Optimization of stereolithography 3D printed photopolymer using halloysite nanotubes reinforcement for hot embossing master mold application

The versatility of Stereolithography (SLA) 3D printing opens new possibilities in the field of hot embossing manufacturing, particularly in producing the vital master mold. This advancement significantly contributes to industrial growth through the application of manufacturing innovation. However, despite its advantages, the inherent low mechanical properties of SLA 3D printed structures raise concerns about their feasibility, especially under high compressive thermal stress. Thus, to optimize the printed structure for application, the photopolymer resin used in the SLA 3D printing process is reinforced with halloysite nanotubes (HNTs), creating a nanocomposite with higher mechanical properties. In this study, further optimization is performed by evaluating three types of photopolymer resins using a series of thermal and mechanical tests. The most optimum resin is used as the base material for the nanocomposite. The nanocomposites are then evaluated using 1 wt%, 3 wt%, and 5 wt% HNTs composition, and then mechanically tested and compared. In addition, the optimum nanocomposite is used to produce mold and is tested in direct hot embossing application. Based on the tests result, the most optimum resin is the high temperature resin with the highest compressive test and good thermal stability. The most optimum composition is the 3 wt% HNTs, showing the highest increase of compressive Young's Modulus and yield strength at 9.25% and 22.12%, respectively. Additionally, in the hot embossing application test, the 3 wt% HNTs nanocomposites successfully transferred a microfluidic device pattern onto a polymethyl methacrylate (PMMA) working material, with the best transferability shown using a hot embossing temperature of 130 degrees C and 3 min holding duration.