pls explain polymerisation of buna-s &buna-n

Buna -s and Buna-n are prepared by co-polymerization.

Co-polymerization is a polymerisation reaction in which a mixture of more than one monomeric species is allowed to polymerise and form a co-polymer

• Butadiene−Styrene co-polymer or Buna -s is produced by co-polymerization of 1,3 butadiene and styrene.

Buna -N

• Obtained by the co-polymerisation of 1, 3-butadiene and acrylonitrile in the presence of peroxide catalyst

• B −