carbon nano tube suspension at the bottom layer. And repeatedly washing the turbid liquid by using clear water to enable the pH value of the turbid liquid to reach 6, and drying the two turbid liquids to constant weight by using a vacuum oven at the temperature of 80 ℃ to obtain 48.5 g of acidified graphene and 48.3 g of acidified carbon nano tubes.
100 g of aliphatic vinyl ether (D) was added to each of two 1000ml beakers, 300 g of aminopropyltriethoxysilane (E) was added to the first beaker, and 100 g of glycidylethoxybutyltriethoxysilane (F) was added to the second beaker. Both beakers were stirred at 45 ℃ and 500rpm for 0.5 hour to obtain two mixed modifiers with 25% aliphatic vinyl ether.
And then taking two 5000ml beakers, respectively adding 1800 g of methanol and 200 g of water, dropwise adding formic acid to adjust the pH value of the solution to 5, respectively adding 500 g of each of the two mixed modifiers into the two beakers, then putting the beakers into an ultrasonic water tank, adjusting the temperature of the water tank to 80 ℃, setting the frequency of ultrasonic oscillation to be 25Hz, simultaneously respectively stirring the solutions in all the beakers by using a stirring paddle at the speed of 1000rpm, keeping the temperature in the beakers stable, and obtaining two mixed hydrolysates after 8 hours, wherein the hydrolysates are used as modified solutions of graphene and carbon nanotubes.
NH2-(CH2)3-Si-(OCH3)3
(E)
Adjusting the frequency of ultrasonic oscillation to 60Hz, keeping the temperature at 70 ℃, adding acidified graphene into a beaker filled with a glycidyl ether oxygen butyl triethoxysilane hydrolysis solution, adjusting the stirring speed to 2500rpm to ensure that the graphene mixed solution is in a flowing state, and modifying for 2 hours under the condition of keeping the temperature and the stirring speed stable. Adding the acidified carbon nano tube into a beaker filled with aminopropyltriethoxysilane hydrolysis solution, adjusting the stirring speed to 2000rpm, ensuring that the carbon nano tube mixed solution is in a flowing state, and modifying for 1 hour under the condition of keeping the temperature and the stirring speed stable. And (2) pouring the modified graphene slurry and the modified carbon nanotube slurry into a 5000ml beaker, then placing the beaker into an ultrasonic water tank, adjusting the temperature of the water tank to 80 ℃, setting the frequency of ultrasonic oscillation to be 25Hz, stirring by using a stirring paddle at the speed of 1000rpm, keeping the temperature in the beaker stable, and obtaining the chemically combined graphene-carbon nanotube slurry after 8 hours. And then, transferring the graphene slurry into a centrifuge, setting the rotation speed of the centrifuge to be 4000 r/min, performing centrifugal separation for 10 min to layer the mixed solution, separating out 1000g of turbid liquid at the bottom layer, washing for 3 times by using methanol, and adding methanol to prepare graphene-carbon nanotube methanol turbid liquid with the total weight of 1000g and the content of chemically combined graphene-carbon nanotubes of about 9.8%.
A15 wt% polyhexamethylene adipamide formic acid solution was prepared by adding 3400 g formic acid to a 10000ml beaker, adjusting the cyclohexane temperature to 80 ℃ using a water bath, adding 600 g polyhexamethylene adipamide (nylon 66), maintaining the temperature constant, and stirring at 2500rpm until the polyhexamethylene adipamide particles completely disappeared and the liquid was completely clear.
And respectively putting the obtained graphene-carbon nano tube methanol turbid liquid and the poly hexamethylene diamine adipate formic acid solution into a glass kettle with a discharge hole at the bottom. And respectively starting stirring devices arranged in the two kettles, stirring the graphene-carbon nanotube methanol suspension at a speed of 3500rpm, and stirring the polyhexamethylene adipamide formic acid solution at a speed of 1000 rpm. The discharge hole positions of the two kettles are adjusted to be close to each other, so that the liquid in the two containers can flow out and can be converged as soon as possible in the falling process, and a 5000ml beaker is taken and placed under the discharge hole positions of the two kettles. And simultaneously opening discharge ports of the two containers, and adjusting the outflow speed of the poly hexamethylene adipamide formic acid solution to be 3.70 times of that of the graphene-carbon nanotube methanol suspension. Keeping the outflow liquid flow of the two kettles stable, and closing the discharge ports of the two kettles simultaneously after 300 g of polyhexamethylene adipate solution flows out. And replacing a 5000ml beaker, placing the beaker under the discharge ports of the two kettles, simultaneously opening the discharge ports of the two containers, and adjusting the outflow speed of the poly (hexamethylene adipamide) formic acid solution to be 1.95 times of the graphene-carbon nanotube methanol suspension. Keeping the outflow liquid flow of the two kettles stable, and closing the discharge ports of the two kettles simultaneously after 300 g of polyhexamethylene adipate solution flows out. And replacing a 5000ml beaker again and placing the beaker under the discharge holes of the two kettles, simultaneously opening the discharge holes of the two containers, and adjusting the outflow speed of the poly (hexamethylene adipamide) formic acid solution to be 1.21 times of the graphene-carbon nanotube methanol suspension. Keeping the outflow liquid flow of the two kettles stable, and closing the discharge ports of the two kettles simultaneously after 300 g of polyhexamethylene adipate solution flows out. And finally, replacing a 5000ml beaker for the first time and placing the beaker under the discharge ports of the two kettles, simultaneously opening the discharge ports of the two containers, and adjusting the outflow speed of the polyhexamethylene adipamoic acid solution to be 0.79 time of the graphene-carbon nanotube methanol suspension. Keeping the outflow liquid flow of the two kettles stable, and closing the discharge ports of the two kettles simultaneously after 300 g of polyhexamethylene adipate solution flows out. Putting the products in four 5000ml beakers into a centrifuge once, performing centrifugal separation for 5 minutes under the condition of 2000 r/min, collecting the lower precipitate, and drying to constant weight at 100 ℃ by using a vacuum oven to obtain four polyhexamethylene adipamide formic acid master batches, wherein the theoretical loading amounts of the graphene-carbon nano tube chemically combined filler are 15%, 25%, 35% and 45% in sequence. The four master batches are sequentially tested by using a Thermal Gravimetric Analyzer (TGA), and the obtained firing allowance at 800 ℃ is 16.0%, 26.2%, 35.8% and 46.1% in sequence, which is almost equivalent to the theoretical loading amount of the filler, and thus, the loading amount of the graphene-carbon nanotube filler in the master batch prepared by the method is controllable.
Example 3:
taking two 3000ml beakers, respectively preparing 2000g of mixed concentrated acid with nitric acid and sulfuric acid in a ratio of 1:3, respectively adding 20 g of commercially available graphene and 10 g of carbon nano tubes, placing the two beakers into an ultrasonic water tank, adjusting the temperature of the water tank to be 60 ℃, carrying out ultrasonic oscillation for 4 hours at a frequency of 25KHz, centrifuging and separating the two obtained mixed slurry for 10 minutes by using a centrifuge under a condition of 4000 r/min, and respectively layering the two mixed slurry to separate out black graphene turbid liquid and black carbon nano tube turbid liquid at the bottom layer. And respectively and repeatedly washing the two turbid liquids by using clear water to enable the pH value of the two turbid liquids to reach more than 6, and drying the two turbid liquids to constant weight by using a vacuum oven at 75 ℃ to obtain 19.6g of acidified graphene and 9.8g of acidified carbon nano tubes.
Two additional 1000ml beakers were charged with 200 grams of aliphatic vinyl ether (A), 300 grams of aminopentyltriethoxysilane in the first beaker, and 380 grams of glycidylethoxyhexyltrimethoxysilane in the second beaker. Stirring was carried out at 1000rpm for 0.5 hour at 40 ℃ in both beakers to obtain two kinds of mixed modifiers.
And taking two 3000ml beakers, respectively adding 1800 g of methanol and 200 g of water, dropwise adding formic acid to adjust the pH value of the solution to 6, respectively adding two mixed modifiers into the two beakers, then putting the beakers into an ultrasonic water tank, adjusting the temperature of the water tank to 70 ℃, setting the frequency of ultrasonic oscillation to be 20Hz, simultaneously respectively stirring the solutions in the two beakers by using a stirring paddle at the speed of 1500rpm, keeping the temperature in the beakers stable, and obtaining the aminopentyltriethoxysilane hydrolysate and the glycidoxy ether hexyltrimethoxysilane hydrolysate after 7 hours.
Adjusting the frequency of ultrasonic oscillation to 40Hz, adjusting the temperature to 65 ℃, adding 9.8g of the obtained acidified carbon nano tubes into the aminopentyltriethoxysilane hydrolysate at one time, adjusting the stirring speed to 1300rpm, adding 19.6g of the obtained acidified graphene into the glycidylethoxy hexyltrimethoxysilane hydrolysate at one time, adjusting the stirring speed to 1300rpm, and modifying for 4 hours under the condition of keeping the temperature of two beakers and the stirring speed stable. And (2) pouring the modified graphene slurry and the modified carbon nanotube slurry into a 5000ml beaker, then placing the beaker into an ultrasonic water tank, adjusting the temperature of the water tank to 80 ℃, setting the frequency of ultrasonic oscillation to be 25Hz, stirring by using a stirring paddle at the speed of 1000rpm, keeping the temperature in the beaker stable, and obtaining the chemically combined graphene-carbon nanotube slurry after 8 hours. And then, transferring the graphene slurry into a centrifuge, setting the rotation speed of the centrifuge to be 4000 r/min, performing centrifugal separation for 10 min to layer the mixed solution, separating out turbid liquid at the bottom layer, washing for 3 times by using methanol, and then adding methanol to prepare graphene-carbon nanotube methanol turbid liquid with the chemically combined graphene-carbon nanotube content of about 2.93%.
A5 wt% polycaprolactam solution was prepared by adding 1900 g of formic acid to a 3000ml beaker, adjusting the formic acid temperature to 60 ℃ using a water bath, adding 100 g of polycaprolactam (nylon 6), keeping the temperature constant, and stirring at 2000rpm until the polycaprolactam particles completely disappeared and the liquid was completely clear.
And respectively putting the obtained graphene-carbon nano tube methanol and polycaprolactam formic acid solution into a glass kettle with a discharge hole at the bottom. And respectively starting stirring devices arranged in the two kettles, stirring the graphene-carbon nanotube methanol suspension at the speed of 1000rpm, and stirring the polycaprolactam formic acid solution at the speed of 1000 rpm. The discharge hole positions of the two kettles are adjusted to be close to each other, so that the liquid in the two containers can flow out and can be converged as soon as possible in the falling process, and a 5000ml beaker is taken and placed under the discharge hole positions of the two kettles. And simultaneously opening the discharge ports of the two containers, adjusting the outflow speed of the polycaprolactam formic acid solution to be 2.34 times that of the graphene-carbon nanotube methanol turbid liquid, keeping the outflow liquid flows of the two kettles stable, and simultaneously closing the discharge ports of the two kettles after the material in one of the kettles flows out. And putting a product in a beaker with the lower end of 5000ml into a centrifuge, centrifuging and separating for 5 minutes under the condition of 2000 r/min, collecting the precipitate at the lower part, and drying to constant weight at 120 ℃ by using a vacuum oven to obtain the nylon master batch with the graphene-carbon nano tube chemical bonding structure and the loading capacity of about 19.8%.
According to the formula shown in Table 1 (all components are calculated according to parts by weight), the raw materials are fully mixed, and then are extruded and granulated at the screw rotating speed of 35rpm at the temperature of 180 ℃ and 220 ℃ by using a double-screw extruder. And then adopting an injection molding method to prepare nylon composite materials containing different graphene-carbon nanotube filling parts, and testing the volume resistivity and the flame retardant property of the materials, wherein the results are shown in table 2. The result shows that the nylon master batch with the graphene-carbon nanotube chemical bonding structure can be used together with the flame-retardant master batch, and the functions of the nylon master batch and the flame-retardant master batch cannot be influenced mutually, so that the conductivity and the flame retardance of the material can be improved simultaneously. In addition, test results also show that the nylon master batch with the graphene-carbon nanotube chemical bonding structure can remarkably improve the conductivity of the material, and the use of 12 wt% of the nylon master batch with the graphene-carbon nanotube chemical bonding structure can improve the conductivity of nylon by more than 5 orders of magnitude, which accords with the assumption that the master batch prepared by the invention improves the conductivity of the material.
TABLE 1
| Sample 0 | Sample 1 | Sample 2 | Sample 3 | Sample No. 4 | |
| Nylon 6 | 70 | 67 | 64 | 61 | 58 |
| Graphene-carbon nanotube master batch | 0 | 3 | 6 | 9 | 12 |
| Halogen-free flame-retardant master batch | 30 | 30 | 30 | 30 | 30 |
| Antioxidant 1010 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 |
| Antioxidant 168 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 |
| Lubricant EBS | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 |
TABLE 2
| Sample 0 | Sample 1 | Sample 2 | Sample 3 | Sample No. 4 | |
| Volume resistivity/Ω · cm | ＞1×1014 | 9×1012 | 3×1012 | 4×108 | 8×107 |
| Fire rating/UL 94 | V-0 | V-0 | V-0 | V-0 | V-0 |
Comparative example 1
The other conditions and steps are the same as those in example 3, except that the graphene is not modified, that is, the modified graphene slurry treated by the modification solution in example 3 is replaced by a methanol dispersion liquid of graphene with an equal mass concentration, and finally the nylon master batch with the graphene-carbon nanotube chemical bonding structure and the loading amount of about 20% is obtained. The compositions of samples 0 to 4 were in accordance with Table 1 of example 3. The difference is only that the nylon master batch containing the carbon nano tube-graphene is replaced by the master batch prepared in the comparative example 1. The volume resistivity of the samples was tested and the results are shown in table 3 below:
TABLE 3
| Sample 0 | Sample 1 | Sample 2 | Sample 3 | Sample No. 4 | |
| Volume resistivity/Ω · cm | ＞1×1014 | 3×1013 | 1×1013 | 7×109 | 1×109 |
Comparative example 2
The other conditions and steps are the same as those in example 3, except that the carbon nanotubes are not modified, that is, the modified carbon nanotube slurry treated by the modification solution in example 3 is replaced by a methanol dispersion of carbon nanotubes with an equal mass concentration, and finally, the nylon master batch with the graphene-carbon nanotube chemical bonding structure and the loading amount of about 20% is obtained. The compositions of samples 0 to 4 were in accordance with Table 1 of example 3. The difference is only that the nylon master batch containing the carbon nano tube-graphene is replaced by the master batch prepared in the comparative example 1. The volume resistivity of the samples was tested and the results are shown in table 4 below:
TABLE 4
| Sample 0 | Sample 1 | Sample 2 | Sample 3 | Sample No. 4 | |
| Volume resistivity/Ω · cm | ＞1×1014 | 7×1013 | 3×1013 | 2×1010 | 3×109 |
As can be seen from comparison of data in tables 2 to 4, in example 3, since the graphene and the nanotube are modified and combined through the chemical bond, the nylon filler containing the graphene-carbon nanotube chemical bonding structure greatly improves the conductivity of the entire material when the amount of the nylon filler is more than 6 wt%, and can reach more than 2 orders of magnitude. The modified graphene and the nanotube are combined through a chemical bond, so that a synergistic effect is generated. In contrast, in the comparative example, since graphene or carbon nanotubes were not modified, they did not bond chemically with each other, and the increase in conductivity was nearly linear with the increase in the amount of filler added, i.e., no synergistic effect was exhibited
Example 4:
taking two 1000ml beakers, respectively preparing 800g of mixed concentrated acid with nitric acid and sulfuric acid in a ratio of 1:3, respectively adding 15 g of carbon nano tubes and 25 g of graphene, placing the two beakers into an ultrasonic water tank, adjusting the temperature of the water tank to be 60 ℃, carrying out ultrasonic oscillation for 4 hours at a frequency of 25KHz, centrifuging the obtained mixed slurry for 10 minutes by using a centrifuge under a condition of 4000 r/min, and layering the mixed slurry to separate out black carbon nano tube suspension on the bottom layer. And repeatedly washing the turbid liquid by using clean water to enable the pH value of the turbid liquid to reach more than 6, and drying the turbid liquid to constant weight by using a vacuum oven at the temperature of 80 ℃ to obtain 14.7 g of acidified carbon nano-tubes and 24.5 g of acidified graphene.
Two 1000ml beakers were separately charged with 200 g of aliphatic vinyl ether (A), 400g of aminoethyltrimethoxysilane was charged into the first beaker, and 350 g of glycidylethoxypropyltriethoxysilane was charged into the second beaker. Stirring was carried out at 1000rpm for 0.5 hour at 40 ℃ in both beakers to obtain two kinds of mixed modifiers.
And then, taking two 3000ml beakers, respectively adding 1620 g of ethanol and 180 g of water, dropwise adding formic acid to adjust the pH value of the solution to 5, respectively adding two mixed modifiers into the two beakers, respectively adding the two beakers, then placing the beakers into an ultrasonic water tank, adjusting the temperature of the water tank to 70 ℃, setting the frequency of ultrasonic oscillation to be 25Hz, simultaneously stirring the mixed solution in the beakers by using a stirring paddle at the speed of 1200rpm, keeping the temperature in the beakers stable, and obtaining two mixed hydrolysis solutions after 4 hours.
Adjusting the frequency of ultrasonic oscillation to 30Hz, keeping the temperature at 70 ℃, adding the obtained acidified carbon nano tube into aminoethyl trimethoxysilane hydrolysate at one time, adjusting the stirring speed to 1500rpm, adding the obtained acidified graphene into glycidyl ether oxypropyl triethoxysilane hydrolysate at one time, adjusting the stirring speed to 1600rpm, and modifying for 6 hours under the condition of keeping the temperature and the stirring speed stable. And (2) pouring the modified graphene slurry and the modified carbon nanotube slurry into a 5000ml beaker, then placing the beaker into an ultrasonic water tank, adjusting the temperature of the water tank to 70 ℃, setting the frequency of ultrasonic oscillation to be 25Hz, stirring by using a stirring paddle at the speed of 2000rpm, keeping the temperature in the beaker stable, and obtaining the chemically-combined graphene-carbon nanotube slurry after 2 hours. And then, transferring the graphene slurry into a centrifuge, setting the rotation speed of the centrifuge to be 4000 r/min, performing centrifugal separation for 10 min to layer the mixed solution, separating out turbid liquid at the bottom layer, washing for 3 times by using methanol, and then adding methanol to prepare graphene-carbon nanotube methanol turbid liquid with the chemically combined graphene-carbon nanotube content of about 3.92%.
1800 g of formic acid were taken and added to a 3000ml beaker, the formic acid temperature was adjusted to 60 ℃ using a water bath, 200 g of nylon 6 pellets were placed, the temperature was kept constant, and stirring was carried out at 1500rpm until the nylon pellets completely disappeared and the liquid was completely transparent, whereby a 10 wt% nylon solution was prepared.
And respectively putting the obtained graphene-carbon nanotube methanol turbid liquid and the nylon formic acid solution into a glass kettle with a discharge hole at the bottom. And respectively starting stirring devices arranged in the two kettles, stirring the graphene-carbon nanotube suspension at the speed of 800rpm, and stirring the nylon formic acid solution at the speed of 800 rpm. The discharge hole positions of the two kettles are adjusted to be close to each other, so that the liquid in the two containers can flow out and can be converged as soon as possible in the falling process, and a 5000ml beaker is taken and placed under the discharge hole positions of the two kettles. And simultaneously opening the discharge ports of the two containers, adjusting the outflow speed of the nylon solution to be 0.92 times of that of the carbon nanotube suspension, keeping the outflow liquid flow of the two kettles stable, and simultaneously closing the discharge ports of the two kettles after the material in one of the kettles flows out. And putting a product in a beaker with the lower end of 5000ml into a centrifuge, centrifuging for 5 minutes under the condition of 2000 r/min, collecting the precipitate at the lower part, and drying to constant weight at 100 ℃ by using a vacuum oven to obtain the nylon 6/carbon nanotube master batch with the total loading of graphene and carbon nanotubes of about 30%.
According to the formulation shown in Table 5, the raw materials were thoroughly mixed and extruded at a screw speed of 35rpm at 230 ℃ and 260 ℃ using a twin-screw extruder to pelletize. Further, the nylon composite material containing the same masterbatch and different glass fiber portions was prepared by injection molding, and the mechanical properties and conductivity of the material were measured, the results of which are shown in table 6. The result shows that the nylon 6/graphene-carbon nanotube master batch can be used together with the reinforced fiber, so that the conductivity of the material is obviously improved, and the mechanical property of the material can be improved to a certain extent.
TABLE 5
TABLE 6
| Sample No. 5 | Sample No. 6 | Sample 7 | Sample 8 | |
| Volume resistivity/Ω · cm | ＞1×1014 | 1×105 | ＞1×1014 | 6×104 |
| Tensile strength/MPa | 112 | 123 | 138 | 147 |
| Flexural Strength/MPa | 147 | 159 | 203 | 213 |
| Flexural modulus/MPa | 4683 | 4803 | 6865 | 7141 |
| Impact Strength/kJ.m2 | 12 | 14 | 12 | 13 |
Example 5:
the graphene-carbon nanotube nylon master batch with the chemical bonding function prepared by the method in the embodiment 4 is prepared by fully mixing the raw materials according to the formula shown in the table 7, and then extruding and granulating at the screw rotating speed of 35rpm at the temperature of 240-260 ℃ by using a double-screw extruder. Further, a nylon composite material containing the same graphene-carbon nanotube chemically-bonded masterbatch, pure graphene, pure carbon nanotube and graphene/carbon nanotube mixture was prepared by an injection molding method, and the conductivity and mechanical properties of the material were tested, with the results shown in table 8. The results show that the graphene-carbon nanotube master batch with the chemical bonding effect can more effectively improve the conductivity of the material compared with the single or mixed use of graphene and carbon nanotubes.
TABLE 7
TABLE 8
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (10)
1. A conductive nylon master batch with a graphene-carbon nanotube composite structure is prepared by taking nylon as a carrier, grafting and modifying a carbon nanotube and graphene, connecting the carbon nanotube and the graphene in a chemical bonding mode to form a composite structure, and loading the composite structure on the nylon carrier.
2. The nylon masterbatch according to claim 1, wherein the total loading of the carbon nanotubes and the graphene is 5-50%, and the mass ratio of the carbon nanotubes to the graphene is 1-5: 1-5; preferably, the total loading amount of the carbon nanotubes and the graphene is 10-30%, and the mass ratio of the carbon nanotubes to the graphene is 1-2: 1-2.
3. The nylon masterbatch according to claim 1, wherein the carbon nanotubes and the graphene are modified by grafting, after being acidified, the carbon nanotubes and the graphene are respectively modified by (i) reacting and grafting the acidified carbon nanotubes with a polyether surfactant and a silane coupling agent with amino groups, and (ii) reacting and grafting the acidified graphene with the polyether surfactant and the silane coupling agent with glycidyl ether groups; the chemical bonding connection is a reaction between amino groups on the carbon nanotubes subjected to the grafting modification and epoxy groups on the graphene subjected to the grafting modification.
4. The nylon masterbatch of claim 3, wherein the polyether surfactant has a chemical structure shown in formula (I), the silane coupling agent having an amino group has a chemical structure shown in formula (II), and the silane coupling agent having a glycidyl ether group has a chemical structure shown in formula (III):
CH3(CH2)m(OCH2CH2)nOH
(Ⅰ)
NH2-(CH2)p-Si-X3
(Ⅱ)
wherein m has a value of between 1 and 20, preferably between 5 and 10; n has a value of between 2 and 10, preferably between 3 and 8; p has a value between 2 and 8; q has a value of between 2 and 8, preferably between 3 and 5; x represents an alkoxy group of C1-C6, such as methoxy, ethoxy, propoxy or butoxy.
5. The nylon masterbatch of claim 4 wherein the polyether surfactant is CH3(CH2)10(OCH2CH2)4OH, the silane coupling agent with the glycidyl ether group is
The silane coupling agent with amino is NH2-(CH2)3-Si-(OCH3)3。
6. The nylon masterbatch according to claim 1, wherein the carbon nanotubes and the graphene are loaded on the nylon carrier, and are obtained by performing convection flocculation on a suspension obtained by chemically bonding the carbon nanotubes and the graphene and a formic acid solution of nylon.
7. The nylon masterbatch according to claim 6, wherein the solvent of the suspension after the chemical bonding of the carbon nanotube and graphene is methanol, and the total mass concentration of the carbon nanotube and the graphene is 0.5-20 wt%, preferably 0.8-15 wt%; the mass concentration of the nylon in the formic acid solution of the nylon is 5-20 wt%, preferably 5-15 wt%;
and the convection flocculation is carried out by mixing the carbon nano tube-graphene turbid liquid and the formic acid solution of nylon according to the flow velocity of 1: 0.5-5, rapidly intersecting the two feed liquids according to opposite flow directions; preferably, the flow rates of the carbon nanotube-graphene suspension and the formic acid solution of nylon are 1: 0.6-4.
8. A process for preparing a nylon masterbatch as claimed in any one of claims 1 to 7 comprising the steps of: (1) respectively carrying out acidification treatment on the carbon nano tube and the graphene; (2) respectively carrying out grafting modification on the carbon nano tube and the graphene after the acidification treatment, and reacting with each other to obtain a chemically bonded carbon nano tube-graphene suspension; (3) and (3) carrying out convection flocculation on the chemically bonded carbon nanotube-graphene turbid liquid and the nylon formic acid solution, carrying out centrifugal separation, and drying to obtain the conductive nylon master batch with the carbon nanotube-graphene composite structure.
9. The method according to claim 8, wherein the step (2) of graft modification comprises preparing a mixture of reagents (i) and (ii):
mixing reagent (i): alcohol-water solution of polyether surfactant and amino silane coupling agent;
mixing reagent (ii): polyether surfactant and alcohol-water solution of silane coupling agent with glycidyl ether group;
putting the carbon nano tube and the graphene which are subjected to the acidification treatment into a mixed reagent (i) and a mixed reagent (ii), and fully reacting to respectively obtain a graft modified carbon nano tube and graphene;
preferably, in the mixed reagent (i), the total concentration of the polyether surfactant and the aminosilane coupling agent is 15-45 wt%, preferably 25-35 wt%; the mass ratio of the polyether surfactant to the amino silane coupling agent is 2-5: 5-8; in the mixed reagent (ii), the total concentration of the polyether surfactant and the silane coupling agent with the glycidyl ether group is 15-45 wt%, preferably 25-35 wt%; the mass ratio of the polyether surfactant to the silane coupling agent with the glycidyl ether group is 2-5: 5-8;
during the grafting modification, the mixed reagents (i) and (ii) are heated to 50-70 ℃, and then the acidified carbon nanotubes and the acidified graphene are added respectively, wherein the adding amount of the acidified carbon nanotubes and the acidified graphene is 1-5 wt% of the mixed reagent (i) or (ii), preferably 2-3 wt%.
10. A polymer composition comprising a polymer and the conductive nylon masterbatch of carbon nanotube-graphene composite structure according to any one of claims 1 to 9, wherein the conductive nylon masterbatch of carbon nanotube-graphene composite structure is used in an amount such that the total mass of carbon nanotube-graphene is 0.3 to 8 wt%, preferably 0.5 to 2 wt% of the polymer composition.
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| CN113249862A (en) * | 2021-05-13 | 2021-08-13 | 晋江市霖园塑胶雨具有限公司 | Anti-static fabric for jacket |
| CN113956652A (en) * | 2021-12-02 | 2022-01-21 | 厦门凯纳石墨烯技术股份有限公司 | Preparation method of antistatic master batch and antistatic master batch |
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