Effects of partial miscibility on the structure and properties of novel high performance blends composed of poly(p-phenylene sulfide) and poly(phenylsulfone)

Abstract

Although super-engineering plastics show superb thermal stabilities and long lifetime, their mechanical properties are often insufficient due to their molecular stiffness, as observed for poly(p-phenylene sulfide) (PPS). In the present study, a novel blend of two super-engineering plastics, PPS and poly(phenylsulfone) (PPSU), was investigated in detail. Differential scanning calorimetry and dynamic mechanical analysis (DMA) measurements revealed for the first time that the PPS/PPSU blends showed partial miscibility. The desirable interfacial adhesion achieved by the partial miscibility and the segmental mobility of PPSU, observed as a transition peak at approximately -100°C in the DMA measurements, most likely contributed to remedying the brittleness of PPS. Furthermore, small-angle X-ray scattering measurements revealed that the PPSU chains intruded into the amorphous region between the PPS lamellae during the crystallization of PPS as a result of the interlamellar segregation of the PPSU chains, which were partially miscible with PPS in the molten state. Thermogravimetric analysis measurements under a nitrogen atmosphere demonstrated that the thermal stabilities of PPS blends were significantly improved by the addition of PPSU.