Enhancement of the optical and mechanical properties of chitosan using Fe2O3 nanoparticles

In this work, the optical and mechanical properties of Fe2O3 nanoparticles (NPs)/chitosan nanocomposite films have been investigated. Nanocomposite films of different weight ratios of Fe2O3 NPs/chitosan (0, 1, 5, 10, 20 and 30 wt%) were fabricated using casting technique. The optical properties of colloidal Fe2O3 NPs and Fe2O3 NPs/chitosan nanocomposite films were recorded using UV-visible spectrophotometer. As the ratio of Fe2O3 NPs to chitosan increases from 0 to 30%, the energy band gap of Fe2O3 NPs/chitosan films decreases from 3.16 to 2.11 eV. This decrease is due to quantum confinement effect. The mechanical properties of the nanocomposite films as a function of sweeping temperature were measured using a dynamic mechanical analyzer. An enhancement in storage modulus, stiffness and glass transition temperature (T-g) has been observed as the ratio of Fe2O3 NPs/chitosan increases. T-g of Fe2O3 NPs/chitosan nanocomposite film shifts towards higher temperature side with respect to pure chitosan film from 152.1 to 166.3 A degrees C as the ratio of Fe2O3 NPs/chitosan increases from 0 to 30 wt%. The increase in T-g is mainly attributed to the decrease in free volumes and vacancies in the nanocomposite films as the weight ratio of Fe2O3 NPs/chitosan increases.