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US-20260124801-A1 - METHOD OF PRECISION 3D PRINTED GLASSY CARBON

US20260124801A1US 20260124801 A1US20260124801 A1US 20260124801A1US-20260124801-A1

Abstract

Disclosed herein are the synthesis and characterisations of the monoacrylate-functionalised phthalonitriles (PNs). Their chemical structures are verified with 1 H nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra to confirm the successful synthesis. Subsequently, photopolymerisable resins, based on the prepared PN monomer, a commercial diacrylate and other additives can be formulated. Being post thermally treated, the PN based resins result in polymeric products with excellent thermal and mechanical performances, suggesting the high-performance nature of the PN based resins. Interestingly, the resins exhibit significant high carbon yield, indicating that they are greatly promising candidates as carbon precursors. As it is found that the resins have good three-dimensional (3D) printing capability and can be fabricated using high-resolution projection micro-stereolithography (PμSL) additive manufacturing technology, complex 3D structured objects are herein printed and performed follow-up post treatment. After being progressively pyrolysed up to 1000° C., the printed objects can be readily converted to glassy carbon (GC) structures with structural integrity and fidelity. Only ˜25% of shrinkage was found for the converted GC structure due to the significantly high char yield of the PN resins. This work not only expands the library of new class of high-performance PN resins for popular additive manufacturing but also features the precision 3D printing of GC with low shrinkage and high carbon yield for the first time.

Inventors

  • Xiao Hu
  • Yong Lu
  • Jingdan Hu

Assignees

  • NANYANG TECHNOLOGICAL UNIVERSITY

Dates

Publication Date
20260507
Application Date
20231009
Priority Date
20221010

Claims (20)

  1. 1 . A compound of formula I: wherein: m and n are independently from 1 to 3; X is a bond, O or NH; R is H or an aliphatic group; and A is an aromatic, a heterocyclic or an aliphatic group and is unsubstituted or is substituted by one of more of the group consisting of halo, OR 1a , and NR 1b R 1c ; R 1a to R 1c are each independently selected from H and C 1 to C 10 alkyl; and Y is a bond, a C 1 to C 10 alkylene group or a —C 1 to C 10 alkylene-O— group, where in the latter group the alkylene portion is directly attached to A and the oxygen atom is directly attached to the carbon of the C═O double bond.
  2. 2 . The compound according to claim 1 , wherein A is an aromatic or aliphatic group and is unsubstituted or is substituted by one of more of the group consisting of OR 1a , and NR 1b R 1c .
  3. 3 . The compound according to claim 2 , wherein A is phenyl and is unsubstituted or is substituted by one of more of the group consisting of OR 1a .
  4. 4 . The compound according to claim 1 , wherein R 1a to R 1c , where present, are H or CH 3 .
  5. 5 . The compound according to claim 1 , wherein X is NH or O, optionally wherein X is O.
  6. 6 . The compound according to claim 1 , wherein n and m are 1.
  7. 7 . The compound according to claim 1 , wherein Y is a —C 1 to C 3 alkylene-O— group, where the alkylene portion is directly attached to A and the oxygen atom is directly attached to the carbon of the C═O double bond.
  8. 8 . The compound according to claim 1 , wherein R is H or CH 3 .
  9. 9 . The compound according to claim 1 , wherein the compound of formula I is selected from:
  10. 10 . A resin precursor formulation for additive manufacturing, comprising: a compound of formula I as defined in claim 1 ; a photoinitiator; and an organic solvent suitable for use in additive manufacturing.
  11. 11 . The resin precursor formulation according to claim 10 , wherein the formulation further comprises one or more of a crosslinking agent a photoabsorber, and a filler.
  12. 12 . The resin precursor formulation according to claim 10 , wherein the formulation is suitable for use in a stereolithography-type additive manufacturing process.
  13. 13 . The resin precursor formulation according to claim 10 , wherein one or more of the following apply: (i) the photoinitiator is selected from one or more of the group consisting of 2,4,6-trimethyl benzoyldiphenyl phosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylphenyl-propane-1-one, and, more particularly, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide); and (ii) the organic solvent is selected from one or more of the group consisting of toluene, chloroform, tetrahydrofuran, and more particularly, toluene, dimethylformamide, and N-methylpyrrolidine.
  14. 14 . The resin precursor formulation according to claim 10 , wherein the resin precursor formulation comprises: a compound of formula I; wherein: m and n are independently from 1 to 3; X is a bond, O or NH; R is H or an aliphatic group; and A is an aromatic, a heterocyclic or an aliphatic group and is unsubstituted or is substituted by one of more of the group consisting of halo, OR 1a , and NR 1b R 1c ; R 1a to R 1c are each independently selected from H and C 1 to C 10 alkyl; and Y is a bond, a C 1 to C 10 alkylene group or a —C 1 to C 10 alkylene-O— group, where in the latter group the alkylene portion is directly attached to A and the oxygen atom is directly attached to the carbon of the C═O double bond; a photoinitiator; an organic solvent suitable for use in additive manufacturing; a crosslinking agent; and a photoabsorber.
  15. 15 . A polymeric resin composition obtained from the polymerisation of a compound of formula I as described in claim 1 .
  16. 16 . The polymeric resin composition according to claim 15 , wherein the polymeric resin composition has one or more of the following properties: (a) a T d that is greater than or equal to 400° C.; (b) a T g that is greater than or equal to 300° C.; (c) a bending strength that is greater than or equal to 100 MPa; (d) a modulus greater than or equal to 3.5 Gpa; (e) a carbon yield, following a sintering process, of greater than or equal to 60%; and (f) a shrinkage value of from 20 to 40%, for a glassy carbon three-dimensional object relative to a green polymeric resin three-dimensional product following a sintering process to provide the glassy carbon three-dimensional product.
  17. 17 . The polymeric resin composition according to claim 15 , wherein the polymeric resin has been formed into a three-dimensional object.
  18. 18 . A process of additive manufacturing, the process comprising: (ai) providing a resin precursor formulation for additive manufacturing as described in claim 10 ; and (aii) controlling a stereolithography-type apparatus to form a three-dimensional object by using the resin precursor formulation, wherein the resin precursor formulation is deposited by the apparatus on a surface in a layer by layer operation and each layer is subjected to a polymerisation reaction before each subsequent layer is laid down.
  19. 19 . A process of providing a three-dimensional glassy carbon object, the process comprising the steps of: (bi) providing a three-dimensional object comprising a polymeric resin material obtained from the polymerisation of a compound of formula I as described in claim 1 ; and (bii) subjecting the three-dimensional object to carbonisation through the application of heat to provide a glassy carbon object.
  20. 20 . (canceled)

Description

FIELD OF INVENTION The current invention relates to novel compounds, resin precursor formulations for additive manufacturing which comprise the novel compounds, polymeric resin compositions obtained from the polymerisation of the novel compounds, methods of additive manufacturing using the resin precursor formulations, methods of providing a three-dimensional (3D) glassy carbon object, use of the novel compound in a method of additive manufacturing and in a method providing a glassy carbon object. BACKGROUND The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge. As one of nature's most plentiful elements, carbon is the foundation of all organic and biological chemistry. Due to their unique characteristics, such as large surface area, low cost, consistent physicochemical properties, and interesting bioactivity, carbon-based materials constitute interesting alternatives in many scientific and technological fields. Numerous research efforts have allowed for the preparation of carbon-based materials to achieve products with particular electrochemical, thermal, mechanical and electrical properties. Amongst various carbon materials, low-ordered and glass-like amorphous carbons that are obtained by the carbonization of some thermosetting resins under inert atmosphere are designated as glassy carbon (GC) or vitreous carbon, which is a hard and isotropic carbon material with high stiffness (Young's modulus of 21 GPa). GC is stiff, fragile and presents a surface fracture similar to that presented by glass. It presents excellent thermal and chemical stability, good impermeability to gases and liquids, good thermal and electrical conductivities and excellent biocompatibility. As a consequence, GC has been explored extensively in versatile technical applications (McCreery, R. L., Chem. Rev., 2008, 108, 2646), such as electrochemical sensors (Fan, S. et al., Chem. Pap., 2020, 74, 4411), energy storage devices (Islam, M. T. et al., Electrochim. Acta, 2020, 360, 136966), electrochemical devices for wastewater decontamination (Hsia, B. et al., Carbon, 2013, 57, 395), tools for precision moulding (Haq, M. R. et al., J. Micromech. Microeng., 2019, 29, 075010), ablative shields (Wang, S. et al., Polym. Degrad. Stabil., 2017, 144, 378), and biomedical implants and tissue engineering. Due to its good biocompatibility, GC may also be applied in many medical applications, such as heart valves, neural implants, and scaffolds for tissue regeneration. The production of GC can be made from precursors like well-defined synthetic polymeric resins (e.g., phenolic and poly(furfuryl alcohol) resins) and biomass of plants (e.g., sucrose (Kubota, K. et al., Chem. Mater., 2020, 32, 2961), cellulose (Kaburagi, Y. et al., Carbon, 2005, 43, 2817), and tannin (Tondi, G. et al., Carbon, 2009, 47, 1480)). Precursor parameters such as molecular structures, weights, and aromatic contents govern the quality of final GC products. In addition, it is known that specific geometries of GC can provide substantial advantages and benefits for advanced applications. However, the processing of GC materials is still a great challenge. Unlike metals, ceramics or polymers, GC can neither be melted, sintered nor polymerized due to its hard and fragile nature, therefore conventional processing methods such as screw extrusion, blending, roll pressing, injection moulding, welding, sintering cannot be used for obtaining complex (e.g. 3D) structures. In recent years, with the rapid development of additive manufacturing (AM) (or 3D printing) technologies, the fabrication of non-processable materials has undergone unprecedented changes because very complex systems that could never be achieved (or with great difficulty) by conventional methods can be realized. The most-employed AM technologies include material extrusion printing (e.g. direct ink writing, DIW; fused deposition modelling, FDM), photopolymerisation printing (e.g. digital light processing, DLP); stereolithography, SLA), and selective laser sintering (SLS) printing. For carbonaceous material printing, the former two methods are mainly utilised and in particular, a wide variety of carbon based materials such as carbon fibres (Sanei, S. H. R. & Popescu, D., J. Compos. Sci., 2020, 4, 98), carbon black, carbon nanotubes (Acquah, S. F. A. et al., Carbon nanotubes and graphene as additives in 3D printing, in Carbon Nanotubes—Current Progress of Their Polymer Composites, M. R. Berber, I. H. Hafez (Eds.), InTech, 2016, DOI: 10.5772/63419), graphene, and graphene oxide (Guo, H. et al., Nano Mater. Sci., 2019, 1, 101) can be easily printed using DIW or FDM via a binder matrix. In contrast, less reports have been made on GC printing from high-performance carbon precursors. Bauer et al. reported the printing of GC nanolattice metamaterials via pyrolysis of a photocur