Claims
- 1. The method of preparing a monodisperse latex having a particle size over 2 microns which comprises:
- (a) combining monodisperse seed particles of a polymer prepared by emulsion polymerization, predetermined amounts of monomer, an emulsifier, at least one inhibitor, a heat-decomposable initiator and water in a closed reaction vessel:
- (b) disposing the reaction vessel containing the resulting mixture in a microgravity environment;
- (c) heating the mixture above the decomposition temperature of said initiator; and
- (d) maintaining the mixture in microgravity at an effective polymerization temperature under mild agitation until growth of seed particles is completed.
- 2. The method of claim 1 wherein said polymer is polystyrene and the monomer is styrene.
- 3. The method of claim 2 wherein the particle size of the seed particles is about 2 microns.
- 4. The method of claim 3 wherein the emulsifier is an anionic surfactant.
- 5. The method of claim 4 wherein the initiator is azobisisobutronitrile or benzoyl peroxide.
- 6. The method of claim 5 wherein the concentration of polymer and monomer in said mixture is 20 to 30 weight percent.
- 7. The method of claim 6 wherein said effective polymerization temperature is from 60.degree. C. to 80.degree. C.
- 8. The method of claim 1 including the additional steps of recovering the resulting enlarged particles and subjecting said particles to additional growth according to steps (a) through (d).
- 9. The method of claim 1 wherein said inhibitor is potassium dichromate.
- 10. The method of claim 9 wherein said mixture includes two inhibitors and said inhibitors are potassium dichromate and tertbutylpyrocatechol.
ORIGIN OF THE INVENTION
The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457).
US Referenced Citations (4)