Optimization Of Process Parameters For Electrophoretic Deposition In Carbon Nanotubes/carbon Fiber Hybrid Composites

Carbon nanotubes (CNTs) have attracted a great deal of interest in the development of high-performance engineering composites, due to their exceptional physical, mechanical, electronic and thermal properties. Incorporation of CNTs into polymer has resulted in great improvements in functional properties; however, the enhancement of mechanical properties was insignificant compared with that in micro-sized fiber reinforced polymers. In order to realize the application of composites for structural and multifunctional parts, it is necessary to develop hybrid composites with microand nano-sized reinforcements. CNT reinforced hybrid composites have been studied in several ways: the addition of CNTs to a matrix with various dispersion methods, the growth of CNTs on substrate reinforcements, CNT sprays, etc. In this study, the electrophoresis deposition (EPD) method has been applied to deposit CNTs on a carbon fabric. By applying an electric field between a copper plate and a substrate, the negatively charged CNTs in a suspension move toward a carbon fabric. The controllable parameters in the EPD process are identified as the deposition time, the voltage, the contents of the CNTs, and the distance between the copper plate and the carbon fabric. In order to determine the optimal process conditions, the Taguchi method for the statistical design of experiment (DOE) has been utilized. Since the interlaminar shear strength (ILSS) of the hybrid composites is associated with the amount and the degree of distribution of the CNTs, it was selected as the response for the analysis of means and signal-tonoise ratio. The ILSS was measured by short-beam test according to ASTM 2344. The composite sample was fabricated by the vacuum-assisted resin transfer molding process. In addition, the distribution of CNTs was examined by Composites: Advances in Manufacture and Characterisation 53 www.witpress.com, ISSN 1755-8336 (on-line) WIT Transactions on State of the Art in Science and Engineering, Vol 88, © 2015 WIT Press doi:10.2495/978-1-78466-167-0/006 scanning electron microscopy. By utilizing the statistical software MINITAB 14 for DOE, the optimal deposition conditions have been determined.