A comprehensive review on polystyrene/waste rubber blends: Effective parameters on mechanical properties

Polystyrene (PS), as a commercial thermoplastic polymer, suffers from brittleness at low temperatures. Blending with elastomers can resolve this defect. In this regard, waste rubbers from tires, shoes, and other sources are promising candidates for some applications. This approach of waste rubber recycling is an environmental-friendly and economical method to produce value-added products. This work aims to comprehensively review all reported cases regarding PS (or high-impact polystyrene, HIPS, and expanded polystyrene, EPS)/waste rubber blends. The influences of different parameters on the mechanical properties were carefully summarized, including mixing conditions (temperature, mixing time, rotor speed, and mixing sequence), rubber content, rubber particle size, compatibilizer addition, rubber devulcanization, and surface treatment of rubber. Some parameters had a negligible effect on the mechanical properties, such as the rotor speed in the mixing process, while significant influences were observed for some parameters, such as rubber content. The effect of some parameters was remarkable only at low or high rubber loading, such as particle size and solvent-inducing surface treatment of rubber, respectively. Finally, the effects of aforementioned parameters on tensile and impact strengths were compared and recommendations for future research in this field were suggested.HighlightsAll reported research regarding PS/waste rubber blends was comprehensively reviewed.All different factors influencing mechanical properties were carefully summarized.The effects of different factors on tensile and impact strengths were compared. Effective parameters on mechanical properties of polystyrene/waste rubber blends.image