Effect of γ-Fe2O3 Nanoparticles on the Crosslinking and Final Properties of PVA/Citric Acid Based Nanocomposites

In this research work, γ-Fe2O3 nanoparticle addition effect on final properties of citric acid-cross-linked poly(vinyl alcohol) was studied. It was observed that citric acid, besides working as a cross-linking agent for poly(vinyl alcohol), also acted as a dispersant agent for γ-Fe2O3 nanoparticles. This double role of citric acid has been proven to be very useful for preparing magnetically responsive nanocomposites with a proper filler dispersion. Infrared spectroscopy and thermogravimetric analysis showed that nanoparticle addition affected the chemical structure of cross-linked poly(vinyl alcohol), while swelling tests demonstrated that for the highest 8 wt % nanoparticle content studied, the cross-linking degree remarkably decreased as it was corroborated by dielectric relaxation spectroscopy. Mechanical properties were improved by cross-linking with citric acid, and results obtained for nanocomposites reflected the reinforcing effect of γ-Fe2O3 nanoparticles together with that on diminishing the cros...