Evaluation of Tensile Properties of Banana PseudoStem Fibers and the Effect of Surface Treatment on Interfacial Shear Strength with PP

Banana pseudostems are an underutilized biomass resource, and their fibers (BPSFs: banana pseudostem fibers) have been reported to exhibit lower tensile strength than other natural fibers. This is often attributed to the fact that tensile strength is typically evaluated based on the apparent cross-sectional area, which includes internal lumens. In this study, X-ray micro-CT was employed to determine the effective cross-sectional area excluding lumens, enabling evaluation of the intrinsic tensile strength of BPSFs. The results showed that the tensile strength calculated using the effective cross-sectional area reached 620 ± 330 MPa, indicating that BPSFs possess a strength level comparable to that of conventional natural fibers. Furthermore, to enhance interfacial adhesion required for application as reinforcement in composite materials, an alkaline surface treatment was applied. A 15-min alkaline treatment resulted in the maximum tensile strength of the fibers, suggesting that the removal of non-cellulosic surface components contributed to strength improvement. In addition, when polypropylene containing 4 wt% maleic anhydride-grafted polypropylene (MAPP) was used as the matrix, the interfacial shear strength exhibited high values after short-duration alkaline treatment.