THE DEGRADATION PROCESS OF POLYSTYRENE - DEPENDENCE OF THE DEGRADATION RATE ON TYPE OF DEGRADATION EQUIPMENT

Polystyrene was degraded in three different types of apparatus at 315~390°C. The first-step degradation rate was measured by the quartz spring method in vacuum. This activation energy is 39.3 kcal/mol. The degradation rate effected by the second degradation step was measured in a long tubular stirred vessel at atmospheric pressure. This rate is less than the first-step rate and its activation energy is 54.2 kcal/mol. In the stirred vessel, which was the same type as industrial equipment, the first-step degradation rate was measured in vacuum and at high stirring speed. At atmospheric pressure and low-speed stirring, the rate effected by the second-step degradation was measured. Mass transfer of the degraded products is hardly affected by the difference in equipment type because the products are boiling in the polymer. The degradation rate and products were considered to be closely related to the type of equipment and the operating conditions. © 1980, Society of Chemical Engineers, Japan. All rights reserved.