单氨基末端超支化聚甘油的可控合成

Controllable synthesis of hyperbranched polyglycerol with a definite aminol terminal

为解决传统超支化聚甘油(HPG)外部结构单一、没有明确分子链末端的缺点,以三羟甲基氨基甲烷(Tris)为原料,合成一种新型引发剂N,N-二苄基三羟甲基氨基甲烷(Bn_2Tris),采用阴离子开环聚合反应引发合成具有明确末端的超支化聚甘油(NH_2-HPG).这种特殊拓扑结构的超支化聚合物分子末端存在一个氨基,并保持了传统超支化聚甘油的化学结构.实验结果显示:改变单体/引发剂的投料比可得到分子质量分别为1 300 g/mol、2 550 g/mol和4 050 g/mol的NH_2-HPG,其对应的粒径分别为1.99 nm、3.07 nm和3.96 nm.研究结果表明:该合成方法能对超支化聚甘油分子质量进行有效调控,尺寸大小可呈现一定的梯度变化;这种分子链末端明确的超支化聚甘油在分离膜、催化载体和生物医学等领域具有潜在的应用前景.

To solve the shortcomings of traditional hyperbranched polyglycerol(HPG)with a single external structure and no clear molecular chain ends,a novel initiator N,N-dibenzylTris(hydroxylmethyl)aminomethane(Bn2Tris)was synthesized by introducing benzyl into tris(hydroxymethyl)aminomethane(Tris).Hyperbranched polyglycerol with single amino terminal(NH2-HPG)was synthesized by anionic ring-opening polymerization.The characteristic of the hyperbranched polymer had special structure in which each molecule contains a fixed amino terminal and retains the surrounding hydroxyl structure.The experiment results showed that Bn2Tris and NH2-HPG were successfully synthesized,and the molecular weight(1 300 g/mol,2 550 g/moland 4 050 g/mol)could be regulated effectively by changing the ratio of monomer to initiator.The synthesized hyperbranched polymer had excellent dispersibility in water with a certain gradient particle sizes of 1.99 nm,3.07 nm and 3.96 nm.The hyperbranched polymer with special structure has potential application prospect in the fields of separation membrane,catalytic carrier and biomedicine.