Ultrasonic degradation of polystyrene. Part 1. A proposed mechanism for degradation

Abstract

Abstract The ultrasonic degradation of macromolecules can be considered to be caused by the rapid pressure changes accompanying the shock wave radiated from a collapsed cavity. Assuming that all the cavities are identical and that the shock wave is similar to that generated by an underwater explosion of TNT, rate constants for the degradation of polystyrene in benzene have been found as a function of molecular weight. The variation in the limiting molecular weight with ultrasonic intensity has been calculated and shown to agree with that obtained experimentally. The theory indicates that the maximum pressure reached during the collapse of a cavity is about 1600 atm.