P 2057 (OTTO) Polysulphone pellets Cas no 25135-51-7 - used as filtration media. Polysulfone was the primary component of the gold-plated lunar extravehicular visor assembly, the iconic gold-film visor portion of the Apollo space-suits worn by Apollo astronauts during their lunar excursions. Polysulfone allows easy manufacturing of membranes, with reproducible properties and controllable size of pores down to 40 nanometres.