Cobalt -mediated radical polymerization of vinyl acetate in a packed column system: simultaneous effective control of molecular weight, separation, and purification

The simultaneous control of the molecular weight, separation, and purification of polyvinyl acetate was achieved using a cobalt-mediated radical polymerization (CMRP) in a packed column with silica gel particles (PC-CMRP). The controlled radical polymerization of VAc in the packed columns was evaluated from the linear time dependence of Ln[M](0)/[M], linear increase of molecular weight with the increase in conversion, and narrow molecular weight distribution. PC-CMRP method was used to produce high-purity polymers with controlled molecular weight and narrow molecular weight distribution without requiring additional purification steps. The high ability of silica gel particles to adsorb free Co(acac)(2) from the polymer matrix leads to the formation of pure polymers with decolorization efficiency = 91%. This method introduced a new capability for separation of polymers with known molecular weights and narrower molecular weight distributions, during the polymerization. Packed column in CMRP reactions can physically lead to the generation of long-lived propagating radicals and thus enhance the probability of producing polymers with a higher molecular weight and lower polydispersity index.