Catalytic chain transfer

Catalytic chain transfer (CCT) is a process that can be incorporated into radical polymerization to obtain greater control over the resulting products.

The method involves adding a catalytic chain transfer agent to the reaction mixture of the monomer and the radical initiator.

Boris Smirnov and Alexander Marchenko (USSR) discovered in 1975 that cobalt porphyrins are able to reduce the molecular weight of PMMA formed during radical polymerization of methacrylates.

[16][17] The best recognized chain transfer catalysts are low spin cobalt(II) complexes[13] and organo-cobalt(III) species, which function as latent storage sites for organo-radicals required to obtain living radical polymerization by several pathways.

The initial commercial outlet was the production of chemically reactive macromonomers to be incorporated into paints for the automotive industry.

Federally mandated VOC restrictions are leading to the elimination of solvents from the automotive finishes and the lower molecular weight chain transfer products are often fluids.