Polymerization-induced phase separation enables fine control over thermoset network morphologies, yielding heterogeneous structures with domain sizes tunable over 1–100 nm. However, the controlled chain-growth polymerization techniques exclusively employed to regulate the morphology at these length scales are unsuitable for a majority of thermoset materials typically formed through step-growth mechanisms. By varying the composition of a binary curing agent mixture in a classic rubber-toughened epoxy thermoset, where the two curing agents are selected based on disparate compatibility with the rubber, we demonstrate facile tunability over morphology through a single compositional parameter. Indeed, this method yields morphologies spanning the nano-scale to the macro-scale, controlled by the relative reactivities and thermodynamic compatibility of the network components. We further demonstrate a profound connection between chain dynamics and microstructure in these materials, with the tunable morphology enabling exquisite variations in glass transition. In addition, previously unattainable control over tensile mechanical properties is realized, including atypical increase of elongation at failure while maintaining the modulus and ultimate strength.

中文翻译：

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橡胶增韧胺固化环氧树脂中的聚合诱导相分离：从纳米尺度到宏观尺度调整形态

聚合诱导的相分离能够对热固性网络形态进行精细控制，产生域尺寸可在 1-100 nm 范围内调节的异质结构。然而，专门用于在这些长度尺度上调节形态的受控链增长聚合技术不适用于通常通过逐步增长机制形成的大多数热固性材料。通过改变经典橡胶增韧环氧树脂热固性材料中二元固化剂混合物的组成，其中两种固化剂是根据与橡胶的不同相容性来选择的，我们证明了通过单个组成参数对形态的轻松可调性。事实上，这种方法产生了跨越纳米尺度到宏观尺度的形态，由网络组件的相对反应性和热力学兼容性控制。我们进一步证明了这些材料中链动力学和微观结构之间的深刻联系，可调的形态使玻璃化转变发生了微妙的变化。此外，实现了以前无法实现的对拉伸机械性能的控制，包括在保持模量和极限强度的同时，破坏伸长率的非典型增加。