Evaluation of the termination mode in the radical polymerization of 2,2,2‐trifluoroethyl α‐fluoroacrylate

Abstract

AbstractThe mode of termination of 2,2,2‐trifluoroethyl α‐fluoroacrylate (FATRIFE) in radical polymerization was studied, and only termination by recombination occurred, which led to telechelic macromolecular structures. The radical polymerization in acetonitrile was carried out to synthesize oligomers with a low number average degree of polymerization ($\overline{\hbox{DP}_{\rm n}}$)cum (about 20), using tert‐butylcyclohexyl peroxydicarbonate (TBCPC) as initiator at 75 °C. The initial [TBCPC]0/[FATRIFE]0 molar ratio was monitored to evaluate its influence on the ($\overline{\hbox{DP}_{\rm n}}$)cum of α‐fluoroacrylic oligomers. The 1H NMR analysis of the polymers showed that the ($\overline{\hbox{DP}_{\rm n}}$)cum values obtained were higher than 40, in spite of a high C0 value. To explain these results, the mode of termination was evaluated using the following kinetic law: ${\bf R}_{\bf pi}\ {\bf\approx}\ [{\bf I}_{2}]_{0}^{0.27}[{\bf M}]_{0}^{1.24}$. The development of kinetic relationships allowed us to calculate the ratio kprt/ki·kp as about 17–30 mol s l−1, and to confirm that primary radical termination (PRT) was in competition with bimolecular macromolecular termination (BMT).© 2002 Society of Chemical Industry