Differential Scanning Calorimetry for Measuring the Curing Degree of Epoxy Powder Materials

The curing degree of epoxy powder materials is a key factor determining their properties. Insufficient curing degree will greatly reduce the mechanical properties and chemical corrosion resistance of the material, making it unable to meet the needs of practical applications; Excessive solidification may cause the material to become brittle, losing its original flexibility and impact resistance. Therefore, accurately measuring the curing degree of epoxy powder materials is of great significance for optimizing material properties, ensuring product quality, and promoting the development of related industries.

Differential Scanning Calorimeter (DSC), as a thermal analysis instrument, plays an important role in determining the curing degree of epoxy powder materials. It can accurately measure the thermal changes of samples during heating or cooling processes. Through in-depth analysis of these thermal data, we can obtain various key information during the curing process of epoxy powder materials, such as curing starting temperature, peak temperature, termination temperature, and curing reaction enthalpy, and accurately calculate the curing degree of the material.

1、 Experimental operation steps

1. Measuring instruments:DZ-DSC400C Differential Scanning Calorimeter

2. Test sample: Epoxy powder

3. Measurement chart:

4. Data analysis:

According to the experimental steps in Appendix B of the standard GB/T23257-2017, the experimental parameters were set for the thermal characteristics test method of epoxy powder and its like layer. After deducting the cooling curve, the above figure was obtained. The gray line represents the third stage test chart of the sample, which shows that the glass transition temperature point of Tg1 is 68.061 ℃, the curing temperature of epoxy powder is 133.719 ℃, and the curing enthalpy is 61.3647J/g. The green line represents the fifth stage test chart of the sample, which shows that the glass transition temperature point of Tg2 is 107.482 ℃.

According to the thermal characteristics requirements in Table 2 of GB/T23257-2017 for epoxy powder coatings, the curing enthalpy of epoxy powder should be ≥ 45J/g and Tg2 should be ≥ 98 ℃. Based on the above experimental data, the epoxy powder coating tested meets the standard requirements.

2、 Practical application cases

1. In the aerospace field, the performance of composite materials is directly related to the safety, reliability, and flight performance of aircraft. Taking the manufacturing of composite materials for aircraft wings as an example, the main structure adopts a composite material with epoxy resin as the matrix and carbon fiber as the reinforcement. Accurately testing the curing degree of epoxy resin through differential scanning calorimetry (DSC) in the research and production process has become a key step in optimizing the properties of composite materials.

2. In the field of chip packaging, epoxy resin is a commonly used packaging material, and its curing degree directly affects the electrical performance, heat dissipation performance, and long-term reliability of the chip. Taking the packaging of smartphone chips as an example, the use of differential scanning calorimetry (DSC) ensures the curing degree of epoxy resin, effectively improving the quality of electronic packaging.

3. In the field of coatings, ships are exposed to harsh marine environments for a long time, facing multiple challenges such as seawater corrosion, adhesion of marine organisms, and ultraviolet radiation. Therefore, the protective performance of ship coatings is crucial. Taking the hull coating of a cargo ship as an example, epoxy resin was used as the main film-forming substance, and the curing rate of the epoxy resin was accurately controlled by differential scanning calorimetry (DSC), effectively improving the protective performance of the coating.

The use of differential scanning calorimetry to test the curing degree of epoxy powder materials is a scientific journey to explore the mysteries of material properties. From the careful selection and preparation of experimental materials in the early stage, to the accurate debugging and calibration of instruments and equipment, to the rigorous operation in the sample preparation process, every link embodies the researchers' persistent pursuit of experimental accuracy.