Physico-chemical description of titanium dioxide-cellulose nanocomposite formation by microwave radiation with high thermal stability

摘要

Titanium dioxide-cellulose nanocomposites were nucleated and grown by decomposition of titanium isopropoxide in ethanol media together with wood cellulose fibers into the microwave-assisted solvothermal (MAS) system; the low temperature and fast formation time of the nanocomposites stand out in this methodology. The MAS method was successfully applied in the synthesis of TiO2 with anatase structure in wood cellulose fibers to produce TiO2-cellulose nanocomposites based on hydrolysis, condensation and subsequent polymerization of titanium nanoparticles on cellulose fibers. Through scanning electron microscope it was possible to confirm nanocomposite formation by impregnation/nucleation/growth of titanium dioxide (TiO2) nanoparticles on the fiber walls. The nanocomposites X-ray powder diffraction showed peaks of crystalline titanium dioxide anatase phase associated to additional cellulose diffraction remarks, as well as the absence of the CaCO3 phase, proving the nanocomposite design concept. This means that the inclusion of TiO2 nanoparticles on fibers does not alter the crystalline structure of cellulose, also confirmed by Fourier-transform mid-infrared spectroscopy. Based on the thermogravimetric analysis, nanocomposites are thermally more stable than pure cellulose, reaching a 19% difference of mass loss reduction.