热分析技术（thermal analysis）是指在程序控制温度下，测量物质的物理性质随温度变化的函数。根据国际热分析协会的归纳，现有的热分析技术可分为9类17种（表4-1）。在这些热分析技术中，差热分析（differential thermal analysis，DTA）、差式扫描量热法（differential scanning calorimentry，DSC）、热重分析（thermogravimetry，TG）、热机械分析应用最为广泛，这些热分析技术可表征的物理量列于表4-2。本章主要介绍这些技术。
表4-1 热分析技术分类
表4-2 几种主要的热分析方法及其测定的物理化学参数
续表(www.xing528.com)
热分析技术的英文描述如下。
Thermal analysis includes a group of techniques in which specific physical properties of a material are measured as a function of temperature.The production of a new high-technology materials and the resulting requirement for a more precise characterization of these substances have increased the demand for thermal analysis techniques.Current areas of application include environmental measurements，composition analysis，product reliability，stability，chemical reactions，and dynamic properties.Thermal analysis has been used to determine the physical and chemical properties of polymers，electronic circuit boards，geological materials，and coal.An integrated，modern thermal analysis instrument can measure transition temperatures，weight losses，energies of transitions，dimentional changes，modulus changes，and viscoelastic properties.
Thermal analysis is useful in both qualitative and quantitative analysis.Samples may be identified and characterized by qualitative investigations of their thermal behavior.Information concerning the detailed structure and composition of different phases of a given sample is obtained from the analysis of thermal data.Quantitative results are obtained from changes in weight and enthalpy as the sample is heated.The temperatures of phase changes and reactions as well as heats of reaction are used to determine the purity of materials.
The use of microprocessors has both enhanced and simplified the techniques of thermal analysis.The sample is heated at a programmed rate in the controlled environment of the furnace.Changes in selected properties of a sample are monitored by specific transducers，which generate voltage signals.The signal is then amplified，digitized，and stored on a magnetic disk along with the corresponding direct temperature responses from the sample.The data may also be displayed or plotted in real time.The microcomputer is used to process the data with a library of application softwares designed for thermal analysis techniques.The multitasking capabilities of some computer systems allow a single microcomputer to operate several thermal analyzer simultaneously and independently.
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