Mechanical and gas permeation behaviour of PVDF/PA6 blend composite

Improving the resistance of the lining material of the flexible riser to CO₂ can effectively prevent the formation of an acidic environment and metal corrosion in the flexible riser annulus. However, it remains a challenge to improve the barrier performance while maintaining the original mechanical properties. Herein, we melt blended PVDF with PA6 in various proportions, characterized by Differential Scanning Calorimetry (DSC), Fourier Transforms iInfrared (FTIR), Scanning Electron Microscope (SEM), and carried out tensile and permeability tests. The results show that the permeability coefficient of the PVDF/PA6 composite is lower than that of the primary PVDF. After blending with PA6, PVDF/15% PA6 elongation at break was only 19.3%, which was significantly lower than that of primary PVDF and PA6. PVDF/10% PA6 shows an 11.43% decrease in CO₂ permeability coefficient and a 20% decrease in elongation at break, which still meets the pipeline use.