Construction of a novel three-in-one biomass based intumescent fire retardant through phosphorus functionalized metal-organic framework and β-cyclodextrin hybrids in achieving fire safe epoxy

Construction of metal-organic framework (MOF) derived hierarchical hybrid (beta CD@P-MOF) as intumescent fire retardant is first proposed to enhance the fire retardancy of epoxy resin (EP), which consists of bio-based phytic acid functionalized MOF(P-MOF) and carbon source beta-cyclodextrin. With only 3% of the novel hybrid, EP composites exhibited a 41% reduction in peak heat release rate (pHRR) and 62% decrease in smoke production rate (SPR). The intumescent char as the physical barrier with closed cell was obtained when the loading of FRs increased (EP/7 beta CD@P-MOF) and the internal char structure was studied by X-ray tomography. The P-MOF simultaneously possessed abundant phosphate and amine groups with the capability to act as an acid source and gas source, thus facilitating the formation of intumescent char. The increased storage modulus (25%) for the EP/7 beta CD@P-MOF sample indicated the development of high performance fire safety EP without deteriorating its mechanical property. In perspective, the construction of MOF derived intumescent systems opens a window for a novel method using MOF as potential fire retardants.