Azo Initiators

Iniper azo-initiators are symmetrical azonitrile compounds. They decompose thermally by cleaving two carbon-nitrogen bonds. This process forms two alkyl radicals and a nitrogen molecule. The resulting tert-akyl radicals remain more stable than most radicals from peroxide initiators. These radicals do not abstract hydrogens from polymer backbones, leading to linear polymer formation and surpressing branched grafting.

Azonitrile decomposition rates experience minor solvent effects. Transition metal, acids, bases, and many other environmental components do not affect them. These conditions provide two advantages for azo-initiators. Their decomposition rates remain predictable. They work for curing resins with various extraneous materials. However, a drawback of azonitriles compared to peroxides is the formation of toxic tetrasubstituted succinonitrile derivatives due to alkyl radical recombination.