โ Scribed by L. A. Errede
No coin nor oath required. For personal study only.
A very convenient and reliable gravimetric method was developed for measuring swelling of poly (styreneco-divinylbenzene) in particulate form. The method is based on the gravimetric procedure reported earlier2 for monitoring liquid uptake by thin (<0.3 mm) microporous composite films, consisting of swellable particulate (80% by weight) enmeshed in poly(tetrafluoroethy1ene) microfibers (20%). The swellability S (in milliliter of liquid absorbed per gram of polymer in equilibrium with excess liquid) for six styco-DVB polymers with crosslink densities* ranging from 0.01 to 0.12 was measured in 19 organic liquids. In each study of S as a function of* the relationship was given by where A = 1/* is the average number of carbon atoms in the "backbone" of the polystyrene segments between cross-link junctions, C is the relative swelling power of the liquid, and* = l / A o is the critical cross-link density above which S is equal to zero.
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