Viscosities are of interest in polymer technology in order to follow the course of a polymerization reaction or to monitor continuously the quality of a product.
For polymer systems, solution or melt, the viscosity can be related to the molecular weight of the polymer.
Viscosity is measured by capillary viscometers or rotating viscometers.
Indirect method to obtain a measure of molecular size that is quick and inexpensive is the Melt Indexer.
It is evident that the Melt Index varies inversely proportionally to the polymer molecular weight.