Thermal stability and curing behavior of acrylate photopolymers for additive manufacturing

Next-generation additive manufacturing processes based on UV-curing acrylate photopolymers extend the barriers of functional part production by deploying rapid processing speeds, complex geometries with high resolutions, and an extended material spectrum. Many technologies introduce temperature-dependent curing and decomposition behavior of acrylates to the list of process-related challenges. This investigation targets a comprehensive analysis of the curing behavior and thermal stability of acrylic photopolymers by implementing analyzing techniques like thermogravimetric analysis, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. Significant parameters such as the UV intensity and the isothermal temperature are varied based on the design of experiments. Characteristic evolving gases at elevated temperatures are identified and discussed towards their relevance for the curing process. The calorimetric results demonstrate increasing reaction speeds with elevated UV intensities as well as a restricted accelerating effect of increasing temperatures. The reaction enthalpy proves to be strongly dependent on the chosen temperature. The results represent the base for the comparison of different kinetic curing models in future investigations.