Physical–chemical properties of recycled samples made from discarded parts of polymers used in flexible pipelines

Polyamide 11 (PA11) is subjected to both a chemical and temperature gradient while it is used in flexible pipes for oil prospecting. Due to contact with fluid in the inner part of the polymer, it is expected that this will influence the properties of a recycled material made of PA11 after decommissioning. To investigate whether oil contact influences how the aged material will affect the recycling process, two recycled types (one considering only the part in contact with the oil and the other considering the opposite part) were investigated using chemical (XPS), thermal (DSC, TGA, and MFI), and mechanical analyses. Our results indicate that the processed samples, including the internal side of the pressure barrier, showed less plasticizer and more heterogeneity but maintained mechanical properties close to mint PA11.