Monomer Concentration in Polymer Particles in Emulsion Polymerization

摘要

The rate of an emulsion polymerization depends on the monomer concentration at the locus of polymerization in the polymer particles. This note suggests a shortcut method of specifying monomer concentration for new monomers, or monomers for which thermodynamic swelling data is unavailable. While the monomer concentration in a polymer particle in moles per liter varies widely, when described as volume fraction monomer, the variance is much smaller. In fact, for ten monomers for which experimental values are available, the volume fraction monomer in a polymer particle in equilibrium with an aqueous phase saturated with monomer of that polymer is 0.67 +/- 0.04. Hence, if no other value is available, one could assume a monomer volume fraction monomer of 0.67 with a good degree of accuracy.