There are some epoxies/adhesives out now that will stick to Polypro.
If you're just trying to coat the exposed fiberglass, this would probably be the way to go (or use normal epoxy, and just hit the glass areas; i.e. don't worry about bonding to the PP.)
The only problem is the Polypropylene bonding epoxies are damned expensive.
3M Scotchweld DP-8005 is one, but is priced at around $20 - 30 US for a 35ml cartridge (you'll most likely want the mixing applicator and nozzles as well.)
I think Loctite and some other brands have similar stuff out, but read the application notes first; some require pretreatment (usually flame treatment) of the plastic to be bonded.