Design,synthesis and characterization of novel biodegradable macrodiols based on poly(DL-lactic acid) and poly(p-dioxanone)

Integrating poly（lactic acid）(PLA),glycolic acid（GA） and ethylene glycol（EG） will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility.In this study,p-dioxanone（PDO） was employed to copolymerize with DL-lactide（LA） via ring-opening melt polymerization using Sn（Oct）;as an initiator and ethylene glycol as a co-initiator.The obtained degradable macrodiols(HO-P（LA-co-PDO）-OH) were just such a copolymer consisting of PLA,GA and EG.;H NMR was employed to characterize the copolymers,and the effect of PDO/LA molar ratios in the feedstock on the molecular weights of HO-P（LA-co-PDO）-OH was investigated by means of endhydroxyl analysis,;H NMR or GPC-MALLs.The results confirmed the successful synthesis of HO-P（LA-co-PDO）-OH and revealed that one end-hydroxyl of the micarodiols was donated by LA or PDO and the other one by the co-initiator EG.In addition, the molecular weights of HO-P（LA-co-PDO）-OH increased with decreasing PDO/LA ratios.