高分子の合成において分子量を制御することは，高分子材料の分子設計において極めて重要です。一例として相田らは，テトラフェニルポルフィリンから調製したアルミニウム-ポルフィリン錯体[(TPP)AlX,1]が，さまざまなモノマーに対し，分子量分布の狭い高分子を合成する優れた開始剤になることを見いだしています。この1を開始剤とする重合では，一度重合が停止した後，モノマーを供給すると再び重合が進行して分子量が増加します。一方，異なるモノマーを追加した場合はブロックコポリマーが生成します。この重合法の最大の特徴は，分子量分布の狭い高分子を重合できる点にあります。

[1] “Polymerization of epoxides catalysed by metalloporphine”

T. Aida, R. Mizuta, Y. Yoshida, S. Inoue, Makromol. Chem. 1981, 182, 1073. DOI: 10.1002/macp.1981.021820408

The catalyst system obtained by the equimolar reaction of diethylaluminium chloride with α,β,γ,δ-tetraphenylporphine exhibits high catalytic activity in the polymerization of propylene oxide to give a polymer with a narrow molecular weight distribution. Average molecular weight of the polymer can be controlled by the initial mole ratio of propylene oxide to catalyst or by the conversion. Ethylene oxide also produces a polymer having a narrow molecular weight distribution.

[2] ”Synthesis of polyester-polyether block copolymer with controlled chain length from β-lactone and epoxide by aluminum porphyrin catalyst”

T. Yasuda, T. Aida, S. Inoue, Macromolecules 1984, 17, 2217. DOI: 10.1021/ma00141a003

[3] “‘Immortal’ polymerization. Polymerization of epoxide catalysed by an aluminium porphyrin–alcohol system”

S. Asano, T. Aida, S. Inoue, J. Chem. Soc. Chem. Commun. 1985, 1148. DOI: 10.1039/C39850001148

Ring-opening polymerization of epoxide catalysed by a (tetraphenylporphinato)aluminium chloride-alcohol system affords a polyether having a controlled molecular weight of narrow distribution with the number of the polymer molecules exceeding the number of aluminium porphyrin molecules; this is due to exchange between the alcohol and the (porphinato)aluminium alkoxide, which is the active species, resulting in the ‘immortal’ nature of the polymerization.

[4] “Stereochemistry of ring-opening reactions of epoxide with aluminum and zinc porphyrins. Relation to the mechanism of ring-opening polymerization”

Y. Watanabe, T. Yasuda, T. Aida, S. Inoue, Macromolecules 1992, 25, 1396. DOI: 10.1021/ma00031a006

[5] “Novel visible-light-driven catalytic carbon dioxide fixation. Synthesis of malonic acid derivatives from CO2, an .alpha.,.beta.-unsaturated ester or nitrile, and diethylzinc catalyzed by aluminum porphyrins”

M. Komatsu, T Aida, S. Inoue, J. Am. Chem. Soc. 1991, 113, 8492. DOI: 10.1021/ja00022a042

[6] “High-speed living anionic polymerization of methacrylic esters with aluminum porphyrin initiators. Organoaluminum compounds as Lewis acid accelerators”

H. Sugimoto, M. Kuroki, T. Watanabe, C. Kawamura, T. Aida, S. Inoue, Macromolecules 1993, 26, 3403. DOI: 10.1021/ma00065a025

 

弊社では数多くの重合開始剤を取り揃えております。詳細は下記リンクより参照ください。
≫ 重合開始剤