Thiadiazole functionalized covalent organic frameworks as oil-based lubricant additives for anti-friction and anti-wear

Abstract

The thiadiazole functionalized covalent organic frameworks (COFs) were successfully prepared via polydopamine (PDA) as a connection layer. The fluorine-containing COF-F was synthesized via solvothermal reaction, which was subsequently wrapped with PDA layer via oxidative polymerization. Finally, the anti-wear agent thiadiazole dimer covalently bonded with PDA via the Michael addition reactions to obtain thiadiazole functionalized COFs (DTD@COF-F). The as-prepared DTD@COF-F exhibits good tribological properties as oil-based lubricant additives, representing a low and stable friction coefficient (0.104), and decreasing the wear volume by 67.8 % comparing to the base oil 500SN. The good lubrication performance mainly benefits from the robust protective tribo-film, while the anti-wear thiadiazole molecule functionalized COFs can absorb onto the friction pairs easily, hence play essential roles in its construction.