示差扫描量热法进展及其在高分子表征中的应用

示差扫描量热法(DSC)是表征材料热性能和热反应的一种高效研究工具,具有操作简便、应用广泛、测量值物理意义明确等优点.近年来DSC技术的发展大大拓展了高分子材料表征的测试范围,促进了对高分子物理转变的热力学和动力学的深入研究.温度调制示差扫描量热法(TMDSC)是DSC在20世纪90年代的标志性进展,它在传统DSC的线性升温速率的基础之上引入了调制速率,从而可将总热流信号分解为可逆信号和不可逆信号两部分,并能测量准等温过程的可逆热容.闪速示差扫描量热法(FSC)是DSC技术近年来的创新性发展,它采用体积微小的氮化硅薄膜芯片传感器替代传统DSC的坩埚作为试样容器和控温系统,实现了超快速的升降温扫描速率以及微米尺度上的样品测试,使得对于高分子在扫描过程中的结构重组机制的分析以及对实际的生产加工条件的直接模拟成为可能.本文从热分析基础出发,依次对传统DSC、TMDSC和FSC进行了介绍,内容覆盖其发展历史、方法原理、操作技巧及其在高分子表征中的应用举例,最后对DSC未来的发展和应用进行了展望.本文希望通过综述DSC原理、实验技巧和应用进展,帮助读者加深对DSC这一常用表征技术的理解,进一步拓展DSC表征高分子材料的应用.

Progress of Differential Scanning Calorimetry and Its Application in Polymer Characterization

Differential scanning calorimetry(DSC)is a highly efficient tool to characterize the thermal properties and to investigate thermal reactions of materials owing to its advantages of simplicity and universality as well as the well-defined measurement results with a clear physical meaning.In recent years,the tremendous development of DSC technique has greatly extended the measurement range for polymer characterization,facilitating the further research on thermodynamics and kinetics of physical transitions in polymer materials.Temperature-modulated DSC(TMDSC),a remarkable advance in DSC technique in 1990s,introduces scanning rate perturbation into the traditional linear heating rate so that the overall heat flux could be separated into reversible and non-reversible signals and furthermore,the reversing heat capacity could be measured in the quasiisothermal process.Fast scanning chip-calorimetry(FSC)is a new progress of DSC technique in recent years,which adopts a miniature chip made of silicon nitride thin films to replace the traditional crucible as the sample holder and temperature controller,thus achieving ultra-fast heating and cooling rates for the measurement with sample mass on micro-and nanogram scale,which makes it possible to analyze the structural reorganization phenomena occurring frequently during temperature scanning and to simulate the actual condition of polymer processing.This review starts with the fundamentals of thermal analysis,followed with a sequential introduction of DSC,TMDSC and FSC by covering their histories,principles,experimental skills as well as their practical examples of polymer characterization.In the end,the prospects of the development and application of DSC are highlighted.We hope this survey would help the readers to gain a deeper understanding of the commonly used DSC technique and encourages them to expand further applications of DSC techniques in polymer characterization.