Effect of Amide Functionalization and Precuring on Tensile Properties of MWCNT/Epoxy Nanocomposites Hermawan Judawisastra,* Christian Harito, Akbar H. Dawam Abdullah Summary: The development of multi-walled carbon nanotube (MWCNT)-epoxy nanocomposites, for structural polymeric composites, has various problems that could decrease their mechanical properties above 2 wt% of MWCNT. One of the major problems is the interface bonding between MWCNT and epoxy. In this research, functionalization and precuring were carried out to strengthen the interface bonding. The effect of treatments on tensile properties of MWCNT-epoxy nanocomposites, with 1 wt% and 5 wt% MWCNT, were studied. MWCNT were prepared by purification process followed by acrylamide functionalization, later varied by the precuring treatment. MWCNT-epoxy nanocomposites, varied from 1 to 5 wt% MWCNT, were produced by solution casting method, continued with compression molding. Characterization of the functionalization was conducted by Fourier Transform Infrared Spectroscopy (FTIR). The tensile properties of nano- composites were determined by tensile test. Scanning Electron Microscope (SEM) was used to examine the interfacial strength of MWCNT in nanocomposites. The results showed that the tensile properties improved significantly on 5 wt % MWCNT nanocomposites as compared to the untreated nanocomposites. The combination of functionalization and precuring exhibited the most significant improvement in tensile properties. The modulus of elasticity increased 78 times higher than untreated nanocomposites, while the tensile strength was 10 times. The improvements on the tensile properties of nanocomposites were due to the enhancement of interface bonding strength by functionalization and precuring treatments. Keywords: amide functionalization; mechanical properties; MWCNT; nanocomposites; precuring; tensile properties Introduction Since the discovery of superior carbon nanotube (CNT) by Ijima, [1] the number of publications related to CNT has increased very rapidly. [2–4] CNT is known as the stiffest fiber, while also inherent tensile strength over 10 times higher than any industrial fibers. [1,2] CNT has become the strongest candidate to be used as reinforcement in polymer matrix composites. Between two common types of CNT, single-walled car- bon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT), MWCNT appears to be favored for application because the higher price of the bulk SWNT. [2] Theoretically, it is well known that the addition of MWCNT will significantly improve the mechanical properties of polymer matrix composites. [6] However, unlike other fiber-reinforced composites, previous work showed that the addition of 0,4 wt % untreated MWCNT could not increase the tensile strength of MWCNT/ epoxy nanocomposites. [7] Moreover, the modulus of elasticity of nanocomposites could even be decreased by the addition of 2 wt% untreated MWCNT within epoxy. [8] Material Science and Engineering Research Group, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132, Indonesia Fax: (þ62)-22-2508144; E-mail: hermawan.judawisastra@material.itb.ac.id Macromol. Symp. 2015, 353, 88–95 DOI: 10.1002/masy.201550311 88 | © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com