Density of Carbon Black by Helium Displacement

Rossman, R. P.; Smith, W. R.

doi:10.1021/ie50405a008

Cited by 39 publications

(24 citation statements)

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“…Apparent densities were determined by flotation of discrete spheres and were checked by the helium gas displacement method. 15 The change with oxygen content (see Fig. 2 ) was linear.…”

Section: Density and Volume Changes During Oxidation Of (I)mentioning

confidence: 86%

Formation and properties of polymer carbon

Winslow¹,

Baker²,

Pape³

et al. 1955

J. Polym. Sci.

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Divinylbenzene (48%)/ethylvinylbenzene copolymer was converted to a series of pyrolytic derivatives. Enough of the carbon bond network remained intact throughout thermal rearrangement and condensation to retain the original gross shape of the copolymer in the final polymer carbon. Although a carbon residue (6% by weight) was obtained by direct heating of the copolymer, yields were increased eightfold by preoxidation or prechlorination. Such an alteration of thermal degradation is obviously a complex process involving both “inhibition,” in the ordinary sense, and a considerable contribution toward an increased valence network density. As a consequence, the average molecular weight of volatile fragments evolved during carbonization is inversely proportional to the oxygen content of the original hydrocarbon polymer. Pyrolysis of divinylbenzene copolymer, containing 18% oxygen, resulted in a 50% volume shrinkage, 50% weight loss, and a 100% density gain. Unless these data are attributable to extensive microporosity, it is difficult to account for the sorption of up to 3 cc. of helium gas per gram of polymer carbon at 30°C. and 600 mm. pressure; and calculated surface areas as large as 1400 sq.m./g. Abrupt changes in the progress of polymer carbon formation occurred between 600 and 700°C. The residue became rigid; vigorous evolution of volatile products, principally hydrogen, suddenly diminished; and paramagnetic resonance absorption (unpaired electron concentration) dropped about tenfold while d.c. resistivity decreased 106 ohm cm. In this region, also, x‐ray patterns were most diffuse, exhibiting no maxima characteristic of carbon scattering in either hydrocarbons or condensed rings. Finally, the x‐ray patterns of polymer carbon intermediates became less diffuse in samples prepared at 700°C. or above. Yet, scattering indicated the presence of crosslinked graphitic layers of such stability that reordering or true graphitization did not occur at 2400°C.

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“…Apparent densities were determined by flotation of discrete spheres and were checked by the helium gas displacement method. 15 The change with oxygen content (see Fig. 2 ) was linear.…”

Section: Density and Volume Changes During Oxidation Of (I)mentioning

confidence: 86%

Formation and properties of polymer carbon

Winslow¹,

Baker²,

Pape³

et al. 1955

J. Polym. Sci.

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“…• Soot density (yO soot ) is 1.8-1.9 g/ml [Rossman and Smith, 1943;Flower and Bowman, 1986;Dobbins, et al, 1994;Wu, et ai, 1997];…”

Section: Discussionmentioning

confidence: 99%

“…The value of soot density is still widely disputed. Amongst the many measurements of soot density, a soot density of 1.8-1.9 g/ml is by far the most commonly cited value in the combustion community [e.g., Rossman and Smith, 1943;Flower and Bowman;, Dobbins, etal, 1994Wu, etal, 1997].…”

Section: Use Of2d-losa To Estimate Soot Mass Emission Ratementioning

confidence: 99%

Sky-scattered solar radiation based plume transmissivity measurements

Chen¹

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“…The density of the neat LDPE was taken as 940 kg/m 3 and that of the CB additive as 1950 kg/m 3 ; hence, the density of the 5%CB‐PE composite was calculated to be 990 kg/m 3 . The specific heat of PE was taken to be 2000 J/kg‐K, and that of CB additive as 710 J/kg‐K; hence, the specific heat of the 5%CB/PE was calculated to be 1935 J/kg‐K.…”

Section: Discussionmentioning

confidence: 99%

A method to assess downward flame spread and dripping characteristics of fire‐retardant polymer composites

et al. 2017

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Summary A method is described to assess the flame retardancy of polyethylene composites by measuring both their downward flame spread rates as well as their combined melting and dripping rates on rectangular rods, ignited at their top. The composite materials were produced by mixing pulverized polymer with organic additives of differing particle sizes, shapes, and mass fractions. The resulting mix was melted in a mold, and then it was solidified into rods. The additives were carbonaceous solids with particle sizes spanning from tens of nanometers to tens of micrometers. The mass fraction of the additives in the polymer matrix varied from 1 to 5 wt%. Upon ignition of the upper tips of the polymer composite rods, the downward flame spread rate and the melting and dripping rate were separately assessed by measuring their mass loss and their heights. The addition to polyethylene of finely sized carbonaceous additives at mass fractions of 4 to 5 wt% proved effective at significantly slowing down its downward flame spread by drastically hindering its dripping tendency. The effectiveness of the additives increased with increasing their mass fraction and decreasing their particle size. High mass fractions of carbon additives resulted in wicking, which can enhance radiatively the heat transfer.

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Density of Carbon Black by Helium Displacement

Abstract: FROM recent x-ray diffraction data (2), it is possible to calculate a limiting density value for a few commercial carbon blacks. The values thus obtained are considerably higher than those generally accepted (4). The experimental values have, for the most part, been determined

Cited by 39 publications

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Formation and properties of polymer carbon

Formation and properties of polymer carbon

Sky-scattered solar radiation based plume transmissivity measurements

A method to assess downward flame spread and dripping characteristics of fire‐retardant polymer composites

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