Gelatin/Chitosan Blend Solutions Rheology: Small and Large-Amplitude Oscillatory Shear Measurements

Abstract

The compatibility between chitosan (CS) (1 wt%–2 wt%) and gelatin (GEL) (2 wt% and 6.25 wt%) solutions was studied by measuring small and large-amplitude oscillatory shear at selected blending ratios (CS/GEL: 25/75, 50/50, and 75/25 w/w) and temperature. CS solutions displayed sol–gel transformation, whereas GEL exhibited predominant solid-like behavior (G′ > G″). The concentration of gelatin significantly influenced the blend rheology. The blend solutions (25/75) produced a physical gel (G′ > G″) at 2 wt% of each polymer. Blending of 2% CS with 6.25% GEL resulted in the weakest and strongest gels at a CS/GEL ratios of 75/25 and 50/50, respectively. The rheological data demonstrated that the 3D printing of the blend solutions could be achieved within a complex viscosity range of 62.63–86.03 Pa·s. The LAOS results demonstrated a perfect elastic relationship between stress and strain of the GEL solution (6.25 wt%) at a lower strain, which transformed to viscous-dominated behavior with increased strain.