Document Type : Full article
1 Department of chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 Department of chemical Engineering, Science and Research Branch, Islamic Azad University, P.O. Box 14155/4933, Tehran, Iran
Suspension polymerization process is commonly used to produce expandable polystyrene. In the conventional method for producing this polymer, two different initiators are added to the process at two different temperature levels. In the industrial scale, this process is time consuming and difficult to control. A new method (Multi-Stage Initiator Dosing, MID) is proposed, in which, the initiator is dosed into the reactor. In the laboratory and bench scale tests of this new method results in better control of the process, shorter reaction times and better quality of the product. Optimum temperature and dosing intervals are determined. The properties of the prepared samples by MID and conventional methods are compared with each other. According to the results obtained with the implementation of new methods for the production of expandable polystyrene reduce time process and consuming amount of initiator and because the initiator dosing in several stages, the suspension control would be easier. Also absorption rate was higher pentane and grain size better than the conventional.