No abstract

Conductance measurements on dilute polyelectrolyte solutions recently carried out by Doty and Othl and by Wall and co-workers2 have shown that 2 0 0 0.3 0.6 POLYMER CONC. (g./rnI.) Y 10' 9

Vinyltoluene-styrene copolymer sulfonic acids in dilute solution exhibit conductance behavior which differs appreciably from that of strong 1:1 electrolytes and other chain polyelectrolytes. The equivalent conductance of the polysulfonic acid shows no observable dependence on either polymer concentration or total solution ionic strength at moderate to very high dilutions. However, sodium poly-p-etyrenesulfonate shows a variation of equivalent conductance with concentration which is functionally identical to behavior observed by other workers for sodium polymethacrylate and poly-4-vinyl-N-n-butylpyridinium bromide. Proton counterions are apparently the major contributors to polysulfonic acid solution conductance, which does not vary greatly with polymer molecular weight. Values of ionic dissociation in methanol-water systems were calculated under the assumption of negligible polysulfonate ion mobility. In the regions 0-60% and 90-100% methanol the dissociation is apparently proportional to the solvent dielectric constant. Elsewhere, the dissociation of the polyacid is not significantly influenced by the methanol content of the solvent.

No abstract

The diffusion of styrene vapor in ethyl cellulose film has been studied as a function of styrene solubility in the film at 50°C. Methods and data are presented for determining the equilibrium solubility of styrene in ethyl cellulose as a function of vapor pressure at 50°C. The permeation rates of styrene vapor through 3‐mil film were determined under steady state conditions for various pressures of pure styrene vapor on one side of the film and vacuum on the other side. From a plot of permeation rates versus styrene solubility the diffusion coefficient was calculated as a function of concentration. Measurements made over a concentration range of 0 to 0.7 g. styrene/cm.3 of unswollen film show that the diffusion coefficient first increases rapidly with concentration, then goes through a maximum, and finally levels off at 10−7 cm.2/sec. In the limited range of 0.06 to 0.10 g./cm.3 the diffusion coefficient varies exponentially with concentration as has been reported for other systems in a similar range. However, such a functionality does not represent the present system over a broad concentration range. These results, if generally applicable to other systems, indicate that the nature of the diffusion process for organic vapors in polymers may be considerably more complicated than formerly supposed.