HOLLOW SHAFT REACTOR - A USEFUL TOOL FOR BULK POLYMERIZATIONS AT HIGHVISCOSITIES, TEMPERATURES, AND POLYMERIZATION RATES

The hollow shaft reactor (HSR) is an extruder-like reactor with intern al recycling of the reaction medium. It has been designed for polymeri zations at high viscosities up to a few hundred Pas. The HSR posesses the following properties: minimum dead volume, maximum recycle ratio, fast and predictable macro mixing, and both the recycle ratio and macr omixing do not depend on the viscosity of the reaction mass in a wide range of viscosities. Because of the controllable shear rate, wall dep osits on the surface can be avoided. The potential performance of this tool has been discussed by numerical simulations of the high-temperat ure bulk polymerization of methyl methacrylate with intermittent initi ator injection. The high-conversion kinetic model, which has been used , takes into account the influence of monomer conversion and weight av erage molecular weight on the termination constant and the influence o f monomer conversion on initiator efficiency and propagation constant.