Investigation of the Structural and Mechanical Properties of PET for the Development of Hydrogen Storage Tank Liner Materials

The aim of this study is to investigate the structural and mechanical properties of PET-based materials for potential use as liner materials in high-pressure hydrogen storage tanks. The research focuses on the effect of post-heat treatment, which influences the crystallinity of PET and, consequently, its mechanical behavior. Standardized specimens produced by injection molding were heat treated at 120 °C and 150 °C for different durations (5, 10, 15, and 30 minutes), followed by rapid quenching in ice water to stop the crystallization process. The degree of crystallinity was determined using differential scanning calorimetry (DSC), while mechanical properties were evaluated through tensile testing. According to the results, higher heat treatment temperature significantly increased the crystallinity and improved the tensile strength, while reducing elongation. Based on the findings, the optimization of heat treatment parameters offers an opportunity to fine-tune the properties of PET, and may serve as a basis for future gas barrier and permeability studies.