ULTRASONIC INITIATION OF POLYMERIZATION

In a previous paper1 it was reported that initiation of polymerization on pure monomer was obtained essentially only when gas bubbles were present so that stable cavitation could occur. With no gas, there was primarily transient cavitation, which resulted in a char rather than a polymer, or in depolymerization when some polymer was already present. This phenomenon has been investigated further. It has been found to occur in a range of temperature and with a number of different gases present. Further investigations have also been carried out on the molecular weight distributions of the resultant polymers and the absolute rates of initiation. © 1990.