中文摘要：

直接以廉价的外消旋乳酸（D，L-LA）和亮氨酸（Leu）为原料，以氧化亚锡为催化剂，采用熔融聚合法合成了新型生物材料聚（乳酸-亮氨酸）共聚物，并用FT-IR、1^H NMR、DSC、GPC、XRD等进行了系统表征，考察了不同投料比对共聚物的影响。随着投料比中亮氨酸含量n（Leu）的增加，共聚物由一定的结晶态转变为无定形态。所得共聚物的肘。在3200～6700之间，Tg都低于均聚物聚外消旋乳酸的Tg，能满足该生物降解材料在药物缓释领域中的应用。

英文摘要：

Using cheap D, L-lactic acid （ D, L-LA） and leucine （Leu） as starting materials,and SnO as the catalyst,a novel biomaterial poly（lactic acid-co-leucine） [P（LA-co-Leu）] was directly synthesized via melt copolycondensation. The copolymer was systematically characterized with FTIR, 1^HNMR, DSC, XRD and GPC. The effects of different feed molar ratios were discussed.With the increase of molar ratio of Leu in the feed, the crystallinity of copolymer gradually disappeared. Their weight-average molecular weights （Mw） were between 3 200 and 6 700, and the glass-transition temperature （ Tg） of copolymers was lower than that of homopolymer poly（ D, L-lactic acid） （PDLLA）, which could meet the requirement for the application in drug delivery of this biodegradable material.