Nitroxide-Mediated Photo-Controlled/Living Radical Polymerization of Methacrylic Acid

• 作者: Eri Yoshida
• 来源期刊: 高分子化学期刊(英文)
• 学科: 化学
• 关键词: Photo-Controlled/Living Radical POLYMERIZATION Nitroxide-Mediated POLYMERIZATION Methacrylic Acid 4-Methoxy-2 2 6 6-Tetramethylpiperidine-1-Oxyl (4-Tert-butylphenyl)diphenylsulfonium TRIFLATE Molecular Weight Control
• 年，卷（期）: 2013,（1）
• 页码范围: 16-22
• 页数: 7页
• 分类号: O6

摘要

The photo-controlled/living radical polymerization of methacrylic acid (MAA) was performed at room temperature by irradiation with a high-pressure mercury lamp using azo initiators and 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as the mediator in the presence of (4-tert-butylphenyl)diphenylsulfonium triflate (tBuS) as the accelerator. Whereas the bulk polymerization yielded polymers with a bimodal molecular weight distribution in both the absence and presence of tBuS, the solution polymerization in methanol produced unimodal polymers with the molecular weight distribution of 2.0 - 2.3 in the presence of tBuS. The molecular weight distribution of the resulting poly (MAA) decreased with an in- crease in tBuS. The dilution of the monomer concentration also reduced the molecular weight distribution. The use of the initiator with a low 10-h half-life temperature also effectively controlled the molecular weight. The livingness of the polymerization was confirmed by obtaining linear increases in the first-order conversion versus time, the molecular weight versus the conversion, and the molecular weight versus the reciprocal of the initiator concentration.