Controlled radical polymerization of n-butyl α-fluoroacrylate.: 1.: Use of atom transfer radical polymerization as the polymerization method

Atom transfer radical polymerization (ATRP) of n-butyl alpha-fluoroacrylate with CuCl and CuBr as the catalyst and 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as the ligand has been studied. Ethyl 2-bromoisobutyrate (2-EBiB) and 3-(trimethylsilyl)propyl 2-bromopropionate (2-SBP) were used as initiators. The latter was used as a probe for H-1 NMR analysis in order to determine the true molecular weight up to about 10 000. In these conditions at T = 90 degreesC, polymerization was controlled as indicated by a plot of M-n = f(alpha(M)), and the effect of the halogen of the catalyst perfectly agrees with the current knowledge of ATRP. In addition, analysis of the CFBr end groups by F-19 NMR further confirmed that the polymerization follows the ATRP mechanism. By calibration of size exclusion chromatography with standards prepared with the 2-SBP initiator, it was shown that the experimental molecular weights were close to the theoretical values. The results were better than those where the molecular weights were determined with polystyrene or poly(methyl methacrylate) calibration. The characteristic values of the Mark-Houwink coefficients have been calculated for poly(n-butyl alpha-fluoroacrylate) in tetrahydrofuran at T = 30 degreesC.