Electroconductive polymers properties

Magnetic properties of fine maghemite particles in an electroconducting polymer matrix. 

There is another type of electrically active polymer that is known as the electroconductive polymer, in which polymer chains contain long conjugated double bonds, and this chemical structure adds electroconductive properties to the polymers. In these cases, the electrically induced deformation is considered to have originated from the electrochemical reactions such as the oxidation and reduction of the polymer chain. For the deformation, some additives such as dopants have been known to be necessary for effective actuation. Therefore, the electrical actuation of these materials has been... 

Electroconductive polymers are a unique class of materials presenting a broad range of material properties. It... 

Dipyrroles, especially those bounded through positions 2 and 3, are abundant in nature [256-262] and possess unique biological properties. Unlike dipyrroles bridged across the nitrogen atoms, in such ensembles, mutual influence of the functional groups, electron excitement, and polarization are transferred especially easily. Therefore, they are often incorporated in electroconductive polymers and various polyconjugated systans with high spectral and electrochemical response to the... 

The carbon blacks used in plastics are usually different from the carbon blacks used in mbber. The effect of carbon black is detrimental to the physical properties of plastics such as impact strength and melt flow. Electroconductive grades of carbon black have much higher surface areas than conventional carbon blacks. The higher surface areas result in a three-dimensional conductive pathway through the polymer at much lower additive levels of the carbon black. The additive concentrations of electroconductive carbon blacks is usually j to that of a regular carbon black (132). 

Since the electroconductivity of pure water is by several orders of m itude hi er than those of polymers, even smaU amounts of moisture markedly reduce electrical insulation properties of foams. For this reason, measuren nt of dielectric properties is a precise, rapid and non-destructive method of monitoring the kinetics and level of moisture absorption. Thus, the establishment of correlations between dielectric properties and the hygroscopicity of plastic foams makes it possible to solve two practical problems how moisture affects dielectric properties and how to determine non-electrical properties by electrical measurements ... 

Fukushima T, Kosaka A, Yamamoto Y et al (2006) Drtunatic effect of dispersed carbon nanotubes on the mechanical and electroconductive properties of polymers derived from ionic liquids. Small 2 554-560... 

In Reference 154, PMMA was selected as it is immiscible with PET. The description of the electroconductive properties of this immiscible polymer blend filled with CB was carried out. To properly analyze the results obtained, models that predicted the selective location of CB in the blend were considered. The presence of CB extensively modified the rheological and conductive properties of the blend. Resistivity decreased similarly in both PET and PMMA with CB concentration. However, the immiscible polymer blend extensively modified this behavior because resistivity became a function of morphology and location of CB in the polymers. Viscosity was observed to be a strong function of PET content at high CB concentrations. Indeed, resistivity decreases continuously (a drop of seven decades) for 20% CB (PET basis) from 0% to 60% PET content. The same behavior (similar slope) was observed for 5% CB, but the conductivity curve was shifted to higher PET contents. It was shown that the preferential CB location in... 

At present time the great attention is given to the study of properties of polymeric nanocomposites produced on the basis of well known thermoplastics (PP, PE, PS, PMMA, polycarbonates, and polyamides) and caibon nanotubes (CN). The CNs are considered to have the wide set of important properties like thermal stabihty, reduced combustibility, electroconductivity, and so on [1-7]. Thermoplastic polymer nanocomposites are generally produced with the use of melting technique [1-12]. 

Conducting polymers exhibit not only electroconductivity but also unique optical and chemical properties [10]. The diversity of properties exhibited by conducting polymers offers these materials to be used in numerous technological applications. Generally, the properties of polymers originate from their chemical (molecular) and physical (morphological) structures. Therefore, it follows that the structures of... 

Since the discovery of insoluble polythiophene and the determination of its electroconductivity in 1980 [241], many studies have been completed to improve the synthetic feasibility and chemical and physical properties of this conjugated polymer. A milestone step in the development of polythiophene occurred in 1985 when the poly(3-alkylthiophene), which was a soluble, processable, and stable polymer, was achieved by introducing an alkyl group... 

It is well known that the extended coniugation of monommc residues is the fundamental property which determines the extent of electroconductivity of an organic polymer.58 The polymer precursor route used to improve the processability of electro-conductive polymers... 

Conductive polymers, such as polyacetylene, polythiophene, polypyrrole, polyisothianaphthene, polyethylene dioxythiophene, polyaniUne, and so on, have interesting properties that make them suitable for use in PEMFCs (Heeger, 2001 Shirakawa, 2001). Their electroconductivity and noncarbon functionalities allow some of them to perform effectively as alternative carbon catalysts or with carbon supports to enhance their catalytic effects. Huang et al. utilized polypyrrole as a conductive polymer support for a platinum catalyst active for the ORR (Huang et al., 2009). Their results show significant resistance to carbon corrosion and improved conductivity over traditional Pt/C catalysts. They report that the platinum on polypyrrole catalyst (Pt/Ppy) has well-dispersed platinum particles of about 3.6 nm in diameter. CV scans up to 1.8 V revealed that there was httle carbon support corrosion on the Pt/Ppy and a twofold increase in activity than Pt black at 0.9 V. 

As mentioned earlier, the addition of powdered metals to polymeric materials eliminates electrostatic charges on their surface. But electric properties of materials such as vulcanized rubbers filled this way are not stable for this reason, powdered metals are used only for polymer-based electroconducting varnishes [5,6] and adhesives [7]. In these cases, the powdered metals (Ag, Au, Ni, Al, Cu) are impregnated with epoxy resins or added to polyamides, PVC, silicones, etc. [1,5,8]. 

Regioregular poly(3-alkylthiophene)s have been shown to have very different properties from their corresponding regiorandom polymers, such as smaller bandgaps, better ordering and crystallinity in their solid states, and substantially improved electroconductivities [88]. The transistor properties of poly(3-alkylthiophene)s have been studied by Bao et al. and field-effect mobility as high as 0.05cm V s and on/off ratios close to 10 have been reported [84]. 

A multicyclic soluble polymer was obtained from the zinc chloride-catalyzed condensation of ferrocene and acetone (IV-18) (27, 28). The polymer was a brown powder softening at 320°-360°C, and was soluble in benzene. Its molecular weight was determined cryoscopically and was about 3000. No crystallinity was detected by X-ray analysis. The material exhibits a signal in its ESR spectrum and has semiconducting properties. Its specific electroconductivity (50°C) was 1.23 x 10 i2 ohm- cm i with an activation energy of 0.67 eV. 

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