Exploring fiber characteristics: Comparative analysis of mechanically extracted banana leaf central rib fibers from Azores and Madeira

This study, to the best of our knowledge, is the first to compare natural fibers extracted from the central ribs of banana leaves from two different Portuguese archipelagos, the Azores and Madeira. With the increasing global need to replace synthetic materials with renewable and biodegradable alternatives, a key barrier to the wider adoption of natural fibers is the variability of their properties depending on geographic origin and processing route. The fibers were mechanically extracted and subjected to different treatments, including biological (water retting), chemical (NaOH), and a combination of both. Their chemical, morphological, thermal, and mechanical properties were characterized using FTIR-ATR, SEM-EDS, XRD, and tensile testing. Chemical composition analysis confirmed cellulose enrichment and impurity reduction after treatment, aligning with improvements in crystallinity and mechanical behavior. While fibers from both archipelagos responded positively to the treatments, slight differences were observed: fibers from Madeira exhibited marginally higher tensile strength and crystallinity than those from the Azores, likely due to variations in local agro-climatic conditions.The results show that the treatments significantly affect fibers' structure and performance. The 10% NaOH treatment led to a marked increase in tensile strength (from 230.66 MPa to 611.80 MPa) and Young's modulus (from 10.08 GPa to 18.66 GPa); however, it also removed key components such as hemicellulose and lignin, potentially compromising structural integrity. In contrast, combining water retting with 1% NaOH provided a more balanced approach, increasing tensile strength from 120.73 MPa to 363.10 MPa while preserving the chemical composition more effectively. These findings highlight the potential of Banana Leaf Central Rib Fibers (BCRF) from both regions as sustainable raw materials for high-performance applications, particularly where mechanical strength and eco-friendly sourcing are essential.