Mechanochemical Degradation of Macromolecules During Laminar Flow

Abstract

Degradation reactions of polymers in solution or in melts under the influence of stress fields constitute an interesting and in some cases almost unique way of causing selective chain scission of macromolecules into fragments of predictable size. Generally, molecular scission follows a first order kinetics with the rate constant strongly dependent on the molecular weight.However, there are conflicting experimental results concerning the effect of po-lymer concentration, the nature of the solvent on the degradation rate and the type of degradation (whether it is a random or selective process). There also appears to be a difference in opinion as to whether the stress or the shear rate is the controlling factor of the degradation process. A recent survey of the mechanochemistry of polymer degradation is given by Casale and Porter (1978, 1979).