Sea urchin testa chitin and its reinforcement effect on pineapple fiber-vinyl ester composite

This study investigates the use of chitin extracted from dead sea urchin shells (testa) to enhance the mechanical and physical properties of vinyl-based composites made using pineapple fiber. The chitin biopolymer is extracted via the thermo-chemical method and mixed with resin before making a composite. The composites were fabricated using the hand layup method and tested in accordance with the American Society for Testing and Materials (ASTM) standards. The resulting composites underwent a series of rigorous examinations to evaluate their mechanical performance, fatigue resistance, wear behavior, and hydrophobicity. Results demonstrated the synergistic effect of combining pineapple fiber and chitin in vinyl ester composites across various compositions. The mechanical properties were improved to higher up to C4 (chitin up to 15 vol. % and pineapple fiber of 40 vol. %) composite after that decreased. However, the wear resistance improved with higher chitin content, as evidenced by a reduced coefficient of friction and specific wear rate. Moreover, an extended fatigue life cycle of 17,732 is observed at 75% of ultimate tensile stress in the C4 composite. The contact angle measurements indicated a retained hydrophilicity with an angle of 86⁰ for the C5 composite. These findings provide crucial insights for advanced material engineering applications, highlighting the significant enhancement in mechanical properties with the incorporation of chitin derived from sea urchin shells. The comprehensive characterization reveals the multifaceted improvements brought about by chitin, paving the way for the development of eco-friendly and high-performance composite materials.