Facile Utilization of Renewable Resources Containing Cyclobutene Mechanophores: Preparation and Properties of High-Toughness Materials with One-Step Cross-Linking by Frontal Ring-Opening Metathesis Polymerization

The latest progress in polymer mechanochemistry demonstrates that the toughness of materials can be enhanced through ring-breaking of mechanophores. The mechanophores currently require complex organic synthesis; in contrast, terpenoid renewable resources with mechanophores are readily available. Here, a series of the expected high-toughness materials are prepared by using caryophyllene with cyclobutane ring units and dicyclopentadiene through frontal ring-opening metathesis polymerization, and this copolymerization method is characterized by one-step cross-linking and fast polymerization kinetics. These copolymers, which can be easily prepared with different concentrations of comonomers, exhibit a wide range of ultimate elongation (11.6-1167.5%), tensile strength (0.1-57.1 MPa), and glass transition temperature (-29 to 86 C-degrees). The new resin formulation can also be used for three-dimensional (3D) printing preparation, eliminating the need for solvents and complicated equipment in the molding process. This method paves the way for manufacturing cross-linked materials with low energy, low cost, and high usage and also provides opportunities for the application of sesquiterpene resources in the field of sustainable chemistry.