Conductive fibres carbon nanotubes

Bokobza, L. Burr, A. Garnaud, G. Perrin, M. Pagnotta, S. (2004) Fibre Reinforcement of Elastomers Nanocomposites Based on Sepiolite and Poly(hydroxyethyl acrylate). Polym. Int. Vol.53, N0.8, pp.1060-1065, ISSN 0959-810 Bonduel, D. Mainil, M. Alexandre, M. Monteverde, F. Dubois, P. (2005) Supvported Coordination Polymerisation A Unique Way to Potent Polyolefin Carbon Nanotube Nanocomposites. Chem. Commun. Vol.l4, No.6, pp.781-783 Bruckner, S. Meille, S. Petraccone, V. Pirozzi, B. (1991) Polymorphism in Isotactic Polypropylene. Prog. Polym. Sci. 16, No.2-3, pp.361-404 Bryning, M. Islam, M Kikkawa, J. Yodh, A. (2005) Very Low Conductivity Threshold in Bulk Isotropic Single-Walled Carbon Nanotube-Epoxy Composites. Ado. Mater. Vol.17, N0.9, pp.1186-1191... 

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). 

Meanwhile, salts and other conductive additives have been found on some occasions to reduce the fibre diameter, but on other occasions to increase it. Researchers obtained finer fibres with CNT-containing solution compared to a CNT-free one. It was also observed that beads formed, especially when the CNT concentration was high or the dispersion of CNT in the solution was poor. On the other hand, it was found that carbon nanotubes led to a broader fibre diameter distribution and, especially, to the occurrence of fibres having larger diameters. According to the reports, this can be explained by the increase in solution viscosity or by the creation of new interfaces between the polymer and CNT. The effect of fillers and additives on fibre diameter varies from system to system, depending on tbe polymer and the solvent as well as the additive. 

The pigmentation of synthetic fibres with carbon black has been practised for a good number of years. Latterly, its potential for promoting electrical conductivity in fibres has been explored. Nowadays, there is rapidly growing interest too within the textiles community in the incorporation of carbon nanotubes into fibres, particularly as a means of reinforcing them. However, their incorporation at a sufficient level would also render the fibres electrically conducting, and no doubt this property will be fully explored over the coming years. 

Beneventi et al. recently reported the preparation of a cellulose poly(pyrrole) composite generated by the impregnation of the fibres with FeCl3 solution, followed by the in situ polymerization of pyrrole [14]. An alternative way of preparing conductive cellulose, based on the incorporation of carbon nanotubes into a cellulose sheet, has also been proposed recently [15,16]. 

The electrical conductivity of polymers can also be increased at higher cost by using carbon fibres or carbon nanotubes. The tiny tubes can be single-walled or multi-walled, typically with eight shells consisting of coiled graphite sheets. One company makes multi-walled tubes around 50 microns long, with an inside diameter of about 5 nm and an outer diameter of 10 to 15 nm. 

M. Skrifvars, A. Soroudi, Melt spinning of carbon nanotube modified polypropylene for electrically conducting nanocomposite fibres, Solid State Phenom. 151 (2008) 43—47. 

Deng H, Zhang R, Reynolds C T, Bilotti E and Peijs T (2009) A novel concept for highly oriented carbon nanotube composite tapes or fibres with high strength and electrical conductivity, Macrvmol Mater Eng 294 749-755. 

Carbon nanotubes hold much promise but are currently very expensive to produce. However, researchers at Rice University have developed a carbon nanotube fibre (Behabtu et al., 2013). The fibre is produced using a wet spinning technique based on the short carbon nanotubes. Figure 1.6 shows the resultant yam used to both power and support a light. A paper by Devaux et al. (2007) describes the preparation and properties of both conductive polymer-based fibres and carbon nanotube-based nanocomposite fibres. 

Soroudi, A., Skrifvars, M., 2010. Melt blending of carbon nanotubes/polyaniline/polypropylene compounds and their melt spinning to conductive fibres. Synth. Met. 160 (11), 1143-1147. http //dx.doi.Org/10.1016/j.synthmet.2010.02.038. 

Synthetic fibres pigmented with carbon black also possess some electrically conductivity, and there is now keen interest in the incorporation of carbon nanotubes into synthetic fibres. Although the main driver is fibre reinforcement, the fibres can also be rendered electrical conducting under the correct processing conditions. No doubt, this approach to electrical conductivity in fibres will be thoroughly pursued in the coming years. 

GlauB et al. (2013) have reported the development of a PVDF fibre with a conductive core. The melt-spun bi-component fibre consists of a conductive polypropylene core (containing a 10 wt % carbon nanotubes and 2 wt% sodium stearate (NaSt)) covered with a PVDF sheath. The piezoelectric effects are achieved by draw winding, which favours the all-trans p phase formation. 

Huang, C.-Y, Wu, C.-C. The EMI shielding effectiveness of PC/ABS/nickel-coated-carbon-fibre composites , Europ. Polym. J. 36(12) (2000), 2729—2737 Hirase, R., Hasegawa, M., Shirai, M. Conductive fibers based on poly(ethylene terephthalate)-polyaniline composites manufactured by electrochemical polymerization , J. Appl. Polym. Sci. 87(7) (2003), 1073—1078 Pbtschke, R, Briinig, H., Janke, A., Fischer, D., Jehnichen, D., Orientation of multi-walled carbon nanotubes in composites with polycarbonate by melt spinning , Polymer 46(23) (2005), 10355-10363... 

M. J. Assael, K. D. Antoniadis, and D. Tzetzis, "The use of the transient hot-wire technique for measurement of the thermal conductivity of an epoxy-resin reinforced with glass fibres and/or carbon multi-walled nanotubes," Composites Science and Technology, vol. 68, pp. 3178-3183,2008. 

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