Emulsion polymerization polypyrroles

Synthesis of polypyrrole nanoparticles was achieved using micro-emulsion polymerization system by oxidation of pyrrole monomer with FeCl3.6H20. As the oxidant was added, the color of the solution changed from colorless to deep greenish black which is an indication of oxidation of conducting polypyrrole. The reaction product polypyrrole was obtained in the form of black powder. 

An electrically conductive polymer composite of polypyrrole and poly(ethyl methacrylate) has been prepared by an emulsion polymerization procedure [ 142]. In this case, the relation between conductivity and the polypyrrole content of the composite exhibited a percolation behavior, with conductivities as high as 6-7 S/ctn. Such composites might be amenable to melt processing for coating formation. Composite films consisting of polypyrrole or poly(N-ethylaniline) filler dispersed in a polyimide matrix have been described for potential use as corrosion control coatings for the A1 alloy AA 2024-T3 [143]. 

Emulsion polymerization of pyrrole was also used to prepare blends of polypyrrole with a poly(alkyl methacrylate) [95]. A chloroform solution of a poly-(alkyl acrylate) and pyrrole was dispersed in an aqueous surfactant solution generating an emulsion. An aqueous solution of an oxidant was added to the emulsion with stirring, polymerizing pyrrole. The precipitated blend could be hot pressed in the form of films with conductivities of 6-7Scm . The curve for the variation of the conductivity of the blend with the oxidant/pyrrole ratio shows a maximum at a ratio of two with subsequent decrease. However, the yield increases to nearly 100% up to a ratio of four. The percolation threshold is approximately 10 wt% of pyrrole. The type and the concentration of the surfactant also affect the yield and conductivity. The mechanical properties of the blend depends on the number of carbons in the alkyl chain of the insulating polymer host. The strain at break of hot-pressed films increases and the stress at break decreases in the direction methyl, ethyl, butyl (Figure 18.3). This is an example where the mechanical properties of the conductive blend could be tailored according to the alkyl substituent in the poly(alkyl methacrylate) used in its preparation. 

A lightweight composite material with high electrical conductivity can be prepared by incorporation of polypyrrole in the pore of a porous divinylbenzene-crosslinked polystyrene host polymer, prepared by an emulsion polymerization method. The recorded conductivity of the composite was 0.5 S cm and the shielding effectiveness (SE) of the composite reach 26 dB at 1.0-2.0 GHz. Polypyrrole-poly(ethylene-co-vinylacetate) composites which possess good electrical and mechanical properties have been made in two steps first, a concentrated emulsion was... 

The simplest way to make a polymer nanoeomposite via inverse emulsion polymerization is to mix the water-solnble monomer and hydrophilic nanoparticles together in the water as a dispersed phase. Kim et al. prepared intercalated condueting polypyrrole (PPy)/Na -MMT nanoeomposite by inverse emnlsion polymerization. They followed a similar preparation method... 

Conducting polymers constitute another category of promising pseudo-capacitive materials. The most common ones include polypyrrole (PPy), polyaniline (PANI), and poly-(3,4)-ethylenedioxythiophene (PEDOT). This group is of particular interest due to low cost and ease of synthesis. These compounds can be polymerized directly onto a collector material via EPD. Alternatively, the polymerization can be done within surfactant emulsions... 

---