A strategy to synthesize phosphorus-containing nickel phyllosilicate whiskers to enhance the flame retardancy of epoxy composites with excellent mechanical and dry-friction properties

To enhance the fire safety and wear resistance of epoxy, phosphorus-containing nickel phyllosilicate whiskers (FP-NiPS) were synthesized using a facile hydrothermal technology, with 9,10-dihydro-9-oxa-10-phosphaphenanthrene as the organic modifier. The impacts of FP-NiPS on the thermal stability, flame retardancy, and mechanical and tribological properties of EP composites were explored. The findings demonstrated that 5 wt % FP-NiPS elevated the limiting oxygen index of the EP composite from 23.8% to 28.4%, achieving a V-0 rating during vertical burning tests. FP-NiPS could enhance the thermal stability of epoxy resin (EP) and facilitate the development of a dense and continuous carbon layer, thereby significantly improving the fire safety of the EP composites. The FP-NiPS led to an 8.2% increase in the tensile strength and a 38.8% increase in the elastic modulus of the EP composite, showing outstanding mechanical properties. Furthermore, FP-NiPS showed remarkable potential in enhancing the wear resistance of EP. The wear rate of 1 wt % FP-NiPS is 2.34 × 10⁻⁵ mm³·N⁻¹·m⁻¹, a decrease of 66.7% compared to EP. This work provides a novel promising modification method to enhance the fire safety, mechanical and wear resistance properties of EP.