Document Type : Research Paper

Authors

1 Department of Mechanical and Aerospace Engineering, Shiraz university of Technology, Shiraz, Iran

2 Department of Material Science and Engineering, Faculty of Engineering, Shiraz University, Shiraz, Iran

Abstract

Vinyl ester resins are widely used in structural composites because of their excellent mechanical properties. One of the main goals of adding nanofillers to polymer matrix is to enhance the Young’s modulus and strength of the original base polymers. Due to the rigid structure of carbon nanotube as well as their aspect ratios, they can effectively increase the elastic modulus and stiffness of the polymer matrix. The main practical target of the present study is to obtain the best distribution of the multi-walled carbon nanotubes (MWCNTs) with carboxylic group in order to simultaneously improve the elastic modulus, tensile strength and toughness of the resulted nanocomposite. In this regard, nanocomposites with six different weight fractions (wt%) of MWCNTs are made and the specimens are subjected to the tensile test. The results exhibit that addition of MWCNTs with low concentration leads to improvement in the mechanical properties of the vinyl ester polymer such that the optimum mechanical properties are obtained with 0.25wt% of MWCNTs. In this case, the fracture toughness, tensile strength and Young’s modulus are respectively enhanced by amount of 52%, 23%, and 14%. In order to validate the experimental results and investigation the role of MWCNTs on tensile behavior of vinyl ester resin, the scanning electron microscope (SEM) is used and the most important failure mechanisms are discussed and studied in details. Also, the experimental results are compared with existing theoretical models and a new correction factor based on Hirsch’s theory and experimental results is introduced for future industrial applications.

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[1] Rodriguez, F. Cohen, C. Ober, C.K. and Archer, L., “Principles of Polymer Systems” CRC Press, 2014.
[2] Jowdar, E. Beheshty, M.H. and Atai, M., “Nano Clay Effect on Morphology, Mechanical Properties and Water Absorption of Vinyl ester-based Nanocomposites” Science and Technology, Vol. 24, No. 2, pp. 83-92, 2011.
[3] Rousseaux, D.D. Sclavons, M. Godard, P. and Marchand-Brynaert, J., “Carboxylate Clays: a Model Study for Polypropylene/clay Nanocomposites” Polymer Degradation and Stability, Vol. 95, No. 7, pp. 1194-1204, 2010.
[4] Saito, R. Dresselhaus, G. and Dresselhaus, M.S., “Physical Properties of Carbon Nanotubes” London: Imperial college press. Vol. 35, 1998.
[5]  Stan, A. Dinca, I. Ban, C. Ilina, S. Donescu, D. Paven, H. Dumitrache, L. Gavrila, L. and Voicu, I., “Epoxy-layered Silicate and Epoxy MWCNTs Nanocomposites” In Applied Mechanics and Materials, Vol. 146, pp. 160-169, 2012.
[6] Gao, X.L. and Li, K., “A Shear-lag Model for Carbon Nanotube-reinforced Polymer Composites” International Journal of Solids and Structures, Vol. 42, No. 5, pp. 1649-1667, 2005.
[7]  Shokrieh, M.M. and Zeinedini, A., “Analytical Prediction of Mode       I strain Energy Release Rate at Crack Growth Initiation of Polymeric Nanocomposites” Journal of Science and Technology of Composites, Vol. 3, No. 1, pp. 1-10, 2016. (in Persian )
[8] De Villoria, R.G. and Miravete. “A. Mechanical Model to Evaluate the Effect of the Dispersion in Nanocomposites” Acta Materialia, Vol. 55, No. 9, pp. 3025-3031, 2007.
[9] Brown, G. M., and Ellyin, F., “Assessing the Predictive Capability of Two‐phase Models for the Mechanical Behavior of Alumina/Epoxy Nanocomposites” Journal of applied polymer science, Vol. 98, No. 2, pp. 869-879, 2005.
[10] Zare, Y. and Garmabi, H., “Analysis of Tensile Modulus of PP/Nanoclay/CaCO3 Ternary Nanocomposite Using Composite Theories” Journal of Applied Polymer Science, Vol. 123, No.4, pp. 2309-2319, 2012.
[11] Shokrieh, M.M., Saeedi, A. and Chitsazzadeh, M., “Mechanical Properties of Multi-Walled Carbon Nanotube/Polyester Nanocomposites” Journal of Nanostructure in Chemistry, Vol. 3, No. 1 pp. 1-5, 2013.
[12] Vahedi, F., Shahverdi, H.R., Shokrieh, M.M. and Esmkhani, M., “Effects of Carbon Nanotube Content on the Mechanical and Electrical Properties of Epoxy-Based Composites” New Carbon Materials, Vol. 29, No. 6, pp. 419-425, 2014.
[13] Esmaili, P., Azdast, T., Doniavi, A., Hasanzadeh, R., Mamghani, S. and lee, R., “Experimental Investigation of Mechanical Properties of Injected Polymeric Nanocomposites Containing Multi-walled Carbon Nanotubes According to Design of Experiments” Journal of Science and Technology of Composites, Vol. 2, No. 3, pp. 1-10, 2015. (in Persian )
[14] Chirita, G., Dima, D., Andrei, G. and Birsan, I.G., “Mechanical Characterization of Graphite and Graphene/Vinyl-Ester Nanocomposite Using Three Point Bending Test” Matrix, Vol. 11, pp. 21-25, 2016.
[15] Alhuthali, A.M. and Low, I.M., “Characterization of Mechanical and Fracture Behaviour in Nano-Silicon Carbide-Reinforced Vinyl-ester Nanocomposites” Polymer-Plastics Technology and Engineering, Vol. 52, No. 9, pp. 921-930, 2013.
[16] Thostenson, E.T. Ziaee, S. and Chou, T.W., “Processing and Electrical Properties of Carbon Nanotube/vinyl Ester Nanocomposites” Composites Science and Technology, Vol. 69, No. 6, pp. 801-804, 2009.
[17] Sabet, S.M., Mahfuz, H., Hashemi, J., Nezakat, M. and Szpunar, J.A., “Effects of Sonication Energy on the Dispersion of Carbon Nanotubes in a Vinyl ester Matrix and Associated Thermo-mechanical Properties” Journal of Materials Science, Vol. 50, No. 13, pp. 729-4740, 2015.
[18] Seyhan, A.T., Tanoğlu, M. and Schulte, K., “Tensile Mechanical Behavior and Fracture Toughness of MWCNT and DWCNT Modified Vinyl-ester/polyester Hybrid Nanocomposites Produced by 3-roll Milling” Materials Science and Engineering: A, Vol. 523, No.1, pp. 85-92, 2009.
[19] Almajid, A., Sorochynska, L., Friedrich, K. and Wetzel, B., “Effects of Graphene and CNT on Mechanical, Thermal, Electrical and Corrosion Properties of Vinylester Based Nanocomposites” Plastics, Rubber and Composites, Vol. 44, No. 2, pp. 50-62, 2015.
[20] Standard Test Method for Tensile Properties of Plastics, Annual Book of ASTM Standard, 06.04, D 638-02a, 46-58, 2002.
[21] Capela, C. Ferreira, J. M. Costa, J. M. and Mendes, N., “Mechanical Properties of Injection-Molded Glass Microsphere-Reinforced Polyamide” Journal of Materials Engineering and Performance, Vol. 25 No. 10, pp. 4256-4265, 2016.
[22] Kravchenko, O.G. Misiego, R. Kravchenko, S.G. Pipes, R.B. and Manas‐Zloczower, I., “Modeling of Hierarchical Morphology of Carbon Nanotube Bundles in Polymer Composites” Macromolecular Theory and Simulations, Vol. 25, No. 6, pp. 524-532, 2016.
 [23] Frankel, N.A. and Acrivos, A., “On the Viscosity of a Concentrated Suspension of Solid Spheres” Chemical Engineering Science, Vol. 22, No. 6, pp. 847-853, 1967.
[24] Gupta, A.K. and Harsha, S.P., “Analysis of Mechanical Properties of Carbon Nanotube Reinforced Polymer Composites Using Multi-scale Finite Element Modeling Approach” Composites Part B: Engineering, Vol. 95, pp. 172-178, 2016.
[25] Espinach, F.X. Julian, F. Verdaguer, N. Torres, L. Pelach, M.A. Vilaseca, F. and Mutje, P., “Analysis of Tensile and Flexural Modulus in Hemp Strands/polypropylene Composites” Composites Part B: Engineering, Vol. 47, pp. 339-343. 2013.
[26] Poveda, R., Gupta, N. and Porfiri, M., “Poisson's Ratio of Hollow Particle Filled Composites” Materials Letters, Vol. 64, No. 21, pp. 2360-2362, 2010.
[27] Zhou, H.W., Mishnaevsky, L., Yi, H.Y., Liu, Y.Q., Hu, X., Warrier, A. and Dai, G.M., “Carbon Fiber/Carbon Nanotube Reinforced Hierarchical Composites: Effect of CNT Distribution on Shearing Strength” Composites Part B: Engineering, Vol. 88, pp. 201-211, 2016.
[28]  Gao, G., Cagin, T. and Goddard III, W.A., “Energetics, Structure, Mechanical and Vibrational Properties of Single-Walled Carbon Nanotubes” Nanotechnology, Vol. 9, No. 3, pp. 184, 1998.