Ford plastic bumper painting failure

Low-surface-energy plastic (PEO) wouldn't accept paint; Ford had to introduce sandblasting to convert to type-two mechanical interlocking. Used to set up the type-one vs. type-two adhesive bonding distinction.

I'll talk to you in a few minutes about how to bond to Teflon, but if you're talking type one adhesive bonding, the lower the surface energy the harder it is to bond to. For example, fifteen or twenty years ago, I had a student at Ford who was looking at — they were going to introduce a new type of plastic bumper. The plastic was PEO, polyethylene oxide or something — I can't remember the full name of it. This PEO had a very low surface energy and they had to paint it. Whenever they tried to paint it, the paint would just peel off. They eventually had to introduce a sandblasting operation to roughen the surface. But you only wanted to roughen a little bit, because you want a nice glossy paint job, so the roughness has to be probably a third or less of the thickness of the paint layer, and the paint layers on cars are pretty thin.