Optimization of Interfacial Bonding between Graphene-enhanced Polyethylene Liners and CFRP Composites using Plasma Treatment for Hydrogen Storage Applications

As the need for sustainable hydrogen storage solutions increases, enhancing the bonding interface between polymer liners and carbon fiber-reinforced polymer (CFRP) in Type IV hydrogen tanks is essential to ensure tank integrity and safety. This study investigates the effect of plasma treatment on polyethylene (PE) and PE/graphene nanoplatelets (GNP) composites to optimize bonding with CFRP, simulating the liner-CFRP interface in hydrogen tanks. Initially, plasma treatment effects on PE surfaces were assessed, focusing on plasma energy and exposure time, with key surface modifications characterized and bonding performance being evaluated. Plasma treatment on PE/GNP composites, with increasing GNP content, was then examined, comparing the bonding effectiveness of untreated and plasma-treated samples. Wedge peel tests revealed that plasma treatment significantly enhanced PE-CFRP bonding, with optimal conditions at 510 W and 180 s resulting in 212 % and 165 % increases in the wedge peel strength and fracture energy, respectively. Plasma-treated PE/GNP composites with 0.75 wt.% GNP achieved a notable bonding enhancement with CFRP, showing 528 % and 269 % improvements in strength and fracture energy over untreated neat PE-CFRP samples. These findings offer practical implications for improving the mechanical performance of hydrogen storage tanks, contributing to safer and more efficient hydrogen storage systems for a sustainable energy future.