Izod impact fracture morphology of rubber‐toughened polysulfone and poly(phenylene sulfide) blends

Blends of polysulfone (PSF) and poly‐phenylene sulfide (PPS) exhibit ductile behavior, below 35% by weight PPS, under tensile loading conditions. However, the blends are notch sensitive to Izod impact. The use of a core‐shell type rubber‐modifier effectively toughens the blends. Notched Izod impact strength rises, from ∼ 50 J/m to about 900 j/m, by increasing rubber content from 0% to 10–15%. It remains constant at a rubber content > 10–15%. Scanning electron microscopy (SEM) is used to study the morphology of the fracture surfaces. At low modifier content (5%), smooth or mesa‐like fracture surfaces are observed. Voids and interfacial debonding are revealed. With a higher concentration of toughening agent (> 10%), some crazing is evidence but not consistent. However, matrix yielding and extensive plastic flow of the PSF/PPS matrix are seen throughout, with a higher level of rubber modifier.