Efficient and Durable Flame-Retardant UHMWPE Fibers Enabled by Interfacial Modification

A simple, environmentally friendly modification strategy to strengthen the interface between ultrahigh molecular weight polyethylene (UHMWPE) and ammonium polyphosphate (APP) was developed. This approach significantly enhances the durability and flame retardancy of UHMWPE fibers. Microscopic morphology and composition analysis verified the successful synthesis of the modified UHMWPE fibers. By precisely adjusting the concentration of the reaction solution and optimizing reaction conditions, hydroxylated UHMWPE exhibited significantly enhanced surface hydrophilicity (water contact angle reducing from 128° to 67°), without compromising its mechanical properties (tensile strength remained above 90%). Durability testing confirmed that the surface hydroxylation of UHMWPE and the grafting of a silane coupling agent (SCA) onto APP synergistically enhanced interfacial bonding. Besides, the binding energy and interfacial shear properties of modified fibers, which were calculated through molecular dynamics simulations, indicated that the hydrogen bond significantly enhanced the interaction between UHMWPE and APP. The combustion test clearly showed the considerable enhancement in the flame retardation of the modified UHMWPE as evidenced by a significant 31% increase in limiting oxygen index as well as substantial reductions of 50.3% and 63.9% in peak heat release rate and total heat release, respectively. The findings presented in this paper provide valuable insights for enhancing the flame retardant properties of UHMWPE fibers, thereby facilitating their widespread utilization in aerospace, military and civil protection. Summary A strategy was proposed to improve interfacial bonding between UHMWPE and APP. Interfacial behavior of UHMWPE/APP was explored by experiment and simulation. UHMWPE fibers after modification possess both flame retardancy and mechanical properties.