Title: Influence of Diisocyanate Reactivity and Processability on Polyurethane Ambient Reactive Extrusion
Authors: Aynslie J. Fritz, Jeffrey S. Wiggins
Abstract: Additive manufacturing (AM) is transforming industrial processes, but key limitations, such as anisotropy and size-scale restrictions, hinder its full potential. The recent development of advanced AM methods, such as ambient reactive extrusion (ARE), have targeted these limitations. In ARE, reactive monomeric materials are pumped through a static mixer, initiating polymerization that continues after deposition, necessitating highly reactive, yet processable materials. Herein, reactivity and processability tradeoffs for ARE polyurethane printing was investigated by creating blends of dicyclohexylmethane-4,4'-diisocyanate (less reactive, ambient liquid) and 4,4'-diphenylmethane diisocyanate (more reactive, ambient crystalline solid) and determining relative crystallinity through differential scanning calorimetry. Polyurethanes were then synthesized using polytetramethylene ether glycol, 1,4-butanediol, and the diisocyanate blends. The relationship between dimensional stability and residual functionality were investigated via real-time Fourier transform infrared spectroscopy and corroborative small amplitude oscillatory shear rheology, resulting in the degree of conversion at the critical storage modulus value of 1000 Pa (print-stability threshold). This research provides a systematic study on the interdependencies of diisocyanate blend reactivity and processability for the ARE synthesis of dimensionally stable polyurethanes.
References: 1. Akindoyo, J. O.; Beg, M. D. H.; Ghazali, S.; Islam, M. R.; Jeyaratnam, N.; Yuvaraj, “A. R. Polyurethane Types, Synthesis and Applications-a Review.” RSC Adv. 6 (115) (2016): 114453–114482. [https://doi.org/10.1039/c6ra14525f.] 2. Ning, L.; De-Ning, W.; Sheng-Kang, Y. “Crystallinity and Hydrogen Bonding of Hard Segments in Segmented Poly(Urethane Urea) Copolymers.” Polymer (Guildf). 37 (16), (1996): 3577–3583. [https://doi.org/10.1016/0032-3861(96)00166-8.] 3. Odian, G. Principles of Polymerization. 4th Edition.; 1996; Vol. 37. 4. Brunette, C. M.; Hsu, S. L.; MacKnight, W. J. “Hydrogen-Bonding Properties of Hard-Segment Model Compounds in Polyurethane Block Copolymers.” Macromolecules 15 (1), (19827): 1–77. [https://doi.org/10.1021/ma00229a014.] 5. Huibo, Z.; Yadong, C.; Yongchun, Z.; Xiangdong, S.; Haiya, Y.; Wen, L. “Synthesis and Characterization of Polyurethane Elastomers.” J. Elastomers Plast. 40 (2), (2008): 161–177. [https://doi.org/10.1177/0095244307085540.] 6. Grady, B. P.; Cooper, S. L.; Robertson, C. G. Thermoplastic Elastomers, Fourth Edi.; Elsevier Inc., (2013). [https://doi.org/10.1016/B978-0-12-394584-6.00013-3]. 7. Weigand, J. J. Dual-Cure Benzoxazine Networks for Additive Manufacturing. December 2019. 8. Kingsley, D. S. Continuous Polymer Reactor Design. May 2012. 9. Ball, T. P. Renewable Source Thermoplastics. 2010. 10. Dilberoglu, U. M.; Gharehpapagh, B.; Yaman, U.; Dolen, M. “The Role of Additive Manufacturing in the Era of Industry 4.0.” Procedia Manuf. 11, (2017): 545–554. [https://doi.org/10.1016/j.promfg.2017.07.148.] 11. Ivanova, O.; Williams, C.; Campbell, T. “Additive Manufacturing (AM) and Nanotechnology: Promises and Challenges.” Rapid Prototyp. J. 19 (5), (2013): 353–364. [https://doi.org/10.1108/RPJ-12-2011-0127.] 12. 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. 23 (1), (2017): 181–189. [https://doi.org/10.1108/RPJ-12-2015-0183.] 13. 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. 15 (February), (2018): 333–336. [https://doi.org/10.1016/j.mtcomm.2018.02.031]. 14. Kunc, V.; Lindahl, J.; Minneci, R.; Pyzik, A.; Gorin, C.; Allen, S.; Wilson, K.; Howard, K. “Additive Manufacturing of Polyurethane Materials.” 2017. 15. Hershey, C. J.; Lindahl, J. M.; Romberg, S. K.; Roschli, A. C.; Hedger, B.; Kastura, M.; Compton, B. G.; Kunc, V. “Large-Scale Reactive Extrusion Deposition of Sparse Infill Structures with Solid Perimeters.” Proceedings of CAMX Conf. Anaheim, California, September 23-26, 2019. pp. 0–6. 16. Lindahl, J.; Hassen, A. A.; Romberg, S. “Large-Scale Additive Manufacturing With Reactive Polymers.” (2018). 17. Michael Szycher. 13 Jul 2012, Structure–Property Relations in Polyurethanes from: Szycher's Handbook of Polyurethanes CRC Press Accessed on: 15 Jan 2021 https://www.routledgehandbooks.com/doi/10.1201/b12343-4 18. Solouki Bonab, V.; Manas-Zloczower, I. “Chemorheology of Thermoplastic Polyurethane and Thermoplastic Polyurethane/Carbon Nanotube Composite Systems.” Polymer (Guildf). 99, (2016): 513–520. [ https://doi.org/10.1016/j.polymer.2016.07.043]. 19. Eceiza, A.; Martin, M. D.; Caba, K. De; Kortaberria, G.; Gabilondo, N.; Corcuera, M. A.; Mondragon, I.; Europa, P. “Thermoplastic Polyurethane Elastomers Based on Polycarbonate Diols With Different Soft Segment Molecular Weight and Chemical Structure : Mechanical and Thermal Properties.” (2008). [https://doi.org/10.1002/pen.] 20. Raftopoulos, K. N.; Janowski, B.; Apekis, L.; Pielichowski, K.; Pissis, P. “Molecular Mobility and Crystallinity in Polytetramethylene Ether Glycol in the Bulk and as Soft Component in Polyurethanes.” Eur. Polym. J. 47 (11), (2011): 2120–2133. [https://doi.org/10.1016/j.eurpolymj.2011.07.020]. 21. Yilgör, I.; Yilgör, E.; Wilkes, G. L.” Critical Parameters in Designing Segmented Polyurethanes and Their Effect on Morphology and Properties: A Comprehensive Review.” Polymer (Guildf). 58, (2015): A1–A36. [https://doi.org/10.1016/j.polymer.2014.12.014.]
Conference: SAMPE NEXUS 2021
Publication Date: 2021/06/29
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