On The Average Number of Radicals per Particle during Free Radical and Living Radical Emulsion Polymerization

The free radical distributions over various polymer particles during conventional free radical emulsion polymerization and the effects of newer controlled radical polymerization chemistries on the radical distribution are calculated and discussed. It is shown that while reversible addition–fragmentation transfer (RAFT) chemistry does not change the free radical distribution from that of conventional free radical chemistry, nitroxide-mediated radical polymerization (NMRP) and atom transfer radical polymerization give very different radical distributions, with the average number of radicals per particle greatly reduced from that of the free radical case. At very high radical flux, the average number of radicals per particle is determined only by the activation/deactivation equilibrium of the control agent.