Mechanical and Hydro‐Mechanical Performance of <scp> <i>Telfairia pedata</i> </scp> Fiber Reinforced Bio‐Based Thermoplastic Polyurethane Composites: Effects of Fiber Loading and Bio‐Based Compatibilizers

ABSTRACT This study offers a comprehensive investigation into the development of bio‐based thermoplastic polyurethane (bTPU) polymer composites reinforced with Telfairia pedata fiber (TPF) as fillers for incorporation into a bio‐based polymer matrix. The TPF, a lignocellulosic stem fiber not previously evaluated in any TPU matrix, was investigated as a reinforcement in a bTPU. The study addresses two gaps: the absence of TPF data in a bio‐TPU system and the lack of a methodical comparison of bio‐based compatibilizers for hydro‐mechanical durability in a fully bio‐derived composite. Alkaline (NaOH) treatment was applied to TPF to enhance fiber‐matrix adhesion, and two biocompatibilizers were compared. Untreated and alkali‐treated TPF (aTPF) were incorporated at 5, 10, and 15 wt%, with 5 wt% aTPF identified as the mechanically optimal loading. Subsequently, two biocompatibilizers (W and B) were introduced at 3, 5, and 7 wt% alongside 5 wt% aTPF, with 5 wt% emerging as the optimum concentration for both series. Surface modification was confirmed by Fourier‐transform infrared (FT‐IR) spectroscopy and scanning electron microscopy (SEM); mechanical behavior by tensile testing and Shore A/D hardness; processability by melt flow index (MFI); and hydro‐mechanical response by water‐uptake measurement combined with post‐immersion mechanical testing. Biocompatibilizer B yields superior tensile performance, with 5 wt% B‐series achieving the highest tensile strength of 30.2 MPa. Although prolonged water exposure led to mechanical losses, biocompatibilizer B effectively reduced moisture‐induced deterioration compared with other formulations. Final optimization confirms that 5 wt% aTPF/5 wt% B‐compatibilizer formulation represents the overall optimum.