Introduction
Viscosity of a polymer solution depends on concentration and size (i.e., molecular weight) of thedissolved polymer. By measuring the solution viscosity we should be able to get an idea about molecular weight. Viscosity techniques are very popular because they are experimentally simple.They are, however less accurate and the determined molecular weight, the viscosity average molecular weight, is less precise. For example, Mv depends on a parameter whichdepends on the solventused to measure the viscosity. Therefore the measured molecular weight depends on the solven tused. Despite these drawbacks, viscosity techniques are very valuable. This chapter discusses the theory and methods for determining polymer molecular weight by measuring solution viscosity