Title: Optimizing Continuous Reactive Additive Manufacturing via Viscosity Manipulation

Authors: Aynslie J. Fritz, Jeffrey S. Wiggins

DOI: 10.33599/nasampe/s.22.0711

Abstract: Continuous reactive additive manufacturing (AM) is immensely valuable for fast production AM and decreased anisotropy, but research efforts are currently hindered due to equipment restrictions. This paper explores the development of a lab-scale continuous reactive additive manufacturing (CRAM) 3D printer, then further demonstrates its utilization. The research presented herein employs a two-component syringe equipped with static mixer to synthesize polyurethanes (PUs) containing various amounts of fumed silica (FS) as a viscosity modifier. The chemorheological properties are analyzed as a function of FS loading level to observe the influence of FS on gel formation. Using the lab-scale CRAM printer, the success and dimensional stability of FS-containing PUs are correlated with the rheological data to provide insight on required chemorheological properties for printing. This study investigates the influence of viscosity modifiers on the chemorheological properties of PUs and further demonstrates the CRAM printability of different FS-containing PU formulations.

References: (1) Dilberoglu, U. M.; Gharehpapagh, B.; Yaman, U.; Dolen, M. The Role of Additive Manufacturing in the Era of Industry 4.0. Procedia Manuf. 2017, 11 (June), 545–554. https://doi.org/10.1016/j.promfg.2017.07.148. (2) Tan, L. J.; Zhu, W.; Zhou, K. Recent Progress on Polymer Materials for Additive Manufacturing. Adv. Funct. Mater. 2020, 30 (43), 1–54. https://doi.org/10.1002/adfm.202003062. (3) Ivanova, O.; Williams, C.; Campbell, T. Additive Manufacturing (AM) and Nanotechnology: Promises and Challenges. Rapid Prototyp. J. 2013, 19 (5), 353–364. https://doi.org/10.1108/RPJ-12-2011-0127. (4) Rios, O.; Carter, W.; Post, B.; Lloyd, P.; Fenn, D.; Kutchko, C.; Rock, R.; Olson, K.; Compton, B. 3D Printing via Ambient Reactive Extrusion. Mater. Today Commun. 2018, 15 (March), 333–336. https://doi.org/10.1016/j.mtcomm.2018.02.031. (5) Duty, C. E.; Kunc, V.; Compton, B.; Post, B.; Erdman, D.; Smith, R.; Lind, R.; Lloyd, P.; Love, L. Structure and Mechanical Behavior of Big Area Additive Manufacturing (BAAM) Materials. Rapid Prototyp. J. 2017, 23 (1), 181–189. https://doi.org/10.1108/RPJ-12-2015-0183. (6) Weigand, Jeremy, J. Dual-Cure Benzoxazine Networks for Additive Manufacturing. 2019. (7) Odian, G. Principles of Polymerization. 4th Edition.; 1996; Vol. 37. (8) Jaúregui-Beloqui, B.; Fernández-García, J. C.; OrgilIs-Barceló, A. C.; Mahiques-Bujanda, M. M.; Martín-Martínez, J. M. Thermoplastic Polyurethane-Fumed Silica Composites: Influence of the Specific Surface Area of Fumed Silica on the Viscoelastic and Adhesion Properties. J. Adhes. Sci. Technol. 1999, 13 (6), 695–711. https://doi.org/10.1163/156856199X00947. (9) Raghavan, S. R.; Walls, H. J.; Khan, S. A. Rheology of Silica Dispersions in Organic Liquids: New Evidence for Solvation Forces Dictated by Hydrogen Bonding. Langmuir 2000, 16 (21), 7920–7930. https://doi.org/10.1021/la991548q. (10) Chiou, B.-S.; Raghavan, S. R.; Khan, S. Effect of Colloidal Fillers on the Cross-Linking of a UV Curable Polymer_Gel Point Rheology and the Winter Chambon Criterion.Pdf. Macromolecules 2001, 34, 4526–4533. https://doi.org/10.1021/ma010281a. (11) Meng, J.; Hu, X.; Boey, F. Y. C.; Li, L. Effect of Layered Nano-Organosilicate on the Gel Point Rheology of Bismaleimide/Diallylbisphenol A Resin. Polymer (Guildf). 2005, 46 (8), 2766–2776. https://doi.org/10.1016/j.polymer.2004.11.087. (12) Altmann, N.; Halley, P. J. The Effects of Fillers on the Chemorheology of Highly Filled Epoxy Resins: I. Effects on Cure Transitions and Kinetics. Polym. Int. 2003, 52 (1), 113–119. https://doi.org/10.1002/pi.1058. (13) Winter H. The Critical Gel. In: Structure and Dynamics of Polymer and Colloidal Systems, NATO Science Series (Series C: Mathematical and Physical Sciences), vol 568. Springer, Dordrecht 2002. (14) Fritz, A. J.; Wiggins, J.S. Interdependencies of Dimensional Stability and Degree of Conversion of Polyurethanes Printed via Continuous, Reactive Additive Manufacturing, CAMX 2021- Dallas, TX; Oct. 17-20

Conference: SAMPE 2022

Publication Date: 2022/05/23

SKU: TP22-0000000711

Pages: 13

Price: $26.00