Sticky carbon

Two important morphological parameters characterizing ball-milled powders are the particle and grain size of constituent phases within the powders. In our laboratory, the size measurement of the powder particles is carried out by attaching loose powder to sticky carbon tape and taking pictures under secondary electron (SE) mode in the SEM. The images are then analyzed by an image analysis software. The size of the powders is calculated as the particle equivalent circle diameter, ECD = AA/nf, where A represents the projected particle area. Usually from -300 to 700 particles are analyzed for each batch. 

Indeed, PET shows an effect of defluidization, as shown in Figure 25.14 [33], Sticky carbon residnes formed by PET are covered by layers of sand. In this way larger particles are formed which can not be flnidized by the gas stream. The defluidization time can be increased by redncing the feed rate of the polymer and increasing the reactor temperature. 

Fig. 5 Fabrication of the sticky carbon electrode in which the aerogel particles are in contact with both the electrolyte and the carbon current collector...

Fig. 6 Voltammetric sweeps for V2O5 aerogels using different electrodes, a Sticky-carbon electrode, b traditional composite electrode. The arrows refer to the intercalation/deintercalation peaks in b (reprinted with permission from the Electrochemical Society)...

Long JW, Ayers KE, Rolison DR (2002) Electrochemical characterization of high-surface-area catalysts and other nanoscale electroactive materials at sticky-carbon electrodes. J Electroanal Chem 522 58-65... 

Carbon-fluorine bonds are quite strong (slightly stronger than C—H bonds) and like polyethylene Teflon is a very stable inert material We are all familiar with the most characteristic property of Teflon its nonstick surface This can be understood by com paring Teflon and polyethylene The high electronegativity of fluorine makes C—P bonds less polarizable than C—H bonds causing the dispersion forces m Teflon to be less than those m polyethylene Thus the surface of Teflon is even less sticky than the already slick surface of polyethylene... 

The carbon black (soot) produced in the partial combustion and electrical discharge processes is of rather small particle si2e and contains substantial amounts of higher (mostly aromatic) hydrocarbons which may render it hydrophobic, sticky, and difficult to remove by filtration. Electrostatic units, combined with water scmbbers, moving coke beds, and bag filters, are used for the removal of soot. The recovery is illustrated by the BASF separation and purification system (23). The bulk of the carbon in the reactor effluent is removed by a water scmbber (quencher). Residual carbon clean-up is by electrostatic filtering in the case of methane feedstock, and by coke particles if the feed is naphtha. Carbon in the quench water is concentrated by flotation, then burned. 

The phosphorus pentoxide is introduced into a small distilling flask (200 c.c.) attached to a short condenser. As the pentoxide absorbs moisture rapidly and becomes sticky, it is convenient to push the neck of the distilling flask through a cork which fits the phosphorus pentoxide bottle, and then to shake in the oxide until the required weight is obtained. The powdered acetamide is immediately introduced and shaken up, and the mixture distilled over a small flame, which is constantly moved about. Add to the distillate about half its volume of water, and then solid potassium carbonate, until no more dissolves. The upper layer of liquid, which consists of methyl cyanide, is separated and distilled over a little fresh phosphorus pentoxide with thermometer. Yield, about 5 grams. 

The new interface model and the concept for the carbon black reinforcement proposed by the author fundamentally combine the structure of the carbon gel (bound mbber) with the mechanical behavior of the filled system, based on the stress analysis (FEM). As shown in Figure 18.6, the new model has a double-layer stmcture of bound rubber, consisting of the inner polymer layer of the glassy state (glassy hard or GH layer) and the outer polymer layer (sticky hard or SH layer). Molecular motion is strictly constrained in the GH layer and considerably constrained in the SH layer compared with unfilled rubber vulcanizate. Figure 18.7 is the more detailed representation to show molecular packing in both layers according to their molecular mobility estimated from the pulsed-NMR measurement. 

Chlorosulphonated polyethylene is obtained by reacting low density polythylene with chlorine in presence of sulphur dioxide using carbon tetrachloride as solvent. The product contains 30 per cent chlorine and 1.5 per cent sulphur. This is a sticky rubbery material and is soluble in chlorinated hydrocarbon solvents. It can be vulcanised by heating with metal oxides like litharge or magnesium oxide in presence of water. The cross-linked product is found to be resistant to chemical attack and is used in gaskets, hoses, etc. 

The earliest mention of the polymerization of isoprene was also made by Williams in 1860 (33). He noted the formation of a "white, spongy mass" when isoprene was left in a bottle with oxygen. Afterwards G. Bouchardat observed that isoprene could be converted to a sticky mass by the action of either carbon dioxide or cold aqueous hydrochloric acid (34). Tilden in 1882 (35) and independently Wallach in 1887 (36) were the first to prepare elastomers of isoprene, but little else was known of their structures. Gladstone and Hibbert (37)... 

Phenolic resin is the most common resin because it is highly sticky with a hard carbon structure and low cost [9,12,13]. The paper is then put inside an oven at around 150-175°C in order to cure the resin and to remove the solvent [9,12]. The amount of phenolic resin that is impregnated also depends on the desired final characferisfics of fhe CFP. For example, high concenfra-fions of fhe phenolic resin reduce fhe fhickness of the paper, but the surface resisfivify decreases significanfly [13]. 

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