Experimental Polymer Mechanochemistry and its Interpretational Frameworks
Experimental Polymer Mechanochemistry and its Interpretational Frameworks
复制标题
实验聚合物力化学及其解释框架
DOI：
10.1002/cphc.201700521
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发表时间：
2017
期刊：
影响因子：
2.9
通讯作者：
Akbulatov S
中科院分区：
文献类型：
--
作者：
Akbulatov S
高分子力化学是一门介于化学、材料科学、物理和工程之间的新兴学科。它的目的是通过与周围环境的相互作用，理解和开发限制在高度非平衡伸展几何构型中的高分子链的独特反应性。大分子链或其链段在机械载荷或聚合物溶液被超声作用或通过突然收缩快速流动时在本体聚合物中被拉伸。越来越多的经验数据表明，无论在哪里使用聚合物，机械力化学现象都很普遍。在过去的十年中，经验力化学取得了巨大的进展，从通过简单的主链均解来研究商品聚合物的裂解，到展示自增强和应力报告材料，以及使用有目的地设计的单体的机械力化学级联。这一进展还没有与发展概念框架相匹配，以便使经验性机械化学观察合理化、系统化和概括化。因此，对机械力化学现象的机械论和/或定量理解仍然是试探性的，几乎没有例外。在这篇综述中，我们旨在将已报道的聚合物机械力化学的宏观表现系统化，并从物理化学家的角度批判性地评估支撑其分子合理化的解释框架。我们提出了一个机械力化学现象的层次结构，它可以指导机械力化学反应的多尺度模型的发展，以匹配化学动力学的艾林方程的广度和实用性。我们讨论了量化和验证机械力化学反应性的方法的局限性，特别是声学聚合物溶液，以确定需要解决的突出问题，以使聚合物机械力化学成为一个严格的定量领域。最后，我们提出了7个问题，这些问题的解决可能会对聚合物机械力化学的发展产生不成比例的影响。
Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non‐equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self‐strengthening and stress‐reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose solution may have a disproportionate impact on the development of polymer mechanochemistry.