Recyclability of take‐back glass fiber‐reinforced blends of polyphenylene oxide with high‐impact polystyrene for high‐performance engineering applications

Abstract Increased recycling of plastics is an essential step toward a more sustainable use of materials, where some of the most challenging fractions are engineering materials and composites. Used pump houses prepared from glass fiber (GF)‐reinforced blends of polyphenylene oxide (PPO) and high‐impact polystyrene (HIPS) obtained through a take‐back scheme (take‐back, TB) were characterized and shredded for use in the preparation of new composites by injection molding. Initial degradation was observed on the surface of the TB parts; however, the core of the material was unaffected. Mechanical reprocessing of regrind and virgin material showed a reduction of tensile strength already at 10% regrind, which was attributed to fiber length reduction during reprocessing. At the same time, Young's modulus and extension at break were largely unaffected, confirming that 25% of TB could be included without any additional loss of properties. As a worst‐case scenario, tests with extensively degraded material showed that Young's modulus and tensile strength would ultimately be reduced with an increasing amount of heavily degraded material and that a balance would have to be found between loss of properties and recycled content for heavily degraded material.