Incorporating steric hindrance into the additive design enables a robust formulation of alumina ink for extrusion-based 3D printing

Goharibajestani, Zahra and Akhlaghi Baghoojari, Omid and Akaoğlu, Can and Afghah, Ferdows and Khani, Navid and Hodaei, Amin and Koç, Bahattin and Akbulut, Özge (2019) Incorporating steric hindrance into the additive design enables a robust formulation of alumina ink for extrusion-based 3D printing. ACS Applied Polymer Materials, 1 (12). pp. 3279-3285. ISSN 2637-6105

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The capabilities of additive manufacturing for fabrication of complex and thin-walled ceramic-based objects are restricted by the availability of ceramics inks. Formulations of current ink systems strictly depend on using a high content of organic additives (5-30 wt%). The high amounts of additives affect uniformity and dimensional accuracy of the final object. Here, we designed a single additive that enables printing of high aspect ratio and thin-walled structures (height/width = 58) from an ink of alumina nanoparticles that comprises very low organic content (i.e., 1.25 wt % of nanoparticles mass). In addition to the generally exploited electrostatic effect, this additive has purpose-driven tailoring to harness steric hindrance to control the viscoelastic response of ceramic suspensions and realize an optimum ink for extrusion-based 3D printing. We pursued a stepwise approach in developing such an additive through synthesis of series of copolymers with backbone monomers of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid and side chains of poly(ethylene glycol). When the optimized additive is used, the suspension attains ∼80 wt % solid loading−99% of the theoretical limit calculated by the Krieger−Dougherty equation. The shrinkage and deflection of the printed patterns as well as compactness and sinter-ability of dried structures are monitored. The printed structures did not experience any deformation or deflection during printing and reached 68% of theoretical density (TD: 3.98 g/cm3) after drying. This compactness allowed sintering at lower temperatures and improved dimensional control of the final product. Our approach to formulate ceramic inks enables the embodiment of fully aqueous systems with the utmost material content and has the potential to expand the limited portfolio of ceramic inks.
Item Type: Article
Uncontrolled Keywords: 3D printing; alumina; suspensions; graft polymers; additives
Divisions: Sabancı University Nanotechnology Research and Application Center
Faculty of Engineering and Natural Sciences
Depositing User: Seyedeh Ferdows Afghah
Date Deposited: 13 Mar 2020 14:56
Last Modified: 04 Aug 2023 20:38

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