Abstract

Spherical Hydrogels are having the tendency to absorb the large amount of water. This results in swelling of the hydrogels that leads to the increase in mass and volume of hydrogels. In the present work this change in the mass and volume of spherical hydrogels at different time interval has been studied. The different swelling related parameters like mass swelling ratio (MSR), equilibrium swelling ratio (ESR), swelling constant (K) which is the characteristic of polymer network of hydrogel bead, diffusional exponent (n) characterizing the mechanism of diffusion of the solvent into the network ,equilibrium water content (EWC), diffusion coefficient of water (D) , number of absorbing sites per unit mass of dry hydrogel ( ÏM) and  number of absorbing sites per unit volume of dry hydrogel (ÏN) were determined for four different colored (Red, Blue, Orange and Green) spherical hydrogels. The linear relationship of log ( ) is observed with log (t) and also between change in volume and change in mass of hydrogel.  The water intake and volume of hydrogel increases with time initially and later there is no appreciable change in water intake and volume due to maximum water absorption i.e. equilibrium swelling of hydrogels.

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