Material PropertiesAnalysis and optimization of polypropylene (PP)/ethylene-propylene-diene monomer (EPDM)/scrap rubber tire (SRT) mixtures using RSM methodology

Response surface methodology (RSM) is a collection of statistical and mathematical techniques useful for developing, improving and optimizing processes. In this work, RSM was applied to the investigation of ternary mixtures of polypropylene (PP), ethylene-propylene-diene monomer (EPDM) and scrap rubber tires (SRT). After appropriate processing in a co-rotating twin extruder and injection moulding, mechanical properties, such as tensile strength and impact strength, were determined and used as response variables. Scanning electron microscopy (SEM) was also used for investigation of the morphology of the different blends and interpretation of results. With specific statistical tools, a minimum number of experiments allowed development of the response surface model and optimization of the concentrations of the components according to mechanical performance.