Study On Structure And Properties Of Epoxy/Carbon Nanotube Hybrid Multi-Scale Composites Manufactured Via Resin Transfer Molding Process

In this paper, Carbon nanotubes (CNTs)/epoxy multi-scale composites were fabricatedvia resin transfer molding (RTM) technique to explore their electrical performance,mechanical properties and deformation behavior. CNTs were dispersed in epoxy by applyingthe dispersing effect of surfactant, Triton X-100, and the cavitation effect of ultrasound, theresulting nanocomposite matrix was used to infiltrate the reinforcing fabric during RTMprocess to fabricate multi-scale composites. The dispersion of CNTs in epoxy and theinfiltration of fibrous reinformcement with CNTs/epoxy suspension were characterized byusing optical microscope and capillary experiment. It was shown that Triton X-100couldimprove the dispersion of CNTs in epoxy to form a percolation network. Triton X-100decreases the percolation thresholds to0.1wt%and0.0075%in glass fiber reinforcedcomposites and carbon/glass hybrid fiber reinforced ones, respectively. High powerultrasound can improve the dispersion of CNTs in epoxy and conductive performance ofcomposites.With the increase in ultrasonic time, the resistivity of composite material decreaseat first and then increase. Transmission electron microscopy (TEM) investigations indicatedthat the evolution in the network structure of the CNTs during mold filling process wasresponsible for the gradient in resistivity of the RTMed laminates. The mechanical properties,such as interlaminar shear strength (ILSS) and flexural properties, of composites fabricated byRTM process decrease due to introducing Triton X-100, as evidenced by fracture surfaceobservation and dynamic mechanical analysis. A L-shaped multi-scale composites was used to,both theoretically and experimentally, examine the effect of CNTs on the shape accuracy. It isfound from the analytical model that CNTs could decrease the deformation angle from1.12oto0.08o. The measured deformation angle of composite material changes from3.01oto0.63oas a result of the incorporation of0.1wt%CNTs, CNTs could reduce crosslinking shrinkage ofepoxy during curing stage to improve the shape accuracy of the resulting composites.