Today we received back a corner sofa that we had returned because a chipboard had broken. (The front leg of the corner piece is attached to the board without direct support underneath. Considering that the side parts hang on the corner piece, there is probably some strain when several people sit on the sofa.) Since I am skeptical of any repairs not done by myself, I immediately started checking if the repair seems okay or if it is just as well to reinforce it further right away. They hadn't made any reinforcements; instead, the chipboard was replaced with a board of some other material that I don't quite know what it is. It looks like it's made of wood fibers but feels more compressed than chipboard; on the other hand, it also reminds me a bit of some kind of plastic. The color is a bit greenish. What kind of material is it, and how does its strength compare to regular chipboard?
Sounds like MDF
MDF is completely smooth on the outside and looks a bit cardboard-like on the cut surface. No fibers are visible at all. I have never seen it in any other color than brown. MDF is also stronger than particleboard, but weaker than plywood.
There is moisture-resistant particleboard (and mdf?) that is used to make bathroom furniture. As far as I know, it is green in color... i.e., the particles are slightly green-tinted, somewhat like pressure-treated wood....sort of.