Mechanical and water absorption properties of nano TiO2 coated flax fibre epoxy composites

•Effect of fibre modification by silane coupling agent and nano titanium dioxide coating is studied.•Tensile, flexural, interlaminar shear strength and water absorption behaviourare observed.•Fibre modified composites show positive response towards mechanical behaviour, indicating a developed interface, the moisture absorption also expressed a reduction.•Fibre surface modification is validated by Scanning Electron Microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) charaterisation. The present study aims at evaluating the mechanical properties such as tensile, flexural and interlaminar shear strength of unmodified and nano TiO2 coated flax fibre composites. Nano TiO2 coating on the flax fibres is done by immersing the fibres in a solution containing ethanol and silane coupling agent in volume ratio 10:1 and further adding nano TiO2. Effect of fibre coating on the composites is also evaluated by conducting water absorption tests. The composites are prepared using the compression molding technique. Results indicate an improvement in the tensile, flexural and interlaminar shear strength values by 22%, 24% and 16% respectively. Water diffusion coefficient of fibre modified composites reduced by 42% for 0.6 wt% TiO2 coated samples. Nanoparticle grafting on the fibre surface by silane treatment enhanced the compatibility between the hydrophilic fibre and hydrophobic polymer matrix. Chemical and mechanical bonding is developed between the fibre and matrix on account to the fibre surface grafting with nano TiO2 and silane coupling agent. Mechanical properties and water absorption resistance are thus improved. Nanoparticle coating on the fibre surface is validated from the scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis.