Cobalt-mediated radical polymerization of vinyl acetate in an alumina column using suspended polyvinyl acetate

Suspended polyvinyl acetate (SPVAc) was used as a solid adsorbent in the controlled radical polymerization of vinyl acetate. Benzoyl peroxide (BPO), cobalt (II) acetylacetonate (Co(acac)(2)) and N, N-dimethylformamide (DMF) were used as initiator, catalyst and ligand, respectively. In the absence of SPVAc solid adsorbent, polymerization yield was 51.56 % (M-n = 31,400 g.mol(-1), PDI = 1.65), in 195 min. In the presence of SPVAc, both polymerization rate and induction time increased and polymerization yield was 65.6 % (M-n = 89,400 g.mol(-1), PDI = 1.47) in 210 min. Suspended polyvinyl acetate was used in the polymerization in a packed alumina column as a top layer. In this method the slow adsorption and desorption of cobalt complex by SPVAc, was followed by the controlled radical polymerization and the final separation step. In the separation step, the green cobalt catalyst was absorbed by the column and the clean polymer (PVAc) with a narrow molecular weight distribution was isolated.