| abstract |
A process for forming a microgel which comprises a crosslinked core and a multiplicity of linear polymeric arms attached to the core, wherein the process comprises (a) first forming a halogen atom terminated prepolymer with a weight average molecular weight from 1,000 to 25,000 by polymerizing monoethylenically unsaturated monomers in the presence of an organic sulfonyl halide, an organic complexing agent and a transition metal (i.e., Cu, Ru, Ni, Re, Pd, Fe, or Rh); and (b) subsequently polymerizing the prepolymer with a mixture of monoethylenically unsaturated monomers and 0.5 to 60 mole percent, based on the total moles of monomer and prepolymer, of multi-olefinic polymerizable monomers to form a microgel with a weight average molecular weight of 10,000 to 100,000,000 and crosslinked core. |