在散装材料中对机械激活的区域化学影响
Yangju Lin1, Meredith H Barbee1, Chia-Chih Chang1
1Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States.
Journal of the American Chemical Society
|November 8, 2018
概括
机色力探测器,就像螺旋衍生物一样,可视化聚合物应力. 这项研究表明,三种螺旋区域同位素对应力有不同的反应,但在相同的高应力水平下激活.
科学领域:
- 聚合物科学
- 材料科学
- 机械化学
背景情况:
- 机色力探针,特别是螺旋衍生物,对于绘制聚合物的应力,应变和断裂是有价值的.
- 了解分子结构和宏观机械反应之间的关系对于设计先进材料至关重要.
研究的目的:
- 研究与三种不同的螺旋区域异构体交联的弹性体的宏观机械反应.
- 将螺旋衍生物的区域异构结构与它们在单轴拉伸负荷下的色度反应相关联.
- 将实验观测与关于机械灵敏度和应变激活的分子建模的预测进行比较.
主要方法:
- 合成含有三种螺旋 (SP) 区域异构体的弹性体:SP{o},SP{m}和SP{p}.
- 将近静态单轴拉伸负荷应用于改性弹性体.
- 用于定量化螺旋衍生物反应的色度分析.
- 分子模型预测机械灵敏度.
主要成果:
- 在拉力负荷下的相对色度反应遵循SP (o) >SP (m) >SP (p) 的顺序,与预测的机械灵敏度保持一致.
- 三种spiropyran区域异构体均表现出无法区分的应变开始,可检测到约90%的单轴应变.
- 在研究的菌株范围 (90- 135%的单轴菌株) 中,异构体的比例反应保持不变.
结论:
- 这项研究表明,虽然spiropyran区域异构体具有不同的敏感性,但在显著的单轴应变下,它们的激活应变的发生是均的.
- 观察到的恒定比度反应与对应力聚合物网络的模拟预期相矛盾,表明复杂的网络行为.
- 这些发现为聚合物分析的机色探针的设计和应用提供了洞察力.
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