Development of Environmentally Sustainable Epoxy Composites with Sunflower Seed Husk Fillers and Study on Thermal and Moisture Properties

This study examines the development and characterization of epoxy composites reinforced with sunflower seed husk (SSH) fillers fabricated using the compression molding technique. SSH fillers were categorized into two distinct particle size distributions, namely, 4-53 mu m and 79-463 mu m, and were incorporated into the epoxy matrix at varying volume fractions ranging from 5% to 20%. The water absorption behavior of the composites was assessed according to ASTM standards, and thermogravimetric analysis (TGA) was employed to evaluate their thermal stability. Furthermore, Grey Relational Analysis (GRA) was used to optimize the composite formulation based on both properties. Experimental findings indicate that an increase in the SSH filler content leads to higher water absorption, whereas thermal stability is generally enhanced with SSH reinforcement. The use of finer particles (4-53 mu m) facilitates better filler-matrix interaction, effectively reducing moisture penetration while maintaining th ermal performance. In contrast, larger SSH fillers (79-463 mu m) contributed to superior thermal resistance, but resulted in higher water absorption. Among the investigated formulations, the composite containing 15% fine SSH filler (S15) exhibited the most favorable balance between thermal stability and moisture resistance. These findings highlight the potential of SSH as an environmentally sustainable reinforcement material for epoxy-based composites. The enhanced thermal properties and controlled moisture absorption make these composites suitable for applications in automotive, marine, and construction industries, where durability and thermal efficiency are critical.