在高密度聚乙烯/异性聚烯混合物中,流感结晶的组成依赖性
McKenzie L Coughlin1, Derek E Huang1, Caitlyn M Edgar1
1Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
Macromolecules
|October 30, 2024
概括
剪切通过增强流动诱导结晶来改善混合高密度聚乙烯 (HDPE) 和异性聚烯 (iPP) 塑料的机械性能. 这一过程抵消了混合物中减少的结晶,使回收更可行.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物科学 聚合物科学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 像高密度聚乙烯 (HDPE) 和同位性聚烯 (iPP) 这样的多聚烯在塑料市场上占据主导地位.
- 由于接口粘附性较低,混合HDPE-iPP混合物的机械性能差,造成了回收挑战.
- 混合循环中的脆性行为源于相隔域在压力下脱离.
研究的目的:
- 调查剪切对HDPE-iPP混合物的结晶动力学和质性质的影响.
- 了解剪切如何影响混合聚烯烯回收的形态和机械行为.
- 确定改善再生HDPE-iPP混合物的可加工性和性能的策略.
主要方法:
- 使用差分扫描热量计 (DSC) 来分析热性质.
- 采用雷奥-拉曼光谱,极化光学显微镜和扫描电子显微镜 (SEM) 进行结构和形态分析.
- 在静止和剪切条件下进行实验,以比较结晶行为.
主要成果:
- 静态混合物显示,当同位性聚烯 (iPP) 形成滴滴阶段时,结晶温度降低,与分离结晶相一致.
- 在所有含有 iPP 的混合物中,与纯 iPP 相比,剪切诱导的延长域和意外增强的流动诱导结晶 (FIC).
- 流动诱导的结晶有效抵消了分离结晶的负面影响,这表明在滴滴阶段的剪切诱导核化.
结论:
- 剪切显著提高了HDPE-iPP混合物的结晶动力学,提高了它们的可加工性.
- 观察到的流动诱导结晶的增强归因于变形iPP域内的微流场.
- 这些发现为改善混合聚烯废物流的机械性能和可回收性提供了一条途径.
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