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How to perform thermal analysis using Shimadzu differential scanning calorimeter?
Date: 2025-12-10Read: 0
Shimadzu differential scanning calorimeterBy measuring the heat flux difference between the sample and the reference material during the programmed temperature control process, the thermodynamic changes of the sample during heating or cooling can be reflected, thereby achieving a systematic analysis of its thermal properties. To perform thermal analysis using this device, it is necessary to sequentially complete sample preparation, experimental condition setting, data collection, and result analysis, and maintain consistent operation in each step to obtain reliable information.
Sample preparation must ensure the suitability of form and quality. Solid samples should be ground to a uniform fineness to avoid uneven heat transfer caused by differences in particle size; Liquid samples should be sealed in inert containers to prevent volatilization or reaction interference. The weighing process needs to be precise, so that the difference in heat capacity between the sample and the reference material is within the detection range of the instrument. At the same time, the mass should not be too small to mask the signal with noise, nor should it be too large to cause obvious temperature gradients. The container material should match the properties of the sample to avoid interactions at high temperatures or specific atmospheres. If the experiment needs to be conducted in a specific atmosphere, the gas inside the chamber should be replaced in advance and the sealing should be checked to ensure that the atmosphere is pure and stable.
The experimental conditions include the determination of temperature program and scanning mode. According to the analysis purpose, choose linear heating, cooling, constant temperature or cyclic mode. The heating or cooling rate should balance resolution and sensitivity. If the rate is too fast, it will reduce peak resolution, while if it is too slow, it will prolong the experimental time and may introduce thermal hysteresis effect. The starting and ending temperatures need to cover the expected range of thermal events, and the reference material is generally selected as a thermally inert material, whose thermal properties remain stable throughout the experiment to provide an effective reference signal.
During the data collection process, it is necessary to monitor the instrument status and curve shape. The instrument will automatically record the changes in heat flow with temperature or time, forming a curve that can be analyzed. During the scanning process, external disturbances should be avoided as they can affect the continuity of heat flow measurements. The baseline morphology should be checked to ensure no significant drift or mutation, otherwise baseline correction is required during data processing. Different thermal events appear as endothermic or exothermic steps, peaks, or inflection points on the curve, and their positions and shapes reflect the corresponding thermodynamic parameters.
The analysis of the results should be based on the characteristics of the curve and the corresponding known thermal behavior. The endothermic peak is often associated with melting, evaporation, or decomposition processes, while the exothermic peak is related to crystallization, solidification, or oxidation reactions. The glass transition is characterized by a gentle shift from the baseline towards the endothermic direction. By analyzing peak temperature, peak area, and shape changes, information on transition temperature, enthalpy changes, and kinetics can be obtained. For multi-component systems, overlapping events can be distinguished through stepwise scanning or modulation modes to improve resolution. When necessary, compare the experimental results with different atmospheres or heating rates to determine the nature of the process and influencing factors.
To ensure reliable analysis, the instrument should be calibrated regularly, including the calibration of the temperature axis and heat flux axis, and the accuracy of peak temperature and peak area should be verified using standard substances. Before and after the experiment, it is necessary to check the cleanliness of the sensors and furnace body to prevent signal deviation caused by contamination. The sample preparation and loading methods should be consistent to reduce the variation introduced by the operation.
passShimadzu differential scanning calorimeterThe key to conducting thermal analysis lies in reasonable sample processing, appropriate program settings, stable data collection, and rigorous result interpretation. This method can systematically reveal the physical and chemical changes of materials during heating, providing quantitative and qualitative thermal property basis for formula optimization, process control, and performance evaluation.