The 2015 vette bumper is TEO, fitting one to the back of my el camino.
The only other raw plastic prep option here is flame treating. By flame treating I don't mean burning the plastic with a torch. You just barely run the flame of a propane torch over the surface,barely even heating the surface, which removes the surface oils but doesn't dry out the whole depth. Teo is some oily crap to work with.
First heard of it as instructions for evercoat filler, but I've never tried it on a spot repair.
Jim C here has done it for years on plastics in general, says it has about same effect as ad pro.
I've done both procedures back to back on totally stripped areas.
Did an experimental stress test before spraying spi epoxy on sanded TEO and embedding a fiberglass matt strip hanging out as a pull handle. Couple weeks later it was handling a decent pull but eventually the epoxy let loose of the TEO. Later realized I forgot to do either prep procedure besides sanding.
Yea it failed my test, but this was way more extreme of a test than duct tape. It did give a fair fight.
With actual TEO split repair or fabrication as I've done, hot air plastic welding with ribbons or thinned out donor material is the best, far superior to any glues. With the backside being a little thicker, it can be as strong or stronger than the surrounding thin ass plastic they use now.
The 2009 manufactured Camaro bumpers I first fooled with were thicker than the 2016 Camaro front & 2016 vette rear I now have.
Haven't done any further experimenting with TEO fabrication. It's so difficult to work with on a fabrication level that on my 2016 updating Camaro bumper to el camino body project I did much more sheetmetal changing to avoid the plastic work. Same for rear.
Just a little more in depth info.......