This document discusses control of polymerization reactors. It outlines several key control problems including controlling reaction rates and temperature, monomer conversion and production rates, molecular weight and distribution, copolymer composition, and particle size and distribution. It then discusses various measurement techniques used for monitoring these properties, including viscosity, composition, surface tension, molecular weight distribution, and particle size distribution. Control is achieved through manipulation of parameters like temperature, feed rates, catalysts, and chain transfer agents.