Interestingly, it is possible to introduce heteroatoms into traditional polymer backbones by a radical route employing a low amount of well-defined cyclic (co)monomers that are prone to an addition-fragmentation mechanism, bridging the best of both worlds. This leads to a socalled radical ring-opening polymerization (rROP) route of which the principle is highlighted in Figure . Such rROP can already be applied with various vinyl comonomers to obtain polymeric materials with highly adjustable (bio)degradable properties. The insertion of weaker bonds into commodity (vinyl) polymers by rROP is a very promising way to shift towards sustainable polymer chemistry, as pioneered by Mecking and coworkers for high density polyethylene and recently reviewed by Guillaneuf et al. for a wide span of polymerization routes and applications. The main rROP advantage is to insert a very low amount of weak bonds to fragmentate the polymer for biodegradation/recycling purposes after its lifetime without (significantly) impacting the properties of the commodity polymer during its use.