I don't know about that. Perpex, or perspex is definitely acrylic. Poly(methyl methacrylate) to be specific. Plexiglass, acrylic, lucite, the stuff you have, it's all the same stuff. I frequently see it listed as shatter resistant. It's becoming more common for plastic or "Nalgene" water bottles, as it doesn't have bisphenol-A in it, though it isn't as resilient as polycarbonate.
Shatter resistant is what I would call it, but I would NEVER trust it for a blast shield. If you want to see there is an easy experiment to do. Take an old CD (not DVD or blueray disk), and bend it in half. It will bend quite a bit, but when you get to a certain point it snaps with quite a lot of force. You can also look at any car that has been in an accident, the head and tail lights are made of PMMA. You could also go to youtube and search for "hockey glass break". Any video on there should be PMMA. They switched over at least 20 or 30 years ago. It is shatter resistant because it bends quite a bit, but when it does shatter, it releases all that stored energy.
Edited by Mumbles, 21 June 2010 - 10:28 PM.