Synthesis of highly crosslinked monodisperse polymer particles: Effect of reaction parameters on the size and size distribution

Abstract

Monodisperse polystyrene particles crosslinked with different concentrations of divinylbenzene were synthesized in the 3.2–9.1 μm size range by dispersion polymerization in an isopropyl alcohol/toluene mixed‐dispersion medium with poly(N‐vinylpyrrolidone) as a steric stabilizer and 2,2′‐azobisisobutyronitrile as a radical initiator. The effects of the reaction parameters such as the crosslinking agent concentration, media solvency (controlled by varying the amount of toluene addition), the initiator concentration, and the stabilizer concentration on the particle size and size distribution were investigated with reference particles with a monodisperse size distribution and crosslinked by 1.5 wt % divinylbenzene. The appropriate increase in media solvency was a prerequisite for preparing crosslinked particles without coagulated and/or odd‐shaped particles. The investigation of the effects of the polymerization parameters also shows that only specific sets of conditions produce particles with a monodisperse size distribution. The glass‐transition temperatures of the particles increased with increasing divinylbenzene concentration. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4368–4377, 2002

Thermally robust highly crosslinked poly(methyl methacrylate-co-divinyl benzene) microspheres by precipitation polymerization

“…Although the dispersion polymerization is quite to the precipitation polymerization except the existence of stabilizer in the polymerization system, the effect of a crosslinking agent on the particle size and uniformity can not be studied since the concentration of a crosslinking agent above 5 mol% relative to a main monomer causes a significant coagulation or deterioration of the final particle shape. [15][16][17] Figure 3 represents the effect of DVB on the yield of the polymerization. The use of "yield" term is more reasonable than "conversion" because the monomer is converted to polymer during the precipitation polymerization and the polymerized substances are classified into two different species; gel and sol.…”

“…The addition of high amount of crosslinking agent (more than 0.5 wt%) in dispersion polymerization introduces a coarse surface of the final polymer particles or even popcornshaped particles. [15][16][17] Most recently, the precipitation polymerization of crosslinkable monomer has been found that fully crosslinked microspheres can be prepared even without any stabilizers in the polymerization system. 18 Several monomers including methacrylate, 19 maleic anhydride, 20 and chloromethyl styrene 21 have been copolymerized to form microspheres with DVB as the crosslinkable monomer using the precipitation polymerization.…”

Size and uniformity variation of poly(MMA-co-DVB) particles upon precipitation polymerization

“…The addition of high amount of crosslinking agent (more than 0.5 wt%) causes a coarse surface of the final polymer particles or even popcorn-shaped particles in dispersion polymerization. 7,13,14 Precipitation polymerization as briefly mentioned earlier has found that fully crosslinked microspheres can be prepared in a simple single stage process. 15 Various monomers including methacrylate, 16 maleic anhydride, 17 and chloromethyl styrene 18 have been copolymerized to form miscrospheres with divinylbenzene (DVB) as the crosslinkable monomer using the precipitation polymerization.…”

Atom Transfer Radical Dispersion Polymerization of Styrene in the Presence of PEO‐based Macromonomer

“…[6] Under such dispersion conditions, selecting a suitable surfactant is of critical importance to control particle formation, since the surfactant/stabilizer can be adsorbed on the surface of the insoluble polymers and affects the colloidial stability of the system. A series of homopolymers, [7][8][9][10] such as poly(Nvinylpyrrolidone) (PVP), block copolymers [11][12][13][14][15] with one block having affinity to the polymer particles and also gradient copolymers [16] have been studied and reported as efficient stabilizers for dispersion polymerization of various monomers.…”