(315j) Experimental Study of Metal-Organic Frameworks (MOFs) As a Novel Type of Flame Retardant for Poly (methyl methacrylate) (PMMA)

Metal-organic frameworks (MOFs) are a new class of porous materials, which possess unique physicochemical properties and have attracted considerable interests from different fields, such as gas storage and separation, catalysis, and drug delivery. Due to the inorganic-organic hybrid nature, MOFs usually have better compatibility with polymers to form well-dispersed polymer composites. UiO-66, a Zr-based MOF, is characterized by remarkable thermal stability and high chemical stability in a wide range of organic solvents and water, which makes UiO-66 be able to withstand the processing conditions of various polymers without undergoing any significant thermal degradations of their functions. Moreover, zirconium ions or zirconium compounds have been found to have certain flame-retardant effects because they can enhance or catalyze the char formation through the dehydrogenation of the polymer. In this study, UiO-66 has been used as a novel flame retardant to improve the flame retardancy of Poly (methyl methacrylate) (PMMA). A small amount of UiO-66 (less than 2 wt. %) was embedded into the PMMA matrix via in situ methods to form MOF-based polymer nanocomposites. The formed nanocomposites are characterized using SEM, XRD, XPS, and FTIR. To evaluate the performance of UiO-66 with different concentrations, the thermostability and flame retardancy of PMMA composites are systematically investigated using thermal gravimetric analysis (TGA) and cone calorimetry. This study will give us some insight into the application of MOFs as a new kind of flame retardant to enhance and improve the fire safety of polymer materials.