Polyethylene carbonate

Dewatering surfactants can be polyoxyethylene, polyoxypropylene, and polyethylene carbonates [1348] or p-tert-amylphenol condensed with formaldehyde, or they can be composed of a copolymer from 80% to 100% alkyl methacrylate monomers and hydrophilic monomers [777]. Such a well treatment fluid may be used in both fracturing and competition operations to enhance and maintain fracture conductivity over an extended period of production. 

T. Tao, L. Zhang, J. Ma, C. Li, Production of flexible and electrically conductive polyethylene-carbon nanotube shish-kebab structures and their assembly into thin films, Ind. Eng. Chem. Res, vol. 51, pp. 5456-5460, 2012. 

The PTC phenomenon, in effect, provides the means of making a thermal switch, operated either by an external change in temperature or by an increase in current that generates heat internally, see Fig. 8.20. A common form of self-regulating heater is made by extruding a strip with the cross-section shown in Fig. 8.21, where the conductive component consists of polyethylene/carbon-black composite that is radiation-crosslinked after fabrication. The strip may be extruded in long lengths... 

A carbon black addition above a percolation threshold of 5 vol% increases the conductivity until a plateau is reached at 20 vol%. " As the level increases above 10 vol%, the viscosity of the filled polypropylene increases rapidly (see Figure 9.9). As with polyethylene, carbon black is preferentially contained in one phase of a two phase blend."" This phenomenon is used in practice to lower the concentration of carbon black required for a certain level of conductivity. Here, again, carbon black is concentrated in the preferred location. Carbon black and copper powder were used to improve connectivity of YBaCuO in ceramic superconductors. "" Dispersion of copper particles and the related changes in conductivity were enhanced by the presence of acrylic acid modifier. ... 

Carbon composites have been developed as alternative materials for carbon paste electrodes because of the limited utility of the latter in most organic solvents. These composites include polyethylene/carbon black [49], Kel-F/graphite [50], carbon black immobilized in cross-hnked polyethylene [51], and epoxy/graphite [52]. A collection of for these materials is available [20]. Thus, for platinum = 0.24 cm/s, for pyrolytic graphites 0.002 <... 

Conjugated Dienes and Other Monomers. Alkyllithiums such as n-butyllithium—and even the growing polyethylene carbon-lithium bond complexed with chelating diamines such as TMEDA—are effective initiators for the polymerization of conjugated dienes such as 1,3-butadiene and isoprene. A polybutadiene of high 1,2-content can be produced from butadiene in hydrocarbon solvents using these N-chelated organolithium catalysts. 

In the context of multifunctionality, carbon black, a polycrystalline material, merits special mention. The surface layer of carbon black particles may contain quinones, phenols, carboxy phenols, lactones, etc. Therefore, apart from being a powerful UV absorber and a quencher of excited states (such as those of carbonyl groups), carbon black acts as a scavenger of free radicals in chain-breaking reactions and as a hydroperoxide decomposer [114, 115]. In polyethylene, carbon black forms a complex with macroradicals [115]. 

Fig. 6.9 The XPS, C is spectra (a) and FTIR spectra (b) measured after aging at different potentials showing the presence of polyethylene carbonate on LiNiojMni 04 electrodes as mentioned therein. Reproduced with permission from [50], copyright (2010) The Eiectiochemical Society...

Banerjee AN, Saha N, Mitra BC, Flexural behavior of unidirectional polyethylene carbon fibres PMMA hybrid composite laminates, J Appl Polym Sci, 60(1), 139-142, 1996. 

In medical applications, it is of basic significance that the radiation absorption characteristics of the medium to be irradiated and that of the calorimetric absorber should be similar. Thus, calorimeters to that purpose have been constructed of water (Domen 1982), graphite (Petree and Lamperti 1967), polystyrene, polyethylene-carbon mixture (Milwy et al. 1958), and A-150 tissue-equivalent plastic (McDonald et al. 1976 Smathers et al. 1977). 

Cohen et al. [68] recently found using AFM that freshly prepared (in polyethylene carbonate) and long-term cycled PPY films showed quite different micromorphologies and mass transport behaviors the freshly prepared PPY films of unusual strictly oriented bunches of short fibrils showed a combined anion-cation transport as a function of the potential, whereas the cycled PPY of a typically granular film only revealed an anion exchange. It is also reported [69] that the repetitive redox cycling of PPY films caused the accumulation of a neutral salt and solvent in the film. 

HYBRID COMPOSITES BASED ON POLYETHYLENE/CARBON FIBRES Compressive and Impact Behaviour... 

We have for a number of years developed polymer-based piezoelectric textile filaments and yarns [44]. Filaments are melt spun and bicomponents core-and-sheath type based on a blend of a normal bulk polymer like high-density polyethylene and the piezoelectric material (PVDF), surrounding a core of a conductive polyethylene-carbon black mixture (see Fig. 28.25). The core is electrically conductive and will act like an electrode. 

Yin et al. [68] investigated the critical resistivity, dispersivity, and percolation threshold of low-density polyethylene carbon black. Li et al. [69] investigated the electrical properties and crystallization behavior of four different kinds of carbon black-filled polypropylene composites, prepared by the melt mixing method. All showed typical characteristics of percolation, but noticeably different percolation thresholds. When using carbon black with a higher structure, smaller particle diameter, and larger surface area, the composite showed better electrical conductivity and a lower percolation threshold. 

Polyethylene carbon nanotube Electrical conductivity and rheological properties 18... 

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