Morphological aspects and mechanical properties of single bamboo fibers and flexural characterization of bamboo/ epoxy composites

TLDR

A novel mechanical extraction process produced long Guadua angustifolia fibers, which were tested in single‑fiber tensile tests and incorporated into unidirectional bamboo/epoxy composites with untreated and alkali‑treated variants, and flexural tests were performed in longitudinal and transverse orientations. The fibers achieved 800 MPa strength and 43 GPa modulus, with untreated fibers giving higher longitudinal flexural strength but alkali treatment improving longitudinal stiffness, while transverse strength rose at lower alkali levels; overall, the results show bamboo fibers are a viable renewable reinforcement comparable to glass or other natural fibers.

Abstract

A novel mechanical extraction process was developed to obtain long bamboo fibers to be used as reinforcement in structural composites. A single-fiber tensile test at four different span lengths for fibers of the bamboo species Guadua angustifolia was performed. Strength values of 800 MPa and Young’s modulus of 43 GPa were obtained. Unidirectional bamboo fiber/epoxy composites (BFC) were produced with untreated and alkali-treated fibers to evaluate the effectiveness of the new reinforcing material. Flexural tests were performed with two fiber orientations (longitudinal and transverse). The longitudinal flexural strength is higher when untreated fibers are used while the treatment benefits the longitudinal flexural stiffness of the composite. Transverse strength increases at lower alkali concentrations, but the transverse three-point bending strength of untreated bamboo in epoxy is already quite high at around 33 MPa. The results illustrate that these bamboo fibers present a natural and renewable option to reinforce composites in several applications where glass fiber and traditional natural fibers are used nowadays.