Which mechanism is non-convertible in the curing processes?

In the context of curing processes, coalescence refers to the mechanism where small particles or droplets within a paint film merge to form a continuous film as the solvent evaporates. This process is reversible; if environmental conditions change, such as an increase in humidity, it is possible for the film to lose its integrity.

The correct response identifies a mechanism that is non-convertible during curing. Polymerization, on the other hand, is a chemical reaction that involves the combination of monomers to form a polymer and is irreversible. Once the polymers are formed, they cannot revert back to their original monomer states. Oxidation is also an irreversible chemical change, typically involving a reaction with oxygen that can further contribute to the hardening and permanence of coatings.

Absorption, like coalescence, can be somewhat reversible. It refers to the process of a substance taking in another substance, which can change under varying conditions.

Thus, among the options, polymerization stands out as a non-convertible mechanism in the curing process due to its irreversible nature.