A series of hydrogels in the form of rod were prepared from Kappa-carrageenan(KC), N-vinyl pyrrolidone) (N-VP) and polyethylene glycol dimethacrylate(14G) by gamma radiation with Co-60 gamma source at room temperature. The properties of the prepared hydrogels,such as the gel strength,the gel fraction and the swelling behavior were investigated. N-VP blending with KC could get excellent KC/PVP hydrogels at certain radiation conditions. The addition of 14G into KC/N-VP system reduced the gelation dose. The gel strength of KC/PVP blend hydrogels containing 14G was higher than that of hydrogels without 14G, but their equilibrium degree of swelling (EDS) was decreased because of higher crosslinking. With the increasing of KC content in the prepared hydrogels,both the gel strength and the EDS were improved together. In addition, the dose and dose rate influenced greatly the preparation and properties of the hydrogels. The gel strength of KC/PVP hydrogels decreased with the increasing of dose-rate,but increased with the increasing of dose from 0 to 30kGy, and then decreased after 30kGy. The change of swelling behavior of KC/PVP hydrogels with the dose/dose-rate is just contrary to the change of the gel strength. The experimental analyses also showed that the polymerizing and crosslinking reaction of N-VP was quicker than the degradation of KC at low dose (less than 30kGy),and the degradation of KC was inhibited in N-VP/KC mixture systems. So an interpenetrating polymer network hydrogel composed of PVP (a chemical crosslinking network) and KC (a physical crosslinking network) was proposed here.
