Effect of Post-Curing on the Thermal Behavior and Mechanical Properties of mSLA-Printed Elastic Photopolymer Resin

Abstract

3D-printing via masked stereolithography (mSLA) enables the fabrication of complex polymer components with high resolution and excellent surface quality. However, mSLA-printed parts often exhibit incomplete polymerization in their as-printed (green) state, resulting in reduced mechanical performance and structural stability. Ultraviolet (UV) post-curing is therefore essential to enhance the degree of conversion and improve material properties. In this study, the effects of UV post-curing time on the mechanical and thermal behavior of mSLA-printed elastic photopolymer resin were investigated. Specimens were fabricated using a mSLA 3D printer and subjected to varied post-curing time under controlled conditions. Characterization was carried out using differential scanning calorimetry (DSC), uniaxial tensile testing (ASTM D412 Type C), and hardness testing (Durometer Type-M). The results indicate that increasing post-curing time promotes further polymerization and improves polymer network. Consequently, improvements in tensile properties, such as elastic modulus, and surface hardness, were observed. However, extended curing may lead to reduced ductility due to increased network rigidity. Overall, the study establishes a post-curing and property relationship and demonstrates the effectiveness of post-curing in improving stiffness. These findings provide practical insights for optimizing post-processing conditions in mSLA-based 3D-printing of elastic photopolymer materials.