Abstract: A macromonomer capable of forming a graft polymer through graft-through polymerization, the macromonomer including a plurality of monomer units including a cycloalkene having a fused ring attached thereto to form a cycloalkene-fused ring monomer where the fused ring decreases the ring strain energy of the cycloalkene to a lower ring strain energy state of 5.3 kcal/mol or lower and where the cycloalkene of the cycloalkene-fused ring monomer is capable of isomerization into a higher ring strain energy state before graft-through polymerization, and at least one polymer sidechain is bonded to the fused ring. Graft polymers formed by the macromonomer include graft polymers and graft copolymers including statistical and block copolymers. The graft (co)polymers are capable of depolymerization under mild conditions into reusable monomer units.