Modeling and Simulation of Methyl Methacrylate Free Radical Polymerization with Intermediate Addition of Initiator and Step Change of Temperature

Curteanu, Silvia

Silvia Curteanu

Modeling and Simulation of Methyl Methacrylate Free Radical Polymerization with Intermediate Addition of Initiator and Step Change of Temperature

Abstract:
In this paper, some models for gel and glass effects - a new empirical model and Chiu’s model - are checked under batch and semibatch, isothermal and nonisothermal reaction conditions. The chemical initiated free radical polymerization of methyl methacrylate is considered to be achieved in a bulk process and the reaction mechanism takes into account the azobisisobutyronitrile decomposition, propagation, chain transfer to monomer and termination by disproportionation. In the exponential relations that represent the dependence of termination and propagation rate constants on monomer conversion (gel and glass effects), the coefficients are polynomials of forth degree in temperature. For batch operating conditions, the simulations performed at different temperatures and initiator concentrations give results close to experimental ones. In semibatch operation, an instantaneous addition of initiator at different reaction times and different temperatures was considered. Step changes in temperature performed at different reaction times represent an other type of operation taken into account in this paper. In the semibatch and nonisothermal reaction conditions, the simulation results of the two models agree with experimental data even if the same values of parameters as for batch isothermal operation were used. This paper demonstrates the generality of the exponential models and also emphasizes the possibility of controlling polymer properties and reaction time by semibatch and nonisothermal operations.

Keywords:
batch; semibatch; free radical polymerization; methyl methacrylate

Issue: 2003 Volume 40, Issue 2

Pages: