EPOXY NANOCOMPOSITES WITH ULTRA-LOW MULTIWALLED CARBON NANOTUBE CONCENTRATIONS FOR UNDERWATER ACOUSTIC APPLICATIONS

摘要

Oxidized multiwall carbon nanotubes (o-MWCNTs) were covalently incorporated into DEGBA epoxies in order to improve the mechanical properties of acoustically transparent castable composites for underwater sonar applications. Formulations for acoustic transparency in water should have the product of the density and longitudinal wavespeed matching that of water. Typical epoxy composites that meet these acoustic criteria do not meet the mechanical strength requirements. In this work, acoustically transparent materials were formulated for sonar dome applications and MWCNTs were incorporated as reinforcement fillers. The longitudinal ultrasonic wave speed and dynamic mechanical properties of the nanocomposite samples were characterized and analyzed. No obvious effect was observed for the longitudinal ultrasonic wave speeds of the nanocomposites with MWCNTs incorporation. Significant increase in static strength and modulus were observed for those samples at ultra-low nanotube concentrations (～ 0.05wt%). Given good dispersion and interfacial bonding, MWCNT reinforcement not only improves the mechanical properties but also maintains the longitudinal acoustic wave speed of the composites, which is desirable for new acoustically transparent materials for underwater applications.