Disclosed herein are polymers, copolymers and polymer systems based on polypropiolactones which can be biodegradable and can enhance the recyclability of polymer systems, which can be functionalized to introduce desired functionality into the polymers and/or which may optionally be prepared from renewable raw materials. Disclosed are novel functionalized beta propiolactones. Some of the novel functionalized beta propiolactones have functional groups bound to the ring structure of the lactone that provide improved polymer systems. Disclosed are novel homopolymers of the functionalized beta propiolactones. Disclosed are novel copolymers based on the functionalized beta propiolactones with beta propiolactone or other monomers which copolymerize with the functionalized beta propiolactones.