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以乳酸(D,L-LA)和L-酪氨酸(Tyr)为原料[n(D,L-LA)/n(Tyr)=95/5],采用梯度升温法,通过直接熔融缩聚合成了系列聚(乳酸-酪氨酸)共聚物(PLA-co-Tyr)。最佳工艺条件为压力0.095MPa,催化剂Sn(Cl)2用量为0.4%(质量分数),聚合温度170℃,反应10h。用特性粘度测试、FT-IR、1 H-NMR、GPC、XRD、DSC等对其进行表征,结果表明,此方法操作简单且成本低廉,系列共聚物与PLA相比,分子链中引入了活性基团,具有较小的Tg,结晶度有所降低,并且通过控制酪氨酸的加入量可以调节聚合物的结晶度。该聚合物分子量能满足用作药物缓释试剂的要求。
(D, L-LA) / n (Tyr) = 95/5] was synthesized by direct melt polycondensation using lactic acid (D, L-LA) and L-tyrosine A series of poly (lactic acid-tyrosine) copolymer (PLA-co-Tyr). The optimum conditions were pressure of 0.095MPa, catalyst Sn (Cl) 2 content of 0.4% (mass fraction), polymerization temperature of 170 ℃ and reaction time of 10h. The results of characterization by intrinsic viscosity test, FT-IR, 1 H-NMR, GPC, XRD and DSC showed that this method was simple and cost-effective. Compared with PLA, Group, has a smaller Tg, the degree of crystallinity is reduced, and the degree of crystallinity of the polymer can be adjusted by controlling the amount of tyrosine added. The molecular weight of the polymer can meet the requirement of being used as a drug sustained release reagent.