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Answer (EN)
A monomer is defined, under Article 3(6) of REACH, as a substance which is capable of forming covalent bonds with a sequence of additional like or unlike molecules under the conditions of the relevant polymer-forming reaction used for the particular process. In other words, it is a substance which, via the polymerisation reaction, is converted into a repeating unit of the polymer sequence.Substances exclusively involved in the catalysis, initiation or termination of the polymer reaction are not monomers.While, monomers are by definition intermediates, the specific provisions for the registration of intermediates under REACH do not apply to monomers.For further information, see section 2.1 of the Guidance for monomers and polymers.