Free radical ring‐opening polymerization and its use to make biodegradable polymers and functionally terminated oligomers

Since a carbon‐oxygen double bond is considerably more stable than a carbon‐carbon double bond, it has been possible to use this driving force to promote free radical ring‐opening polymerization of unsaturated heterocyclic compounds. This process, for the first time, has permitted the introduction of functional groups, such as esters, amides and carbonates, into the backbone of addition polymers. Hydrolysis of the copolymers with common monomers produced oligomers capped with hydroxyl, amino or carboxylic acid groups. The presence of an ester group in a copolymer, such as in a copolymer of ethylene, render the copolymer biodegradable.