The zirconium-containing MOF metal organic framework UiO66 (University of Oslo Zirconium 1,4-dicarboxybenzene, a MOF known for its exceptional stability) was functionalised with an amine and with phytic acid (PA, which can be bio-sourced and contains 60% phosphorus), in a one-step synthesis. Both UiO66-NH4 and PA-UiO66-NH2 were tested as PIN flame retardants at 2, 5 and 10% w/w in epoxy resin (Epoxyhedraz C). 5% loading of the phytic acid + ammonia UiO66 achieved UL94-V1 (3.2 mm), whereas pure epooxy and even 10% ammonia (only) UiO66 in epoxy did not. 5% of the phytic acid + ammonia UiO66 also reduced both peak heat release and total smoke production by over 40% compared to neat epoxy. Emission of carbonyls and styrenes in burning were reduced compared to neat epoxy. The PA-UiO66-NH2 also showed to increase cross-linking in the epoxy structure, resulting in a small increase in storage modulus.
“Green Synthesis of Biomass Phytic Acid-Functionalized UiO-66-NH2 Hierarchical Hybrids toward Fire Safety of Epoxy Resin”, J. Zhang et al., ACS Sustainable Chem. Eng 2019 http://dx.doi.org/10.1021/acssuschemeng.9b05658