AbstractsChemistry

The practical and theoretical importance of membrane phenomena has long been recognized. The study of the passage of material into and out of living cells, and experimental techniques such as ultrafiltration and dialysis have long required the use of membranes. More recently, an intensive search has been in progress for membranes suitable for determination of molecular weights of high polymers by osmotic pressure measurements. The subject of this investigation Is the cellophane membrane. This material has been used as a membrane in osmotic pressure determinations of high molecular weight materials in organic solvents. The treatment of the cellophane and its accommodation to such systems has been semi-empirical and consequently certain anomalous results have been reported (1) (2). One of the purposes of this investigation is to establish a mechanism of permeability through cellophane consistent with the other known properties of cellulose such as swelling and sorption. Permeability rates, void volumes and electrical conductance measurements were made to establish the size and number of pores and the specific surface of the membrane. Based upon these observations, a mechanism for permeability through cellophane has been advanced.