were obtained respectively by a5min ring opening polymerization (ROP) ofε-caprolactone (CL) and lactide (LA) with stannous octoate as catalyst under microwave irradiation. PCL (Mw over40kg·mol
-1
) was also prepared from the microwave-assisted polymerization of CL initiated by benzoic acid. Ibuprofen-PCL controlled release system was formed directly by the ROP of CL mixed with Ibuprofen. Heating behavior of CL and LA by microwaves had significan effect on their microwave polymerization.