215 DETERMINING THE TENSILE PROPERTIES AND DISPERSION CHARACTERIZATION OF CNTS IN EPOXY USING TEM AND RAMAN SPECTROSCOPY M. Bourchak, 1* K. A. Juhany, 1 N. Salah, 2 R. Ajaj, 3 A. Algarni, 1 and F. Scarpa 4 Keywords: carbon nanotubes, dispersion, tensile properties, sonication, transmission electron microscopy In this work, transmission electron microscopy (TEM) and Raman spectroscopy were used to assess the dispersion quality of carbon nanotubes (CNTs) in an epoxy matrix. Its ultimate tensile strength (UTS), engineering strain, local strain, and the elastic tensile modulus were determined experimentally. The effect of CNT sonication time in an ethanol medium was also evaluated. A statistical analysis using the t-test approach was employed to clarify how the use of CNTs affects the mechanical properties of the matrix. An increase in the UTS by 10 and 7% was observed in the cases of 0.1 wt.% single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs), respectively, but the elastic modulus increased signifcantly when using MWCNTs. A TEM analysis indicated that the dispersion quality was proportional to the content of CNTs. It is concluded that a CNT-reinforced epoxy matrix is highly sensitive to the amount of CNTs, which can explain the conficting properties reported for such matrices in the literature. 1. Introduction CNTs are some of the most widely investigated types of nanomaterials used to improve the mechanical properties of epoxy-based matrix systems [1]. The potential of improvement of their mechanical makes these nanocomposites ideal materials for a wide range of applications (aerospace, automotive, biomedical, etc.) [2, 3]. A large amount of research work has been performed to study the effect of adding CNTs to an epoxy matrix on its mechanical properties. The main factor Mechanics of Composite Materials, Vol. 56, No. 2, May, 2020 (Russian Original Vol. 56, No. 2, March-April, 2020) 1 Aerospace Engineering Department, King Abdulaziz University, Jeddah 21589, KSA 2 Center of Nanotechnology, King Abdulaziz University, Jeddah 21589, KSA 3 Department of Aerospace Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE 4 Bristol Composites Institute (ACCIS), University of Bristol, BS8 1TR Bristol, UK *Corresponding author; tel.: +966 12 6400000 Ext. 72345; e-mail: mbourchak@kau.edu.sa 0191-5665/20/5602-0215 © 2020 Springer Science+Business Media, LLC Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 56, No. 2, pp. 321-336, March-April, 2020. Original article submitted March 26, 2019. DOI 10.1007/s11029-020-09874-6