Ionic Liquid Functionalized Silica Aerogels as Reinforcing Agents for Epoxy Nanocomposites

In this study, the effect of ionic liquid embedded silica aerogels on the mechanical properties of epoxy composites was investigated. The study consisted of two parts. In the first part, silica aerogels were synthesized by one-step sol–gel method and dried by supercritical drying. Two different silica aerogel powders with/without ionic liquid were prepared to investigate the effect of ionic liquid both on the physicochemical characteristics and the dispersion behavior of the silica aerogel. Various analyses such as FTIR, SEM/EDX, TGA, PSD and Zeta Potential analysis were conducted in order to investigate the effect of the contribution of ionic liquid on the physicochemical and textural structures of these powders and to identify the surface charge characteristics of the aerogels. According to characterization results, silica aerogels prepared by including ionic liquid, resulted in superior characteristics with lower density (0.16 g/cm 3 ), higher porosity (93%), higher thermal stability (up to 400 °C), higher zeta potential value (28 mV) and smaller average particle diameter (40 nm). In the second part, silica aerogel-epoxy nanocomposites were produced by changing silica aerogel content and mechanical analyses of the composites were conducted. To examine the mechanical properties of nanocomposites, tensile and three-point bending tests were performed. The results have shown that the composites containing 1 wt% ionic liquid in silica aerogel had superior modulus of elasticity (4156.27 MPa) and tensile strength (51.96 MPa) compared to that of neat epoxy which had the elasticity modulus of 3538.08 MPa and tensile strength of 47.98 MPa.