pic: Team 2614's Cracked Plexi

[Andy Baker]

One of the ways to tell the difference between acrylic (aka: Plexiglas) and polycarbonate (aka: Lexan) is the color of the edges.

Acrylic has a white edge.
Polycarbonate has a blue edge.

The producers of polycarbonate resin call this a "blueness index", if I recall correctly.

On this picture, many of the edges appear white. I only see blue edges where there are 2 layers of plastic. My guess is that we are looking at an acrylic sheet. And, of course, acrylic is much more brittle than polycarbonate.

Look at these two pages on www.matweb.com:

Extruded Acrylic
Extruded Polycarbonate

If you check out the "mechanical properties" of these two materials, they look somewhat similar in their strengths and properties, until you see the "Izod Impact, Notched" rating:

Acrylic has a rating of 0.3-1.1 ft-lb/in
Polycarbonate has a rating of 0.9 - 18.0 ft-lb/in

The higher value of the polycarbonate means that it can take an impact hit much better than acrylic.

Andy B.