The rare earth compound, scandium trifluoromethanesulfonate [Sc(OTf)(3)], has been used as a water-tolerant catalyst for the synthesis of star-shaped poly(E-caprolactone)s (SPCLs) with trimethylol propane as trifunctional initiator in solvent at 40 degrees C. Triarm SPCLs have been successfully prepared. The molar mass of SPCLs were determined by end-group H-1 NMR analyses, which could be well controlled by the molar ratio of the monomer to the initiator, and were independent of the amount of Sc(OTf)(3) used. Differential scanning calorimetry analyses suggested that the maximal melting point, the cold crystallization temperature, and the degree of crystallinities of SPCLs increased with the increasing of the molar mass and were lower than the linear poly (e-caprolactone) (LPCL) with similar molar mass. Furthermore, polarized optical microscopy indicated that LPCL showed fast crystallization rate and good spherulitic morphology with apparent Maltese cross pattern, whereas SPCLs exhibit much lower crystallization rate and poor spherulitic morphology. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 1943-1948, 2010