A practical methodology for the computer modeling of multicomponent chain-growth polymerizations, namely, free-radical and ionic systems, has been developed. This is an extension of a paper by Hamielec, MacGregor, and Penlidis (Multicomponent free-radical polymerization in batch, semi-batch and continuous reactors. Makromol. Chem., Macromol. Symp. 1987, 10/11, 521). The approach is general, providing a common model framework which is applicable to many multicomponent systems. Model calculations include conversion of the monomers, multivariable distributions of concentrations of monomers bound in the polymer chains and molecular weights, long- and short-chain branching frequencies, chain microstructure, and cross-linked gel content when applicable. Diffusion-controlled termination, propagation, and initiation reactions are accounted for using the free-volume theory. When necessary, chain-length-dependent diffusion-controlled termination may be employed. Various comonomer systems are used to illustrate the ...

Mathematical Modeling of Multicomponent Chain-Growth Polymerizations in Batch, Semibatch, and Continuous Reactors: A Review

Modelling particle size distributions and secondary particle formation in emulsion polymerisation

Mathematical modeling and computer simulator/database for emulsion polymerizations

I. INTRODUCTION Emulsion polymerization often has significant advantages over homogeneous bulk or solution polymerization. Aside from the obvious physical advantages when a polymer latex is the final product as in paints or other coatings, there are distinct processing advantages. For example, low viscosity and good temperature control can often be achieved in an emulsion polymerization when this is impossible in bulk. In addition, high molecular weight polymer can usually be produced at much higher reaction rates in an emulsion polymerization reactor than in a bulk polymerization. For these and other reasons, emulsion polymerization has become a multibillion dollar/year processing operation in terms of sales in the United States alone.

On the Mathematical Modeling of Emulsion Polymerization Reactors

On inverse miniemulsion polymerization of conventional water-soluble monomers.

The emulsion polymerization of vinyl acetate was carried out at 50°C using sodium lauryl sulfate as an emulsifier and potassium persulfate as an initiator, and the role of the polymer particles produced in this system was studied on the basis of a previous theory. The low value of the average number of radicals per particle obtained in this work, i.e. in the range 0.01 - 0.5, is explained by introducing a mechanism of a rapid escape of monomeric radicals produced by the chain-transfer reaction which occurs dominantly in the polymer particles. Semiempirical equations are proposed for the estimation for the average number of radicals per particle over the whole range of monomer conversion.

Kazuhide Nakagawara

Papers

The role of polymer particles in the emulsion polymerization of vinyl acetate