Experimental Assessment of Polymeric Materials for 100% Hydrogen Transportation and Distribution

Hydrogen is emerging as a clean energy carrier with the potential to replace conventional fuels, necessitating the development of robust infrastructure for its safe transport and storage. This study examines the impact of hydrogen exposure on the mechanical properties of three polymeric materials polyamide nylon, high-density polyethylene (HDPE), and polytetrafluoroethylene (PTFE) under moderate conditions (20°C, 10 bar, 24 hours). Mechanical properties such as strength, ductility, toughness, and stiffness were assessed through tensile and bending tests on exposed and unexposed samples to evaluate material compatibility in 100% hydrogen environments.

Polyamide Nylon exhibited marginal increases in maximum force and tensile stress at maximum force, with significant improvements in tensile strain at maximum force (+42.42%) and at break (+38.65%), indicating enhanced ductility and toughness. Bending tests revealed a slight increase in flexural stress (+5.18%) and minor reductions in displacement (-5.73%) and modulus (-1.16%). However, the elastic modulus decreased significantly (-14.53%), indicating reduced stiffness. These results suggest nylon’s suitability for applications requiring flexibility and energy absorption, though its decreased rigidity may limit its utility in high-stiffness scenarios.

HDPE showed slight reductions in maximum force and tensile stress (~5%) following hydrogen exposure but demonstrated substantial improvements in tensile strain at break (+124.02%), as well as moderate gains in force (+7.90%) and stress (+7.79%) at break. The elastic modulus decreased by 9.87%, indicating enhanced flexibility but reduced stiffness. In bending tests, HDPE experienced decreased flexural strength (-7.71%) and displacement (-2.40%) alongside a slight increase in stiffness (+4.62%). These findings highlight HDPE’s improved ductility and toughness, making it suitable for flexible hydrogen distribution systems. However, its reduced strength and stiffness may necessitate reinforcement for high-load applications.

PTFE experienced minor reductions in tensile strength and stress at break (~3–5.8%) and a significant decrease in elastic modulus (-40.64%), reflecting considerable softening. However, tensile strain at maximum force increased by 22.12%, indicating improved flexibility. Bending tests showed increases in flexural strength (+16.18%) and stiffness (+39.39%), though displacement at maximum flexural stress slightly declined (-6.98%). These results suggest PTFE’s suitability for applications requiring high flexibility and resistance to bending loads but limited utility in load-bearing roles due to its reduced stiffness and strength.

Hydrogen exposure under moderate conditions enhances ductility and toughness across nylon, HDPE, and PTFE while reducing stiffness. Nylon and HDPE demonstrated minimal strength degradation, making them viable for flexible hydrogen transport systems. PTFE’s significant stiffness reduction may restrict its use to non-structural applications. These findings contribute critical insights into material selection for hydrogen infrastructure. Further research under varying pressures, temperatures, and durations is recommended to ensure the long-term reliability of these polymers in real-world applications, advancing hydrogen-based energy systems.