Insights into the Molecular Motion of Benzotriazole in the Volatile Corrosion Inhibitor Packaging: A Detection and Mass Transfer Study

A new methodology using microwave extraction, gas-diffusion microextraction (GDME) and high-performance liquid chromatography-mass spectrometer (HPLC-MS) was developed for the analysis of the quantitative detection of gaseous and solid benzotriazole (BTA) and the mass transfer behavior of BTA in volatile corrosion inhibitor (VCI) packaging. The best extraction conditions of BTA in the VCI films were obtained, and the vapor pressure of BTA in the VCI packaging was detected and characterized by a mathematical model using the new methodology. The migration content of BTA in the VCI films and the BTA content on the surface of the films were detected, and the diffusion coefficients at three temperatures were calculated. The vapor pressure and diffusion coefficients of BTA increased with increasing temperature, and the volatilization of BTA promoted the migration of BTA from the VCI films. Moreover, a molecular dynamics (MD) simulation was performed to determine the migration of the BTA molecules within the VCI films at three temperatures; the overall trend of the experimental values was the same and the simulated values were generally within two orders of magnitude of the corresponding experimental values, with the difference likely due to the ignoring of the crystallinity of LDPE.