Metal-Complex Rubber Composition for Recyclable Durable Crosslinks

The patent changes the chemical parameters of the crosslinking system by introducing metal complexes with specific coordination chemistry. The metal ion (e.g., Zn²⁺, Co²⁺, Ni²⁺) forms coordinate covalent bonds with nitrogen-containing functional groups (such as pyridine, imidazole, or triazole groups) grafted onto the polymer chains. This parameter change in bonding mechanism enables both high durability through strong crosslinks and recyclability through controlled bond dissociation at elevated temperatures, resolving the contradiction between reliability and ease of manufacture.

The patent creates a composite crosslinking system combining organic functional groups grafted on polymer chains with inorganic metal ions. This composite structure forms coordination crosslinks that exhibit both the strength needed for durability and the reversibility needed for recycling. The organic-inorganic composite nature of the crosslinking agents enables the rubber to maintain physical properties while being recyclable, addressing the contradiction between reliability and manufacturability.

The patent modifies the thermal parameters of bond dissociation by designing metal-coordination crosslinks with specific activation energies. The coordinate covalent bonds between metal ions and nitrogen functional groups remain stable at service temperatures but dissociate at controlled rates at elevated temperatures (e.g., 150-200°C). This parameter change enables recycling at moderate temperatures without the harsh conditions that would degrade the polymer chains, thus maintaining physical properties while achieving recyclability.

The patent introduces dynamic reversibility to the crosslinking system. The metal-coordination crosslinks can dynamically form and break under different temperature conditions. During service, the crosslinks remain intact providing structural integrity. During recycling, the crosslinks reversibly dissociate at elevated temperatures, allowing the rubber to be reprocessed. This dynamic behavior enables both recyclability and preservation of physical properties, resolving the contradiction between productivity and reliability.

The patent changes the energy parameter of crosslink breaking by utilizing the temperature-dependent nature of coordinate covalent bonds. The metal-nitrogen coordination bonds have bond dissociation energies that are high enough to provide strength at service temperatures but become accessible at moderate elevated temperatures during recycling. This parameter change in bond energy versus temperature enables both high strength and ease of breaking crosslinks for recycling, resolving the contradiction between strength and ease of manufacture.

The patent replaces traditional sulfur-based crosslinking mechanisms with metal-coordination chemistry. Instead of relying on polysulfide bond breaking which requires harsh conditions, the patent uses coordinate covalent bonding between metal ions and nitrogen ligands. This substitution of the crosslinking mechanism provides both the strength needed for durability and the controlled reversibility needed for easy breaking during recycling, addressing the contradiction between strength and ease of manufacture.