关键词: 可视反应器, 临界乳光现象, 超临界降解, 聚苯乙烯, 动力学

Abstract: A visible micro-reactor was used to study the phase transition of polystyrene degradation in supercritical toluene. Polystyrene could be dissolved into toluene in a few minutes with the temperature increasing. The gas-liquid interface disappeared, companying with the opalescent phenomenon, when the temperature and pressure were slightly higher than the critical point of toluene. Moreover, the properties of thermal degradation and supercritical degradation of polystyrene were studied. The results showed that the conversion rate of polystyrene in supercritical toluene was much higher than that of thermal degradation. Moreover, during the beginning stage of degradation, the molecular weight decreased quickly with producing amounts of small molecular products, while conversion rate of polystyrene of thermal degradation was low. The system of supercritical degradation was a homogenous phase with low density and viscosity, and increased the transmission property, which increased the degradation velocity polystyrene substantially. Polystyrene degradation was a first order reaction. In the temperature range of 330~370℃, the activation energy of thermal degradation was 186.1 kJ/mol, while the activation energy of supercritical degradation was 143.5 kJ/mol due to its homogenous phase of reaction system.

Key words: visible reactor, opalescent phenomenon, supercritical degradation, polystyrene, kinetics