6533b7dcfe1ef96bd1273210

RESEARCH PRODUCT

Extension of GPC Techniques

subject

description

Abstract Most of the common GPC gels exhibit pore sizes which are too small to separate very extended molecules, e.g., native cellulose in solution. Several gel types were tested with vinyl polymers of molecular weights up to 107 and with cellulose nitrate. Large pore size Styragel with acetone as solvent proved to be the most favorable gel system yielding effective separations for polymers with coil diameters in solution up to 4000 A. The evaluation of GPC runs usually requires a separate calibration procedure. We attempted to determine the molecular weight of the eluate directly as it leaves the column. This is done by a special automatic viscometer that allows measurement of the viscosity of small cuts (e.g., 0.5–1 ml) of the effluent volume. A set of six capillary viscometers are loaded and unloaded continuously. The details of the apparatus are described and examples of the performance reported.