Optimisation of Additives to Maximise Performance of Expandable Graphite-Based Intumescent-Flame-Retardant...

Area of Science:

• Materials Science
• Polymer Chemistry
• Fire Safety Engineering

Background:

• Polyurethane (PU) polymers require enhanced flame retardancy for safety applications.
• Traditional intumescent flame retardant (IFR) systems are crucial for improving polymer fire performance.
• Investigating synergistic effects of low-cost additives is key to developing effective flame-retardant materials.

Purpose of the Study:

• To evaluate the synergistic flame retardant effects of expandable graphite (EG), ammonium polyphosphate (APP), fibreglass (FG), and vermiculite (VMT) in polyurethane (PU) composites.
• To determine the optimal composition for enhanced flame retardancy and smoke suppression.
• To assess the impact of these additives on the mechanical properties of PU composites.

Main Methods:

• Synthesized PU composites with varying weight percentages (wt.%) of EG, APP, FG, and VMT.
• Utilized Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), tensile strength tests, and cone calorimetry for analysis.
• Investigated the formation and compactness of the protective layer during combustion.

Main Results:

• PU composites with 40 wt.% EG demonstrated superior flame retardant performance compared to lower concentrations.
• The 40 wt.% EG formulation reduced peak heat release rate by 88%, total smoke release by 93%, and CO2 production by 92% compared to the control PU.
• Fibreglass (FG) addition ameliorated the decrease in tensile strength observed with other flame-retardant additives.

Conclusions:

• A synergistic effect between EG, APP, FG, and VMT significantly enhances flame retardancy and smoke suppression in PU composites.
• The compactness of the protective layer is crucial for the observed flame retardant performance.
• These developed PU composites offer a viable strategy for flame-retardant and smoke-suppressing materials in construction applications.