The monomer is the smallest repeating part of a polymer having low molecular mass. An example of a monomer is- acrylonitrile, vinyl chloride, etc.
Buna -N is a synthetic rubber and it is obtained through the polymerization of buta-1,3-diene, and acrylonitrile in the presence of a peroxide catalyst such as benzoyl peroxide.
The chemical structure of buta-1,3-diene is: .
The chemical structure of Acrylonitrile is:
Therefore, buta-1,3-diene and prop-2-ene-1-nitrile (acrylonitrile) are the monomers of Buna-N.