Thermomechanical properties of imidazolium ionic liquid-modified mwcnt/carbon fiber/epoxy hybrid composite laminates

Hybrid composite laminates with nanofillers are high performance materials for thermal and structural applications. In this work, multiwall carbon nanotubes (MWCNT) were non-covalently modified by treating them with 1 wt% or 5 wt% of ionic liquid (IL), 1-butyl-3-methylimidazolium chloride. The treated MWCNT were dispersed in epoxy resin (weight content: 0.2-2 wt% or 1 to 3 wt%, respectively) and used to obtain hybrid composite laminates based on carbon fibers (CF) molded by hand layup and vacuum bagging techniques. The hybrid composite laminate containing 1 wt% of MWCNT modified with 1 wt% of IL showed the best mechanical and thermomechanical properties, including an increase of 210% and 151% in flexural strength and modulus, and an increase of 101%, 116% and 29.3% in storage modulus, loss modulus and damping, respectively. Scanning and transmission electron micrographs showed the enhanced MWCNT dispersion and network at low IL content, justifying its improved mechanical properties. The application of a low amount of IL dispersant was found a promising approach to prepare MWCNT/CF/epoxy composites with enhanced properties.