Instituto de Ciencia y Tecnología de Polímeros (CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain.
Soft Matter. 2017 Apr 19;13(16):2983-2994. doi: 10.1039/c7sm00104e.
Shape-memory elastomers based on a commercial rubber cross-linked by both ionic and covalent bonds have been developed. The elastomeric matrix was a carboxylated nitrile rubber (XNBR) vulcanized with magnesium oxide (MgO) providing ionic interactions that form hierarchical structures. The so-named ionic transition is used as the unique thermal transition responsible for the shape-memory effect (SME) in these elastomers. These ionic interactions fix the temporary shape due to their behavior as dynamic cross-links with temperature changes. Covalent cross-links were incorporated with the addition of different proportions of dicumyl peroxide (DCP) to the ionic elastomer to establish and recover the permanent shape. In this article, the SME was modulated by modifying the degree of covalent cross-linking, while keeping the ionic contribution constant. In addition, different programming parameters, such as deformation temperature, heating/cooling rate, loading/unloading rate and percentage of tensile strain, were evaluated for their effects on shape-memory behavior.
已经开发出了基于商业橡胶的形状记忆弹性体，该橡胶通过离子键和共价键交联。弹性体基质是一种羧基化丁腈橡胶（XNBR），用氧化镁（MgO）硫化，提供形成分级结构的离子相互作用。所谓的离子转变被用作这些弹性体中形状记忆效应（SME）的独特热转变。由于其随温度变化的动态交联行为，这些离子相互作用固定了临时形状。共价交联通过向离子弹性体中添加不同比例的过氧化二异丙苯（DCP）来引入，以建立和恢复永久形状。在本文中，通过改变共价交联的程度来调节 SME，同时保持离子贡献不变。此外，还评估了不同的编程参数，如变形温度、加热/冷却速率、加载/卸载速率和拉伸应变的百分比，以研究它们对形状记忆行为的影响。
