Fully bio‐based flax/furan versus carbon/glass epoxy composites: Scope and limitations in terms of fire and physico‐mechanical performances

Abstract

AbstractFire and mechanical performances of a bio‐based flax/furan resin composite are evaluated and, in order to assess their commercial potential, compared with those of conventional carbon/glass fiber‐reinforced composites. Fire retardant (FR) variants of flax/furan were obtained by adding FRs to the resin and using (i) flax or (ii) FR‐treated flax fabrics. With (i), the fire hazard of the composite could be reduced to minimum, without detrimental effect on the mechanical properties. However, use of FR‐flax fabric (ii) led to impairment of mechanical properties. This indicated that for optimized fire and mechanical properties, use of a FR in the resin matrix suffices; there is no advantage in using a FR‐treated flax fabric. Natural aging of the samples for 10 years followed by water aging indicated that water absorption in flax/furan composites was much higher than in comparable carbon/epoxy composites. While there was evidence of released acidic components such as acetic acid, oxalic acid, and so forth, in flax/furan composites, mainly from oxidative degradation of furan resin, there was no evidence of leaching of FR additives from the matrix. However, FR treatment of flax fabric affected the fiber–matrix interfacial adhesion, leading to considerable water absorption during aging and disintegration of the reinforcement.Highlights Furan resins are naturally fire retardant, burn only under forced combustion. FR flax/furan composites obtained by adding FRs to the resin or the flax fabric. FR treatment of the flax impairs mechanical properties and water tolerance. FRs in the resin neither affect mechanical properties nor leach out in water.