## 3 Results and Discussion
### Physicochemical Properties of JSP
#### 3.3.2 Rheological Behavior of JSP
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**JSP (\%, _w/v_)** & **NaCl (mol/L)** & **KCl (mol/L)** & \(n\)** & \(k\) (Pa.s\({}^{n}\))** & \(R^{2}\) \\ \hline  & 0.0 & 0.0 & 0.54 \(\pm\) 0.014 & 0.030 \(\pm\) 0.002 & 0.99 \\
**0.25** & 0.5 & 0.0 & 0.58 \(\pm\) 0.020 & 0.028 \(\pm\) 0.006 & 0.98 \\  & 0.0 & 0.5 & 0.60 \(\pm\) 0.018 & 0.022 \(\pm\) 0.005 & 0.98 \\  & 0.0 & 0.0 & 0.50 \(\pm\) 0.007 & 0.060 \(\pm\) 0.007 & 0.99 \\
**0.50** & 0.5 & 0.0 & 0.57 \(\pm\) 0.024 & 0.055 \(\pm\) 0.003 & 0.97 \\  & 0.0 & 0.5 & 0.55 \(\pm\) 0.030 & 0.058 \(\pm\) 0.001 & 0.97 \\  & 0.0 & 0.0 & 0.48 \(\pm\) 0.004 & 0.174 \(\pm\) 0.001 & 0.99 \\
**0.75** & 0.5 & 0.0 & 0.54 \(\pm\) 0.020 & 0.168 \(\pm\) 0.016 & 0.99 \\  & 0.0 & 0.5 & 0.54 \(\pm\) 0.024 & 0.167 \(\pm\) 0.014 & 0.98 \\  & 0.0 & 0.0 & 0.44 \(\pm\) 0.011 & 0.26 \(\pm\) 0.012 & 1.00 \\
**1.0** & 0.5 & 0.0 & 0.49 \(\pm\) 0.008 & 0.24 \(\pm\) 0.018 & 0.99 \\  & 0.0 & 0.5 & 0.51 \(\pm\) 0.005 & 0.20 \(\pm\) 0.022 & 0.97 \\  & 0.0 & 0.0 & 0.43 \(\pm\) 0.015 & 0.60 \(\pm\) 0.005 & 1.00 \\
**1.50** & 0.5 & 0.0 & 0.47 \(\pm\) 0.026 & 0.55 \(\pm\) 0.024 & 0.97 \\  & 0.0 & 0.5 & 0.45 \(\pm\) 0.030 & 0.57 \(\pm\) 0.035 & 0.99 \\  & 0.0 & 0.0 & 0.40 \(\pm\) 0.018 & 1.30 \(\pm\) 0.012 & 1.00 \\
**2.0** & 0.5 & 0.0 & 0.42 \(\pm\) 0.025 & 1.25 \(\pm\) 0.042 & 0.98 \\  & 0.0 & 0.5 & 0.43 \(\pm\) 0.021 & 1.22 \(\pm\) 0.034 & 0.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Consistency and flow behavior index of JSP solutions in water and monovalent salts. Figure 6: Flow behavior of JSP aqueous solutions at different concentrations ranging from 0.25% to 2.0% (_w/v_) at 25 \({}^{\circ}\)C.  
independently of the nature of the solution. The \(k\) values decreased with adding salts and increasing temperatures [34; 57]. The frequency dependence of \(G^{\prime}\) (storage modulus) and \(G^{\prime\prime}\) (loss modulus) of JSP (1.0% and 2.0%, _w/v_) at 25 \({}^{\circ}\)C is described in Figure 8. Typical gel-like behavior was observed since \(G^{\prime}\) was higher than \(G^{\prime\prime}\), ranging from 0.063 to 62.83 rad/s. The gap increased between \(G^{\prime}\) and \(G^{\prime\prime}\) for JSP concentrations (1.0% and 2.0%, _w/v_) and increasing frequencies (0.063-62.83 rad/s) showed a significant viscoelasticity of JSP [33; 34; 58]. The dynamic mechanical loss tangent, also named damping factor (tan \(\delta\) = \(G^{\prime\prime}\)/\(G^{\prime}\)), is a characteristic parameter for the assessment of viscoelastic behavior [51; 52]. The values of tan \(\delta\) were less than 1 and confirmed the elastic behavior of JSP solutions in water. These values slightly dropped with increasing frequencies (from 0.063 to 62.83 rad/s) and the polymer energy was dissipated by an elastic flow [34; 58]. The critical overlap concentration C* (g/L or %) was evaluated by plotting the specific viscosity (\(\eta_{sp}\), (Pa.s)) vs. JSP concentrations from 0.25% to 2.0% (_w/v_) in water (Figure 9). Figure 9 shows that the specific viscosity increased with increasing polysaccharide concentrations (from 1% to 2.0%, _w/v_) and the change in slope between the two linear segments helped estimate C* [33; 34; 59; 60]. The C* of JSP at 25 \({}^{\circ}\)C in water was calculated at around 7.5 g/L and the slopes of the linear segments below and above the C* were, respectively, 2.5 and 4.5. This practical value of C* was consistent with the theoretical one estimated in Section 3.2.1 (6.5 to 13.1) and the ks value was around 0.57. Figure 7: Effect of (**A**) NaCl and KCl (0.5 M) solutions at 25 \({}^{\circ}\)C and (**B**) temperature on apparent viscosity of JSP solutions (1.0–2.0%, _w/v_).