(657e) Synthesis and Characterization of Novel Multi-Functional Multi-Layered Nanopapers

Integrated structures of nanoparticles like free standing nanopapers and films are attractive because they can translate the superior mechanical and physical properties of individual nanoparticles at the nanoscale to the macroscale. Bucky papers made primarily out of single walled carbon nanotubes (SWNTs) have been studied for their superior electrical, thermal and mechanical properties. However, Bucky papers and the current manufacturing methods are very expensive. This work reports a novel multi-functional multi-particle nanopaper technique. Carbon nanofibers (CNFs), carbon nanotubes, nanoclays and their combinations with different surface chemistries were integrated into multi-layer nanopapers using a vacuum-assisted spray system. A mild amine surface functionalization method was used to attach positive charge onto the nanoparticles, while a hard acid modification method was used to attach a negative charge. The electrostatic interactions between nanoparticles in the layer-by-layer process can substantially increase the strength and handling safety of the nanopapers, while the amine functionalization can enhance bonding between the nanopapers and the polymer matrix such as epoxy to make stronger composites. The nano/micro-structure of these papers was characterized using scanning electron microcopy (SEM) and charge properties were characterized using a zeta potentiometer. The mechanical and electrical properties of the nanopapers were tested using a Rheometrics Solids Analyzer and a Keithley conductivity instrument respectively and analyzed for structure/property relationships. The nanopapers were covered on top of a conventional glass fiber/epoxy composite in both pre-preg and resin transfer molding (RTM) processes. The properties of the molded composites with and without the nanopaper were tested. It is found that the presence of the nanopaper coating can greatly improve the surface hardness, wear and erosion resistance, and electric/thermal conductivities, important for many industrial applications.