Abstract
Three different microcapsules, namely dicyclopentadiene (DCPD)-urea formaldehyde (UF) based single-walled microcapsules, DCPD-UF-Siloxane (DCPD-UF-Si) based double-walled microcapsules and DCPD-Carbon nanotubes-UF based dual-core microcapsules were synthesized, and their corresponding self-healing composites were prepared. This paper mainly focuses on the synthesis procedure of various microcapsules and a comparative study on the effect of microcapsules over the final composite properties. The core content of the microcapsules was measured and compared with theoretical calculations. DSC & TGA analyses have shown that the novel microcapsules (DCPD-UF-Si, DCPD-CNT-UF) and their composites have better thermal stability compared to DCPD-UF microcapsules. Epoxy-carbon fiber (2 wt.%) composite specimens with three different microcapsules were tested for surface morphology, mechanical, thermal and electrical properties. SEM analysis has shown that the microcapsules have a rough outer surface and smooth inner surface. The average diameter and shell thickness of the microcapsules were measured for all types of microcapsules. Addition of double-walled and dual-core microcapsules has reduced the glass transition temperature of the composites by 10 °C. Also, SHC with DCPD-UF-Si and DCPD-CNT-UF microcapsules have shown better thermal stability (300 °C) compared to DCPD-UF microcapsules (220 °C). The incorporation of CNT based microcapsules inside the composite has also improved the electrical conductivity by 2.2 times, without compromising on self-healing efficiency (78 %). Therefore, these novel microcapsules can be potential candidates for making multifunctional polymer composites for aerospace, windmills and automotive applications.
Acknowledgments
This research work was funded by Structural Technologies division (S-0-310), National Aerospace Laboratories (CSIR-NAL), Bangalore-India. We acknowledge S. Vedaprakash (CSIR-NAL, Bangalore) for his technical assistance in making epoxy composites and Dasmat Baskey for making composite specimens through water-jet cutting. We thank, Kalavathi and Manikandanath, for SEM and TGA analysis respectively. We also acknowledge Sri Ganesh and for DSC analysis and Benudhar Sahoo for electrical resistivity measurement.
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: None declared.
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
Aissa, B., Tagziria, K., Haddad, E., Jamroz, W., Loiseau, J., Higgins, A., Asgar-Khan, M., Hoa, S.V., Merle, P.G., Therriault, D., et al.. (2012). The self-healing capability of carbon fiber composite structures subjected to hypervelocity impacts simulating orbital space debris. ISRN Nanomater. 35: 1205, https://doi.org/10.5402/2012/351205.Search in Google Scholar
Brown, E.N., Kessler, M.R., Sottos, N.R., and White, S.R. (2003). In situ poly(urea-formaldehyde) microencapsulation of dicyclopentadiene. J. Microencapsul. Micro Nano Carriers 20: 719–730, https://doi.org/10.3109/02652040309178083.Search in Google Scholar
Blaiszik, B.J., Sottos, N.R., and White, S.R. (2008). Nanocapsules for self-healing materials. Compos. Sci. Technol. 68: 978–986, https://doi.org/10.1016/j.compscitech.2007.07.021.Search in Google Scholar
Blaiszik, B.J., Kramer, S.L.B., Olugebefola, S.C., Moore, J.S., Sottos, N.R., and White, S.R. (2010). Self-healing polymers and composites. Annu. Rev. Mater. Res. 40: 179–211, https://doi.org/10.1146/annurev-matsci-070909-104532.Search in Google Scholar
Caruso, M.M., Blaiszik, B.J., Jin, H., Schelkopf, S.R., Stradley, D.S., Sottos, N.R., White, S.R., and Moore, S. (2010). Robust double-walled microcapsules for self-healing polymeric materials. ACS Appl. Mater. Interfac. 2: 1195–1199, https://doi.org/10.1021/am100084k.Search in Google Scholar PubMed
Caruso, M.M., Schelkopf, S., Jackson, A., Landry, A.M., Braunab, P.V., and Moore, J.S. (2009). Microcapsules containing suspensions of carbon nanotubes. J. Mater. Chem. 19: 6093–6096, https://doi.org/10.1039/B910673A.Search in Google Scholar
Guadagno, L., Vertuccio, L., Naddeo, C., Calabrese, E., Barra, G., Raimondo, M., Sorrentino, A., Binder, W.H., Michael, P., and Rana, S. (2019). Reversible self-healing carbon-based nanocomposites for structural applications. Polymers 11: 903, https://doi.org/10.3390/polym11050903.Search in Google Scholar PubMed PubMed Central
Jolley, S.T., Williams, M.K., Gibson, T.L., and Caraccio, A.J. (2011). Developing flexible, high-performance polymers with self-healing capabilities NTRS - NASA technical reports server. In: 3rd international conference on self-healing materials. June 27–29. Bath, UK.Search in Google Scholar
Kessler, M.R. (2008). Delamination behavior of composites, 1st ed. Chapter-22 (section 22.3.2). U.K: Woodhead publishing limited.Search in Google Scholar
Lee, H.C. and Jiang, H.R. (2019). Laser-induced carbon nanotube microcapsules formation through depletion enhanced deposition. AIP Adv. 9: 095062, https://doi.org/10.1063/1.5120811.Search in Google Scholar
Mauldin, T.C. and Kessler, M.R. (2010). Self-healing polymers and composites. Int. Mater. Rev. 55: 317–346, https://doi.org/10.1021/ma902021v.Search in Google Scholar
Ma, Y., Zhang, Y., Liu, J., Sun, Y., Ge, Y., Yan, X., and Wu, J. (2020). Preparation and characterization of ethylenediamine-polyurea microcapsule epoxy self-healing coating. J. Mater. 13: 326, https://doi.org/10.3390/ma13020326.Search in Google Scholar PubMed PubMed Central
Mookhoek, S.D., Blaiszik, B.J., Fischer, H.R., Sottos, N.R., White, S.R., and Zwaaga, S.V. (2008). Peripherally decorated binary microcapsules containing two liquids. J. Mater. Chem. 18: 5390–5394, https://doi.org/10.1039/B810542A.Search in Google Scholar
Naveen, V., Raja, S., and Deshpande, A.P. (2020). Self-healing microcapsules encapsulated with carbon nanotubes for improved thermal and electrical properties. RSC Adv. 10: 33178–33188, https://doi.org/10.1039/D0RA06631A.Search in Google Scholar
Naveen, V., Raja, S., and Deshpande, A.P. (2019). A two-step approach for synthesis, characterization and analysis of dicyclopentadiene–urea formaldehyde–siloxane-based double-walled microcapsules used in self-healing composites. Int. J. Plast. Technol. 23: 157–169, https://doi.org/10.1007/s12588-019-09247-2.Search in Google Scholar
Raimondo, M. and Guadagno, L. (2013). Healing efficiency of epoxy-based materials for structural application. Polym. Compos. 34: 1525–1532, https://doi.org/10.1002/pc.22539.Search in Google Scholar
Sun, D., Li, B., Ye, F., Zhu, X., Lu, T., and Tian, Y. (2018). Fatigue behavior of microcapsule-induced self-healing asphalt concrete. J. Clean. Prod. 188: 466–476, https://doi.org/10.1016/j.jclepro.2018.03.281.Search in Google Scholar
Tzavidi, S., Zotiadis, C., Porfyris, A., Korres, D.M., and Vouyiouka, S. (2020). Epoxy loaded poly(urea-formaldehyde) microcapsules via in situ polymerization designated for self-healing coatings. J. Appl. Polym. Sci. 137: 49323, https://doi.org/10.1002/app.49323.Search in Google Scholar
Then, S., Neon, G.S., and Kasim, N.H.A. (2011). Optimization of microencapsulation process for self-healing polymeric. material. Sains Malays. 40: 795–802.Search in Google Scholar
Ullah, H., Khairun, A., Man, Z.B., and Ismail, M.B.C. (2016). Synthesis and characterization of urea-formaldehyde microcapsules containing functionalized polydimethylsiloxanes. Procedia Eng. 148: 168–175, https://doi.org/10.1016/j.proeng.2016.06.519.Search in Google Scholar
Vintila, I.S., Iovu, H., Alcea, A., Cucuruz, A., Mandoc, A.C., and Vasile, B.S. (2020). The synthetization and analysis of dicyclopentadiene and ethylidene-norbornene microcapsule systems. Polymers 12: 1052, https://doi.org/10.3390/polym12051052.Search in Google Scholar PubMed PubMed Central
Yuan, Y.C., Yin, T., Rong, M.Z., and Zhang, M.Q. (2008). Self-healing in polymers and polymer composites. Concepts, realization and outlook: a review. Express Polym. Lett. 2: 238–250, https://doi.org/10.3144/expresspolymlett.2008.29.Search in Google Scholar
Yin, D., Ma, Li., Geng, W., Zhang, B., and Zhang, Q. (2015). Microencapsulation of n-hexadecanol by in situ polymerization of melamine–formaldehyde resin in emulsion stabilized by styrene–maleic anhydride copolymer. Int. J. Energy Res. 39: 661, https://doi.org/10.1002/er.3276.Search in Google Scholar
Yang, H., Mo, Q., Li, W., and Gu, F. (2019). Preparation and properties of self-healing and self-lubricating epoxy coatings with polyurethane microcapsules containing bifunctional linseed oil. Polymers 11: 1578, https://doi.org/10.3390/polym11101578.Search in Google Scholar PubMed PubMed Central
Yakovlev, E.A., Yakovlev, N., Gorshkov, N.V., Yudintseva, T., Burmistrov, I., and Lyamina, G. (2018). Enhancement of mechanical and electrical properties of epoxy-based composites filled with intact or oxidized carbon nanotubes. Compos. Mech. Comput. Appl. An Int. J. 10: 241–251, https://doi.org/10.1615/CompMechComputApplIntJ.2018027488.Search in Google Scholar
Yu, C., Youn, J.R., and Song, Y.S. (2020). Tunable electrical resistivity of carbon nanotube filled phase change material via solid-solid phase transitions. Fibers Polym. 21: 24–32, https://doi.org/10.1007/s12221-020-9468-9.Search in Google Scholar
Zhang, C., Wang, H., and Zhoum, Q. (2018). Preparation and characterization of microcapsules based self-healing coatings containing epoxy ester as healing agent. Prog. Org. Coat. 125: 403–410, https://doi.org/10.1016/j.porgcoat.2018.09.028.Search in Google Scholar
Zhang, Y., Wang, Y., Li, Y., Huang, Z., Yaseen, A., and Tan, Y. (2021). Study on the thermal stability of urea-formaldehyde resin microcapsules with nanosilica incorporation by molecular dynamics simulation and experiments. Macromol. Theory Simul. 30: 5, https://doi.org/10.1002/mats.202100009.Search in Google Scholar
Zamal, H.H., Barba, D., Aissa, B., Haddad, E., and Rosei, F. (2020). Recovery of electro-mechanical properties inside self-healing composites through microencapsulation of carbon nanotubes. Sci. Rep. Nat. Res. 10: 2973, https://doi.org/10.1038/s41598-020-59725-6.Search in Google Scholar PubMed PubMed Central
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