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Molecular sieves supported recyclable catalyst for atom transfer radical polymerization using hydration approach Part A Polymer chemistry

Aggarwal, Ravi, Baskaran, Durairaj
Journal of polymer science 2017 v.55 no.23 pp. 3875-3883
activation energy, ambient temperature, catalysts, molecular weight, polymerization, polymers, sieves
Molecular Sieves (MS) were used as a recyclable support for atom transfer radical polymerization. The catalyst complex, CuBr₂/ligand was supported on hydrated MS and used for the polymerization of benzyl methacrylate at room temperature in anisole. The polymerization using CuBr₂/PMDETA (pentamethyl diethyltetraamine) catalyst that is physically held by the hydration of MS exhibited moderate control and produced catalyst free polymers (<0.1 ppm) with narrow molecular weight distribution (Mw/Mₙ ≤ 1.33). The polymerization occurred at the interface between the hydrated support and the solution containing initiator and monomer. The hydrated MS supported catalyst was recycled efficiently without a significant loss in activity. The polymerization proceeded in a “living”/controlled manner as was evident from first‐order time conversion plots. The split kinetics experiment affirmed that there was no propagation in the solution in the absence of the supported catalyst. The reaction order plot showed zero‐order dependence on the bulk initiator concentration in solution. The results of MS supported catalyst were compared to Na‐clay supported catalyst system and the improved results were attributed to high self‐diffusion coefficient and low diffusion activation energy of water on its surface. Published 2017.§ J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3875–3883