Poly -carbon black composites

E. S. Tillman and N. S. Lewis, Mechanism of enhanced sensitivity of linear poly(ethylenimine) - carbon black composite detectors to carboxylic acid vapors , Sensors And Actuators B - Chemical 96, 329 (2003). 

The same authors [217] also reported studies on electrically conductive poly(N-vinylcarbazole)-carbon black composites. The conductive composites with higher proportions of carbon-black showed much higher electrical conductivities, however, 20-60% and 100% weight losses were observed in the temperature ranges of 250°-450°C and 600°C, whereas the initial decomposition of the composite material started at 200°C. 

Wang P, Ma Z, Zhao Z, Jia L (2007) Oxygen reduction on the electrocatalysts based on pyrolysed non-noble metal/poly-o-phenylenediamine/carbon black composites new insight into the active sites. J Electroanal Chem 611 87-95... 

Poly(carbon monofluoride), (CF ) (Figure 14.2) has been known since 1934 when Ruff and co-workers16 prepared a gray compound of composition CF0.92. In 1947 W. and G. Rodorff7,18 reported a series of compositions of CF0.68 to CF0.99, varying in color from black in the case of CF0 68 through gray to white in the case of CF0.99 ... 

Poly(carbon monofluoride) is a white compound, often reported to be explosive and unstable but found in our research results to be stable in air at temperatures up to at least 600°C. In fact, poly(carbon monofluoride) is the most thermally stable fluoropolymer known. It decomposes upon heating at 800°C or under a high vacuum at 580°C to form a series of polyolefinic fluorocarbons. 19 The compounds with compositions in the range of CFo s to CFos are nearly black. The CFos to CF0.95 compounds become gray and the CF095 to CFuj... 

Although a majority of these composite thermistors are based upon carbon black as the conductive filler, it is difficult to control in terms of particle size, distribution, and morphology. One alternative is to use transition metal oxides such as TiO, VO2, and V2O3 as the filler. An advantage of using a ceramic material is that it is possible to easily control critical parameters such as particle size and shape. Typical polymer matrix materials include poly(methyl methacrylate) PMMA, epoxy, silicone elastomer, polyurethane, polycarbonate, and polystyrene. 

Electroconductive resin compositions, which are useful for packaging electronic devices, have been described. In general, electroconductive resin compositions are made up from a thermoplastic resin and an electroconductive filler, mostly carbon black. Polyphenylene ether) resins are known to impart heat resistance. For general purposes, a poly(styrene) (PS) resin and an ABS resin are superior to other resins in that even if carbon black is incorporated in a large amount, there will be no substantial decrease in the flowability or... 

Fig. 8.16 Conductivity of a composite formed from carbon-black coated poly(vinylacetate) pellets (Grunlan et al., 2001). Reprinted by permission of John Wiley Sons, Inc.

Organic matrices are divided into thermosets and thermoplastics. The main thermoset matrices are polyesters, epoxies, phenolics, and polyimides, polyesters being the most widely used in commercial applications (3,4). Epoxy and polyimide resins are applied in advanced composites for structural aerospace applications (1,5). Thermoplastics Uke polyolefins, nylons, and polyesters are reinforced with short fibers (3). They are known as traditional polymeric matrices. Advanced thermoplastic polymeric matrices like poly(ether ketones) and polysulfones have a higher service temperature than the traditional ones (1,6). They have service properties similar to those of thermoset matrices and are reinforced with continuous fibers. Of course, composites reinforced with discontinuous fibers have weaker mechanical properties than those with continuous fibers. Elastomers are generally reinforced by the addition of carbon black or silica. Although they are reinforced polymers, traditionally they are studied separately due to their singular properties (see Chap. 3). 

Depending on their structure, the polymers containing heterocycles have various applications. For example, poly(furfuryl alcohol) is used in composite materials with fillers such as sand and concrete, in copolymers with formaldehyde, etc. Some of the polymers from this group have special properties such as good electrical conductivity (after appropriate doping). Among these polymers are poly(thiophene-2,5-diyl) and particularly polypyrrole, CAS 109-97-7, (usually in carbon black doped with an organic acid anion). The structure of this polymer is shown below ... 

In blends composed of immiscible polymers, amorphous polymer does not affect the crystallization of crystallizable polymer, but if two polymers are miscible, amorphous polymer acts as diluent and affects crystallization of the second polymer. Poly(E-caprolactone) is a crystallizable component of the blend with poly( vinyl butyral), which is studied in compositions containing carbon black. Typically, blends of these two polymers form very large spherulites, and it is interesting to find out how carbon black affects crystallization and other properties of the blend as well as the distribution of carbon black in relationship to the spherulites. Figure... 

Park, J. and Shaw, B.R. (1989). Electrochemical performance of crosshnked poly(styrene)-co-poly(vinylpyridine) composite electrodes containing carbon blacks. Anal. Chem., 61, 848—52. 

Wang, N., Zhang, X., Ma, X., Fang, J. Influence of carbon black on the inoperties of plasticized poly(lactic acid) composites. Polym. Degrad. Stab. 93, 1044-1052 (2008)... 

Electrospun carbon precursor fibers, based on polyacrylonitrile (PAN] and mesophase pitch, having diameters in the range from 100 nm to a few microns, were stabilized and carbonized. These carbon nanofibers had a very high aspect ratio. Nanopores were produced in CNFs made from PAN by a high-temperature reaction with water vapor carried in nitrogen gas by increasing the surface area per unit mass of carbon black. For conductive CNT/polymer composite fibers, CNTs were incorporated into poly(vinylidene fluoride) (PVDF) in iV,iV-dimethylformamide [DMF] solutions and electrospun to form CNT/PVDF fiber mats.The thinnest fiber was obtained as 7 0 nm in diameter. 

Plastics waste can also serve as a source of chemical raw materials. The potential possibilities are considerable, here, since about 25%-30% of plastics consumed are thrown away as waste each year. The following process has proved to be useful hydrolyzable plastics are first hydrolyzed to their monomers below about 200° C the monomers are fractionally distilled off. Then, the poly(vinyl chloride) in the mixture is dehalogenated to poly(olefins) at about 350° C. The residues are then pyrolyzed at about 600-800° C in a sand-fluidized bed. The product fractions are very dependent on the composition of the pyrolyzed material. Generally, however, up to 40% fractions of the economically desirable aromatics are obtained by this high-temperature pyrolysis, and, indeed, when additional steam is blown into the system to reduce carbon char formation. Alternatively, what is known as a low-temperature pyrolysis can be carried out at about 400° C in poly(ethylene) wax as reaction medium. In this case, readily volatile oils of high olefin content are obtained together with waxes and carbon black. 

NR composites and nanocomposites can be fabricated by three main techniques, namely latex compounding, solution mixing and melt blending. A variety of nanofillers, such as carbon black, silica, carbon nanotubes, graphene, calcium carbonate, organomodified clay, reclaimed rubber powder, recycled poly(ethylene terephthalate) powder, cellulose whiskers, starch nanocrystals, etc. have been used to reinforce NR composites and nanocomposites over the past two decades. In this chapter, we discuss the preparation and properties of NR composites and nanocomposites from the viewpoint of nanofillers. We divide nanofillers into four different types conventional fillers, natural fillers, metal or compound fillers and hybrid fillers, and the following discussion is based on this classification. 

In some cases, the polysiloxane was in the form of a composite—for example, with sulfonated cross-linked polystyrene particles, carbon black,acrylate latexes,or sodium dodecyl sulfate. Counterintuitively, the addition of impenetrable nanofillers can actually increase the permeability of a membrane. Also, siloxane-imide copolymers have shown some interesting properties in membrane separations, as have polysiloxanes containing poly(ether amine) groups. ... 

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