Xu Jiaxi, Wang Xin, Hadjichristidis Nikos
Polymer Synthesis Laboratory, Physical Sciences and Engineering Division, KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.
Nat Commun. 2021 Dec 8;12(1):7124. doi: 10.1038/s41467-021-27377-3.
The synthesis of well-defined block copolymers from a mixture of monomers without additional actions ("one-pot/one-step") is an ideal and industrially valuable method. In addition, the presence of controlled alternating sequences in one or both blocks increases the structural diversity of polymeric materials, but, at the same time, the synthetic difficulty. Here we show that the "one-pot/one-step" ring-opening terpolymerization of a mixture of three monomers (N-sulfonyl aziridines; cyclic anhydrides and epoxides), with tert-butylimino-tris(dimethylamino)phosphorene (t-BuP) as a catalyst, results in perfect diblock dialternating terpolymers having a sharp junction between the two blocks, with highly-controllable molecular weights and narrow molecular weight distributions (Ð < 1.08). The organocatalyst switches between two distinct polymerization cycles without any external stimulus, showing high monomer selectivity and kinetic control. The proposed mechanism is based on NMR, in-situ FTIR, SEC, MALDI-ToF, reactivity ratios, and kinetics studies.
由单体混合物在无额外操作的情况下（“一锅法/一步法”）合成结构明确的嵌段共聚物是一种理想且具有工业价值的方法。此外，在一个或两个嵌段中存在可控的交替序列会增加聚合物材料的结构多样性，但同时也会增加合成难度。在此，我们表明以叔丁基亚氨基三（二甲氨基）磷烯（t-BuP）为催化剂，三种单体（N-磺酰基氮丙啶、环状酸酐和环氧化物）的混合物进行“一锅法/一步法”开环三元聚合，可得到在两个嵌段之间具有清晰连接点的完美二嵌段双交替三元共聚物，其分子量高度可控且分子量分布狭窄（Ð < 1.08）。该有机催化剂在无任何外部刺激的情况下在两个不同的聚合循环之间切换，显示出高单体选择性和动力学控制。所提出的机理基于核磁共振、原位傅里叶变换红外光谱、尺寸排阻色谱、基质辅助激光解吸电离飞行时间质谱、竞聚率和动力学研究。
