o-Vanillin based MOFs as phosphorus-free flame retardant for reinforced epoxy resin

Bio-based metal-organic frameworks (MOFs) offer the potential to construct high-performance composites. Element-based design can help avoid the potential risks associated with phosphorus-based flame retardants while simultaneously enhancing the flame retardancy efficiency of bio-based materials. In this study, bio-based organic ligand oVBZMI was synthesized from o-vanillin and coordinated with Zn2+ to prepare the ZIF-oV. The nanocomposite epoxy resin EP/ZIF-oV was prepared using epoxy resin as the matrix. The influence of the composites structure on the mechanical properties was analyzed using multi-dimensional characterization methods. Additionally, the effect of ZIF-oV on the flame retardancy of epoxy resin was investigated. The results indicate that the nanocomposite epoxy resin exhibits outstanding flame retardancy and enhanced mechanical performance at low loading levels. This can be attributed to the multifunctional synergistic effect of well-controlled MOFs in terms of composition and morphology. This work proposes an efficient polymer modification method for constructing advanced composites, while offering new strategies for reducing dependence on petroleum resources.