Is synthetic rubber biodegradable

Synthetic rubber is not biodegradable. This is because it is not made from organic materials and is made from chemicals. I don't know how fast or how much the monomers used might affect it, but found a study identifying bacterial enzymes that will degrade both natural and synthetic rubbers, but Answers doesn't like people citing their sources so I can't link to it.

As for the previous answer, all rubber is an organic polymer, just like plastic. And for that matter all organic compounds are chemicals like pretty much anything else you'll encounter in life, and being organic doesn't mean microbes can eat it easily-particularly when it comes to polymers, but there are also persistent organic pollutants, or POPs.

If you're wondering whether you can compost it, I'd say best not for your garden's sake; if you're trying to dispose of large quantities, I'd say hire an expert; if you're wondering whether to avoid rubber products on environmental grounds, probably best to look for a more reliable source of information.

As to whoever wrote the original answer, please don't spout nonsense on topics you don't understand and justify it with Words you don't know the meaning of.