Engineering MXene surface with POSS for reducing fire hazards of polystyrene with enhanced thermal stability

Highlights: • A functionalized POSS-Ti₃C₂T_x has been prepared via a facile surface-manipulation approach. • Upon addition of 2 wt% of POSS-Ti₃C₂T_x, a 39.1 % reduction in the peak heat release rate of PS is obtained. • A 54.4 % reduction in the peak CO production rate of PS is achieved. • The initial temperatures of PS in nitrogen and air also increase by 22 °C and 39 °C, respectively. • The good fire safety is due to the adsorption, catalytic and barrier effects of POSS-Ti₃C₂T_x. High-performance MXene-based polymer nanocomposites are highly desirable for diverse industry applications due to their exceptional mechanical, thermal and other properties. Nevertheless, it remains an intractable challenge to create flame retardant polymer/MXene nanocomposites due to the difficulty to achieve uniform dispersion of MXenes. Here, we reported a facile strategy for the surface manipulation of two-dimensional titanium carbide nanosheets (Ti₃C₂T_x) with 3-aminopropylheptaisobutyl-polyhedral oligomeric silsesquioxane (AP-POSS) (POSS-Ti₃C₂T_x) through electrostatic interactions. The POSS-Ti₃C₂T_x is steadily dispersed in many polar solvents. Upon incorporated into polystyrene (PS), the combined effect of AP-POSS and MXene makes the resultant PS nanocomposites exhibit significantly improved thermal and thermoxidative stability, e.g. 22 °C and 39 °C increases in the temperature at 5 wt% mass loss under nitrogen and air, respectively. Meanwhile, a 39.1 % reduction in the peak heat release rate, a respective 54.4 % and 35.6 % reduction in the peak CO production rate and the peak CO₂ production rate was achieved, which are superior to those of its own and previous counterparts. This outstanding fire safety is attributed to the combination of adsorption, catalytic and barrier effects of POSS-Ti₃C₂T_x. Hence, as-designed functionalized MXenes can be effectively applied in PS to formulate multifunctional polymer nanocomposites attractive for wide potential applications.