Monomer formulations and methods for 3d printing of preceramic polymers

Abstract

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.

What is claimed is: 
     
         1 . A preceramic monomer formulation for 3D-printing and cationic polymerization, said monomer formulation comprising:
 (a) a monomer molecule containing (i) non-carbon atoms and (ii) two or more functional groups selected from the group consisting of aliphatic ether, cyclic ether, vinyl ether, epoxide, cycloaliphatic epoxide, oxetane, and combinations, analogues, or derivatives thereof;   (b) a cationic photoinitiator or photoacid generator; and   (c) a 3D-printing resolution agent selected from the group consisting of UV absorbers, fluorescent molecules, optical brighteners, and combinations thereof.   
     
     
         2 . The formulation of  claim 1 , wherein said non-carbon atoms are selected from the group consisting of Si, B, Al, Ti, Zn, P, S, Ge, and combinations thereof. 
     
     
         3 . The formulation of  claim 1 , wherein at least 10% (on an atom basis) of said non-carbon atoms is Si. 
     
     
         4 . The formulation of  claim 1 , wherein said formulation contains more than one type of said monomer molecule. 
     
     
         5 . The formulation of  claim 1 , wherein said cationic photoinitiator or photoacid generator is present in a concentration from about 0.001 wt % to about 10 wt % in said formulation. 
     
     
         6 . The formulation of  claim 1 , wherein said cationic photoinitiator or photoacid generator generates a Brønsted acid when exposed to light. 
     
     
         7 . The formulation of  claim 1 , wherein said formulation comprises a photoacid generator, and wherein said photoacid generator is a non-ionic photoacid generator. 
     
     
         8 . The formulation of  claim 1 , wherein said formulation further comprises a thermal cationic initiator. 
     
     
         9 . The formulation of  claim 1 , wherein said formulation comprises said cationic photoinitiator that is active at a first wavelength, and wherein said formulation further includes a radiation-trigger Brønsted acid generator active at a second wavelength substantially different from said first wavelength. 
     
     
         10 . The formulation of  claim 1 , wherein said 3D-printing resolution agent is present in a concentration from about 0.001 wt % to about 10 wt % in said formulation. 
     
     
         11 . The formulation of  claim 1 , wherein said 3D-printing resolution agent is selected from the group consisting of 2-(2-hydroxyphenyl)-benzotriazole, 2-hydroxyphenyl-benzophenones, 2-hydroxyphenyl-s-triazines, 2,2′-(2,5-thiophenediyl)bis(5-tert-butylbenzoxazole), 2,2′-(1,2-ethenediyl)bis(4,1-phenylene)bisbenzoxazole, and combinations thereof. 
     
     
         12 . The formulation of  claim 1 , wherein said formulation further comprises a UV sensitizer that forms an excited state under UV light absorption. 
     
     
         13 . The formulation of  claim 1 , wherein said formulation further comprises from about 0.1 vol % to about 70 vol % of solid-phase fillers.