Extraction and characterization of a novel cellulosic fiber from <i>Delonix regia</i> pod for polymer composite applications

The increasing global demand for sustainable and eco-friendly materials has driven significant interest in natural fibers as alternatives to synthetic reinforcements in polymer composites. Delonix regia pods possess fibrous structures that have not been extensively explored for material applications. This study focuses on the extraction and characterization of cellulosic fibers from Delonix regia pods and evaluates their suitability for use in polyester-based polymer composites. The Delonix regia pod fibers were extracted using a chemo-mechanical retting process with sodium hydroxide and were subsequently characterized. The extracted fibers were incorporated into polyester polymer in varying weight fractions of 0, 10 and 20 wt. % using the handlay-up method. The mechanical properties, morphology and infrared spectroscopy of the fibers and the developed composites were characterized. The results show that the extracted fibers have a yield of approximately 72% with bulk density and moisture content of 0.238 g/cm 3 and 4.60%, respectively. The average tensile properties of the fibers were 44.07 MPa, 2.06 GPa, and 3.71% for strength, modulus and elongation at break. It was also observed that the fibers are composed of 51.40% cellulose, 20.80% hemicellulose, and 16.71% lignin. The tensile properties of the composites with higher filler content were reduced due to increased fiber heterogeneity in the matrix. The Delonix regia pods fibers shows potential for use in polymeric composite production.