The Continuous polymerization of F.-caprolactone initiated by titanium phenoxide was carried Out in both an internal mixer and a twin-screw extruder. The polymerization was performed under different processing conditions, including various temperatures and screw speeds. To perform a kinetic study, samples were collected along the time axis (internal mixer) and along the screw axis (extruder). Size exclusion chromatography and proton nuclear magnetic resonance were used to Study the evolution of the, conversion degree with mixing time and with the extruder. The rheological behavior was also characterized. Temperature had a strong effect on conversion in the internal mixer, whereas in the twin-screw extruder, both temperature and screw speed played major roles. The specificity of the titanium phenoxide to lead to high-molar-mass poly(F.-caprolactone) under these processing conditions was also confirmed. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3480-3487, 2008