PPS for short. Common brand names are Ryton, Procon, Torcon, Fortran and a few others. Generally good until 180 d C, exhibits excellent resistance to moisture, & acids but disintegrates with high O2 content. Best suited for coal fired boilers essentially where temperatures are within 180 d C & O2 content < 4%. With a 100% PTFE base fabric, & blended with 15% to 30% PTFE fibres wuth the PPS fibres, experience shows that tolerance to O2 is somewhat better.