Modeling and Investigation of the Swelling Kinetics of Acrylamide-Sodium Acrylate Hydrogel

Abstract

The acrylamide-sodium acrylate hydrogel was synthesized by free radical polymerization of the method of solution polymerization. Dynamic swelling tests were conducted at 25, 40, and 60°C temperatures, in order to investigate the swelling properties of the synthesized hydrogel. The results have shown that swelling content and swelling rate of the hydrogel increase with increasing the swelling water temperature. The diffusivity values changed from1.81×10-7to2.97×10-7 m2 s−1over the temperature range. The activation energies were found as 3.56, 3.71, and 3.86 kJ mol−1at 25, 40, and 60°C, respectively. The experimental drying curves obtained were fitted to a three different models, namely, Peleg’s, first-order absorption kinetic, and exponential association equation models. All the models applied provided a good agreement with the experimental data with high values of the coefficient of determination (R2), the least values of the reduced chi-square (χ2), and root mean square error (RMSE). Comparing the determination of coefficient, reduced chi-square, and root mean square error values of three models, it was concluded that the exponential association equation model represents swelling characteristics better than the others.

Rational Design, Synthesis and Evaluation of γ-CD-Containing Cross-Linked Polyvinyl Alcohol Hydrogel as a Prednisone Delivery Platform

“…By contrast, γ-CDHSA2 and γ-CDHSA3 were higher, 450% and 600%, respectively, as depicted in Figure 9 . As has been described in other works [ 50 , 51 ], the swelling index depends on the nature of the polymer, the average molecular weight, the degree of crosslinking, the rigidity of the polymer chain and the network mesh size as well as external conditions, such as pH and temperature [ 50 , 51 ], Moreover, the swelling index observed could be related with the absorption mechanism, which is determined by the diffusion process of water into the pores of hydrogel [ 52 ].…”

Modelling of AAm-co-alginate hydrogels swelling kinetics

“…Empirical models, namely, the Peleg (4), first-order swelling kinetic (5) and exponential association model (6) were used to describe the swelling process during the swelling of hydrogel samples. 17,18 1 2 o t S S k k t = + + (4) where S o is the water content at t=0 (g water /g dry gel ), S is the water content at any time (g water /g dry gel ), t is the swelling time (s), k 1 is a kinetic constant of the model (s x (g water /g dry gel )) and k 2 is a characteristic constant of the model (g water /g dry gel ).…”

Practical Investigation of Gels Containing Aristolochia (<i>Aristolochia Clematitis</i>) Extract

“…The variation of the swelling content, per time unit, of the hydrogel is known as swelling rate, Q R [10] and is calculated using the formula (3):…”

“…Based on the Davidson -Peppas model [14] the swelling of the hydrogels can be characterized by the F swelling fraction equation (4) (4) where F is the swelling fraction, Q e is the equilibrium swelling degree, n is the solvent's diffusion exponential and k is the constant that changes depending on the structure of the gel's network [10,13]. In order to determine the type of diffusion, one must know the value of n. The diffusion's exponential can be determined from the slope of the line obtained from the graphic representation of the lnF, depending on the lnt; one should take into consideration the data from the graph in the region where the swelling has not reached equilibrium, where just 60% of the solvent's mass has permeated the gel's structure.…”