物理化学学报 >> 2020, Vol. 36 >> Issue (6): 1905081.doi: 10.3866/PKU.WHXB201905081

所属专题: 热分析动力学和热动力学

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超快扫描量热技术表征高分子结晶动力学

何裕成,谢科锋,王优浩,周东山,胡文兵*()   

  • 收稿日期:2019-05-29 录用日期:2019-08-02 发布日期:2019-08-16
  • 通讯作者: 胡文兵 E-mail:wbhu@nju.edu.cn
  • 作者简介:胡文兵,1966年生。1995年在复旦大学获得博士学位;分别于1998–1999年赴德国弗莱堡大学物理系Strobl研究组、2000–2001年美国田纳西大学化学系Wunderlich研究组、2001–2003年荷兰物质科学研究院(FOM)原子与分子物理研究所Frenkel研究组从事博士后研究。现任南京大学教授。主要研究方向为采用蒙特卡洛分子模拟和Flash DSC方法研究高分子结晶机理及材料热导率表征
  • 基金资助:
    国家自然科学基金(21474050);国家自然科学基金(21734005);教育部长江学者创新团队(IRT1252);中科院交叉学科创新团队项目

Characterization of Polymer Crystallization Kinetics via Fast-Scanning Chip-Calorimetry

Yucheng He,Kefeng Xie,Youhao Wang,Dongshan Zhou,Wenbing Hu*()   

  • Received:2019-05-29 Accepted:2019-08-02 Published:2019-08-16
  • Contact: Wenbing Hu E-mail:wbhu@nju.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21474050);the National Natural Science Foundation of China(21734005);Program for Changjiang Scholars and Innovative Research Team in University(IRT1252);CAS Interdisciplinary Team, China

摘要:

高分子结晶行为是高分子材料加工过程研究的热点,因为高分子组分和加工工艺控制着高分子结晶及其产物性能。差示扫描量热仪(DSC)是研究高分子结晶动力学常规手段。但是,普通DSC所能达到的最快降温速率一般无法抑制较快的样品结晶,结晶行为将在等温结晶动力学测试之前发生,因此可进行等温结晶的研究温度范围局限于较低结晶过冷度的高温区域。近年来,具有超快速升降温扫描速率和精准控温的快速扫描芯片量热仪(FSC,其商业化版本Flash DSC 1)得到了广泛应用。FSC可以抑制高分子样品在升降温过程中的结晶成核,避免对之后的结晶动力学测试产生影响。因此FSC技术将高分子结晶动力学的研究温度区间延伸至具有较大过冷度的低温区,加深了我们对高分子结晶成核机理以及高分子工业加工过程的理解。本文首先介绍了由初级成核方程描述的高分子结晶动力学原理,初级成核自由能位垒(ΔG*)和扩散活化能位垒(ΔU)分别控制了高低温区的结晶动力学。我们还总结了FSC技术的发展,包括氮化硅薄膜芯片技术、快速扫描量热仪、商业化Flash DSC 1在不同高分子结晶熔融行为研究中的应用。然后介绍表征高分子等温结晶动力学的方法,其中包括样品制备、质量估算、消除热历史、临界扫描速率的确定等,并举例介绍FSC在高分子结晶动力学研究中的应用,涵盖高分子总结晶动力学、结晶成核动力学、高分子焓松弛对结晶成核的影响、FSC联用技术等方面。应用举例中对应形貌和结晶信息,分析了通过FSC测试得到的结晶成核动力学特点。另外通过比较不同结构特点的高分子,总结了我们对结晶动力学行为的基本理解。总之,FSC技术是一种能够提供相转变动力学和热力学信息的高效工具,特别是应用于分析只能在快速扫描中得到的样品结构变化信息。同时我们希望本文能够帮助读者考虑超快扫描量热技术在其他材料研究上的应用,包括合金、药物、生物大分子等。

关键词: Flash DSC, 高分子, 结晶动力学

Abstract:

Biological systems can be regarded as complex and open thermodynamic systems. All processes involved in biological growth and metabolism are accompanied by material and energy exchange. During metabolism, energy in the organisms is released in the form of heat, i.e., metabolic heat, which is the basis for development in the field of biothermochemistry. The calorimetric method considers the thermal effects produced by the various forms of action as the research object, to reveal the law of energy change and quantitative energy conversion. Studying the thermodynamic processes of complex biological systems and related reactions through microcalorimetry and thermodynamic methods reflects the intrinsic laws of life-related processes macroscopically and intrinsically. With the tremendous development and progress in microcalorimetry in terms of the temperature measurement accuracy, stability of temperature control, automation, and multi-functionalization, calorimetry has been widely used in life sciences. It can be used to describe macroscopic processes such as ecosystems and biological evolution, observe organismal and cell growth, examine mitochondrial metabolism, and study problems at the molecular level, including enzymatic reactions and interactions between small molecules and biomacromolecules. Herein, the application of biomass calorimetry in the life sciences is reviewed. The status and progress of biomass calorimetry at different biological and structural levels, such as the ecosystem, biological, organ, cellular, subcellular, and molecular levels are introduced. For example, soil microbial metabolic activity is a universal index for evaluating soil quality. The growth and metabolism of organisms as well as the physical and chemical processes of substances in soil are often accompanied by heat release, which is usually a non-selective signal. The use of isothermal microcalorimetry to nonspecifically monitor and record soil microbial metabolic characteristics has promoted the study of microbial metabolism in complex soil systems. The application of calorimetry to the study of tissues and organs mainly involves the calorimetric study of isolated animal and plant tissues and organs. Calorimetry of animal and microbial cells is considered the most common application of calorimetry in life sciences research. It mainly involves the classification and identification of bacteria, their growth and metabolism, inhibition mechanisms of drugs on microbial growth, principles of kinetics, and the thermodynamic characteristics of microbial growth and metabolism. However, owing to the lack of specificity of biomass calorimetry and the lack of direct access to information at the molecular level, more applications of calorimetry combined with other analytical techniques (especially in biology, medicine, and pharmacy) are needed in the future.

Key words: Flash DSC, Polymer, Crystallization kinetics

MSC2000: 

  • O642