STUDIES ON MECHANICAL PROPERTIES OF CARBON NANOTUBES/HIGH-DENSITY POLYETHYLENE NANOCOMPOSITES BY SMALL PUNCH TECHNIQUE HARSH MEHTA * ,x , HMANTHA WANGSHUL y,{ and S. KANAGARAJ z Department of Mechanical Engineering Indian Institute of Technology Guwahati Guwahati-781039, India * harshmehta18@gmail.com y ruggt4u@gmail.com z kanagaraj@iitg.ernet.in Carbon nanotubes have been used as a reinforcing element to improve the properties of polymer matrix. An attempt has been made to investigate the mechanical behavior of carbon nanotubesÀhigh-density polyethylene (CNTÀHDPE) nanocomposites using a small punch technique. The designed punch assembly was fabricated and mounted on the Universal Testing Machine. The experimental setup was calibrated using aluminum and mild steel where the relative error was found to be within 7%. The mechanical properties of the nanocomposites, were studied by varying the weight fraction of CNT in HDPE. It was found that Young's modulus and ultimate strength of nanocomposites were increased by 37% and 36%, respectively for 1 wt% of CNTs in HDPE and they were found to increase linearly with an increase in CNT concentration. It is concluded that the small punch technique was successfully developed and tested to characterize the mechanical properties of HDPE and CNTÀHDPE nanocomposites. Keywords : Nanocomposites; high-density polyethylene (HDPE); carbon nanotubes (CNT); small punch technique. 1. Introduction Since early 90s, carbon nanotubes (CNTs) have become popular among researchers because of its remarkable properties. Researchers are trying to explore the possibilities of enhancing mechanical properties of polymers by making composites using CNT as a reinforcing material. Although several studies have been focused on producing nano- composites, many practical challenges concerning their fabrication still remain, compromising the full realization of their enormous potential. The extent of enhancement of properties depends on the uni- form dispersion of nanotubes in the polymer matrix. In this study, HDPE was chosen as a polymer due to its known excellent mechanical and chemical properties. Various approaches have been proposed to study the mechanical behavior of nanocomposites. How- ever, it is very di±cult to get standard test speci- mens from the operating conditions of the implants. In the past decade, small punch technique (SPT) has been successfully used to characterize the x Presently working at Aircraft R & D Centre, HAL, Bangalore. { Presently working at Godrej À Sara Lee Ltd, Mumbai. International Journal of Nanoscience Vol. 10, Nos. 1 & 2 (2011) 247À251 # . c World Scienti¯c Publishing Company DOI: 10.1142/S0219581X1100782X 247