How does "Anaerobic Adhesive" curing mechanism works?

The basic element in anaerobic adhesive is a monomer from the acrylic family, which combines chemically to form a polymer or group of molecules.Molecules of an anaerobic monomer contain 2 carbon atoms that are double bonded to each other.

The "active" ingredient in this monomer is called a “free radical”. “Free radical” has an affinity (strong attraction) for carbon, but prefers to react with oxygen molecules (at aerobic condition).

When “free radical” reacts with oxygen molecules, it forms a stable liquid like the original monomer. This process is continued as long as the present of oxygen molecules.

When no oxygen is present, the free radical then reacts with the carbon of the double bonded atom of the monomer molecule (at anaerobic condition). A reaction is caused which makes that molecule react with another molecule and begin a chain reaction that produces a solid polymer chain.

Figure 2-1 shows the phases of anaerobic adhesive:
ana

Phase 1: In liquid state (1), the adhesive is kept stable through a constant supply of
oxygen.

Phase 2: When the adhesive is enclosed in the joint gap and separated from the oxygen supply (2), the preoxides are changed into free radicals through a reaction
with the metal ions.

Phase 3: The free radicals then initiate the formation of polymer chains (3).

Phase 4:The cured state (4) shows a solid structure with “cross-linked” polymers chains.