Variations in the mechanical properties of end products from mixed plastics

From well selected polymers, using an experimental plan methodology, we show the different influences (nature, processing conditions, composition) on the properties of end products from mixed plastics such as strain and stress at rupture, flexural modulus, impact strength and extrusion flow rate. From models, it is possible to adjust necessary formulations to obtain a good quality level and, eventually, an improvement of poor properties. Mixed plastics can be considered as a polyethylene matrix containing other polymers such as polypropylene (PP), polystyrene (PS) or poly(vinyl chloride) (PVC). Poly(ethylene terephthalate) (PET) is neglected in this study. Properties such as strain at rupture or impact strength are drasticly affected by the level of polypropylene, polystyrene or poly(vinyl chloride): 5 or 10% nullify these properties. Other properties such as stress at rupture, flexural modulus or extrusion flow rate highly depend on the relative ratio of polymers. To improve the poor properties or to obtain a good level in a property, it is necessary to add well adapted compatibilizers or to dope the mixed plastics material by one of the polymers.