Polyphosphazene functionalized magnesium hydroxide core-shell architecture fire retardant: Toward a fire-safe multifunctional styrene-butadiene-styrene asphalt
Asphalt pavements are extensively utilized in tunnel pavement owing to comfortable driving, low noise, short-time construction, and simple maintenance. However, asphalt is a flammable material. To enhance fire retardancy of styrene-butadiene-styrene asphalt (SBSA) and its mixture with a preserved pavement performance, a novel hierarchical core-shell architectured fire retardant, cyclic cross-linked polyphosphazene-functionalized magnesium hydroxide (MH@CPZN), was validated via a chemically guilding assembly in this study. The fire retardancy and smoke suppression properties of SBSA containing MH@CPZN were found to be significantly improved.The MH@CPZN (10 wt%)-incorporated SBSA presented a remarkably higher limiting oxygen index (LOI) of 27.4 % relative to 21.5 % of SBSA with MH and 19.8 % of neat SBSA. In parallel, cone calorimeter test results showed that the peak heat release, peak smoke production rate and CO production of SBSA after an inclusion of 10 wt% MH@CPZN were reduced by 40 %, 35 % and 27 %, respectively, with a 20 s delayed ignition time. A large-scale fire test of asphalt mixture revealed a significant suppression of flame propagation after an addition of MH@CPZN. Moreover, the char yield at 800 °C was significantly increased to 24.1 wt% relative to 14.1 wt% of neat SBSA. A comprehensive analysis demonstrated a co-existence of multi-scale optimization of char microstructure in the condensed and radical quenching due to an interface-located polyphosphazene. Additionally, the high-temperature deformation resistance of SBSA was effectively enhanced after the incorporation of MH@CPZN. In perspective, a hierarchical assembly based on polyphosphazene and metal hydroxides exploits a facile yet practical route for multifunctionally reinforcing asphalt and its mixture with well-preserved fire retardant and pavement performance.
危险品化学品经营许可证（带存储）