Diazirines are three-membered rings with one carbon and two double-bonded nitrogen atoms.
On exposure to moderate heat (approx. 80 to 140oC), near-UV light (350 nm), or electrical current, diazirines rapidly break down into carbenes, which insert themselves into C–H, N–H, and O–H bonds. When two diazirine units are present in a single molecule, the resulting bis-diazirine acts as a crosslinker, covalently bonding two polymer chains together at the same time.
Diazirines react with even the most unreactive polymers, such as polyethylene and polypropylene, that are particularly challenging to bond. BondLynx, a bis-diazirine, can be used directly as a polymeric adhesive or applied to polymer textiles to link and strengthen the fibres.