New Polymer Composites Made of Recycled Polystyrene with Red Mud and Wind Blade Waste: An Industrial Ecology Case

The development of composites with the waste of industries close to each other would mean an interesting case of industrial symbiosis in search for using less financial and natural resources. This paper presents the development of polymer composites made of three types of waste, produced by industries located in the same region and distant at most 25 km from each other: electronic waste, red mud (obtained during aluminium production), and the waste of wind turbine blades' manufacturing (epoxy resin/glass fibre). Composites were obtained incorporating 5%, 10%, and 15% of industrial waste (red mud and epoxy/fibre) in a matrix of recycled high-impact polystyrene (HIPS) from discarded electronic equipment. Tests were performed to obtain the melt flow index and the composites' water content and study the mechanical properties (tensile and impact) of test specimens produced with the composites by injection moulding (temperature from 200 to 250°C, the injection pressure of 45 MPa, and the injection time of 2.5 s). Results showed that the composites have water content and melt flow index within the specifications for recycled HIPS and are usually more rigid than it, reaching values for Elasticity Modulus up to 34% higher. Therefore, these composites can be applied when materials with more stiffness than HIPS are required.