Absolutely. A friend of mine founded a company to produce carbon-net-zero biodegradable plastics. Their seed round went well, and making great progress, and are currently raising a series A. If anyone's interested in learning more, email me steven.buss@gmail.com.
The thought is kind of horrifying, but you could even make it a closed process - send your old phone to the factory, where it's burned to produce the plastics for your new phone.
That would open up a pretty good avenue for "recycling" then, and could possibly reduce waste plastic in the environment
As I learned today in another thread [1], the only problem would be that plastic is usually doped with additional elements that I assume we would somehow have to deal with when burning it.