Enhanced multifunctional performance of flash graphene-polymer composites via nitrogen doping

Despite the considerable potential of graphene and its derivatives to enhance the multifunctional properties of polymers, their practical applications remain limited by challenges such as agglomeration, interfacial incompatibility, and high costs. In this study, low-cost, highly dispersible, and scalable flash graphene (FG) and nitrogen-doped flash graphene (N-FG) were introduced as alternatives for fabricating high-density polyethylene (HDPE) and thermoplastic polyurethane (TPU) composites. This work demonstrates that nitrogen doping further improves mechanical strength, gas barrier properties, and UV resistance through three synergistic mechanisms. Specifically, the tensile strength of the 0.5 wt% N-FG composite increased by 42.4% due to the introduction of hydrogen bonding at the filler-matrix interface, which strengthens interfacial adhesion and facilitates stress transfer. Meanwhile, oxygen permeation was reduced by 39.8%, 16.4% higher than that of the FG composite, attributed to N-doping-induced modulation of adsorption energies and electron localization, which optimizes gas dissolution and enhances gas barrier properties. Furthermore, UV absorption intensity increased by 26.7%, as nitrogen incorporation tuned the band gap, effectively mitigating photo-oxidative degradation; with 1 wt% N-FG, the carbonyl index of HDPE decreased by 7.8-fold. These findings highlight the multifunctional benefits of N-FG, offering a cost-effective solution for applications in food packaging and lightweight gas storage.