Simulation of AA + B′B″ type reversible polymerizations with mass transfer of condensation product

J of Applied Polymer Sci

Ghosh

1983

SynopsisWiped-film reactors carrying out AA + B'B" type reversible polycondensations (where A, B , and B" are functional groups, with B' and B" reacting with A a t different rates) have been simulated.The governing mass balance equations have been solved for two transport models of this reactor (one by Auk and Mellichamp and the other by Amon and Denson) using a combination of finite difference and the Runge-Kutta methods. The increase in the number-average chain length p n of the polymer formed in the reactor is computed as a function of the various rate constants and the parameters characterizing the reactor. fin is found to be most sensitive to the surface area of the film and to the temperature used, both for the equal reactivity as well as for the unequal reactivity cases. For the latter, the effect of the reactivity ratio for the forward rate constants is more significant than that of the equilibrium constants. Results of the two models are also compared under similar conditions and it is found that under equivalent conditions, the Amon-Denson model gives slightly higher pn than the Ault-Mellichamp model.

Simulation of reversible AA + B′B″ polycondensations in wiped film reactors

Gupta

J of Applied Polymer Sci

Ghosh

1983

Solution of final stages of polyethylene terephthalate reactors using orthogonal collocation technique

Polymer Engineering & Sci

Gupta

Madan

et al. 1984

The formation of polyethylene terephthalate (PET) has been modeled to have reactions with monofunctional compounds, redistribution, and cyclization reactions in addition to the usual polycondensation step. In the final stages, the overall polymerization is mass-transfer controlled and solution of the reactor performance equations have been determined through the orthogonal collocation technique. This technique is found to be considerably more efficient for PET reactors compared to the finite difference method; the use of ten collocation points gives resu!ts which are close to the exact solution.

Solution of mass transfer in step growth polymerization in films with bulk in equilibrium

Khanna

Polymer Engineering & Sci

1989

Self Cite

We have analyzed step growth polymerization in a flat film with finite mass transfer resistance. We have shown rigorously that the molecular weight distribution (MWD) at equilibrium is given by the Flory distribution, and under reaction the form of the MWD does not change if the feed is either pure monomer or in equilibrium initially. Extensive computations have shown that it is possible to split the film into growing interfacial and shrinking bulk regions. It is possible to obtain similarity transformations of concentrations of condensation product, and polymer as time invariant profiles. Based on this finding, we have determined a solution for step growth polymerization with finite mass transfer in films. The results lie within 5% of the “exact” numerical computations, for all possible variations of parameters.