OPTIMAL TEMPERATURE FOR THE CONTROL OF THE PRODUCT QUALITY IN BATCH POLYMERIZATION - SIMULATION AND EXPERIMENTAL RESULTS

A method to determine an optimal temperature profile that guarantees p roducts having controlled molecular weight distribution (MWD) and desi red values of molecular weight (M(w)) is presented. The base case is t he batch polymerization of MethylMethAcrylate, initiated by AIBN. On t he basis of the kinetic model, the optimal temperature profile is dete rmined by imposing that the value of the instantaneous chain length is maintained constant, thus counteracting the effects of the increase o f viscosity, which leads to broad MWD. Some approximations permit to e xpress, in a straightforward way, the relationship between the optimal temperature and the conversion as a function of the initial condition s. The validity of the simplifying hypotheses that have been assumed i s confirmed first by simulation results and then by a comparison with experimental runs conducted in a lab-scale unit, with determination of MWD made by means of GPC. The obtained results suggest that it is pos sible to decouple the problem: acting on the operating temperature to control the MWD, acting on initial temperature, and initiator concentr ation to influence the M(w). The possibility of application to industr ial reactors has also been investigated,taking into account their pecu liarities and constraints. (C) 1995 John Wiley and Sons, Inc.