Editorial: Recent advances in flame retardant polymeric materials and composites

Polymeric materials and their composites have been extensively utilized in critical engineering sectors including construction, transportation, and electronics, etc.However, the safety performance of these materials, especially flame retardancy, is crucial for sustainable development. The urgent demand is propelling flame retardant science and technology into a new phase of innovation, resulting in numerous novel material and technologies that require systematic summarization and integration. Therefore, this research topic seeks to synthesize the latest progress in flame-retardant polymeric materials and composites, covering the following three key aspects:• Development of novel flame-retardant materials• Modification strategies for flame-retardant materials and polymer matrix *Corresponding author. E-mail: [email protected] (X. L Chen), [email protected] (J. Sun)• Integration of flame-retardant polymeric materials with machine learningThe design of novel flame-retardant systems compatible with diverse polymer matrixes constitutes a major research thrust. Chen et al. (2023) developed a self-assembled flame retardant system (HCCP@EG) using expandable graphite (EG) and hexachlorocyclotriphosphazene (HCCP) to enhance the flame retardancy of rigid polyurethane foam (RPUF). The resulting network structure and synergistic effects substantially improve thermal stability and char formation, offering a straightforward strategy for producing RPUF products with enhanced fire safety. Li et al. (2024) synthesized cobalt-doped nanosheet flame retardants (PAMA-Co) with excellent catalytic performance, which effectively suppresses the "popcorn effect" of EG and improves both safety and practicality in polypropylene (PP). From an environmental sustainability, Tang et al. (2025) repurposed lanthanum carbonate (La2O2CO3) intercalated kaolinite waste after phosphate adsorption (La₂O₂CO₃-Kaol@P) to protect epoxy resin (EP). This approach induces the formation of nano-to micro-scale dual carbon layers that inhibits the degradation of polymer, achieving precision enhancement in flame retardancy and enabling interdisciplinary application.Although the incorporation of flame retardants can enhance flame resistance, it often compromises the mechanical properties of composites due to interfacial compatibility issues. Researchers are therefore continuously exploring modification strategies to balance these properties. Faraz (2024) systematically investigated the synergistic effects of organic and inorganic fillers, halloysite nanotubes (HNT), magnesium hydroxide (MHO), and chitosan infused ammonium polyphosphate (CAP), on both flame retardancy and mechanical properties of vinyl ester/flax composites. It is revealed that CAP and MHO contribute significantly to both properties, while HNT has negligible effects on enhancement of flame retardance but shows greater effect in deteriorating the tensile properties. Chen et al. (2024) adopted a chemical modification strategy using polymeric methylene diphenyl diisocyanate (PAPI) as a coupling agent to construct cross-linked structures between bamboo fiber (BF) and stereo-complex crystal polylactic acid (SC-PLA). This method balances mechanical performance with heat resistance, accompanied by a reduced ecological toxicity at specific formulation ratios via life cycle assessment. Ran et al. (2025) introduced reactive epoxy groups to address the low compatibility of aluminum diethylphosphinate (ADP) and melamine pyrophosphate (MPP) flame retardants with polybutylene terephthalate (PBT) under humid and hot conditions. The resulting composites (PBT/EP@FR), fabricated by straightforward reactive extrusion, maintained satisfactory mechanical and flame-retardant properties even after hygrothermal aging, demonstrating broad application prospects in electronics and new energy vehicles.With the advancement of data-driven approaches, machine learning has opened new avenues for the prediction of flame-retardant properties and the optimization of