Synthesis of AB block and A2B2 and A3B3 miktoarm star-shaped copolymers using ω-end-functionalized poly(methyl methacrylate) with a hydroxyl group prepared by organocatalyzed group transfer polymerization
Synthesis of AB block and A2B2 and A3B3 miktoarm star-shaped copolymers using ω-end-functionalized poly(methyl methacrylate) with a hydroxyl group prepared by organocatalyzed group transfer polymerization
复制标题
利用有机催化基团转移聚合法制备的带有羟基的ω端官能化聚甲基丙烯酸甲酯合成AB嵌段和A2B2和A3B3米托臂星形共聚物
作者：
Eric;O.-T.;Chen;Y.;Takada;K.;Sato;S.-i.;Satoh;T.,Kakuchi;T
以甲基丙烯酸甲酯为原料，经有机催化基团转移聚合、端基封端硅酮缩醛的Mukaiyama-Aldol封端，合成了不同端羟基的聚甲基丙烯酸甲酯S(PMMA)，研究了其合成微臂星形聚合物的反应。为了进一步阐明这一方法，详细考察了催化剂、聚合物链长和苯甲醛衍生物对ω末端功能化效率(%F)的影响。以苯甲醛为终止剂对活性聚甲基丙烯酸甲酯末端进行亲电封端，制得了结构无缺陷的端羟基ω功能化聚甲基丙烯酸甲酯(PMMA-OH)。此外，分别以对苯二甲醛和苯-1，3，5-三甲醛为原料，合成了两臂双羟基PMMA(PMMA2-OH2)和三臂三羟基星形PMMA(PMMA3-OH3)，其羟基位于聚合物链中心。然后将得到的PMMA-OH、PMMA2-OH2和PMMA3-OH3作为大分子引发剂用于D-丙交酯(DLA)的开环聚合(ROP)，合成了AB嵌段共聚物和A2B2和A3B3型杂臂共聚物。
The synthesis of miktoarm star-shaped polymers has been studied using various poly(methyl methacrylate)s (PMMAs) functionalized with a hydroxyl group, which were prepared by organocatalyzed group transfer polymerization (GTP) of methyl methacrylate, followed by Mukaiyama aldol-type termination of a silyl ketene acetal (SKA) moiety at the living PMMA end. To further elucidate this method, the effects of the employed catalysts, polymer chain length, and benzaldehyde derivatives on the ω-end-functionalization efficiency (%F) were investigated in detail. The electrophilic termination of the living PMMA end with benzaldehyde as the terminator produced a structurally defect-free ω-end-functionalized PMMA with a hydroxyl group (PMMA-OH). In addition, a two-arm PMMA with two hydroxyl groups (PMMA2-OH2) and a three-arm star-shaped PMMA with three hydroxyl groups (PMMA3-OH3), whose hydroxyl groups were located at the polymer chain centers, were prepared using terephthalaldehyde and benzene-1,3,5-tricarbaldehyde, respectively. The PMMA-OH, PMMA2-OH2, and PMMA3-OH3 obtained were then used as macroinitiators for the ring-opening polymerization (ROP) of D-lactide (DLA) to synthesize an AB block copolymer, and A2B2 and A3B3 type miktoarm copolymers.