Dynamic mechanical, tensile fatigue and water absorption behaviour of polyester composites comprises of Amaranthus dubius stem natural fiber and its root waste crystalline cellulose

This study aims to address the research gap of manufacturing a biodegradable composite material using economically sound and abundant waste reinforcements for eco-friendly applications. The primary aim of this research study was to examine how the addition of novel root cellulose and stem fiber of Amaranthus dubius influence fatigue and dynamic mechanical and hydrophobic behavior of an industrial grade polyester resin. Both the fiber and cellulose underwent silane treatment process before being utilized for composite fabrication. Utilizing the hand layup method, the composite were prepared and the test specimens were then cut in compliance with the applicable American Society for Testing and Materials (ASTM) standards. The findings of this study show that the highest fatigue life counts for composite designation PA3 is 30862, 28041, and 24384 for 25%, 50%, and 75% ultimate tensile stress, indicating that the composites with 3.0 vol.% cellulose improved the fatigue strength of composites. Similarly, the addition of cellulose and fiber improved the energy storage and reduced the loss factor due to improved visco-elastic properties. The addition of cellulose improved the energy storage while reducing the energy dissipation factor. Additionally, the lowest contact angle of 74 is observed for composite which contains 5.0 vol.% of cellulose, and it is still in hydrophobic range. These properties improved lightweight polyester composites which could be used in home infrastructure, commercial infrastructure products like man-hole covers and hand rails, and automotive applications since the produced composites are made out of cheaper and effective natural reinforcements.