Cyclopentyl methyl ether as a green solvent for reversible-addition fragmentation chain transfer and nitroxide-mediated polymerizations

Abstract

Cyclopentyl methyl ether (CPME) was successfully used as an environmentally friendly alternative to the regularly employed organic solvents (e.g., tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dichloromethane (DCM) and dimethylformamide (DMF)) for the reversible-addition fragmentation chain transfer (RAFT) polymerization and nitroxide-mediated polymerization (NMP) of vinyl chloride (VC) and styrene (S). Methyl acrylate (MA) and vinyl acetate (VAc) were also successfully polymerized via RAFT using CPME. The kinetic data showed a linear increase of the molecular weight with the monomer conversion for both polymerization methods. The k^app_p data obtained in CPME were in the range of the values reported for THF, DMSO, DCM and DMF, while the final conversions were higher. The polymer samples were comprehensively characterized by ¹H nuclear magnetic resonance spectroscopy (¹H-NMR), ³¹P-NMR, matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF-MS) and size exclusion chromatography (SEC). The “livingness” of the PVC macroinitiators prepared by RAFT and NMP were confirmed by chain-end characterization and successful reinitiation experiments. The data presented here prove that CPME is an excellent green substitute to avoid the use of toxic solvents for RAFT and NMP.