Measurement of chain transfer to monomer constants in ketene acetal homo- and copolymerization

The chain transfer to monomer constants (<em>C</em><sub>M</sub>) in homopolymerization of 2-methylene-1,3-dioxepane and its copolymerization with styrene are determined under different conditions using the chain length distribution analytical method. The obtained chain transfer constant value <em>C</em><sub>M</sub> = (1.2-1.6) × 10<sup>−2</sup> is 2-3 orders of magnitude higher than that for polymerization of vinyl monomers such as styrene, MMA and others. Therefore, the chain transfer to monomer is the main chain-growth termination reaction in radical ring-opening polymerization of ketene acetals.