DSC measurement of curing and glass transition temperature of epoxy powder coatings

Epoxy powder is a type of powder coating composed of epoxy resin and other additives. Epoxy coatings are generally divided into oil-based epoxy coatings and water-based epoxy coatings to ensure the environmental and practical performance of products. They are used in bridges, ships, underwater coatings, chemical anti-corrosion coatings, and coal mine facilities for anti-corrosion purposes. Whether plasticizers and curing agents are added, and changes in the composition of epoxy resin can affect the glass transition temperature of the coating. Therefore, we need to accurately measure its glass transition temperature to make it suitable for different application environments.

DZ-DSC300C is an experimental device with temperatures ranging from -40 ℃ to 600 ℃Differential scanning calorimeterThe equipment has a wide range of experimental temperatures and can be applied to thermal analysis of various materials such as resin, plastic, rubber, etc. Among them, vitrification and curing are two of them. The corresponding parameters can be measured by collecting the changes in heat absorption and release of the test sample during the heating process.

　　Test method:Weigh about 10mg of the sample and place it in a 60ul aluminum crucible container. Heat it up to 80 ℃ at a rate of 20 ℃/min and then quickly cool it down to room temperature. Set the following parameters (Figure 1) to conduct another temperature rise and fall experiment on the sample, and obtain the experimental spectrum for analysis (Figure 2).

Figure 1

Figure 2

　　Analysis of experimental results:The blue curve represents stage heating, with a Tg temperature of 52.31 ℃. There is an exothermic curing process between 151.13 ℃ and 219.15 ℃, which releases 17.7767J/g of heat; The black curve represents the second heating process, with a Tg of 73.76 ℃. From this experiment, we can see that the glass transition temperatures of the two heating stages are different. This is because the epoxy powder still undergoes a curing reaction during the secondary heating process. After testing samples with different degrees of curing, we can conclude that the higher the curing degree of the resin, the higher the glass transition temperature tested. For more information about DZ-DSC300C differential scanning calorimeter products, please consult:.