I can identify what they are made from either from a recycling code (which probably isn't on something that small) or by putting a flame to an edge and sniffing the fumes. (Yeah, that's what makes me as messed up as I am. lol)
My first bet would be nylon, but the problem with nylon is that it is hygroscopic enough that it can be brittle in very dry environments. Like say for somebody that lives in a desert? Polyester is not quite as "tough" but is less vulnerable to moisture changes.
Hell, if we make a mold I can shoot about damn near anything in it and we can test durability if anyone wants to be a guinea pig!
2007 2.4L N/A. Stock + some pretty crap.