Why Extruded Acrylic Smell Bad

[Qijian Neo]

The fact that extruded acrylic produce much more smoke and smell worse than cast acrylic.

But why?
Cast and extruded acrylic are both made by pure PMMA, right? Or is it?

Need some discussion here:
1) Is that extruded acrylic chemically same as cast acrylic (pure PMMA)?
If so, why they smell differently, since acrylic do not decompose during laser cut.

2) Is that smell came from pollutant during recycle?
Maybe some styrene* are included? Anyone tried cut extruded acrylic that smell the same with cast?


*There's one type of extruded "acrylic" actually made out of Methylene Styrene Polymer (Polystyrene + PMMA), we called MS board here in Malaysia.
From my supplier, they said MS board can contain up to 70% Styrene Polymer, but people still can sell them as "acrylic".