Thermal and Physicochemical Characterizations of Biocomposite Materials with Potato Starch Matrix Loaded with Raffia Farinifera Fiber

• Potato starch biocomposites reinforced with Raphia farinifera fibers were prepared. • FTIR confirmed strong starch–fiber interactions and lignocellulosic integration. • Raffia fibers enhanced thermal stability and char residue formation. • Water sensitivity and vapor permeability were significantly reduced. • Controlled biodegradability was achieved for sustainable packaging use. This study focuses on the development and characterization of biocomposites based on potato starch reinforced with Raphia farinifera fibers. The main objective was to improve the thermal, hydric, and environmental properties of starch-based bioplastics. FTIR analyses revealed clear fiber–matrix interactions, evidenced by the intensification of O–H and C–O–C bands and the appearance of lignin-associated peaks around 1600–1510 cm⁻¹, confirming the incorporation of lignocellulosic components into the matrix. Thermogravimetric (TGA/DTG) analyses showed a notable improvement in thermal stability: the main degradation temperature increased from 347 °C for BP to 361 °C for BPFR5 and BPFR7.5, while the final residue increased from 6% (BP) to 21% (BPFR10), reflecting enhanced thermal resistance. Hydric tests revealed a marked reduction in water sensitivity. Solubility decreased from 27.78% (BP) to 16.07% (BPFR10); moisture absorption dropped from 8% to 3–6.5% depending on fiber content; and water vapor permeability decreased from 3.26 × 10⁻⁹ mol·m⁻¹·s⁻¹·Pa⁻¹ (BP) to 1.04 × 10⁻⁹ mol·m⁻¹·s⁻¹·Pa⁻¹ (BPFR10). These results indicate a denser structure and reduced overall polarity. Biodegradation tests confirmed that all biocomposites were degradable, with mass loss decreasing from ≈70% (BP) to 30–45% for fiber-rich formulations, due to the higher resistance of lignin and crystalline cellulose. The BPFR5 and BPFR7.5 formulations exhibited the most balanced performance, combining improved thermal stability, enhanced water resistance, and controlled biodegradability. Overall, the results highlight the potential of raphia fibers as natural reinforcements for the development of biodegradable materials suitable for environmentally friendly packaging applications.