Development of Eco-friendly Shock-absorbing Cork Composites Enhanced by a Non-Newtonian Fluid

Cork composites present interesting properties for several applications such as damping, shock absorption, crashworthiness and thermal insulation. In this work, the enhancement of their impact resistance, by means of shear thickening fluid (STF) reinforcement was studied. The analysis was carried in multi-layered structures consisting of cork laminates with STF as the interfacial element. To make the study concise, a constant thickness was established for the structure and the variables were the number of cork laminates and thus, the thickness of each laminate and the amount of STF. The STF employed was based on fumed silica and polyethylene glycol (PEG). Rheological measurements were carried out on the developed STF, which was also subjected to scanning electron microscopy (SEM). The multi-layered composite structures were subjected to low-energy impact testing, for three energy levels: 5, 10 and 15 J. Direct comparison was established between cork structures with and without STF, determining the influence of STF in the impact performance. Results are promising, reducing the maximum impact force for some designs (max. reduction of 36%), showing the potential of STF to enhance the impact performance of cork composites.