Preparation of Uniform Poly (Acrylamide-co-DVB) Microspheres in a Low Toxicity Solvent by Dispersion Polymerization

Uniform poly (acrylamide-co-DVB) microspheres (DVB = divinylbenzene) with number-average diameter varying from 1.65 to 2.86 µm and polydispersity index from 1.011 to 1.176 were prepared in a low toxicity solvent, i.e. ethanol/water mixtures, by dispersion polymerization using octylphenol polyoxyethylene (10) ether as the stabilizer and 2,2′-azobisisobutyronitrile as the initiator. The parameters, such as solvent composition, initiator concentration, and monomer composition, which influence both the product yield and morphology, were investigated by gravimetry and scanning electron microscopy. The results indicate that for the formation of uniform microspheres, there exists a threshold for each parameter. At the maximum threshold, blobs would apparently appear on the surface of the microspheres. Below or above the thresholds would result in doublet- or triplet-shaped particles, flocs, or a mixture of both. The yield of the uniform microspheres could be up to ~35 % by changing the parameters moderately within the threshold range.