Improving flame resistance of aircraft interiors via electrospun polymeric nanocomposite fibers
The future of aircraft design relies on the adoption of advanced, next-generation materials engineered for multifunctionality. This study presents a scalable approach to enhancing flame retardance in electrospun Sulfonated Poly Ether Ether Ketone (SPEEK), Poly Ether Imide (PEI), and Poly Imide (PI) nanofibers through multifunctional additives such as 9,10-Dihydro-9-Oxa-10-Phosphaphenanthrene-10-Oxide (DOPO), Tannic Acid (TA), Hexagonal Boron Nitride (h-BN), Graphene, and Boric Acid (BA). Uniform fiber formation was achieved through optimized electrospinning of the polymer systems, despite increased viscosity from the additives. Comprehensive characterization (SEM, FTIR, TGA, WCA, UL-94) revealed strong structureproperty relationships as a function of additive type and concentration. The results demonstrate that optimized electrospun nanofibers with tailored additive incorporation, particularly BA, DOPO, h-BN, and TA, achieve significantly enhanced thermal stability, controlled morphology, and superior flame retardancy (UL-94 V-0) through synergistic char formation, barrier effects, and interfacial interactions. Quantitatively, thermal degradation temperatures increased by up to ~30-80 °C, and char residue improved substantially, correlating directly with enhanced flame-retardant performance. Among the three polymer systems evaluated, PEI-based systems consistently achieved UL-94 V-0 ratings across multiple additive combinations and exhibited high thermal stability up to 480 °C, making them the most suitable candidates for flame-critical applications. SPEEK-based systems exhibited the smallest fiber diameters, making them the most suitable candidates for nanoscale applications. PI-based systems exhibited the highest water contact angles, making them ideal for hydrophobic applications. This work illustrates a tunable, halogenfree nanofiber system with enhanced flame retardancy, offering a multifunctional pathway towards advanced aerospace applications.
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