THE INFLUENCE OF MEMBRANE PREPARATION ON THE OSMOTIC PRESSURE OF POLYVINYL ACETATE IN ACETONE

Abstract

A full account of the experimental procedures used to determine the number average molecular weights of a series of polyvinyl acetates is given. Adsorption of polyvinyl acetate on a cellophane membrane is demonstrated. The importance of this phenomenon is increased when cells of large ratio of membrane surface to cell volume are used. The presence of small amounts of sodium hydroxide in the membrane eliminates detectable adsorption and alters the osmotic pressure values. This change does not appear to be due to imperfect semipermeability of the membranes, and no adequate explanation of the phenomenon has been as yet discovered.