a radical addition is a reaction mechanism of organic chemistry, with which a molecule with carbon - carbon double bond of atoms or atomic's groups (added) becomes added. This chemical reaction is started by radicals and runs, if it is not stopped, as radical nuclear chain reaction. The expiration is similar to the radical substitution.
For the start of the reaction initiators so mentioned are needed, with whose assistance the first radicals are produced. In addition peroxides are suitable. In addition, instead light or high temperatures is able to start the radical addition.