Attainable Regions for Polymerization Reaction Systems

Abstract

A method is described for determining the limits of number-average molecular weights, polydispersities, monomer conversions, residual initiator concentrations, and reactor network residence times that are possible in isothermal polymerizations. The general approach provides a visual representation of the “attainable region” and reactor networks which achieve the attainable limits. The approach is based on an extension of the work of Glasser et al. (1987) to polymerization systems and is illustrated with a specific example of the free-radical polymerization of poly(methyl methacrylate). The results show how design conditions affect the range of attainable number-average molecular weights; the results indicate that much higher molecular weights than those typically produced in industry are feasible. The results also demonstrate that while many reactor networks can produce a desired molecular weight, only a few carefully selected networks can yield the narrowest molecular weight distributions. These include a CSTR reactor, a CSTR reactor with a bypass feed stream, and a CSTR reactor followed by a PFR reactor.