Thermal Analysis of 1,6-Hexanediol Diacrylate-Based Green Bodies Containing GYAGG:Ce Fabricated by DLP 3D Printing

The thermal decomposition of DLP-printed green bodies containing a cross-linked 1,6-hexanediol diacrylate matrix filled with complex oxide powder of a cerium-activated garnet structure (GYAGG:Ce) was investigated. Non-isothermal thermogravimetric measurements were performed under an argon atmosphere at heating rates of 2, 4, 8 and 20 °C/min (four independent measurements for each heating rate). The main mass-loss stage occurs at approximately 350-470 °C. With the increase in the heating rate, the mean DTG peaks shift to a higher temperature: from 387.1 ± 10.3 °C at 2 °C/min to 427.9 ± 15.2 °C at 20 °C/min. The kinetics of thermal decomposition were investigated using isoconversional analysis methods. The apparent activation energy of the main mass-loss peak calculated by the Kissinger method was 200.85 kJ/mol (R² = 0.99). Gas-phase mass-spectrometric analysis tentatively assigned signals to water, CO, CO₂, and acrylate-derived fragments of organic chains. A thermal analysis-guided debinding schedule was developed and experimentally demonstrated, resulting in the production of bulk ceramics with measurable optical translucence (the full transmittance and in-line transmittance were 54.5% and 12%, respectively, for a sample 1.2 mm thick). The absence of large cracks and delamination was observed in both green and brown bodies by scanning electron microscopy.