Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE This work develops a modification strategy for melamine-formaldehyde fibers via ionic liquid/water systems and glutaraldehyde crosslinking. Computational screening and simulations clarify anion-dominated interactions, achieving fibers with improved ductility, char yield, and thermal stability for advanced flame-retardant polymer applications. These fibers open new avenues for sustainable flame-retardant materials without compromising mechanical performance.

ABSTRACT
Melamine-formaldehyde (MF) fibers are key flame-retardant materials for protective textiles and high-temperature filtration, but their industrialization is limited by high brittleness and reliance on organic solvents. This study proposes a modification strategy using an ionic liquids (ILs)/water system combined with glutaraldehyde (GA) crosslinking. Five ILs exhibiting excellent solubility for MF-GA (MFG) prepolymers were screened via the COSMO-RS model. Atomic simulations (Multiwfn and VMD) confirmed that IL-prepolymer interactions are dominated by hydrogen bond (HBond) and electrostatic forces, with anions playing a significantly stronger role in dissolution and molecular stabilization. Continuous MFG fibers prepared by wet-dry spinning using the optimized [Emim]DEP/water system showed a 15.8% increase in elongation at break. The char yield reached 22.3% (a 36.8% increase compared to unmodified MF fibers' 16.3%), demonstrating enhanced thermal stability. The performance improvement is attributed to the uniform crosslinked network and the dual function of ILs in plasticizing and stabilizing reaction intermediates through anion-dominated effects. This integrated “computational screening - atomic simulation - preparation of long fibers” scheme offers a green route for optimizing MF fibers and clarifies the core principle of anion regulation in IL-prepolymer dissolution.