OICC Press Journal of Nanostructure in Chemistry 2193-8865 3 1 (December 2013) 2013 04 25 Mechanical properties of multi-walled carbon nanotube/polyester nanocomposites 10.1186/2193-8865-3-20 EN Mahmoud M Shokrieh Composites Research Laboratory, Center of Excellence in Experimental Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846-13114, IR Ali Saeedi Composites Research Laboratory, Center of Excellence in Experimental Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846-13114, IR Majid Chitsazzadeh Nanocomposites Research Laboratory, Iran University of Science and Technology, Narmak, Tehran, 16846-13114, IR Journal Article 2013 04 25 Abstract Carbon nanotubes (CNTs), due to their superlative mechanical and physical properties, have shown a high potential to improve properties of polymeric composites. Adding CNTs into polymers at very low weight fractions can improve mechanical properties of the resulting nanocomposites. In the present paper, multi-walled carbon nanotubes (MWCNTs) at different weight ratios (0.05, 0.1, and 0.5 wt.%) were added to polyester. Mechanical stirring and sonication technique were used to achieve good dispersion state of MWCNTs in the polymeric matrix. The results of mechanical tests (tensile and flexural) exhibit improvements of tensile and flexural strengths by 6% and 20%, respectively, at only 0.05 wt.% MWCNT. Improvements in Young's modulus and flexural modulus were also observed. Scanning electron microscopy was employed to determine the dispersion state of nanotubes in the matrix as well as the fracture surface properties.