透露聚合物接种热塑性弹性体中的变形机制,通过In Situ小角度X射线散射
Vincent M Torres1, Erik Furton2, Jensen N Sevening2
1Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
ACS applied materials & interfaces
|October 10, 2023
概括
嵌入式热塑性弹性体 (TPEs) 由于独特的纳米结构重组和裂纹形成,具有增强的机械性能. 这项研究揭示了线性与移植的聚乙烯-聚乙烯-丁乙烯-聚乙烯 (SBS) 块共聚合物的明显变形机制.
科学领域:
- 聚合物科学 聚合物科学
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
背景情况:
- 热塑性弹性体 (TPE) 通过聚合物化学提供可调节的特性,对于各种应用至关重要.
- 在TPE中非线性宏分子架构比线性对应物增强了机械性能,但变形机制仍然不清楚.
- 了解这些机制是设计具有定制性能的先进TPE的关键.
研究的目的:
- 阐明线性聚乙烯-聚乙烯-聚乙烯-聚乙烯 (SBS) 和移植的SBS热塑性弹性体中的独特变形机制.
- 为了将变形过程中的纳米结构演变与宏观机械增强相关联.
- 提供有关结构与财产关系的见解,这些关系决定了TPE的性能.
主要方法:
- 在位小角度X射线散射 (SAXS) 在单轴延伸过程中的测量.
- 对线性SBS (100%SBS) 和接种SBS (30%SBS,70%) 块共聚合物的比较分析.
- 显微镜和散射模式分析,观察纳米结构的变化和变形模式.
主要成果:
- 线性SBS变形一致,显示域间距变化和高延伸端段拉出.
- 接种的SBS表现出叶片形态和叶片域重新排列和延伸期间裂的双重机制.
- 萨克斯揭示了偏好的叶片面方向平行于拉伸方向和纤维状的形成,在SBS移植的crazes.
结论:
- 接种引入了新的物理交叉链接,使得TPE中显著的纳米结构域重组和自我增强成为可能.
- 在移植的SBS中观察到的域重定向和craze形成有助于它们的优异机械性能.
- 在现场SAXS提供了对TPE性能提高的变形机制的关键见解.
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