Sagawa Katsutoshi, Uchiyama Mineto, Watanabe Hironobu, Homma Chihiro, Kamigaito Masami
Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Precis Chem. 2024 Oct 15;2(12):628-633. doi: 10.1021/prechem.4c00066. eCollection 2024 Dec 23.
Dual control of the molecular weight and tacticity in proton transfer anionic polymerization (PTAP) of methyl methacrylate (MMA) was investigated by using various ligands in the presence of a bulky potassium base catalyst and an organic compound with a weakly acidic C-H bond as dormant species in toluene at 0 °C. The tacticity of the resulting poly(MMA) (PMMA) produced without ligands was nearly atactic (// = 22/54/24). However, the use of 18-crown-6 as a ligand afforded predominantly syndiotactic PMMA ( ≈ 58%), whereas the use of chiral bis(oxazoline) ligands gave slightly isotactic-rich PMMA ( ≈ 32%). Molecular weight control of PMMA was achieved ( = 1.1-1.2) by adding 1,1-diphenylethanol as a reversible terminator while maintaining control of the tacticity with the above ligands. Stereoblock PMMA consisting of atactic and syndiotactic segments was successfully synthesized via sequential PTAP using macroinitiator/macro-CTA methods.
在0°C的甲苯中，以体积庞大的钾碱催化剂和具有弱酸性C-H键的有机化合物作为休眠物种，通过使用各种配体，研究了甲基丙烯酸甲酯（MMA）质子转移阴离子聚合（PTAP）中分子量和立构规整度的双重控制。在没有配体的情况下生成的聚（MMA）（PMMA）的立构规整度几乎是无规的（// = 22/54/24）。然而，使用18-冠-6作为配体主要得到间同立构的PMMA（≈58%），而使用手性双（恶唑啉）配体得到略富含等规立构的PMMA（≈32%）。通过加入1,1-二苯基乙醇作为可逆终止剂，在使用上述配体保持对立构规整度控制的同时，实现了PMMA分子量的控制（ = 1.1-1.2）。通过使用大分子引发剂/大分子CTA方法的连续PTAP成功合成了由无规和间同立构链段组成的立构嵌段PMMA。
