Porous particles, their aqueous dispersions, and method of preparation
AssigneeRohm and Haas Company
InventorRobert Mitchell Blankenship
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Abstract
A method of forming, by polymerization in an aqueous dispersion at pressures in excess of one atmosphere, a plurality of porous particles having at least one polymeric phase and, additionally, having a pore filling phase containing a fugitive substance is disclosed. Replacement of the fugitive substance with a gas is further disclosed. Gas-filled porous particles and their aqueous dispersions are also disclosed.
Claims27
A method of preparing an aqueous dispersion of a plurality of porous particles, wherein said porous particles comprise at least one polymeric phase and a pore filling phase, comprising the steps of:
- a) forming a reaction mixture in a closed pressure vessel, said reaction mixture comprising:
- i) at least one monomer;
- ii) water;
- iii) a dispersing agent;
- and
- iv) at least one fugitive substance;
- b) forming a plurality of droplets comprising said monomer and said fugitive substance as a dispersed phase in water;
- c) polymerizing said monomer to form said polymeric phase;
- d) causing said polymeric phase and said pore filling phase to phase separate from one another, forming said porous particles;
- and
- e) reducing the pressure in said pressure vessel to atmospheric pressure;
- and
- wherein said pore filling phase comprises said fugitive substance.
An aqueous dispersion of a plurality of porous particles, said porous particles comprising:
- a) at least one polymeric phase;
- and
- b) a pore filling phase;
- wherein said pore filling phase comprises a substance selected from the group consisting of a fugitive substance, a replacement gas, and combinations thereof.
A plurality of porous particles, said porous particles comprising:
- a) at least one polymeric phase;
- and
- b) a pore filling phase;
- wherein said pore filling phase comprises a substance selected from the group consisting of a fugitive substance, a replacement gas, and combinations thereof;
- and
- wherein the effective glass transition temperature of the polymeric phase is 10° C. to 50° C.
Dependencies are inferred from the claim text.