Investigation of zinc borate-reinforced epoxy composites produced via additive manufacturing: thermal and mechanical analysis

Purpose The purpose of this study is to investigate the production and performance of zinc borate–reinforced epoxy composites produced via additive manufacturing. This study aims to evaluate the effects of different zinc borate reinforcement ratios on the mechanical, thermal and fire retardancy properties of the composites. By analyzing the results, this study seeks to provide a deeper understanding of the potential of zinc borate as an eco-friendly flame retardant in advanced polymer composite applications. Design/methodology/approach Epoxy composites were reinforced with zinc borate at weight fractions of 0.5%, 1%, 2% and 3% using the stereolithography additive manufacturing method. The mechanical properties were characterized through tensile, three-point bending and dynamic mechanical analysis. Thermal properties were assessed using thermogravimetric analysis, and flame retardancy was evaluated with specific fire retardancy tests. Microstructural and chemical properties were examined via scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy analyses. In addition, hardness and thermal conductivity tests were performed to provide a comprehensive evaluation of the composites. Findings The incorporation of zinc borate significantly improved the thermal stability and mechanical properties of epoxy composites. Zinc borate acted as an effective flame retardant due to its hydrate groups, which enhanced thermal stability. However, the flame retardancy performance was found to be insufficient at lower reinforcement rates. This study highlights the potential of zinc borate as a multifunctional additive for enhancing the durability and performance of epoxy composites while emphasizing the need for further optimization to achieve superior flame retardancy. Originality/value This study represents an innovative approach by combining eco-friendly zinc borate reinforcement with advanced additive manufacturing techniques to produce high-performance polymer composites. It provides valuable insights into the interplay between reinforcement ratios and composite properties, offering a pathway for the optimization of zinc borate–reinforced materials. The findings contribute to the growing field of sustainable material development and establish a foundation for future studies in flame-retardant polymer composites.