Impact of talcum reinforcement on gaseous hydrogen permeation and long-term properties of high-density polyethylene

Hydrogen is seen as a suitable alternative fuel for future energy systems, but transporting it efficiently and safely is still a challenge. High-density polyethylene (HDPE) pipelines offer a good balance of cost and mechanical performance, although their relatively high permeability to hydrogen remains a limiting factor.
This study investigates the incorporation of talc fillers into HDPE to enhance its barrier properties without compromising mechanical performance. Two different talc types, differing in particle sizes, were added at 10, 20, and 30 wt%, and the resulting composites were evaluated through hydrogen permeability testing; thermal analysis via differential scanning calorimetry and thermogravimetric analysis; melt flow rate measurements to assess processability; short-term mechanical testing including tensile tests, Charpy impact tests, and dynamic mechanical analysis; long-term mechanical testing using fatigue crack round bar specimens; and microstructural characterization using scanning electron microscopy.
Talc addition significantly reduced hydrogen permeability, up to 40% at the highest content, while increasing stiffness and thermal stability. The talc with finer particles and better dispersion led to better mechanical performance, particularly in fatigue resistance, compared to the coarser talc. At high filler contents, embrittlement and reduced impact strength were observed. HDPE composites with 10–20 wt% of the finer talc achieved an optimal balance between reduced permeability and preserved long-term durability. These findings support their potential as cost-effective, high-performance materials for future hydrogen pipeline applications.