Formulations with active functional additives for 3D printing of preceramic polymers, and methods of 3D-printing the formulations
This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.
1. A 3D-printing composition comprising:
(a) from about 10 vol % to about 99 vol % of one or more preceramic, UV-curable monomers;
(b) from about 1 vol % to about 70 vol % of solid-phase functional additives, wherein said functional additives have at least one average dimension from about 5 nanometers to about 50 microns, and wherein said functional additives are characterized by the property that at a temperature of 800° C., said functional additives react with said preceramic, UV-curable monomers, or a polymer derived therefrom to cause an increase in volume of said composition;
(c) a photoinitiator or photoacid generator; and
(d) a 3D-printing resolution agent,
wherein said functional additives are selected from the group consisting of scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, zinc, boron, aluminum, gallium, silicon, germanium, phosphorus, titanium silicide, chromium silicide, magnesium silicide, zirconium silicide, molybdenum silicide, and combinations thereof.
2. The composition of claim 1 , wherein said preceramic, UV-curable monomers are selected from unsaturated ethers, vinyls, acrylates, methacrylates, cyclic ethers, epoxies, oxetanes, thiols, or a combination thereof.
3. The composition of claim 1 , wherein said preceramic, UV-curable monomers are selected from silazanes, siloxanes, silanes, carbosilanes, or a combination thereof.
4. The composition of claim 1 , wherein said preceramic, UV-curable monomers contain (i) non-carbon atoms selected from the group consisting of Si, B, Al, Ti, Zn, P, S, Ge, and combinations thereof, and (ii) two or more functional groups selected from the group consisting of aliphatic ethers, cyclic ether, vinyl ether, epoxide, cycloaliphatic epoxide, oxetane, and combinations, analogues, or derivatives thereof.
5. The composition of claim 1 , wherein said preceramic, UV-curable monomers contain (i) non-carbon atoms selected from the group consisting of Si, B, Al, Ti, Zn, P, S, Ge, N, ), and combinations thereof, and (ii) two or more C═X double bonds, two or more C≡X triple bonds, or at least one C═X double bond and at least one C≡X triple bond, wherein X is selected from C, S, N, O, or a combination thereof.
6. The composition of claim 1 , wherein said functional additives are characterized by the property that at a temperature of 800° C., said functional additives react with said preceramic, UV-curable monomers.
7. The composition of claim 1 , wherein said functional additives are characterized by the property that at a temperature of 800° C. under a heating atmosphere, said functional additives are reactive with one or more gases contained in said heating atmosphere.
8. A 3D-printing composition comprising:
(a) from about 10 vol % to about 99 vol % of one or more preceramic, UV-curable monomers, wherein at least some of said preceramic, UV-curable monomers contain thiol groups;
(b) from about 1 vol % to about 70 vol % of solid-phase functional additives, wherein said functional additives have at least one average dimension from about 5 nanometers to about 50 microns, and wherein said functional additives are characterized by the property that at a temperature of 800° C., said functional additives reactively bind with sulfur contained in said thiol groups of said monomers;
(c) a photoinitiator or photoacid generator; and
(d) a 3D-printing resolution agent,
wherein said functional additives are selected from the group consisting of scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, zinc, boron, aluminum, gallium, silicon, germanium, phosphorus, titanium silicide, chromium silicide, magnesium silicide, zirconium silicide, molybdenum silicide, and combinations thereof.
9. The composition of claim 8 , wherein said functional additives are selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, chromium, niobium, chromium silicide, titanium silicide, magnesium silicide, zirconium silicide, molybdenum silicide, and combinations thereof.
10. A ceramic structure comprising a pyrolyzed form of a 3D-printed, UV-cured composition according to claim 8 .
11. The ceramic structure of claim 10 , wherein said ceramic structure contains sulfur in a concentration from about 0.1 wt % to about 30 wt % on an elemental sulfur basis.
12. The composition of either one of claims 1 or 8 , wherein said functional additives are in the form of fibers, whiskers, nanotubes, nanorods, flat platelets, microparticles with average diameter from 1 micron to 100 microns, nanoparticles with average diameter from 1 nanometer to 1000 nanometers, or combinations thereof.
13. The composition of either one of claims 1 or 8 , wherein said functional additives are coated with one or more compounds or chemical groups that polymerize or crosslink said monomer when exposed to UV radiation and/or heat, and optionally wherein said compounds or chemical groups are selected from the group consisting of unsaturated ethers, vinyls, acrylates, methacrylates, cyclic ethers, epoxies, oxetanes, and combinations thereof.
14. The composition of either one of claims 1 or 8 , wherein said functional additives are covalently bonded to one or more compounds or chemical groups selected from the group consisting of unsaturated ethers, vinyls, acrylates, methacrylates, cyclic ethers, epoxies, oxetanes, amines, hydroxyls, isocyanates, hydrides, and combinations thereof.
15. The composition of either one of claims 1 or 8 , wherein at least some of said functional additives contain a surface treatment that increases the compatibility, solubility, and/or bonding reactivity of said functional additives with said monomers.
16. The composition of either one of claims 1 or 8 , wherein said composition further comprises a reactive or non-reactive surfactant and/or a reactive or non-reactive wetting agent.
17. The composition of either one of claims 1 or 8 , wherein said functional additives are at least partially transparent to UV light.
18. The composition of either one of claims 1 or 8 , wherein said functional additives are at least partially reflective of UV light.