92] - Determination of Molecular Weights by Osmometry

Abstract

Publisher Summary This chapter focuses on the determination of molecular weights by osmometry. Molecular weights of polymers in the range 15,000 to 1,500,000 may be determined by osmometry. Several osmometers have been designed and developed for this purpose; the most widely used ones being the Fuoss–Mead and Zimm–Meyerson types or modifications thereof. It is convenient to have an osmometer of relatively simple construction which is easily cleaned and loaded. It is desirable because the osmometer requires only a small quantity of polymer solution, attains equilibrium in a relatively short time, and is relatively insensitive to temperature variation. The membrane for this instrument is supported by a sintered glass bulb which may be a common gas diffuser. Since the volume of the cell is small, the instrument is not sensitive to small temperature variation.