Batch thermally initiated bulk

A mathematical model for styrene polymerization, based on free-radical kinetics, accounts for changes in termination coefficient with increasing conversion by an empirical function of viscosity at the polymerization temperature. Solution of the differential equations results in an expression that calculates the weight fraction of polymer of selected chain lengths. Conversions, and number, weight, and Z molecular-weight averages are also predicted as a function of time. The model was tested on peroxide-initiated suspension polymerizations and also on batch and continuous thermally initiated bulk polymerizations. 

The predictive capabilities of the new kinetic model were demonstrated by a direct comparison of model predictions with experimental measurements on monomer conversion, number and weight average molecular weights and molecular weight distribution. The polymerization was carried at different temperatures in a batch, bulk polymerization system. In the temperature range of 100 - 150 °C, a chemical initiator (e.g., Dicumyl Peroxide, DCP) was employed in combination with the thermal initiation of styrene. On the other hand, at higher temperatures (150 - 180 °C), the polymerization was initiated exclusively by the thermal initiation mechanism. 

The computer program simulates the batch polymerization of styrene and has been applied to the relatively low temperature peroxide-initiated polymerization typical of suspension processes and to higher temperature bulk, thermal conditions. It has been useful in the design of new suspension processes and for more general process analysis. 

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