Monolithic polymer crosslinked composite materials and methods of making
OwnerNicholas Leventis, Sudhir Mulik +1inventors
InventorsNicholas Leventis, Sudhir Mulik, Chariklia Sotiriou-Leventis
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Abstract
A bidentate free radical crosslinking initiator binds chemically to silica and silica rich surfaces and enables the free radical based polymerization of various materials such as styrene, divinylbenzene and methylmethacrylate onto silica and silica rich surfaces. When used in connection with aerogels, the resultant crosslinked aerogels exhibit greatly increased strength with only nominal increase in density.
Claims20
A method of coating a surface comprising the steps of:
- providing a surface having hydroxyl groups;
- exposing the surface to a bidentate free radical crosslinking initiator, the free radical crosslinking initiator comprising terminal ends each able to form a chemical bond with a hydroxyl group, and a backbone extending between the terminal ends, the backbone able to cleave to produce a pair of cleaved ends, each cleaved end having a free radical;
- reacting a hydroxyl group of the surface with each of the terminal ends of the bidentate free radical crosslinking initiator;
- cleaving the backbone of the bidentate free radical crosslinking initiator to produce a surface bound free radical at each cleaved end;
- initiating polymerization of a compound by the surface bound free radicals produced;
- and
- forming a coating of polymer on at least a portion of the surface.
A method of producing a monolithic product, the monolithic product comprising an assembly of three dimensionally dispersed, polymer coated, nanoparticles, the method comprising the steps of:
- providing a gel, the gel comprising nanoparticles having surfaces comprising a surface bound bidentate free radical crosslinking initiator;
- exposing the gel to compound able to polymerize;
- allowing the bidentate free radical crosslinking initiator to initiate polymerization of the compound at the gel surfaces;
- forming a polymer coating on at least a portion of the surfaces;
- and
- drying into a monolithic product.
A monolithic product comprising:
- a three dimensional assembly of nanoparticles with void space between nanoparticles, the nanoparticles having surfaces comprising hydroxyl groups;
- and
- a polymer coating covering at least some of the surfaces of the nanoparticles and filling at least some of the void space between nanoparticles;
- the polymer coating having been formed by surface initiated polymerization of constituent monomers of the polymer at locations on nanoparticle surfaces that had been modified by reaction of the hydroxyl groups on the surfaces with a bidentate free radical crosslinking initiator.
Dependencies are inferred from the claim text.