以乳酸为原料,辛酸亚锡为催化剂,采用梯度升温法,在168℃、0.098 MPa下直接熔融缩聚合成端羟基改性聚乳酸共聚物聚（乳酸/1,4丁二醇）[P（LA/BDO）]、聚（乳酸/二乙醇胺）[P（LA/DEA）]和聚（乳酸/ε-己内酯）[P（LA/CL）]。用乌氏黏度法、红外光谱（FT-IR）、核磁共振（1H-NMR）、差示扫描量热（DSC）、热重分析（TGA）及X射线衍射（XRD）等对聚合物进行了表征。结果表明,三种端羟基聚合物的Tg均比PLA的低,改性剂的引入降低了聚乳酸的刚性,起到了一定的增塑作用;各聚合物热稳定性较好,为一步分解;P（LA/CL）和P（LA/BDO）的结晶度比PLA有所降低,柔韧性增强,而P（LA/DEA）为无定型聚合物,这种无定型结构有利于材料的降解。
The hydroxyl-terminated modified polylactic acid copolymers of poly（lactic acid/1,4-butanediol）[P（LA/BDO）],poly（lactic acid/diethanolamine）[P（LA/DEA）] and poly（lactic acid/ε-caprolactone）[P（LA/CL）]were synthesized via directly melt polycondensation with D,L-racemic lactic acid（D,L-LA） as raw material and stannous octoate as catalyst.The copolymerization reaction was performed at the temperature of 168 ℃ and the pressure of 0.098 MPa using linear heating method.The copolymers were characterized by viscosity-average molecular weight,Fourier transform infrared spectrum（FT-IR）,1H nuclear magnetic resonance spectrum（1H-NMR）,differential scanning calorimetry（DSC）,thermogravimetric analysis（TGA） and X-ray diffraction（XRD）.The results demonstrate that Tg of the hydroxyl-terminated copolymers is lower than that of PLA,reducing the rigidity of PLA with certain plasticization;The copolymers have good thermal stability for one-step decomposition;Compared with PLA,the crystallinity of P（LA/CL） and P（LA/BDO） decreases,and the flexibility increases.While P（LA/DEA） is amorphous polymer,this amorphous structure is conducive to the degradation.
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