Evaluation of DOPO and Nano-Silica Modified Epoxy Resin Systems as Low Viscous, Flame Retardant Additives for Infusion and Injection Processing of Carbon Fiber Reinforced Plastics

Abstract:

In the present study, a low viscous (complex viscosity between 200 to 500 mPas at 60 °C), flame retardant epoxy resin formulation is prepared and transferred to the carbon fiber reinforced plastic (CFRP) laminate using resin transfer molding (RTM) method. For the laminate production, a 12k carbon fiber fabric with an areal weight of 400 g/m2 is used to achieve a fiber volume content of approximately 60 vol % carbon fibers. Subsequently the unmodified laminate is produced, varying carbon fiber volume content to study its effect on flame retardant properties. As additives, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) modified epoxy resin and nanosilica particles delivered in an epoxy novolac masterbatch are added to the neat novolac resin system. The mixture is cured with isophorone diamine (IPDA) and polyetheramine hardener blend, resulting in a glass transition temperature of 104 °C for the unmodified laminate. Flame retardant properties of the materials are tested using cone calorimeter and thermal gravimetrical analysis. In addition, the mechanical behavior of the systems is evaluated via three-point bending method in static and dynamical loadings. In order to get deeper information on the resulting flame retardant mechanisms of the additives, the residual cone calorimeter char is analyzed with scanning electron microscopy, indicating the different flame retardant mechanisms of phosphorous and silica as well as the combination of both additives.

• Periodical: Key Engineering Materials (Volume 809)
• Pages: 3-8
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.809.3
• Online since: June 2019
• Authors: Markus Häublein*, Karin Peter, Alexander Brückner, Volker Altstädt
• Keywords: Carbon Fiber Reinforced Plastic, DOPO, Epoxy Resin, Flame Retardant, nan-SiO₂

References

[1] D. Ratna, Handbook of thermoset resins, iSmithers, (2009).

[2] C. Wang, J. R. Berman, L. L. Walker and A. Mendoza, Meta-Bromobiphenol Epoxy Resins: Applications in Electronic Packaging and Printed Circuit Board, J. Appl. Poly. Sci. 34 (1991) 1315-1321.

DOI: 10.1002/app.1991.070430713

[3] P. Wang, F. Yang, L. Li, Z. Cai, Flame-retardant properties and mechanisms of epoxy thermosets modified with two phosphorus-containing phenolic amines, J. Appl. Polym. Sci. 133 (2016).

DOI: 10.1002/app.43953

[4] S. M. Unlua, S. D. Doganb and M. Doganc, Comparative study of boron compounds and aluminum trihydroxide as flame retardant additives in epoxy resin, Polym. Adv. Technol. 25 (2014), 769-776.

DOI: 10.1002/pat.3274

[5] S. V. Levchik and E. D Weil, Review: Thermal decomposition, combustion and flame-retardancy of epoxy resins-a review of the recent literature, Polym. Int. 53 (2004), 1908-1929.

DOI: 10.1002/pi.1473

[6] S. H. Yum, J. U. Roh, J. M. Park, J. K. Park, S. M. Kim, W. I. Lee, Assessment of particle distribution in particle-containing composite materials using an electron probe microanalyzer, Composites Science and Technology 82 (2013), 38-46.

DOI: 10.1016/j.compscitech.2013.04.008

[7] R. M. Perez, J. K. W. Sandler, V. Altstädt, T. Hoffmann, D. Pospiech, M. Ciesielski, M. Döring, U. Braun, U. Knoll, B. Schartel, Effective halogen-free flame retardants for carbon fibre-reinforced epoxy composites, Journal of Materials Science 41 (2006), 4981-4984.

DOI: 10.1007/s10853-006-0134-4

[8] W. Zhang, X. Li, L. Li, R. Yang, Study of the synergistic effect of silicon and phosphorus on the blowing-out effect of epoxy resin composites, Polymer Degradation and Stability 97 (2012), 1041-1048.

DOI: 10.1016/j.polymdegradstab.2012.03.008