Abstract
Work reported recently described a “unit work” concept, according to which the flow behavior of a rubber-carbon black mixture was shown to be a function of the mixing work input. These results were shown to be independent of the size of the mixer, the speed of the mixer, and mixing time so long as the temperature-time profiles were similar, the same loading procedure was employed, and the same loading volume percentages were used. This concept provides a means to characterize not only the effect of various polymers, extenders, fillers, and minor additives, but also the uniformity of a given major constituent, which, in the case of an elastomer, may be a processability index. The work described in this paper is the application of the unit work concept to some of these areas : emulsion styrene-butadiene polymers, extenders, and fillers. By means of this concept of mixing, laboratory investigation can be translated, not only qualitatively, but much more important, quantitatively, into factory operations. The effects of polymer molecular weight and bound-styrene content changes, as well as changes in carbon blacks, such as those typified by the new tread blacks, can be investigated in the laboratory, and compounding adjustments can be made there, so that factory production time is not taken for new compound development.
Piroxicam Loading onto Mesoporous Silicas by Supercritical CO2 Impregnation
