“…Moreover, the pendent functional groups can facilitate covalent pro-drug attachment as well as other modifications. Recently, many polycarbonates with functional groups have been synthesized, such as carboxyl [7], hydroxyl [8], amino [9], vinyl [10,11], benzyl [12], etc. The synthesis of novel cyclic monomers containing a variety of functionalities has become an important method for the development of new biodegradable polymer materials with special properties for different applications.…”