ABSTRACT
The rapid growth of materials science has provided many types of functional materials. One such type of functional material is a hydrogel. Hydrogels are crosslinked networks of hydrophilic polymer molecules that can swell but do not dissolve in water; however, they can retain a significant amount of water in their structures. Due to their unique characteristics such as swelling, deswelling, hydrophilicity, and biocompatibility, the hydrogels are used in several applications related to tissue engineering, pharmaceutics, biomedical, agriculture, ophthalmic, dental, cosmetics, waste treatment, separation, intelligent/smart textiles, and sensors. The performance characteristics of the hydrogels not only depend on the hydrophilic nature or chemical composition but very much on the type and number of crosslinks formed during the synthesis and development of hydrogels. In the last decade, several scientists have extensively reported the synthesis of hydrogels based on natural and synthetic polymers such as polysaccharides (carboxy methyl cellulose (CMC), chitosan, albumin, poly (hydroxyl alkyl methacrylates), poly (acrylamide), poly(ethyleneoxide) (PEO), poly(N-vinyl -2-pyrrolidone) (PVP), poly(vinylalcohol) (PVA), polyethylene glycol (PEG), etc.,) by various routes. Hydrogels are generally prepared by ( 1) polymerization of hydrophilic monomers and crosslinking simultaneously or sequentially (i.e., polymerization followed by crosslinking) and ( 2) chemical modification or functionalization of the polymers which exhibit desired hydrogel properties. The hydrogels may be physically crosslinked or chemically cross-linked with or without crosslinking agents. Radiation crosslinking is one of the important methods used to prepare hydrogels for various applications due to its technical benefits. This chapter focuses on the research findings reported in the last decade in the area of synthesis or crosslinking of hydrogels using high energy radiation.
