Conducting polymer composites and blends

U. Riaz, S. M. Ashraf, Conductive Polymer Composites and Blends. In Nanostructured Polymer Blends Elsevier, 2014 pp. 509-538. 

Functionalized Solvent-Processable Polymers Conducting Polymer Composites and Blends Electrodeposition of Conducting Polymers... 

Highly Electrically Conductive Polymer Composites and Blends... 

In this study novel methods of preparing highly electrically conductive polymer composites and blends have been studied. A chemical diffusive polymerization process for preparing highly electrically conductive poly(vinylchloride)-polypyrrole composite has been developed. And a method of preparing conductive poly(vinylacetate)-polypyrrole composite film by casting on a substrate has also been developed. 

One more fact, important in practice, lies in that a of the compositions based on heterogeneous blends of polymers obtained by the method 3, depends considerably on mixing temperature Tm. This is bound up with a variation of the polymer viscosity with the temperature on being introduced into the polymer mixture, a filler becomes distributed mostly in the less viscous polymer and, if the viscosity of polymers is almost the same, it is distributed comparatively uniformly and a of the composition decreases. Therefore, the dependence of a of the conducting polymer composite on Tm has a minimum (by a factor of 102 to 104) in the Tm region when the viscosities of the polymer components are close. 

ZRI06] Zribi K., Feller J.F., Elleuch K., et al., Conductive polymer composites obtained from recycled poly(carbonate) and rubber blends for heating and sensing applications , Po/g ie s for Advanced Technologies, vol. 17, pp. 727-731,2006. 

At the moment, fabrication of conducting composites and blends, in which polypyrrole is associated with another polymer that has higher mechanical properties, is probably the most developed application of these materials. This is the case of antistatic applications, for which not very high electrical conductivities (in the range 10 -10 S cm" ) are required [196-200]. 

Zhang Y C, Dai K, Tang J H, Ji X and Li Z M (2010) Anisotropically conductive polymer composites with a selective distribution of carbon black in an in situ microfibrillar reinforced blend, Mater Lett 64 1430-1432. 

Gao J F, Yan D X, Yuan B, Huang H D and Li Z M (2010) Large-scale fabrication and electrical properties of an anisotropic conductive polymer composite utilizing preferable location of carbon nanotubes in a polymer blend, Compos Sci Technol 70 1973-1979. 

Hu J W, Li M W, Zhang M Q, Xiao D S, Cheng G S and Rong M Z (2003) Preparation of binary conductive polymer composites with very low percolation threshold by latex blending, Macromol Rapid Commun 24 889-893. 

Nontoxic Citrates Nontoxic citrate plasticizers derived from natural citric acid, such as triethyl citrate (TC), tributyl citrate (TBC), acetyl triethyl citrate (ATC), acetyl tributyl citrate (ATBC), and triacetine, have been shown to be effective plasticizers for PLA [27-29]. Some gas permeability tests have been performed to assess the potential use of PLA and nontoxic citrate plasticizer blends in food packaging and other applications. The effect of ATBC on PLA barrier properties was studied by Coltelli et al. [30] using PLA mixed with ATBC (10-35 wt%), followed by compression molding. Yu et al. [31] blended PLA/ATBC mixmres with carbon black (CB) to form electrically conductive polymer composites. Fourier transform infrared (FTIR) experiments revealed that the interaction between the PLA/ATBC matrix and the CB filler was increased by the addition of ATBC. Water vapor permeability values decreased with an increase in ATBC content (at constant CB levels). For example, at 30wt% CB, the WVP of the PLA decreased from 0.66 x 10 kgm/(msPa) (at 0% ATBC) to 0.10 X 10 kgm/(msPa) with the addition of 30% ATBC. 

Field-smoothing effects in electric cables are important for the use of conducting polypyrroles. High-tension power cables present normally carbon-loaded polymers between the insulating layer and the conducting metal [304]. The role of this conductive layer is to prevent field inhomogeneities at the insulator layer. Polypyrrole composites and blends could also replace carbon-black loaded polymers in these fields. 

Another antistatic composition comprises a 10 90 blend of PHT and polystyrene [778] or polyheteroaromatic compounds, e.g. PBT, and polymeric sulfate [671], or an electrically non-conductive polymer matrix and POT [779]. Silver halide photographic materials containing electrically conductive polymers, e.g. PT, PMT, PET, poly(3-methoxythiophene), poly(3-cyanothiophene), poly(3-fluorothiophene), poly(3-nitrothiophene), poly(3-bromothiophene), poly-(3,4-dibromothiophene), poly(3,4-dimethylthiophene), are claimed to have improved antistatic properties [780-783]. 

Conductive polymer composites can be defined as insulating polymer matrices which have been blended with filler particles such as carbon black, metal flakes or powders, or other conductive materials to render them conductive. Although the majority of applications of polymers in the electrical and electronic areas are based on their ability to act as electrical insulators, many cases have arisen more recently when electrical conductivity is required. These applications include the dissipation of electrical charge from rubber and plastic parts and the shielding of plastic boxes from the effects of electromagnetic waves. Consequently, materials scientists have sought to combine the versatility of polymers with the electrical properties of metals. The method currently used to increase the electrical conductivity of plastics is to fill them with conductive additives such as metallic powders, metallic fibres, carbon black and intrinsically conducting polymers such as polypyrrole. 

---