I don't see that listed but I used 3 PVC pipes and two 45-degree PVC couplings for about 5 years as a curtain rod above a bay window in my breakfast nook.
I painted them black and glued a finial on each end to disguise it. Nobody ever noticed, which is quite disappointing.
Why paint it at all? If it's a curtain rod that uses moving rings the friction is almost entirely at the top. Just apply some painter's tape at the top when painting it.
If you do want to paint it spray paint gives great results, but make sure to use plastic primer. To make it even sturdier apply a clear coat spray paint over the colored spray paint you use (so 3 layers: primer, paint, clear coat).
I don't see that listed but I used 3 PVC pipes and two 45-degree PVC couplings for about 5 years as a curtain rod above a bay window in my breakfast nook.
I painted them black and glued a finial on each end to disguise it. Nobody ever noticed, which is quite disappointing.