Carbon nanotubes conductive plastics

In order to render a plastic conductive although it is, by nature, an electrical and thermal insulator (with the exception of intrinsically conducting polymers, ICPs), we need to dope it with electrically conductive fillers such as steel microfibers (pFSs) [FEL 06], CNPs [FEL 01] or indeed carbon nanotubes [FEL 11]. By gradually varying the proportion of fillers in the polymer matrix, we see that its resistance goes... 

Other, nanometer-scale forms of carbon, such as nanotubes and graphenes, have been proposed as ESD fillers, though their early use may be greater with engineering polymers. Carbon nanotubes (CNTs), in diameters of lO-lOOnm, can induce the conductivity needed for electrostatically paintable plastic automotive body panels, for example. They are also said to be replacing carbon black and fiber in small, detailed electronics applications [6-5]. 

Due to the exceptional properties of carbon nanotubes (CNTs), such as high electrical and thermal conductivity and excellent mechanical properties, they are expected to have great potential as fillers for polymeric matrices. CNTs are incorporated in electrically insulating polymer materials to achieve electrostatic dissipative behavior or electrical conductivity and improved mechanical properties. Current applications for such nanocomposites include electrostatically dissipative plastic housing or fuel lines, as well as lightweight and electrostatically paintable plastic components replacing metals in car panel applications. Incorporation of CNTs in polymers on an industrial scale is... 

Recently, nanostructured carbon-based fillers such as Ceo [313,314], single-wall carbon nanotubes, carbon nanohorns (CNHs), carbon nanoballoons (CNBs), ketjenblack (KB), conductive grade and graphitized carbon black (CB) [184], graphene [348], and nanodiamonds [349] have been used to prepare PLA-based composites. These fillers enhance the crystalUza-tion ofPLLA [184,313,314].Nanocomposites incorporating fibrous MWCNTsandSWCNTs are discussed in the section on fibre-reinforced plastics (section 8.12.3). 

Various approaches have been suggested to reduce the number of fires at petrol filling stations caused by static electricity. One suggestion is metal door handles. Conducting additives are used to provide static dissipation in fuel systems, but there are difficulties in achieving adequate mechanical properties in polyethylene fuel tanks when carbon black is used as a filler. Doubts have also been raised in some quarters about whether some plastic fuel tanks will be able to meet the requirements for PZEVs , or partial zero emissions vehicles, required by California s new emission standards. Inergy Automotive recommends capless filler systems with locking mechanisms. Carbon nanotubes are likely to find a role in antistatic protection. 

The electrical conductivity of carbon nanotubes in insulating plastics is a topic of considerable interest. The potential applications include electromagnetic... 

The above data suggest that SWNT can be used to greatly increase the modulus and strength of plastics and fibers. Also, since one-third of the SWNT are electrically conducting, these fibers have been proposed as nanowires in a new generation of reduced size electronic equipment, such as fuel cell electrodes (75). An early application, in fact, utilizes carbon nanotubes blended into polyamides to protect against static electricity in auto fuel systems (76). 

In the UK, researchers at Cambridge University have devised a method of growing vertical carbon nanotubes on a flexible plastic substrate which gives scope for further research into potential applications especially where flexibility is a key element of the product design. At Sheffield University the research project involves the dispersion of nano-sized droplets of PEDOT (or other conducting polymers) into a polyethylene oxide polymer electrolyte matrix. Together with a suitable redox couple, where oxidation and reduction are considered together as complementary processes, it is possible to produce efficient, switchable windows for microwaves. 

Applications corrosion protection, EMI shielding, filler to make plastic conductive, materials having electric conductivity, montmorillonite-PANI coated, protection against static electricity, synthesis of carbon black coated by PANI (Eonomer), synthesis of hybrid filler (multiwalled carbon nanotubes+PANI particles) plastics addition of 8-15 wt% lowers surface resistivity of plastics to 1E4-1E9 ohm coatings and inks Perento, J, Polymers in Electronics 2007, Rapra, 2007, paper 5. 

Li, Z and Z. Xiang. 2009. Soft conductive polyurethane foam plastic for industrial applications comprises polyether glycol, vulcabond, steamed water, stannous octoate, triethylene diamine compounds, silicon oU and carbon nanotubes. Patent CN101250321-A, China. 

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