Which part of metal-organic frameworks affects polymers' heat release, smoke emission and CO production behaviors more significantly, metallic component or organic ligand?

Metal-organic frameworks (MOFs) have been widely used to improve fire safeties of polymers as burgeoning flame retardants. There is no report about the influence of MOFs' compositions on enhancing fire safety of polymers. This work synthesized 9 pristine MOFs, including 3 MOFs with 1,3,5-tricarboxylic acid as organic ligands, which were added into polystyrene and epoxy resin, respectively. To deeply investigate impacts of MOFs' components, heat release, smoke emission and CO production behaviors were detected during the combustion processes of polymer/MOFs. It is clear that cobalt-based MOFs had better flame-retardant performance than other MOFs with same organic ligands. While the influence of organic ligands is irregular, affected by corresponding metallic components. The type of polymers also affects flame-retardant performance of MOFs. This work systematically analyzed the influence of MOFs' components on performance of polymer composites, which provides guidelines and database for further application of MOFs as flame retardants. [Display omitted] •H2BTC, 2-MIM, and H3BTC based MOFs were prepared with different metal salts.•MOFs' impact on heat release, smoke/CO emission behaviors is detected and studied.•Studied the role of MOF's components in improving fire safety of polymers.•Co-MOFs have the best performance, while the role of organic ligands is irregular.