Hemp-Epoxy Structural Bio-Composite
topic
Hemp-epoxy structural composites use woven hemp fabric (200–600 g/m², plain or twill weave) or unidirectional hemp sliver impregnated with low-viscosity epoxy resin (viscosity 500–2,000 mPa·s, fibre volume fraction 35–55%) by hand layup, vacuum infusion (vacuum 0.08–0.09 MPa), or resin transfer moulding (RTM, injection pressure 2–5 bar, cycle time 15–30 min). Tensile strength of 80–150 MPa and modulus of 8–15 GPa at 45% Vf — 50–70% of equivalent E-glass/epoxy (tensile strength 200–350 MPa, modulus 20–35 GPa) but at 40% lower density achieving comparable specific properties. Silane surface treatment of hemp (APTMS 1–3% in ethanol) improves fibre-epoxy IFSS from 12 to 22–28 MPa, increasing composite tensile strength by 25–35%. Applications in wind turbine blades (2–5 m prototype scale), surfboards, bicycle frames, and architectural panels where moderate structural performance with maximum bio-content is desired. Carbon footprint of hemp-epoxy composite is 2.5–4.0 kg CO₂e/kg versus 8–12 kg CO₂e/kg for CFRP, supporting bio-composite adoption in sustainability-driven markets.
Role
Enables structural bio-composite applications in renewable energy, sports equipment, and architecture where hemp-epoxy's specific mechanical properties meet design requirements while delivering 60–70% lower carbon footprint than carbon fibre composites for non-critical structural components.