玻璃成型聚合物中不寻常的非线性和非指数性
Gaopeng Shi1, Xuhong Zheng1, Yuanbiao Liu2
1College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China.
The journal of physical chemistry. B
|September 5, 2025
概括
聚烯 (PVP) 复合物的离子相互作用降低了动态异质性,将热力学特性与玻璃过渡动态联系起来. 这项研究揭示了盐添加如何影响脆弱性和放松性,
科学领域:
- 聚合物物理
- 材料科学
- 热力学
背景情况:
- 聚合物中的玻璃过渡表现出复杂的动态,包括非Arrhenius,非指数和非线性特征.
- 这些动态参数往往是经验相关的,但底层的热力学起源仍然存在争议.
- 聚烯 (PVP) 和其盐复合物为研究这些相关性提供了一个模型系统.
研究的目的:
- 系统地研究PVP/盐复合物的动态异质性参数和热力学特性之间的相互关系.
- 阐明离子相互作用在调节玻璃过渡行为的作用.
- 建立一个热力学框架来理解聚合物玻璃中的异质动力学.
主要方法:
- 使用放松参数对PVP/盐复合物的热力学分析.
- 在玻璃过渡温度 (Tg) 和热量歇斯底里 (ΔHR) 中测量热容量跳跃 (ΔCp).
- 用亚当-吉布斯模型将热力学因素与脆弱性 (m),非指数性 (β) 和非线性 (x) 等动态参数相关联.
主要成果:
- 引入离子相互作用减少了动态脆弱性 (m),非指数性 (β) 和非线性 (x),破坏了已建立的经验相关性.
- 增强的ΔCp表明热力学因素是x和m同时下降的主要驱动因素.
- 一个x > β的异常表明延迟时间分布的物理不均性有助于非指数动态,与离子相互作用的较低激活能量相关.
结论:
- 热力学特性,特别是 ΔCp 和 ΔHR,对于理解聚合物玻璃形成的动态异质性和脆弱性至关重要.
- 离子相互作用通过改变热力学和动力学参数显著影响玻璃过渡的动态.
- 这项研究为解释异质动力学提供了一个新的热力学框架,加强了热力学和聚合物动力学之间的联系.
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