Visco-elastic properties of chitosan-titania nano-composites

Chitosan-titania (Chitosan-TiO2) nano-composites have been prepared via the sot-gel process. Tetraethylorthotitanate (C8H20O4Ti) was used as a precursor to introduce titania network in the matrix. Different techniques have been used to characterize structure and morphology of the resulting hybrid. The inter-phase dynamics have been studied using dynamical mechanical thermal analysis (DMTA). Shift in glass transition (T-g) towards higher temperature, increased storage modulus and reduced loss modulus were observed on addition of titania in the matrix. The maximum value for storage modulus (6.7 GPa at 50 degrees C) and that of T-g at 160.9 degrees C was observed with 30 wt% of titania in the matrix. The improvement in the mechanical properties of the polymer was due to the homogeneous and ordered distribution of titania particles (5-25 nm) in the chitosan matrix resulting from the large interfacial interaction between the basic sites (NH2) available on the polymer chains and Lewis acidic sites from titanium. (C) 2011 Elsevier Ltd. All rights reserved.