Sound Velocities in Graphene-Based Epoxy Nanocomposites

Elastic properties of epoxy-based nanocomposites (ENCs) filled with bare and TiO2-deposied multi-layered graphene nanoplatelets (MLG) have been tested by using a phase-frequency continuous-wave ultrasound probing (USP). The dian epoxy CHS-EPOXY 520 curried with diethylenetriamine (DETA) was the polymer matrix for the nanocomposites. The nanoplatelets of the specific surface area Sf ~ 790 m2/g consist of several dozen loosely bound monoatomic graphene layers with an area of about least 5×5 μm2. MLG-mass-loading (φf,m) of the nanocomposites varied from 0.1 % to 5.0 % by weight. Anatase- TiO2 particles, being of about 50 nm in diameter and of Sf ~ 1500 m2/g, have been deposited on MLG in mass concentration of about 1 %. Elastic moduli of the ENCs (namely, the Lame’s constants, the Young’s module, the compression module, and the Poisson’s ratio) have demonstrated negligible variation with φf,m varying regardless the type of filling particles. However, MLG:TiO2-hybrid nanoparticles have proven to impact stronger on the moduli as compared to bare MLG. This result shows a capability to modify molecular structure of epoxy resins by controlling surface reactivity of MLG embedded in the resin.