With the purpose to decrease the crystallinity of poly(-caprolactone) (PCL)

a small amount (8.5 mol%) of 2

2-dimethyltrimethylene carbonate (DTC) was added to copolymerize with -caprolactone (CL) using lanthanum tris(2

6-di-tert-butyl-4-methylphenolate) (La(OAr)3) as catalyst. The produced polyester P(CL-co-DTC) (PCD) was wellcharacterized by 1H-NMR

SEC

DSC and WAXS. The results showed random copolymer PCD was synthesized. DSC and WAXS results proved PCD had a much lower crystallinity (c = 28.1%) compared to that of PCL (c = 44.7%). PCD

as well as PCL homopolymer containing 8 wt% salicylic acid as a model drug was electrospun into ultrafine fibers with the diameter around 1 m and further submitted to in vitro drug release test. The results showed that the PCD electrospun mat exhibited a controlled drugrelease behavior while the PCL one displayed a burstrelease behavior. The DSC and WAXS results showed PCL electrospun fibers had a much higher crystallinity (c = 79.3%) than that of PCD electrospun fibers (c = 40.3%) and this explained the difference of drugrelease behaviors of the two electrospun mats. It was the non-crystalline domains involved in PCD that facilitated the compatibility between the polymer matrix and salicylic acid and allowed the drug to be released in a controlled way through the thermal motion of the polymer chain. This study provided a strategy for a better drug inclusion and release behavior by lowering the crystallinity of matrix material.