Effects of alkali treatment on the poly(furfuryl) alcohol–flax fibre composites

Abstract

Flax fibre was treated with low concentrations of alkali and used to prepare poly(furfuryl alcohol) (PFA)-based composites through in situ polymerization of furfuryl alcohol. The properties of low concentrations of alkali-treated flax fibre and flax fibre–reinforced composites were characterized for their structure and properties by X-ray diffraction, scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis, dynamic mechanical analysis, water absorption and flexural measurements. The alkali-treated flax fibre showed increased cellulose content and crystallinity index with smooth surfaces of the microfibres. PFA composites exhibited dispersed microfibres within PFA matrix with agglomerates. There was also a clear increase in thermal stability, storage modulus and damping factor for all treated PFA composites. Poor resistance to water uptake was also observed for the PFA composites, even though the highest alkali treatment improved the resistance compared to the untreated composite. PFA–flax biocomposites were characterized by improved flexural strength and modulus, except the untreated which showed the opposite.