中文摘要：

采用Discover微波精确有机合成系统及其单模聚焦微波辐射技术与空压气体同步冷却技术,分别以脂肪酶和辛酸亚锡为催化剂,聚乙二醇（PEG）为大分子引发剂引发消旋丙交酯（D,L-LA）开环聚合制备PLA-PEG-PLA共聚物,通过正交实验研究了功率、催化剂种类和用量、时间和温度对共聚物产率的影响,确定了最佳合成条件。在此基础上,改变n（D,L-LA）/n（PEG）投料比制备了不同组成的PLA-PEG-PLA共聚物,采用IR、1 H NMR、GPC和表面接触角测定对共聚物进行了表征。结果表明,在微波作用下,两种催化剂均可催化体系反应得到共聚物,但脂肪酶的催化效率较低,对应共聚物的分子量不高;原料配比对共聚物的组成与性能有显著影响,随n（D,L-LA）/n（PEG）值增大,共聚物的分子量增大;由于引入了亲水性的聚乙二醇链段,共聚物的亲水性明显优于单一的PLA材料。

英文摘要：

PLA-PEG-PLA tri-block copolymer was synthesized by precision microwave organic synthesis system which combining single-mode focusing microwave radiation technology and synchronized pneumatic gas cooling technology.In the experiment,PPL or Sn（Oct）2 as a catalyst respectively,and poly（ethylene glycol） as a co-initiator to initiate the bulk ring-opening polymerization of D,L-LA.In order to find the best reaction conditions,the influences of macrowave power,the type and content of catalyst,irradiation time and reaction temperature on the yield of copolymers were analyzed by orthogonal test.Furthermore,PLA-PEG-PLA tri-block copolymers with different composition were perpared by changing the n（D,L-LA）/n（PEG） feed ratio.The structure and properties of the tri-block copolymer were studied by IR,1H NMR,GPC and surface contact angle measurements.Results showed that PLA-PEG-PLA tri-block copolymer was both successly obtained using the two catalysts under single-mode focus microwave irridation,but the catalyst sufficiency of the PPL was low than that of the Sn（Oct）2.The n（D,L-LA）/n（PEG） feed ratio had a strong influence on the structure and properties of tri-block copolymer,higher n（D,L-LA）/n（PEG） feed ratio led to copolymer with higher molecular weight.Compared to pure PLA,the copolymers show higher hydrophilicity due to the incorporation of hydrophilic PEG units in the copolymers.