A strategy to improving the fire-performance of flax fibre/epoxy skin- and balsa wood-core sandwich composites without degrading their inherent mechanical properties

Environmental sustainability in engineering is giving an impetus for the creation and development of new composite materials using bio-based resources. The use of natural fibre reinforcements in structural composites has attracted a lot of interest from researchers; however, these fibres aggravate an existing challenge with fibre/polymer composites when used in moderate to extreme thermal environments - they are flammable. This paper presents an innovative strategy to improving the fire performance of flax fibre-reinforced balsa wood-core sandwich composites without adversely altering their intrinsic mechanical properties. A thin glass fibre veil impregnated with fire retardant (ammonium polyphosphate) is bonded onto the sandwich composite surface intended for heat exposure. Cone calorimeter tests were conducted to assess the fire reaction properties of the composites with/without fire protection