Takahashi Rintaro, Sugawara-Narutaki Ayae
Department of Macromolecular Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.
Laboratory for Biomaterials and Bioengineering, Institute of Integrated Research, Institute of Science Tokyo, 2-3-10, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
ACS Polym Au. 2025 Feb 13;5(2):129-133. doi: 10.1021/acspolymersau.4c00095. eCollection 2025 Apr 9.
Recently, it has been reported that various polymethacrylates synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization may be depolymerized by heating them to 120 °C in solution. However, insights into the mechanisms and kinetics remain limited. In this work, we monitored the depolymerization process of poly(benzyl methacrylate) in -xylene using time-resolved small-angle X-ray scattering (SAXS). The results revealed that the weight-average molecular weight gradually decreased, while the z-average radius of gyration remained almost unchanged until approximately half of the repeating units were converted. This unexpected behavior could be well-reproduced by a kinetic model of end-to-end depolymerization (unzipping). This study provides the first direct observation of the structural evolution during depolymerization via an unzipping mechanism.
最近有报道称，通过可逆加成-断裂链转移（RAFT）聚合合成的各种聚甲基丙烯酸酯在溶液中加热到120°C时可能会解聚。然而，对其机理和动力学的了解仍然有限。在这项工作中，我们使用时间分辨小角X射线散射（SAXS）监测了聚（甲基丙烯酸苄酯）在对二甲苯中的解聚过程。结果表明，重均分子量逐渐降低，而直到大约一半的重复单元转化之前，z-平均回转半径几乎保持不变。这种意外行为可以通过端到端解聚（拉链式）动力学模型很好地再现。本研究首次直接观察到通过拉链式机理解聚过程中的结构演变。
