This research investigates the feasibility of bamboo fibre-reinforced bio-derived polycarbonate composites for secondary aerospace applications. Motivated by the need for sustainable alternatives to synthetic composites, the study focuses on the effects of chemical fibre treatments on mechanical, thermal, and interfacial performance. Bamboo fibres were treated using alkali (2–8% w/v), silane (2-8g/L), and acetylation methods. Acetylated fibres were excluded early due to structural degradation.

Comprehensive fibre characterisation included density, water absorption, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and single fibre tensile testing. Notably, 2% NaOH-treated fibres exhibited a tensile strength of 249 MPa, and 5 g/L silane-treated fibres reached 194 MPa, compared to 110 MPa for untreated fibres. TGA showed improved thermal stability with onset degradation temperatures of 277◦C for 5 g/L silane compared to 267◦C for untreated fibres.

Treated fibres were used to fabricate unidirectional laminates via solvent-based prepreg processing with Durabio, followed by compression moulding. Composite testing included tensile, flexural, and microscopic cross-sectional analysis. The highest tensile strength of 162 MPa and flexural strength of 184 MPa were recorded for composites with 2 g/L silane-treated fibres, with 5 and 8 g/L silane laminates being only slightly lower than that. Untreated composites recorded 121 MPa and 154 MPa, respectively. Void content decreased from 21% for untreated to 18% for silane-treated, accompanied by a bonding efficiency of 95% for the 5 g/L silane laminate, indicating significantly improved fibre-matrix bonding efficiency. This was supported by optical microscopy, which showed more cohesive interfaces and reduced delamination in silane-treated laminates. Alkali-treated fibres, however, consistently showed worsening properties and quality on the composite level due to fibre degradation and poor bonding.

The study concludes that silane treatment, particularly at 2 g/L, enhances fibre-matrix compatibility, leading to superior composite performance. Future work is recommended in areas including environmental durability, manufacturing optimisation, and closed-loop recycling, with potential expansion to other bio-based matrices.