Modified fique tow fibers as a reinforcing agent in the manufacture of biocomposite materials: Extraction and characterization

• The modification of fique tow fibers enhances their potential for application as reinforcement in biopolymeric matrices, increasing the flexural elastic modulus by 30 %. • Utilizing byproducts derived from fique and cassava contributes to the circular economy, enabling a 15 % greater utilization of fique leaf byproducts and a 50 % utilization of cassava root, represented as cassava bran. • Biocomposite material with potential applications in the production of single-use containers, reinforcement of recycled plastic for construction materials, and biodegradable pots. • Biocomposite material with potential application in the production of single-use food containers, exhibiting hydrophobic behavior for up to 900 seconds. This study evaluates the effects of successive treatments on fique tow fibers (NF) for their application in biocomposites materials. The fibers underwent autoclaving (AF), delignification with 5 % NaOH (DF), and bleaching with 5 % NaClO for 30 (BF30), 60 (BF60), and 90 (BF90) minutes. Chemical composition, crystalline structure, thermal stability, and surface morphology were significantly altered by these treatments. FTIR confirmed the removal of hemicellulose and lignin, with BF90 exhibiting 85.71 % crystallinity due to increased cellulose content. Alkaline treatment created surface grooves, while bleaching caused fibrillation, enhancing fiber-matrix adhesion. Thermal analyses demonstrated improved stability, particularly in BF60 and BF90. Biocomposites with cassava bran showed that BF60 improved the flexural modulus by 20 % and reached a contact angle of 113.67°, indicating hydrophobicity. SEM analysis of the biocomposites revealed improved adhesion between cassava brain and bleached fibers. A strong Pearson correlation (0.99) was found between the fibers’ color coordinates and mechanical properties, emphasizing the influence of surface modification. The increase in thermal stability was evidenced in biocomposites made with BF60. The study highlights the combined use of NaOH and NaClO as an effective method for enhancing the properties of fique fibers for biopolymer reinforcement, offering a sustainable alternative to synthetic composites.