KR20110078154A - Carbonnanotube-polymer nanocomplex with fluidizing bed multi-walled carbon nanotube, and preparation method thereof - Google Patents

Abstract

PURPOSE: A carbonnanotube-polymer nanocomplex is provided to ensure excellent conductivity while maintaining excellent thermal properties of a polymer itself and to facilitate the process control. CONSTITUTION: A method for preparing a carbonnanotube-polymer nanocomplex comprises a step of preparing a compound by melting and mixing 80-89.5 weight% of polycarbonate, 0.5-5.0 weight% of fluidized layer multilayer carbon nanotubes, and 10-15 weight% of glass fiber at 280-350 °C and 20-70 rpm. The method further comprises the steps of: pre-heating the polycarbonate at 50-90 °C; and applying paraffin-alkane group oil to the surface of the polycarbonate before the melting and mixing step.

Description

Carbon nanotube-polymer nanocomplex with fluidized bed multi-walled carbon nanotube and method for manufacturing the same {Carbonnanotube-polymer nanocomplex with fluidizing bed multi-walled carbon nanotube, and preparation method

In the present invention, carbon nanotubes prepared through thermoplastic polycarbonate resin and fluidized bed equipment are introduced into an extruder, and extruded by controlling temperature and speed, thereby maintaining fluidity of multi-walled carbon nanoparticles having excellent conductivity. The present invention relates to a tube-polymer nanocomposite and a method of manufacturing the same.

Carbon nanotubes (CNTs) used in the present invention were discovered by Dr. Iijima in 1991, and have excellent characteristics due to the structure in which the graphite structure is rolled in a cylinder form having a diameter of 1-100 nm. Has attracted intensive attention from academia and industry. It is a material that is applied to various fields because of its excellent mechanical robustness and chemical safety as well as the characteristics of semiconductors and conductors depending on its structure, its small diameter, long length, and hollowness.

Depending on the form of curling, it is divided into single-walled carbon nanotube, multi-walled carbon nanotube, and nanotube rope. It is known that the properties are known as single-walled carbon nanotubes, but they are not used much yet because of their high price. It is also possible to form a symmetrical structure of zigzag and armchair according to the carbon arrangement, but in practice, instead of this symmetrical structure, a chiral hexagonal honeycomb is arranged spirally along the tube axis. It also has a chiral structure.

Finally, among the properties of CNTs, there is an electroconductive property, which has been used in the present invention. Its characteristics are that CNT has a high aspect ratio, various structures and properties according to the synthesis method, excellent electrical conductivity, high mechanical strength, and chemically inert surface.

The electrical conductivity of CNTs is 10.3 to 10.5 Ω / cm, which is higher than existing carbon-based additives, and the particle size is fine, so that a highly conductive polymer material can be designed in a relatively small amount. (1/2 to 1/15 of carbon black, 1/5 to 1/6 of carbon fiber to give the same level of conductivity).

Such research and development of carbon nanotubes are being conducted in various fields, and various applications such as field emission displays (FEDs), composite resins, and electrode materials for batteries have been realized. In addition, mass production technology is beginning to develop in multi-walled nanotubes, such as experimental plants targeting commercial plants.

Multi-walled carbon nanotubes have electrical properties similar to graphite, and are much superior to single-walled carbon nanotubes in chemical stability, mechanical strength, etc., and coupled with their unique shapes, they have great industrial potential as electron-emitting materials and mechanical materials. While promoting the practical use of the multi-walled carbon nanotubes, the biggest challenge is to establish a synthesis technology that can be supplied in large quantities at low cost.

In 1998, Frank measured the conductivity by loading carbon nanofibers on mercury liquid using Scanning Probing Microscopy (SPM). As a result, it became known that carbon nanotubes exhibit quantum behavior and have breakthrough conductivity. In 1999, Sanvito et al. Reaffirmed Frank's results by measuring the conductivity of multi-walled carbon nanotubes using scattering techniques, and the quantum conduction channels in the multi-walled carbon nanotubes react to the interwall reaction. It was observed that the electron flow of each carbon nanotube was rearranged by this reaction.

The elasticity of single-walled carbon nanotubes is an active area of research in the field of nanotubes. In general, single-walled carbon nanotubes are 10 to 100 times stronger than steel and resistant to physical impact. If you apply force to the bend without damage, if you remove the force has the nature of returning to its original state. The elastic modulus of single-walled carbon nanotubes is highly dependent on diameter and structure, while the modulus of multi-walled carbon nanotubes is largely dependent on diameter, according to a 1999 report by Forro et al. Instead, it largely depends on structural aspects such as defects in nanotubes.

Carbon nanotubes are expected to be widely used not only in the next generation electronic information industry but also in various industries due to their excellent properties and various applicability.In Japan, Germany, France, UK, etc. In order to secure competitiveness in the field and secure competitiveness of high-performance composite materials, we are conducting researches on the synthesis and application of carbon or notubes with national support, especially in electronic emitters and display applications, secondary batteries and fuel cells, and nano device systems. The research on mechatronics, high functional complexes, etc. is expected to be more active in the future.

The technology using carbon nanotubes is being developed in the form of a method of replacing existing carbon fibers with carbon nanotubes and developing a material suitable for the required characteristics by making the most of the properties of carbon nanotubes. Composite materials based on the mechanical properties of carbon nanotubes are mainly composed of polymer-based composite materials. In addition, attempts have been made on carbon-carbon composite materials and carbon-ceramic composite materials. In addition, it is attempting to develop a functional material such as a conductive thin film utilizing properties other than the mechanical properties of carbon nanotubes. For example, a patent has been disclosed in which carbon nanotubes are used as electromagnetic interference (EMI) blocking materials.

Japan Toray Co., Ltd. is a thermoplastic resin containing carbon fibers and carbon nanotubes (JP2002-097375, JP2003-238816), a method for producing a polymer composite material containing carbon nanotubes (JP2003-286350) and polyamide of thermoplastic resins. Based on the description of the composition containing the carbon nanotubes (JP2004-067952) was disclosed, Rice University has since disclosed a technique for adding carbon nanotubes during the polymerization (US20050074390). After the basic techniques of the carbon nanotube-containing polymer composite materials have been published, many technologies of the carbon nanotube-containing composite materials have been disclosed.

In addition to the heat-resistant resins, Korea University has ultra-high molecular weight polyethylene (KR2003-005710) containing carbon nanotubes, and Geogia Tech Research Co., Ltd. uses composite materials containing carbon nanotubes (US685410) based on acrylonitrile, and tire companies. A composite material containing carbon nanotubes based on rubber (KR2005-0027415, JP2004-123770, etc.) has been disclosed, and the scope of application of the technology is gradually expanding.

Just as carbon black or carbon fiber is used as a conductive medium in a polymer support, research into nanocomposites that can be applied to optoelectronics using high electrical conductivity of carbon nanotubes is also underway.

 Hyperion of the United States has disclosed a technology for nanocomposites containing carbon nanotubes based on polyvinylidene fluoride (PVDF) (US678702, US6746627, US2004 0217336). The main contents are the electrical conductivity and surface of carbon nanotubes. TECHNICAL FIELD The present invention relates to a technique of applying lubricating properties to raw materials for sliding parts.

Other patents include technologies for electrically conductive composites, EMI shielding materials, antennas, medical device components, etc. that utilize the electrical conductivity properties of carbon nanotubes.

In order to improve the electrical properties of conventional polymer resins, many studies have been conducted through the addition of fillers such as carbon black, carbon fiber, steel fiber, and silver flakes. Too many expensive fillers are required for improvement, and there are many problems in processing with resins.

Therefore, research on carbon nanotubes-polymer nanocomposites that improve the electrical properties by adding a small amount of carbon nanotubes instead of conventional fillers or by reducing the amount of conventional fillers and adding carbon nanotubes together is carried out. In-situ polymerization method (KR2006-0077993) in which nanotubes are mixed with a polymer monomer and then polymerized, solution mixing method (KR2007-0071960) in which a polymer is dissolved in a solvent and mixed with carbon nanotubes, and under high shear Melt mixing method (KR2006-0007723) which melts a polymer and mixes with a carbon nanotube, etc. are mentioned.

The in-situ polymerization method and the solution mixing method is necessary to disperse the carbon nanotubes in the solvent by ultrasonic waves, which takes a lot of time to disperse, and can not increase the size of the reaction tank used for dispersion, greatly increasing the productivity There are falling and costly problems.

In addition, carbon nanotubes are very low in bulk density (bulk density), so the weight occupy per unit volume is difficult to handle unlike other additives, there is a problem that is very expensive.

Thermoplastic polycarbonate is one of the most important engineering plastics in the nanocomposite industry.It is one of the most important engineering plastics in the industry, and it has excellent impact resistance and heat resistance.It is widely used in parts of electric / electronic products such as TFT-LCD and other industrial materials such as fax and copier parts. It is utilized. Generally, a blend of polycarbonate and acrylonitrile-butadiene-styrene copolymer (ABS) is used a lot, but there is a problem in that heat resistance is inferior to that of using polycarbonate alone.

Therefore, the above-mentioned problem is solved, while maintaining the basic properties of the resin in the composite, it is easy to control the process during manufacturing, and a polymer capable of expressing sufficient electrical conductivity while using a small amount of fluidized bed multi-walled carbon nanotubes. -Development of fluidized-wall multi-walled carbon nanotube nanocomposites is urgently needed.

In order to solve the problems of the prior art as described above, the present invention, by injecting carbon nanotubes manufactured through thermoplastic polycarbonate resin and fluidized bed equipment into an extruder, and extruded by controlling the temperature and speed, the excellent thermal properties of the polymer itself An object of the present invention is to provide a fluidized bed multi-walled carbon nanotube-polymer nanocomposite having excellent conductivity and a method of manufacturing the same.

According to the present invention, in the method for producing a carbon nanotube-polymer nanocomposite, the method comprises 80 to 89.5% by weight of polycarbonate, 0.5 to 5.0% by weight of fluidized bed carbon nanotubes and 10 to 15% by weight of glass fibers from 280 to It provides a method for producing a carbon nanotube-polymer nanocomposite characterized in that the compound is prepared by melting and mixing at 350 ℃ and 20 to 70 rpm conditions.

The present invention also provides a method comprising the step of preheating the polycarbonate to 50 to 90 ° C. and applying paraffin to alkanes oil to the surface of the polycarbonate, prior to melting and mixing. .

The present invention also provides a carbon nanotube-polymer nanocomposite prepared by the above production method.

As described above, according to the present invention, by injecting carbon nanotubes manufactured through thermoplastic polycarbonate resin and fluidized bed equipment into an extruder and controlling the temperature and speed of extrusion, the conductive properties of the polymer itself are maintained as they are. This excellent fluidized bed multi-walled carbon nanotube-polymer nanocomposite and its manufacturing method are effective.

In addition, the carbon nanotubes used in the present invention are fluidized bed multi-walled carbon nanotubes, and the density is about 1/3 to 1/5 lighter than that of conventional nanotubes. It is effective in increasing conductivity.

According to the present invention, a method for preparing a fluidized-bed multi-walled carbon nanotube-polymer nanocomposite having excellent conductivity is primarily composed of 80 to 89.5 wt% polycarbonate and 0.5 to 5.0 wt% carbon nanotube using a tumble dryer and a blender. Preparing); It characterized in that it comprises a step of mixing 10 to 15% by weight of the glass fiber in the compound chip. It goes through two stages, but in the actual line, all of them are done in one step from the input of raw materials to the formation of chips.

The polymer used in the nanocomposite is not particularly limited, but polycarbonate is preferably used for heat stability, and in particular, the polycarbonate is preferably blended in an amount of 80 to 89.5% by weight. When the content of the polycarbonate is less than 80% by weight of the total content of the nanocomposite, a problem of low impact strength of the produced nanocomposite may occur, and when the content of the polycarbonate exceeds 89.5% by weight, the manufacturing cost may increase.

Carbon nanotubes are not particularly limited, but the carbon nanotubes used in the present invention are multi-walled carbon nanotubes produced in fluidized bed equipment, and have different characteristics from those of conventional carbon nanotubes. Manufactured using the prepared catalyst, the density is about 1/3 to 1/5 lighter than that of foreign carbon nanotubes. In the case of using this, the manufacturing cost is very low compared to the general multi-walled carbon nanotubes as well as the single wall, thereby having an excellent effect on economics and commercialization.

Looking at the process of the multi-walled carbon nanotubes first to prepare a catalyst. The process of making the catalyst consists of solvent preparation, precipitation, distilled water removal, drying, and grinding, in which the catalyst also contains metal components. Generally, there are four types of reagents used in the production of catalysts, which occur during the process of blending them. These metal components are divided into necessary components and unnecessary components, and these unnecessary phases can be eliminated by changing the drying method in the drying part of the catalyst manufacturing process. The drying method used in this patent uses spray drying, which removes some of the metal due to its high temperature as it dries. Therefore, the density of the catalyst is reduced, thereby reducing the density of the multi-walled carbon nanotubes.

The compound is preferably prepared from 80.0 to 89.5% by weight of polycarbonate, 10 to 15% by weight of glass fibers and 0.5 to 5.0% by weight of carbon nanotubes at 280 to 350 ° C and 20 to 70 rpm.

When manufacturing carbon nanotube-polymer composite, it is easy to control carbon nanotube which is difficult to handle because bulk density is too low, and shows excellent electrical properties even when using a small amount of expensive carbon nanotube. The efficiency is high and the dispersion degree of the carbon nanotubes in the composite is improved, thereby improving the electrical conductivity.

Preferably, the composite contains carbon nanotubes in an amount of 0.5 to 5.0 wt%. If the composite is less than 0.5 wt%, the surface resistance of the nanocomposite is low, resulting in poor electrical properties. Compared to the conductive additives, economics are a problem, and problems occur in the impact strength portion of the nanocomposite.

Extruders and mixers improve the dispersion of carbon nanotubes in fluidized-bed multi-walled carbon nanotube-polymer nanocomposites and facilitate handling of the fluidized-bed multi-walled carbon nanotubes, thereby allowing the multi-walled carbon nanotube-polymer nanocomposites It has a very good effect in manufacturing large capacity.

It is preferable to perform melt mixing at the processing temperature of 280-350 degreeC, and it is more preferable to carry out at 320-350 degreeC. If the processing temperature is less than 280 ℃, polycarbonate resin is not sufficiently melted, excessive shear force is applied or fluidized bed carbon nanotubes are not dispersed, and if the processing temperature exceeds 350 ℃, the resin deteriorates or remelt There is a problem of deterioration of physical properties.

Mixing is more preferably carried out under the conditions of 20 to 70 rpm, but if the RPM is less than 20 rpm, the resin does not melt, causing a load on the screw or cylinder, and the dispersion of carbon nanotubes also occurs, If it exceeds 70rpm, there is a problem in that the resin is not sufficiently mixed and deterioration of the resin may occur.

 Polycarbonate and carbon nanotubes are made of the nanocomposite by the melt compounding method, by dispersing the carbon nanotubes evenly into the polymer substrate under a high temperature and high shear force by using an extruder, to prepare a nanocomposite, Compared to In-situ Polymerization and Solution Mixing, large capacity can be achieved and manufacturing cost can be lowered.

Flowable multi-walled carbon nanotube-polymer nanocomposite having improved conductivity according to the present invention is characterized in that it is prepared by the method for producing the nanocomposite.

In order to uniformly mix the fluidized bed carbon nanotubes during compound preparation, it is necessary to preheat the polycarbonate entering the compound to 50 to 90 ° C., and to evenly apply paraffin to alkan oil to the surface of the polycarbonate. At this time, if the preheating temperature is less than 50 ℃, carbon nanotubes are not evenly mixed, and if it exceeds 90 ℃, the physical properties of the compound is inferior. After the above step, it is preferable to insert the fluidized bed carbon nanotubes, mix well using a tumble dryer or a mixer, and then prepare a compound chip using an extruder.

According to the present invention, the carbon nanotube-polymer nanocomposite to which the conductivity-enhanced fluidized-layer multi-walled carbon nanotube is applied is manufactured by the method of manufacturing the nanocomposite.

The fluidized, multi-walled carbon nanotube-polymer nanocomposite having improved conductivity according to the present invention is an excellent polymer material showing excellent electrical properties while using a small amount of expensive carbon nanotubes. It can be usefully used as a basic material of the device, and can be effectively applied to products that require electromagnetic shielding or electrostatic dispersion.

[ Example  And Comparative example ]

In Table 1, in Comparative Examples 1 and 2 using carbon nanotubes instead of the fluidized bed, electrical conductivity may be deteriorated as compared with Examples 1 to 5 using the fluidized bed carbon nanotubes. In particular, Comparative Example 1, even without oil treatment, has the lowest electrical conductivity.

TABLE 1

(◎: Very good, ○: Good, △: Normal, X: Bad)

Claims (3)

In the manufacturing method of carbon nanotube-polymer nanocomposite, The method comprises melting and mixing 80-89.5 wt% polycarbonate, 0.5-5.0 wt% fluidized bed multi-walled carbon nanotubes, and 10-15 wt% of glass fibers at 280-350 ° C. and 20-70 rpm. Method of producing a carbon nanotube-polymer nanocomposite, characterized in that the preparation. The method of claim 1, In a step prior to melting and mixing, preheating the polycarbonate to 50 to 90 ° C., and applying paraffin to alkanes oil to the surface of the polycarbonate. A carbon nanotube-polymer nanocomposite prepared by the method according to claim 1 or 2.