
Preparation, Characterization, and Evaluation 299
The increasing of the swelling degree would be expected from the increase in surface
area with decreasing particle size of hydrogel [28]. Additionally, the ultimate degree
of swelling increased as the particle size becomes smaller. This is attributed to more
water molecules being held in the volume between the particles. However the swelling
the network of hydrogel began to destroyed and malformed by crushing and its swell-
ing behavior ...