Metals (ferrous & non-ferrous) are susceptible to environmental physical, chemical, or electrochemical deterioration when these come in contact with moisture and oxygen. Metals form an oxide layer on the surface which indirectly protects metal if oxide is denser than the parent metal. Only oxygen or only water cannot cause corrosion of the metals, both constituents must be present together to cause corrosion.

There are plenty of technologies available to protect metals from atmospheric corrosion such as barrier coatings like paint, plastic, and powder, peelable coatings, rust preventive oils, cathodic protection, dip galvanization, etc. restricting metal surfaces from acidic vapors, chloride, bromide corrosion. The major problems arise while the packaged part or equipment is unpacked. The paint, oil, or coating leaves a residue while cleaning [1].

Polyethylene film offers many advantages as a packing material. Polyethylene packaging in conjunction with Vapor Corrosion Inhibitors (VCI) is the most effective solution to metal jobs in the transportation industry. The impermeable morphology of the film makes packaged objects free from water vapor, oxygen in combination with most other contaminants in the atmosphere. However, the diffusion of VCI molecules into the headspace of the package became a concern when it encounter a high level of acid gas contaminations. The film is available in markets with different sizes ranging from 25-150 µm thickness and combination with metalized aluminum layers (multilayer films). Conventional polyethylene films are more permeable to water vapor, acid, and other gas constituents than the multilayer films. The diffusivity varies with thickness and the type of polymeric materials. In addition to ease of handling, it is also fully recyclable.

VCIs are organic compounds that include primary, secondary amines, and azole compounds. Cyclohexyl ammonium carbonate (CHAC), diisoporopylammonium nitrite (DIPAN) and dicyclohexyl ammonium nitrite (DICHAN)[2], Benzotriazoles [3], 6-methoxy-aminobenzothiazole derivatives[4], 1,6-diaminohexane [5] for Al, Zn, Mild Steel (MS). The parent compounds have specific vapor pressure under ambient conditions to essentially cover the surface of the metal by adsorption. In presence of moisture, the VCI active becomes polarized, and is attracted towards anode or cathode of the metal which protects the metal corrosion from the electrochemical process by adsorbing ions on the surface. Among these chemistries, primary amines are ecologically safe, non-toxic in nature, and are also admissible in REACH compliance.