Mechanical properties of short flax fibre bundle/polypropylene composites: Influence of matrix/fibre modification, fibre content, water uptake and recycling

The aim of this work was to compare the effect of modification way of short flax fibre bundle/polypropylene (PP) composites on mechanical properties. Modification was carried out on fibre surface and also modifying PP matrix using several amounts of maleic anhydride-polypropylene copolymer (MAPP) as compatibilizer. The optimum doses of two different MAPP compatibilizers have been obtained. The effect of fibre bundle loading on composite mechanical properties was also analysed. The influence of water uptake on the sorption characteristics of composites has been studied by immersion in distilled water at room temperature. The effects of fibre bundle loading and also the use of MAPP modification on both water sorption and mechanical properties were also evaluated. Results showed that using MAPP as coupling agent, mechanical properties of composites improved, and water uptake rate clearly decreased. However, after long period of water immersion mechanical properties drastically decreased. On the other hand, mechanical recycling of flax fibre bundle/PP composites has been shown to be feasible.