Coalescence and Breakup of Droplets in Suspension Polymerization of Styrene

Abstract

For the purpose of investigating the mechanism of coalescence and breakup of liquid droplets in the process of suspension polymerization of styrene, a dual-step operation where bulk polymerization is carried out up to a certain conversion as preliminary step prior to suspension polymerization was investigated. It was found that a narrower droplet size distribution is obtained by this operation with increase of conversion attained in the bulk polymerization step.
The following empirical equation was obtained to represent the rates of coalescence and breakup of droplets as a function of impeller speed and physical properties of droplets :
dN/dt=2.9×10n_r^3.4·d_p^3.4·σ^-2.1·μ_d^-0.5·Δρ^-0.2·N-3.0×10²n_r^1.8·d_p^3.9·σ^-2.8·μ_d^0.8·Δρ^-1.0·N²
It was, furthermore, found that the final particle size distribution of polymer is determined within a reaction time of 5 hours or about 0.8 conversion.