Abstract: Blends of poly(phthalazinone ether sulfone ketone)(PPESK ) and polyarylate ( PAR)were prepared via melt mixing.  The miscibility, processability, and thermal/mechanical properties of the blends were investigated using dynamic mechanical thermal analysis (DMTA)，scanning electron micro-scope ( SEM )，and thermogravimetric analysis(TGA).DMTA revealed the partial miscibility of the blends. PAR strongly promoted the processability of the blends, however, reduced their thern}al stability.

Key words: poly(phthalazinone ether sulfone ketone), polyarylate, miscibility, thermal behavior