Mechanophores with a Reversible Radical System and Freezing-Induced Mechanochemistry in Polymer Solutions and Gels
Mechanophores with a Reversible Radical System and Freezing-Induced Mechanochemistry in Polymer Solutions and Gels
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DOI：
10.1002/anie.201412413
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发表时间：
2015-05-18
影响因子：
16.6
通讯作者：
Otsuka, Hideyuki
中科院分区：
文献类型：
--
作者：
Imato, Keiichi;Irie, Atsushi;Otsuka, Hideyuki
聚合物材料中共价键断裂的可视化和定量评估对于理解失效、疲劳和劣化机制以及提高材料的寿命、耐久性、韧性和可靠性非常重要。基于二芳基联苯并呋喃酮的机械基团自由基系统能够通过电子顺磁共振波谱对机械基团的断裂进行原位定量评估，并估计外力沿聚合物链引起的机械能。聚合物溶液通过冷冻的凝固可能产生力，但不会裂解力基团。另一方面，交联导致超过80kJmol(-1)的力有效传播到一些机械载体，导致它们裂解并产生有色稳定自由基。这种机械探针概念也有可能阐明聚合物领域的其他有争议的问题。
Visualization and quantitative evaluation of covalent bond scission in polymeric materials are highly important for understanding failure, fatigue, and deterioration mechanisms and improving the lifetime, durability, toughness, and reliability of the materials. The diarylbibenzofuranone-based mechanophore radical system enabled, through electron paramagnetic resonance spectroscopy, insitu quantitative evaluation of scission of the mechanophores and estimation of mechanical energy induced along polymer chains by external forces. The coagulation of polymer solutions by freezing probably generated force but did not cleave the mechanophores. On the other hand, cross-linking led to efficient propagation of the force of more than 80kJmol(-1) to some mechanophores, resulting their cleavage and generation of colored stable radicals. This mechanoprobe concept has the potential to elucidate other debated issues in the polymer field as well.