P 6004 (OTTO) Poly(methyl methacrylate) average Mw ~996,000 Cas 9011-14-7 - used as a shield to stop beta radiation emitted from radioisotopes. P 6004 (OTTO) Poly(methyl methacrylate) average Mw ~996,000 Cas 9011-14-7 - used in sheet form as a lightweight or shatter-resistant alternative to glass. P 6004 (OTTO) Poly(methyl methacrylate) average Mw ~996,000 Cas 9011-14-7 - used in PMMA grades destined for heat processing, since this stabilizes the polymer to depolymerization ("unzipping") during processing.