Predicting average molecular weights and branching level for self-condensing vinyl copolymerization in a CSTR
May 20-25, 2018
A continuous stirred-tank reactor (CSTR) model is developed for production of arborescent polyisobutylene (arbPIB, shown in Figure 1), using multidimensional method of moments. ArbPIB is a promising biomaterial, suitable for human implantation, especially for breast reconstruction after cancer surgery.[1,2] To our knowledge, arbPIB has only been produced via carbocationic polymerization in batch and semi-batch reactors, never in a CSTR. ArbPIB is made by copolymerizing IB monomer with an inimer, which is a molecule that contains an initiating group and vinyl group. As such, inimers act both as initiators and monomers, forming T-shaped branching points in the polymer. The CSTR model is used to predict dynamic changes in average branching level and number-average and weight-average molecular weights ( and ). Simulations of this self-condensing vinyl copolymerization (SCVCP) show a tendency toward higher polydispersity and higher branching level compared to batch reactor simulations conducted using the same recipes and residence times. At high inimer feed concentrations and/or long residence times, the model predicts that a CSTR will not reach steady-state operation due to increasing toward infinity. As a result, there is a narrow operating range in which inimer feed concentrations can be adjusted to achieve a desired steady-state . If SCVCP is to be conducted in a CSTR, it will be important to ensure that residence times and inimer feed concentrations are selected within the stable operating window (Figure 2).
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Bradley D. Buren, Kimberley B. McAuley, Yutian R. Zhao, and Judit E. Puskas, "Predicting average molecular weights and branching level for self-condensing vinyl copolymerization in a CSTR" in "Polymer Reaction Engineering X (PRE 10)", John Tsavalas, University of New Hampshire, USA Fouad Teymour, Illinois Institute of Technology, USA Jeffrey Stubbs, HP Inc., USA Jose R. Leiza, University of the Basque Country, Spain Eds, ECI Symposium Series, (2018). https://dc.engconfintl.org/prex/38