Sandwich composites are increasingly used in high-performance application due to their high specific stiffness, strength and thermal insulation. The sandwich composites were developed using honeycomb and carbon fibre reinforced composite face sheet in this study. Expandable graphite (EG) weighting 5 wt% and 10 wt% were filled in honeycomb or coated on face sheet to improve the fireproof performance. The vertical burning test, cone calorimetry test, thermal insulation analysis, scanning electron microscopy and mechanical test were taken into account.With the increase of EG in the sandwich composites, a significant improvement on flame retardancy with better thermal insulation, lower values of peak heat release rate and MAHRE were confirmed for sandwich composite with EG both coated and filled. In addition, the sandwich with EG coated on face sheet presented better fire resistivity and thermal insulation properties when compared to that with EG filled in honeycomb. However, more total smoke release was also observed for EG coated composites due to partial combustion of resin withinsufficient heat and oxygen. Furthermore, no significant effect on the mechanical properties of composites was confirmed from both fireproof approaches.
References
[1]
Gibson, R.F. (2011) Principles of Composite Material Mechanics. 3rd Edition, Taylor & Francis, Abingdon.
[2]
Wakeman, M.D., Cain, T.A., Rudd, C.D., Brooks, R. and Long, A.C. (1999) Compression Moulding of Glass and Polypropylene Composites for Optimised Macro- and Micro- Mechanical Properties 3. Sandwich Structures of GMTS and Commingled Fabrics. Composites Science and Technology, 59, 1153-1167.
https://doi.org/10.1016/S0266-3538(98)00155-9
[3]
Constantin, N., Sandu, M., Sandu, A. and Gavan, M. (2017) Damage Identification and Mechanical Assessment of Impacted Sandwich Composites. Procedia Engineering, 188, 178-185. https://doi.org/10.1016/j.proeng.2017.04.472
[4]
Horold, A., Schartel, B., Trappe, V., Korzen, M. and Bünker, J. (2017) Fire Stability of Glass-Fibre Sandwich Panels: The Influence of Core Materials and Flame Retardants. Composite Structures, 160, 1310-1318.
https://doi.org/10.1016/j.compstruct.2016.11.027
[5]
Vitale, J.P., Francucci, G. and Stocchi, A. (2017) Thermal Conductivity of Sandwich Panels Made with Synthetic and Vegetable Fiber Vacuum-Infused Honeycomb Cores. Journal of Sandwich Structures & Materials, 19, 66-82.
https://doi.org/10.1177/1099636216635630
[6]
Kim, M. and Choe, J. (2016) Development of the Fire-Retardant Sandwich Structure Using an Aramid/Glass Hybrid Composite and a Phenolic Foam-Filled Honeycomb. Composite Structures, 158, 227-234.
https://doi.org/10.1016/j.compstruct.2016.09.029
[7]
Anjang, A., Chevali, V., Lattimer, B., Case, S., Feih, S. and Mouritz, A. (2015) Post-Fire Mechanical Properties of Sandwich Composite Structures. Composite Structures, 132, 1019-1028. https://doi.org/10.1016/j.compstruct.2015.07.009
[8]
Laoutid, F., Bonnaud, L., Alexandre, M., Lopez-Cuesta, J.-M. and Dubois, P. (2009) New Prospects in Flame Retardant Polymer Materials: from Fundamentals to Nanocomposites. Materials Science and Engineering: R: Reports, 63, 100-125.
https://doi.org/10.1016/j.mser.2008.09.002
[9]
Rakotomalala, M., Wagner, S. and Doring, M. (2010) Recent Developments in Halogen Free Flame Retardants for Epoxy Resins for Electrical and Electronic Applications. Materials, 3, 4300-4327. https://doi.org/10.3390/ma3084300
[10]
Weil, E.D. (2011) Fire-Protective and Flame-Retardant Coatings—A State-of-the- Art Review. Journal of Fire Sciences, 29, 259-296.
https://doi.org/10.1177/0734904110395469
[11]
Bar, M., Alagirusamy, R. and Das, A. (2015) Flame Retardant Polymer Composites. Fibers and Polymers, 16, 705-717. https://doi.org/10.1007/s12221-015-0705-6
[12]
Kandare, E., Kandola, B.K., McCarthy, E.D., Myler, P., Edwards, G., Jifeng, Y. and Wang, Y.C. (2011) Fiber-Reinforced Epoxy Composites Exposed to High Temperature Environments. Part II: Modeling Mechanical Property Degradation. Journal of Composite Materials, 45, 1511-1521. https://doi.org/10.1177/0021998310385024
[13]
Kandare, E., Kandola, B.K., Myler, P. and Edwards, G. (2010) Thermo-Mechanical Responses of Fiber-Reinforced Epoxy Composites Exposed to High Temperature Environments. Part I: Experimental Data Acquisition. Journal of Composite Materials, 44, 3093-3114. https://doi.org/10.1177/0021998310373511
[14]
Wu, T.-C., Tsai, K.-C., Lu, M.-C., Kuan, H.-C., Chen, C.-H., Kuan, C.-F., Chiu, S.-L., Hsu, S.-W. and Chiang, C.-L. (2012) Synthesis, Characterization, and Properties of Silane-Functionalized Expandable Graphite Composites. Journal of Composite Materials, 46, 1483-1496. https://doi.org/10.1177/0021998310373511
[15]
Focke, W.W., Badenhorst, H., Mhike, W., Kruger, H.J. and Lombaard, D. (2014) Characterization of Commercial Expandable Graphite Fire Retardants. Thermochimica Acta, 584, 8-16. https://doi.org/10.1016/j.tca.2014.03.021
[16]
Focke, W.W., Muiambo, H., Mhike, W., Kruger, H.J. and Ofosu, O. (2014) Flexible PVC Flame Retarded with Expandable Graphite. Polymer Degradation and Stability, 100, 63-69. https://doi.org/10.1016/j.polymdegradstab.2013.12.024
[17]
Camino, G., Duquesne, S., Delobel, R., Eling, B., Lindsay, C. and Roels, T. (1974) Polyurethanes-8 Mechanism of Expandable Graphite Fire Retardant Action in Polyurethanes. ACS Symposium Series, American Chemical Society, Washington DC.
[18]
Chung, D. (2016) A Review of Exfoliated Graphite. Journal of Materials Science, 51, 554-568. https://doi.org/10.1007/s10853-015-9284-6
[19]
Khalili, P., Tshai, K. and Kong, I. (2017) Natural Fiber Reinforced Expandable Graphite Filled Composites: Evaluation of the Flame Retardancy, Thermal and Mechanical Performances. Composites Part A: Applied Science and Manufacturing, 100, 194-205. https://doi.org/10.1016/j.compositesa.2017.05.015
[20]
Mngomezulu, M.E., Luyt, A.S., Chapple, S.A. and John, M.J. (2018) Effect of Expandable Graphite on Thermal and Flammability Properties of Poly(Lactic Acid)-Starch/Poly(?-Caprolactone) Blend Systems. Polymer Engineering & Science, 58, 1619-1629. https://doi.org/10.1002/pen.24751
[21]
Cheng, J.-J. and Zhou, F.-B. (2016) Influence of Expandable Graphite on Flame Retardancy and Mechanical Properties of Organic-Inorganic Hybrid Material Based on Sodium Silicate and Polyisocyanate. Journal of Thermal Analysis and Calorimetry, 126, 1417-1426. https://doi.org/10.1007/s10973-016-5621-5
[22]
Wang, N., Xu, G., Wu, Y., Zhang, J., Hu, L., Luan, H. and Fang, Q. (2016) The Influence of Expandable Graphite on Double-Layered Microcapsules in Intumescent Flame-Retardant Natural Rubber Composites. Journal of Thermal Analysis and Calorimetry, 123, 1239-1251. https://doi.org/10.1007/s10973-015-5011-4
[23]
Yang, S., Wang, J., Huo, S., Wang, M., Wang, J. and Zhang, B. (2016) Synergistic Flame-Retardant Effect of Expandable Graphite and Phosphorus-Containing Compounds for Epoxy Resin: Strong Bonding of Different Carbon Residues. Polymer Degradation and Stability, 128, 89-98.
https://doi.org/10.1016/j.polymdegradstab.2016.03.017
