Segregated and two‐environment reactor models—calculation of molecular weight distributions

Abstract

SynopsisAn efficient procedure is presented for calculating molecular weight distributions for segregated reactors and two-environment reactor models.' Calculation of molecular weight distributions for segregated flow or twoenvironment mixing models by conventional methods are long and require a considerable amount of computer time. Therefore, few, if any, calculated molecular weight distributions have been presented in the literature for these mixing models.If the method of characteristics and the continuous variable assumption as presented by Zeman and Amundsonl and used by Timm et al.6 are used, the time required to calculate a distribution is greatly reduced. This calculation procedure is illustrated as follows for a stepwise polymerization with no termination. The method can, however, be readily extended to other types of polymerization mechanisms. The reaction mechanism is I + M + P 1For the batch reactor, the production of polymer chains is given by d P . dt = aM or in terms of the continuous variable assumption,where 7 is the continuous variable for the chain length and j is the discrete variable. By use of the method of characteristics, the solution for eq. (3) is P ( t ( t ) , t ) = Pl(t0)(