Anaerobic adhesives cured by a redox initiated free radical mechanism have been known in industry for over two decades. Typical formulations contain (meth)acrylic monomers, stabilizers, accelerators, a fluorescing thiophene derivative used as an inspection aid, and other ingredients to modify polymer properties and rheology. The mechanism is a convoluted array of oxidation and reduction reactions and efforts to succinctly describe the process are still being postulated. Commercially, the reaction proceeds by the addition of a transition metal to an adhesive composition containing a peroxide as a free radical source. The general reaction scheme is shown in Figure 1 where m represents the transition metal and M is the monomer.
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