PROCESS FOR PREPARING RECYCLABLE TEMPLATE HOLLOW PARTICLES USING SOLVENT-BASED SILICA PRECURSORS
The disclosure provides a process for making hollow inorganic particles comprising: providing a recyclable template particle in an aqueous dispersion, wherein the recyclable template particle is prepared from an organic monomer; coating the recyclable template particle with a solvent based silica precursor; maintaining the pH at about 7 to about 10 to form core/shell particles comprising a silica treatment on the recyclable template particle; removing the core/shell particles; and removing the recyclable template particle from the core/shell particles to form a hollow silica particle.
1 . A process for making hollow inorganic particles comprising:
(a) providing a recyclable template particle in an aqueous dispersion, wherein the recyclable template particle is prepared from an organic monomer;
(b) coating the recyclable template particle with a solvent based silica precursor;
(c) maintaining the pH at about 7 to about 10 to form core/shell particles comprising a silica treatment on the recyclable template particle;
(d) removing the core/shell particles; and
(e) removing the recyclable template particle from the core/shell particles to form a hollow silica particle.
2 . The process of claim 1 wherein the recyclable template particle is a solid particle.
3 . The process of claim 1 wherein the recyclable template particle is a hollow particle.
4 . The process of claim 1 wherein the solvent based silica precursor is tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS) tetrapropyl orthosilicate (TPOS), tetrabutyl orthosilicate (TBOS), tetrahexyl orthosilicate, diethoxydimethylsilane, ethoxytrimethylsilane, methoxytrimethylsilane, trimethoxy(octyl)silane, triethoxy(octyl)silane, methoxy(dimethyl)octylsilane, or 3-aminopropyl-(diethoxy)methylsilane or siloxanes with general formula RSi(OR) 3 , R 1 R 2 Si(OR) 2 , or R 1 R 2 R 3 SiOR, wherein R, R 1 , R 2 , and R 3 are alkyl groups of about 1 to about 20 carbon atoms, aryl groups of about 6 to about 10 carbon atoms, or combinations thereof.
5 . The process of claim 4 wherein the solvent based silica precursor is tetraethyl orthosilicate (TEOS) or tetrapropyl orthosilicate (TPOS).
6 . The process of claim 1 wherein the recyclable template particle comprises poly-(methylmethacrylate), poly-(alphamethylstyrene), polyamide or polystyrene.
7 . The process of claim 1 wherein the recyclable template particle comprises polyacetal, poly(lactic acid) or polyester.
8 . The process of claim 6 wherein the recyclable template particle comprising a silica treatment is heated to promote depolymerization.
9 . The process of claim 8 wherein the thermal depolymerization occurs at temperatures of about 50° C. to about 600° C.
10 . The process of claim 7 wherein the recyclable template particle comprising a silica treatment is treated with acid.
11 . The process of claim 1 wherein the particle formed is about 100 nm to about 900 nm in size.
12 . The process of claim 1 wherein the organic monomer comprises styrene, methyl methacrylate, α-methylstyrene, lactic acid, formaldehyde, aminoacids, hydroxyacids, diacids and dialcohols, or diacids and diamines.
13 . The process of claim 1 wherein the pH is maintained at about 8 to about 10.