Property–composition dependence of polyurethane–poly(vinyl chloride) polyblends

The dynamic mechanical properties of polyblends of a polyurethane (PU) elastomer and poly(vinylchloride) (PVC) at five compositions were studied at 110 Hz, between −120 and 120°C. The study also included tensile testing at 25°C, and examination of polyblend morphology and fire‐retardant properties. The results were analyzed using suitable two‐phase mechanics models valid for such systems. This analysis, together with the morphological evidence and the thermomechanical spectra, indicate that these polymer alloys are essentially heterogeneous and their useful mechanical properties are due to good adhesion between the two phases. This conclusion is also corroborated by the tensile properties study. Fire retardancy is significant only above ∼60% by weight of PVC.