cyclopolymerization

Cyclopolymerization is a polymerization process in which cyclic monomers or monomers capable of intramolecular cyclization polymerize to form polymers in which new rings are generated as the chain grows. The process can proceed by radical, ionic, coordination, or other polymerization mechanisms, depending on the monomer and catalyst, and often involves a sequence of cyclization events coupled to chain propagation. A defining feature is the formation of ring structures during growth, which can yield polymers with annulated or polycyclic backbones and often enhanced rigidity or conjugation compared with conventional polymers.

Monomers used in cyclopolymerization frequently include strained cyclic olefins, cyclic dienes, enynes, and diynes. These substrates can undergo cyclization that locks in ring systems as the polymer chain extends. The resulting materials often exhibit unique topologies, including polycyclic and fused-ring motifs, and their properties—such as thermal stability, stiffness, and optical characteristics—are strongly influenced by the degree and pattern of cyclization along the chain.

Control over molecular weight and dispersity can be challenging due to competing side reactions and multiple reactive sites. Catalyst choice, solvent, temperature, and monomer design are important parameters for achieving desired activity and selectivity.

Applications of cyclopolymerized materials appear in advanced polymers and functional materials, including high-temperature plastics and optoelectronic or structural applications where rigid, polycyclic backbones are advantageous. Cyclopolymerization intersects with related cyclization-driven polymerizations and ring-opening polymerization approaches, offering routes to architectures not accessible by conventional polymerization.