[EndlessAzure]

Old thread but was trawling the forums looking for this information because I'm in the process of making some repairs myself. I though it was worth making a correction:

The bumpers are made out of polypropylene (PP). It's clearly stamped on the part (this type of material information can be found stamped on almost every plastic part on the car.)

Knowing the bumper is made of PP is critically important because it's a Low Surface Energy (LSE) material: most adhesives/epoxies/glues don't work on it, especially if you need the repair to be strong and hold load.

There are specialized structural adhesives out there that are made to work with PP, but you need to know what to look for AND they tend to be expensive (3M DP8005 / DP8010 and Infinity Bond MMA 500). Your budget option is to use a primer (like Loctite 770) and cyanoacrylate glue (i.e. super glue) BUT usually a repair like this won't be strong unless you have a really close fit and get it put back together with precision.