Hydrogels containing poly(vinyl alcohol)(PVA)

poly(N-vinyl pyrrolidone)(PVP) and water soluble chitosan(ws-chitosan) have been prepared by gamma ray irradiation. The hydrogel properties were investigated in relation to the irradiation dose

the ws-chitosan content and the addition of plasticizers(poly(ethylene glycol)(PEG) or glycerol). It is found that the gel fraction increases with increasing of the irradiation dose up to 27 kGy and then levels off with further irradiation. Increasing ws-chitosan content and the addition of plasticizers(PEG or glycerol) will reduce the gel fraction and strength of the hydrogels

while the swelling capacity is improved significantly. The storage modulus obtained from rheological measurements reveals that the strength of the hydrogels increases with increasing of the irradiation dose and saturates at doses above 27 kGy.