Investigation of the physical, chemical and thermal properties of a novel lignocellulosic fiber extracted from the leaf stalk.

Natural plant fibers are inexpensive, lightweight, renewable, and environmentally friendly, making them sustainable substitutes for synthetic materials. This study aims to identify alternative, eco-friendly replacements for nonbiodegradable fibers used in polymer composites. To achieve this goal, the fibers from leaf stalks were thoroughly characterized, with a focus on their physical, mechanical, thermal, and morphological properties. The hygroscopic properties (moisture content and regain), density, and chemical composition of the fibers were evaluated following ASTM D2654, ASTM D1909, ASTM D891-18, and TAPPI standards, respectively. Chemical composition analysis revealed that the fiber contained 54.25 wt% cellulose, 20.12 wt% hemicellulose, and 15.17 wt% lignin, contributing to its enhanced mechanical properties. The crystallinity, surface structure, chemical bonds, and thermal behavior of the fibers were analyzed XRD, SEM, FTIR, and TGA techniques. This novel fiber has a moisture content and regain percentages of 9.17% and 10.1%, respectively. Its average tensile strength is 151 MPa for a 20 mm gauge length (GL) and 136.8 MPa for a 30 mm gauge length (GL), with a crystallinity index of 67.37%, in which the size of the crystals is 15.64 nm. The fiber degradation begins at a maximum temperature of 550 °C. This original fiber holds potential for applications in the production of cellulose nanoparticles, fiber-reinforced composites, biomaterials and so on.