Polyester materials have a wide range of applications in medical fields

in particular

they can be used as a drug releasing materials in the human body. Polyesters used as drug releasing materials need to meet the requirements of having enough modification sites to facilitate bonding drug molecules or other small molecules. For conveniently and efficiently bonding of small molecular to the polyester chains

the current hot reaction-" click reaction" have to be invovled to bond small molecular

which requires to introduce the functional groups into the polyester chain for the " click reaction". Therefore

it is necessary to prepare cyclic ester monomers functionalized with double bonds and triple bonds for further ring-opening polymerization to obtain polyesters with double bonds and triple bonds on the chains. In this review

we introduce the functional cyclic ester monomers which polymers can be modified by " click reaction" in recent years. We divided the cyclic ester monomers into three kinds to introduce the synthetic methods in details. Research progresses of the results in the functional polyesters are highlighted

with focusing on the molecular bonded with the polyester chains and the new properties they have. Furthermore

the applications of the functional polyesters materials are prospected.