Chemical and Mechanical Characterization of Unprecedented Transparent Epoxy–Nanomica Composites—New Model Insights for Mechanical Properties

Abstract

Two nanomicas of similar composition, containing muscovite and quartz, but with different particle size distributions, have been used to prepare transparent epoxy nanocomposites. Their homogeneous dispersion, due to the nano-size, was achieved even without being organically modified, and no aggregation of the nanoparticles was observed, thus maximizing the specific interface between matrix and nanofiller. No exfoliation or intercalation has been observed by XRD, despite the significant dispersion of the filler in the matrix which produced nanocomposites with a loss in transparency in the visible domain of less than 10% in the presence of 1% wt and 3% wt of mica fillers. The presence of micas does not affect the thermal behavior of the nanocomposites, which remains similar to that of the neat epoxy resin. The mechanical characterization of the epoxy resin composites revealed an increased Young’s modulus, whereas tensile strength was reduced. A peridynamics-based representative volume element approach has been implemented to estimate the effective Young’s modulus of the nanomodified materials. The results obtained through this homogenization procedure have been used as input for the analysis of the nanocomposite fracture toughness, which has been carried out by a classical continuum mechanics–peridynamics coupling approach. Comparison with the experimental data confirms the capability of the peridynamics-based strategies to properly model the effective Young’s modulus and fracture toughness of epoxy-resin nanocomposites. Finally, the new mica-based composites exhibit high values of volume resistivity, thus being excellent candidates as insulating materials.

Physical-Chemical Properties of Nano-Sized Phyllosilicates: Recent Environmental and Industrial Advancements

“…), nanoclays can be used as environmentally friendly fillers in polymeric materials. Mechanical strength and biodegradability can be improved by adsorbing small amounts of nanoscale clay particles into the polymer matrix [18,93]. Polymer-nanoclay composites are successfully applied in several fields, such as aerospace, automotive, petroleum, biomedical, construction, and wastewater treatment.…”

“…However, Trinh et al [114] observed that most sustainable polymer alternatives cannot compete with traditional plastics in gas and moisture barrier properties. Recently, improved moisture barrier properties were obtained by the encapsulation of nanoclay platelets into epoxy resin [93,95,106,[115][116][117]. Organically modified montmorillonite is a commonly used nanoclay dispersed in epoxy resins with filling amounts ranging from 1 to 10 wt% [117].…”