Guanine was investigated as a potential green corrosion inhibitor to API 5L X65 carbon steel in HCl 0.1 mol.dm^-3 solution, at pH = 2.0, under hydrodynamic conditions using electrochemical, weight loss and Raman spectroscopy experiments. Cyclic voltammetry and potentiodynamic polarization curves suggested that Guanine does not change the metal/solution interface appreciably and weight loss tests confirmed the low inhibition efficiency (IE) of Guanine in protecting the X65 steel in this corrosive medium. An IE = 22% was determined after 48 h of exposure, a value lower than that reported in the literature on the mild steel/Guanine/HCl system. Raman spectroscopy was employed to gain insight on the nature of the steel/Guanine interaction and the results pointed out to a weak physisorption of the molecule, thus explaining the very low IE values obtained.

In this work, two different grades of poly(vinylidene fluoride) (PVDF) commonly used in offshore applications, one with 3% of dibutyl sebacate (DBS) plasticizer and the other a copolymer containing chlorotrifluoroethylene (CTFE), were subjected to an aging process in contact with a fluid containing hydrocarbons, pyridine, and aniline at high temperature for 90 days. For comparison, control experiments using the same hydrocarbon‐based medium without pyridine and aniline were performed for 7 and 30 days and evaluated by selected analyses, including mass variation and FTIR‐ATR. The samples were analyzed using Fourier transform infrared spectroscopy (FTIR), x‐ray photoelectron spectroscopy (XPS), mass variation measurements, tensile testing, and differential scanning calorimetry (DSC), while the greenish solid byproduct observed only during aging of PVDF 60512 was analyzed by Raman spectroscopy and energy dispersive x‐ray fluorescence spectrometry (EDXRF). PVDF 60512 exhibited a more pronounced response under the investigated conditions, including higher mass variation, more evident spectroscopic changes, and greater changes in mechanical and thermal behavior, whereas PVDF M800 showed comparatively less pronounced changes. The control experiments showed comparatively limited mass and FTIR‐detectable changes over the first 30 days relative to the N‐containing medium, supporting the distinct response observed under the complete aging condition. The presence of CTFE units may contribute to this behavior, although other differences between the commercial grades cannot be excluded. A possible reaction mechanism involving CTFE units was proposed to interpret the chemical changes observed in PVDF 60512.