The Effect of cellulose oxidation on interfacial bonding of nano-TiO₂ coating to flax fibers

In this study, flax fibers were oxidized in order to improve the interfacial adhesion of cellulosic fibrils to a TiO₂ coating. The TiO₂ coating was created on the flax fiber by a Sol–Gel dip-coating technique. The effect of cellulose oxidation and the consequent TiO₂ grafting was studied on cellulose crystalline structures using X-ray diffraction. X-ray photoelectron spectroscopy was used to compare the reactivity of TiO₂ Sol with oxidized and non-oxidized cellulosic fibers. In addition, transmission electron microscopy and atomic force microscopy were applied to characterize the quality of the interface between the fibers and TiO₂ coating. Finally, the effect of cellulose oxidation on the mechanical properties of TiO₂-grafted flax strands was investigated by tensile tests. The results showed that the oxidation increased significantly the reactivity of the cellulosic surfaces with TiO₂ Sol. This method was able to increase the quality of the interface between flax fiber and TiO₂ coating, which improved the thermal resistance of the fibers. Eventually, the oxidation of the fiber together with the TiO₂ grafting increased significantly both ductility and maximum tensile strength of the flax strands.