Application of Ecuadorian Ferrotitaniferous Sands in Reinforcing Epoxy Composites

Ecuadorian ferrotitaniferous sands (FS), an abundant natural resource, can be considered as promising fillers for polymer matrixes due to their inherent mechanical properties and magnetic nature. Until now, this raw and underrated resource has only been used as a cement clinker additive and agro-industrial fertilizer, but not as a polymer reinforcement. Thus, epoxy composites were prepared by incorporating 2, 4 and 6 wt.% of chemically untreated and ball-milled FS, with the purpose of assessing the effects of the reinforcing particles on the mechanical and thermal properties of the as-prepared composites. Through microindentation, the optimum FS content was defined as being 6 wt.%, which increased both the elastic modulus and hardness in ~6% when compared to the neat matrix. Micromechanical models viz., the modified rule of mixtures and Halpin-Tsai predicted the Young’s modulus of the composites and supported the experimental results. The epoxy composite reinforced with the optimum FS content also presented the highest increase in storage modulus (E’), as evaluated by dynamic mechanical analysis (DMA). Additionally, the damping parameter (tanδ) for all composites was maintained, indicating that impact absorption and the glass transition temperature of the matrix was unaffected by the FS filler.