The ring-opening polymerization of ε-caprolactone (CL) in the presence of water

alcohol and carboxyl acid at moderate temperature (80℃) has been investigated

indicating that carboxyl group does not initiate the polymerization of CL

but can accelerate the hydroxyl-initiated polymerization of CL

and the catalytic-ability of the carboxyl acid depends upon its acidity. Thus

a series of α -hydroxyl-ω-carboxyl (1

2

3) functional telechelic oligocaprolactones were synthesized by the polymerizations of CL initiated with hydroxy-acids glycollic acid

DL-malic acid

or citric acid at a moderate temperature (80℃).The products were characterized by the acid-base titration

hydroxyl value titration

UV

FTIR and 1H-NMR analysis

respectively.The mechanism of carboxyl-catalyzed hydroxy-initiated CL polymerization was also described.