SUSPENDED EMULSION, A NEW PROCESS FOR VINYL-CHLORIDE POLYMERIZATION -MORPHOLOGY CONTROL THROUGH SURFACE-ACTIVE ADDITIVES

Suspended emulsion is a new polymerization process in which a water ph ase containing the initiator is suspended in an organic phase containi ng the monomer; the polymer formed is insoluble in both the organic an d water phases. The final morphology of the polymer is a powder of gra ins (around 100-300 microns) formed with agglomerates of primary parti cles (around 1 micron). This article describes the effects of small am ounts of either suspending agents (water-soluble polymers) or surfacta nts. These effects concern mainly the morphology (grain and particle s ize), but also the polymerization kinetics. A rather homogeneous distr ibution of grains and particles inside the grain may be obtained by us ing a cellulosic polymer as the suspending agent and an anionic surfac tant such as sodium dodecyl sulfate. (C) 1994 John Wiley & Sons, Inc.