Abstract: A method of producing vinyl polymer particles by suspension polymerization comprising: combining an aqueous media and a tricalcium phosphate to a reaction vessel; adding a pH stabilizing agent to the reaction vessel; adding a vinyl monomer to the reaction vessel; adding a peroxide initiator, e.g., which also generates CO2 as a result of primary or secondary decomposition, to the reaction vessel; adding surfactant or a water soluble free radical initiator to generate surfactant in situ to the reaction vessel; maintaining the reactor contents at greater than or equal to 90° C. until a density of a dispersed phase becomes substantially equal to that of a continuous phase; adding a blowing agent to the reaction vessel; raising the temperature of the reaction vessel to greater than or equal to 100° C.; and collecting polymer particles having a particle size distribution.

Abstract: A method of producing vinyl polymer particles by suspension polymerization comprising: combining an aqueous media and a tricalcium phosphate to a reaction vessel; adding a pH stabilizing agent to the reaction vessel; adding a vinyl monomer to the reaction vessel; adding a peroxide initiator, e.g., which also generates CO2 as a result of primary or secondary decomposition, to the reaction vessel; adding surfactant or a water soluble free radical initiator to generate surfactant in situ to the reaction vessel; maintaining the reactor contents at greater than or equal to 90° C. until a density of a dispersed phase becomes substantially equal to that of a continuous phase; adding a blowing agent to the reaction vessel; raising the temperature of the reaction vessel to greater than or equal to 100° C.; and collecting polymer particles having a particle size distribution.

Abstract: The present invention relates to a process for the emulsifier-free preparation of water expandable polymer beads. The process comprises the steps of: a) providing an emulsifier-free monomer composition comprising styrene and a polar comonomer comprising a carbon-to-carbon double bond, b) prepolymerizing the monomer composition to obtain a prepolymer composition comprising styrene, the polar comonomer and their copolymer, c) adding an aqueous dispersion of nanoclay to the prepolymer composition to obtain an inverse emulsion, d) suspending the inverse emulsion obtained by step c) in an aqueous medium to yield an aqueous suspension of suspended droplets and e) polymerizing the monomers in the droplets of the suspension obtained by step d).