Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Polyphenyl sulfone (PPSU) is a highly stable and rigid polymer with good chemical and mechanical resistance used in automotive and aerospace industries in high‐temperature applications during long‐operating cycles. PPSU foams are applied as core materials in lightweight composites ensuring high strength, fire resistance, thermal and acoustic insulation. In this paper, PPSU slabs are foamed using CO<jats:sub>2</jats:sub>, N<jats:sub>2</jats:sub>, and He as blowing agents (BAs). An experimental campaign is carried out to estimate the BAs' diffusivity in the polymer. In details, CO<jats:sub>2</jats:sub> diffusivity ranges from 8E‐11 to 1E‐09 m<jats:sup>2</jats:sup>/s at temperatures from 220 to 260°C; diffusivity of N<jats:sub>2</jats:sub> ranges from 2E‐10 to 5E‐09 m<jats:sup>2</jats:sup>/s (220–260°C) and it is 4E‐09 m<jats:sup>2</jats:sup>/s for He at 220°C. Foaming tests reveal an expansion ratio as high as 400% for CO<jats:sub>2</jats:sub>, 130% for He, and 150% for N<jats:sub>2</jats:sub>.Scanning electron microscopy analysis is also performed on produced samples, obtaining a cell number density of 1.3E07, 2.6E05, and 1.8E06 cells/cm<jats:sup>3</jats:sup> when saturating, respectively, with CO<jats:sub>2</jats:sub> at 220°C and 100 bar, N<jats:sub>2</jats:sub> at 220°C and 100 bar, and He at 230°C and 100 bar.</jats:p>