Preparation and characterization of microcellular injection molded foams from high-performance blends based on PPS-modified PPBESK

Obtaining foams of poly-containing biphenyl moieties (phthalazinone ether sulfone ketone; PPBESK) by applying the microcellular injection molding method is very difficult because of the high melt viscosity of the materials used. To overcome this limitation, polyphenylene sulfide (PPS) was used to improve the rheological properties of PPBESK. PPBESK/PPS blends of different proportions were prepared using the melt mixing method. The rheological behavior, phase behavior, interfacial tension, and mechanical properties of the blends were then investigated. The results clearly indicate that PPS can improve the melt processability of PPBESK. However, due to the strong adhesion between the PPS and PPBESK phases, the introduction of PPS did not cause any loss of the mechanical and thermal properties of PPBESK. Accordingly, microcellular foams from modified PPBESK were prepared by microcellular injection molding with supercritical nitrogen as foaming agent. A closed cell microcellular morphology with an average cell size of 17.7 um and cell density of 10⁹ cells cm⁻³ was obtained.