The problem of restoring the life cycle of polymers using the example of waste electronic and electrical equipment (WEEE) consists in carefully separating polymers by type and increasing the mechanical characteristics of polymers after their aging. It is shown that when separating polystyrene plastics based on impact-resistant polystyrene, the material also includes polyolefins, in particular, filled polypropylene. On this basis, a model system containing high-impact polystyrene and chalk-filled polypropylene was chosen. The effect of modifying additives such as SEBS, maleinated polystyrene and polypropylene on the physical and mechanical characteristics of impact-resistant polystyrene, including in the presence of filled polypropylene, has been studied. The influence of the composition of the composition on its thermal stability, as well as the thermal stability of industrial batches of secondary impact-resistant polystyrene from the WEEE has also been determined. As a result, using the example of a model system, ways of possible modifycation of the high-impact polystyrene from WEEE are shown in order to obtain a commercial product with improved characteristics.