Thursday, April 29, 2010

Flocculated Carbon Nanotube Film Used to Mass Produce Cost-Effect Polymer and Metal Composites

Tsinghua University (Beijing City, CN) and Hon Hai Precision Industry CO., Ltd (Tu-Cheng City, TW) reveal  in U.S. Patent Application 20104808, a carbon nanotube composite that includes a carbon nanotube structure and a number of nanoparticles. The carbon nanotube structure includes a plurality of carbon nanotubes connected to each other via van der Waals force. The nanoparticles are distributed in the carbon nanotube structure. The carbon nanotubes in the carbon nanotube composite are connected to each other to form a carbon nanotube structure and are arranged in an orderly or disorderly fashion.

The carbon nanotube composite and the method have the following advantages. Firstly, the mechanical strength and toughness of the carbon nanotube composite  is improved because the carbon nanotubes in the carbon nanotube composite  are connected to each other to form a carbon nanotube structure and arranged orderly or disorderly, which overcomes the entanglement of the carbon nanotubes. Secondly, good conductivity is achieved for the carbon nanotube composite  because the carbon nanotubes  are employed as a frame of the carbon nanotube composite. Finally, fewer or no the carbon nanotubes are destroyed because it is unnecessary to use high temperatures to process or surface treat the carbon nanotube. 

Referring to FIG. 4, the flocculated carbon nanotube film can include a plurality of long, curved, disordered carbon nanotubes entangled with each other. Further, the carbon nanotubes  in the flocculated carbon nanotube film can be isotropic. The carbon nanotubes  can be substantially uniformly dispersed in the flocculated carbon nanotube film. Adjacent carbon nanotubes  are attracted by van der Waals attractive force to form an entangled structure with micropores defined therein. It is understood that the flocculated carbon nanotube film is very porous. Sizes of the micropores can be less than micrometers.

The porous nature of the flocculated carbon nanotube film will increase specific a surface area of the carbon nanotube structure. Further, due to the carbon nanotubes in the flocculated carbon nanotube film being entangled with each other, the carbon nanotube composite  employing the flocculated carbon nanotube film has excellent durability, and can be fashioned into desired shapes with a low risk to the integrity of the flocculated carbon nanotube film. The thickness of the flocculated carbon nanotube film can range from about 0.5 nm to about 1 mm.

FIG. 2 is a scanning electron microscope (SEM) image of a drawn carbon nanotube film used in the carbon nanotube composite
FIG. 3 is an SEM image of a pressed carbon nanotube film used in the carbon nanotube composite and having a number of carbon nanotube arranged along different orientations.
FIG. 4 is an SEM image of a pressed carbon nanotube film used in the carbon nanotube composite and having a number of carbon nanotubes arranged along a same orientation.
 Length and width of the carbon nanotube film can be arbitrarily set as desired. A thickness of the carbon nanotube film is in a range from about 0.5 nm to about 100 micrometers. The carbon nanotubes in the carbon nanotube film can be single-walled, double-walled, multi-walled carbon nanotubes, and combinations thereof. Diameters of the single-walled carbon nanotubes, the double-walledcarbon nanotubes, and the multi-walled carbon nanotubes can, respectively, be in the approximate range from about 0.5 nm to about 50 nm, about 1 nm to about 50 nm, and about 1.5 nm to about 50 nm.

 After the flocculating step, the carbon nanotubes are tangled together by van der Walls attractive force to form the flocculated carbon nanotube film as shown in FIG. 4. Thus, the flocculated carbon nanotube film has good tensile strength. The flocculated carbon nanotube film includes a plurality of micropores formed by the disordered carbon nanotubes. A diameter of the micropores is less than about 100 microns. As such, a specific area of the flocculated carbon nanotube film is extremely large. Additionally, the flocculated carbon nanotube film is essentially free of binders and includes a large amount of micropores. The method for making the flocculated carbon nanotube film is simple and can be used in mass production. 

 The nanoparticles may be adhered on a surface of the carbon nanotubes. When the carbon nanotubes are distributed in a number of carbon nanotube films which may be drawn carbon nanotube films, flocculated carbon nanotube films, pressed carbon nanotube films, or their combinations, the nanoparticles may be dispersed in among the carbon nanotube films. The nanoparticles of the carbon nanotube composite may be isolated from each other, whereby the nanoparticles can have a high specific surface area. Understandably, the nanoparticles may be connected with one another.

The nanoparticles may be nanofibers, nanotubes, nanopods, nanospheres, nanowires, and combinations thereof. The nanoparticles may be made of metal, nonmetal, alloy, metal oxide, polymer, and any combination thereof. The nonmetal may be carbon, diamond, and so on. The alloy may be selected from magnesium alloy, aluminum alloy, and their combination. The metal oxide may be copper oxide, zinc oxide, and so on. The polymer may be polyaniline, polypyrrole, and their combination. In the present embodiment, the nanoparticles are nanospheres made of metal, such as copper (Cu), zinc (Zn), and cobalt (Co). The nanoparticles have a diameter of about 0.3 nm to about 500 nm. The weight percent of the nanoparticles in the carbon nanotube composite 100 is in a range of about 0.01% to about 99%. 

2 comments:

  1. Really very much appreciable share. The author had described about the product in a much presentable manner. Same as this service provider, countless firms are available near to our reach who are applicable in offering several variants of carbon foil (carbonfolie) in huge collection of stock.

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  2. America has made great progress in graphene, but China will get it to the production floor long before the US. They don't make anything anymore, too sheepish, the us is all about debt, and selling debt rather than making anything or creating real wealth for the US citizens. The US's capital scenario is sad very sad. A country that doesn't invest in itself choosing to do so in China. Shame on US business.

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