Recycled polyolefin-based thermoplastic waste reinforced with recycled nylon fibre for sustainable prosthetic socket materials: Mechanical, thermal, microstructural, and finite element evaluation

This study evaluates recycled polyolefin-based thermoplastic waste reinforced with recycled nylon fiber as a sustainable candidate material for prosthetic socket applications. Recycled polyolefin-based thermoplastic waste (PW), recycled nylon fiber waste (NHFW), and PW/NHFW composites were fabricated through melt compounding and compression moulding, followed by mechanical, thermal, microstructural, statistical, and finite element analyses. Relative to PW, which exhibited a tensile modulus of 245.74 MPa, tensile strength of 37.57 MPa, flexural modulus of 422.09 MPa, and flexural strength of 36.89 MPa, the PW/NHFW composite achieved 311.61 MPa, 38.55 MPa, 571.98 MPa, and 50.75 MPa, respectively, corresponding to improvements of 26.8%, 2.6%, 35.5%, and 37.5%. One-way ANOVA confirmed that material composition significantly affected tensile strength (F = 156.26, p = 2.56E-09) and flexural strength (F = 530.95, p = 1.95E-12). Tukey HSD analysis further showed that NHFW had significantly higher tensile strength than both PW and PW/NHFW, whereas PW/NHFW was not significantly different from PW in tensile strength (mean difference = 0.98 MPa; p = .315). In contrast, all flexural pairwise comparisons were significant, including the improvement of PW/NHFW over PW (mean difference = 13.86 MPa; q = 13.91), indicating that nylon fiber reinforcement was expressed more strongly under bending than under uniaxial tension. Impact and hardness testing showed that PW/NHFW achieved an impact strength of 7.08 kJ/m 2 and hardness of 14.48 HRM. Thermal analysis confirmed adequate processing stability, while microscopy revealed fiber embedment, fiber bridging, and dispersed nylon reinforcement, with local pull-out and debonding indicating interfacial limitations. Finite element predictions reproduced the experimental tensile and flexural trends and showed improved stress redistribution in PW/NHFW. Overall, the findings demonstrate that recycled polyolefin-based thermoplastic/nylon fiber composites offer a promising material-level platform for sustainable prosthetic socket development.