Preparation of Metal–Organic Frameworks and Their Application as Flame Retardants for Polystyrene

In this work, iron-based and cobalt-based metal–organic frameworks (MOFs) were successfully synthesized by a facile solvothermal method. The obtained MOFs were added into polystyrene (PS) as flame retardants for the first time. The results of thermal gravimetric analysis and cone calorimetry indicated the addition of MOFs significantly enhanced the thermostability and flame retardancy of the PS composites. Compared with that of neat PS, greater than 14% and 28% decreases in the peak heat release rate were observed for PS/Fe-MOF and PS/Co-MOF, respectively, suggesting a flame retardant effect of MOFs. Based on thermogravimetric analysis–infrared spectrometry results and the analysis of combustion residues, the possible mechanism of the enhanced thermostability and flame retardancy of the PS composites was proposed as the combination of thermal barrier effect and catalytic effect of MOFs, which would allow promising application in the development of fire safety polymer materials.