Issue 50

G.V. Seretis et alii, Frattura ed Integrità Strutturale, 50 (2019) 517-525; DOI: 10.3221/IGF-ESIS.50.43 524 (a) The most significant parameter for tensile strength is the time and for flexural strength is the temperature. Therefore, for slow temperature increase values, i.e. 1-5 °C/min, the effect of the heating rate on both the tensile and the flexural performance of the cured laminated nanocomposites is not considerable. (b) The optimum performance was obtained for temperature values greater than the glass transition temperature T g . It is known that when T cure ˃ T g , the reaction proceeds rapidly at a rate driven by chemical kinetics. Therefore, it is obvious that both tensile and flexural performance of the epoxy matrix laminated nanocomposites is mainly controlled by the chemical kinetics. (c) The Full Quadratic regression model was used to predict the tensile response of the nanocomposites, since the respect- ive main effects plots were more linear or shown clear trends. On the other hand, for the flexural performance, where the respective main effects plots neither were linear nor shown clear trends, the Poisson regression model was used to achieve high accuracy in prediction. R EFERENCES [1] Gao, L., Zhang, Q., Guo, J., Li, H., Wu, J., Yang, X., Sui, G. (2016). Effects of the amine/epoxy stoichiometry on the curing behavior and glass transition temperature of MWCNTs-NH2/epoxy nanocomposites, Thermochim Acta, 639, pp. 98-107. [2] Fu, Y., Zhong, W.H. (2011). Cure kinetics behavior of a functionalized graphitic nanofiber modified epoxy resin, Thermochim Acta, 516, pp. 58–63. [3] Ellis, B. (1993). Chemistry and Technology of Epoxy Resins, London, New York: Blackie Academic & Professional, An imprint of Chapman & Hall. [4] Wisanrakkit, G., Gillham, J.K. (1990). Glass transition temperature (Tg) as an index of chemical conversion for high- Tg amine/epoxy system: chemical and diffusion controlled reaction kinetics, J. Appl. Polymer Sci., 41(11-12), pp. 2885–2929. [5] Moussa, O., Vassilopoulos, A.P., Castro, J., Keller, T. (2012). Time temperature dependence of thermomechanical recovery of cold-curing structural adhesives, Int. J. Adhes. Adhes.,35, pp. 94–101. [6] Maljaee, H., Ghiassi, B., Lourenço, P.B. (2017). Effect of synergistic environmental conditions on thermal properties of a cold curing epoxy resin, Compos. Part B-Eng., 113, pp. 152-163. [7] Chang, C.Y., Houang, L.W., Chou, T.Y. (2006). Effect of process variables on the quality of compression resin transfer molding, J. Reinf. Plast. and Comp., 25, pp. 1027-1037. [8] Oh, J.H., Lee, D.G. (2002). Cure cycle for thick glass/epoxy composite laminates, J. Comp. Mat., 36, pp. 19-44. [9] Rai, N., Pitchumani, R. (1997). Optimal cure cycles for the fabrication of thermosetting matrix composites, Polym. Compos. 18(4), pp. 566–81. [10] Li, M., Zhu, Q., Geubelle, P.H., Tucker III, C.L. (2001). Optimal curing for thermoset matrix composites: thermo- chemical considerations, Polym. Compos., 22(1), pp. 118–31. [11] Moussa, O., Vassilopoulos, A.P., Keller, T. (2012). Effects of low-temperature curing on physical behavior of cold- curing epoxy adhesives in bridge construction, Int. J, Adhes. Adhes. 32, pp. 15–22. [12] Mijovic, J., Fishbain, A., Wijaya, J. (1992). Mechanistic modeling of epoxy amine kinetics. 2. Comparison of kinetics in thermal and microwave fields, Macromolecules, 25, pp. 986–989. [13] Kwak, M., Robinson, P., Bismarck, A., Wise, R. (2015). Microwave curing of carbon–epoxy composites: Penetration depth and material characterization, Compos. Part A-Appl. S., 75, pp. 18–27. [14] Johnston, K., Pavuluri, S.K., Leonard, M.T., Desmulliez, M.P.Y., Arrighi, V. (2015). Microwave and thermal curing of an epoxy resin for microelectronic applications, Thermochim Acta, 616, pp. 100–109. [15] Barbosa, A.Q., da Silva, L.F.M., Abenojar, J., Figueiredo, M., Ochsner, A. (2017). Toughness of a brittle epoxy resin reinforced with micro cork particles: Effect of size, amount and surface treatment, Compos. Part B-Eng., 114, pp. 299-310. [16] Thipprakmas, S. (2010). Application of Taguchi technique to investigation of geometry and position of V-ring indenter in fine-blanking process, Mater. Des., 31, pp. 2496-2500. [17] Parida, A.K., Routara, B.C., Bhuyan, R.K. (2015). Surface roughness model and parametric optimization in machining of GFRP composite: Taguchi and Response surface methodology approach, Materials Today: Proceedings, 2, pp. 3065- 3074. [18] Rout, A.K., Satapathy, A. (2012). Study on mechanical and tribo-performance of rice-husk filled glass–epoxy hybrid composites, Mater. Des. 41, pp. 131-141.