Li Heng, Luo Huitong, Zhao Junpeng, Zhang Guangzhao
Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China.
ACS Macro Lett. 2018 Dec 18;7(12):1420-1425. doi: 10.1021/acsmacrolett.8b00865. Epub 2018 Nov 19.
One-step synthesis of block copolymer from mixed monomers is of great interest and challenge. Using a simple non-nucleophilic organobase as the catalyst, we have achieved sequence-selective terpolymerization from a mixture of phthalic anhydride (PA), an epoxide, and -lactide (LA). Alcohol-initiated alternating copolymerization of PA and epoxide occurs first and exclusively because PA is substantially more active than LA for reacting with base-activated hydroxyl. When PA is fully consumed, LA polymerizes from the termini of the first block while excess epoxide stays intact because of the mild basicity of the catalyst. The two polymerizations thus occur tandemly, both in chemoselective manners, so that an aromatic-aliphatic block copolyester is generated in this one-step synthesis. The effectiveness and versatility of this approach is demonstrated by the use of ethylene oxide and several monosubstituted epoxides as well as mono-, di-, or tetrahydroxy initiators.
由混合单体一步合成嵌段共聚物极具吸引力且颇具挑战。我们使用一种简单的非亲核有机碱作为催化剂，实现了由邻苯二甲酸酐（PA）、一种环氧化物和丙交酯（LA）的混合物进行序列选择性三元聚合。PA和环氧化物的醇引发交替共聚首先且唯一地发生，这是因为PA与碱活化的羟基反应的活性远高于LA。当PA完全消耗时，LA从第一个嵌段的末端聚合，而过量的环氧化物由于催化剂的弱碱性而保持完整。因此，这两种聚合以化学选择性方式串联发生，从而在这一步合成中生成一种芳族 - 脂肪族嵌段共聚酯。通过使用环氧乙烷和几种单取代环氧化物以及单羟基、二羟基或四羟基引发剂，证明了该方法的有效性和通用性。
