Claims
- 1. A coated ceramic powder comprising a plurality of ceramic particles and a siloxane star-graft coating polymer encapsulating at least a portion of said particles, said coating polymer comprising:
- Si (w,x,y,z)
- where w, x, y and z are the mole percent tetrafunctional, trifunctional, difunctional and monofunctional monomeric units, respectively, and wherein w, x, y and z are about 45-75, 5-25, 5-45 and 5-10, respectively, wherein:
- w is tetraethylorthosilicate;
- x is selected from the group consisting of .gamma.-glycidoxypropyltrimethoxysilane, n-hexyltrimethoxysilane, isobutyltrimethoxysilane, .gamma.-methacryloxypropyltrimethoxysilane, n-octadecyltrimethoxysilane, and n-propyltrimethoxysilane;
- y is selected from the group consisting of dicyclohexyldimethoxysilane, diethyldiethoxysilane, dimethyldichlorosilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, di-n-hexyldichlorosilane, n-hexylmethyldichlorosilane, methyldodecyldiethoxysilane, neophylmethyldimethoxysilane, and n-octylmethyldimethoxysilane; and
- z is selected from the group consisting of n-octadecyldimethylmethoxysilane, triethylsilanol, trimethylethoxysilane, and trimethylmethoxysilane.
- 2. A method of preparing a coated ceramic powder comprising a plurality of ceramic particles and a siloxane star-graft coating polymer encapsulating at least a portion of said particles, the method comprising the steps of:
- (a) polymerizing each of a tetrafunctional siloxane monomer, a trifunctional siloxane monomer, a difunctional siloxane monomer and a monofunctional siloxane monomer;
- (b) adding a quantity of ceramic powder to a reaction vessel;
- (c) shear mixing said ceramic powder for a time sufficient to wet substantially all of said powder surface;
- (d) adding the siloxane polymer prepared in step (a) to said reaction vessel containing said shear mixed ceramic powder;
- (e) shear mixing said shear mixed ceramic powder and said siloxane polymer for a time sufficient to form a siloxane polymer coated ceramic powder;
- (f) separating said coated ceramic powder from the components remaining in said reaction vessel, wherein:
- said tetrafunctional siloxane monomer is tetraethylorthosilicate;
- said trifunctional siloxane monomer is selected from the group consisting of .gamma.-glycidoxypropyltrimethoxysilane, n-hexyltrimethoxysilane, isobutyltrimethoxysilane, .gamma.-methacryloxypropyltrimethoxysilane, n-octa-decyltrimethoxysilane, and n-propyltrimethoxysilane;
- said difunctional siloxane monomer is selected from the group consisting of dicyclohexyldimethoxysilane, diethyldiethoxysilane, dimethyldichlorosilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, di-n-hexyldichlorosilane, n-hexylmethyldichlorosilane, methyldodecyldiethoxysilane, neophylmethyldimethoxysilane, and n-octylmethyldimethoxysilane; and
- said monofunctional siloxane monomer is selected from the group consisting of n-octadecyldimethylmethoxysilane, triethylsilanol, trimethylethoxysilane, and trimethylmethoxysilane.
- 3. A siloxane star-graft polymer for coating and encapsulating ceramic particles, said coating polymer comprising:
- Si(w,x,y,z)
- where w, x, y and z are the mole percent tetrafunctional, trifunctional, difunctional and monofunctional monomeric units, respectively, and wherein w, x, y and z are about 45-75, 5-25 and 5-45 and 5-10, respectively, wherein:
- w is tetraethylorthosilicate;
- x is selected from the group consisting of .gamma.-glycidoxypropyltrimethoxysilane, n-hexyltrimethoxysilane, isobutyltrimethoxysilane, .gamma.-methacryloxypropyltrimethoxysilane, n-octadecyltrimethoxysilane, and n-propyltrimethoxysilane;
- y is selected from the group consisting of dicyclohexyldimethoxysilane, diethyldiethoxysilane, dimethyldichlorosilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, di-n-hexyldichlorosilane, n-hexylmethyldichlorosilane, methyldodecyldiethoxysilane, neophylmethyldimethoxysilane, and n-octylmethyldimethoxysilane; and
- z is selected from the group consisting of n-octadecyldimethylmethoxysilane, triethylsilanol, trimethylethoxysilane, and trimethylmethoxysilane.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 08/827,229 filed Mar. 29, 1997, entitled "Siloxane Star-Graft Polymers, Ceramic Powders Coated Therewith And Method Of Preparing Coated Ceramic Powders".
US Referenced Citations (29)
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Number |
Date |
Country |
0389138 |
Sep 1990 |
EPX |
0665004 |
Aug 1995 |
EPX |
2217987 |
Nov 1989 |
GBX |
WO 9006103 |
Jun 1990 |
WOX |
WO 9009777 |
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WOX |
Non-Patent Literature Citations (1)
Entry |
Sol-Gel Science, Academic Press, Chapters 3 and 4, Brinker et al. 1990. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
827229 |
Mar 1997 |
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