SUSPENSION POLYMERIZATION

Abstract

In a typical suspension polymerization system, one or more water-insoluble monomers containing oil-solube initiator(s) are dispersed in the continuous aqueous phase by a combination of strong stirring and the use of small amounts of suspending agents (stabilizers). Suitable conditions of mechanical agitation are maintained while the monomer droplets are slowly converted from a highly mobile liquid state, through a sticky syrup-like dispersion (conversion 20–60%), to hard solid polymer particles (conversion > 70%) [1–3]. The stabilizers hinder the coalescence of the monomer droplets first, and later stabilize tHe polymer beads whose tendency to agglomerate may become critical when the polymerization has advanced to the point where the polymer beads become sticky.