Polyvinyl alcohol (PVA) hydrogel was prepared by means of chemical crosslinking with boric acid as the crosslinker. The optimum ratio of crosslinker to PVA was sought based on the studies of elasticity and swelling behavior of PVA hydrogel. The influence of temperature on the elasticity and the influence of swelling time

salt concentration

and temperature on the swelling ratio were tested. The results show that with the increase of crosslinker

the swelling ratio and elastic modulus value of PVA hydrogel gradually increased

and when reached maximum

then decreased with the increase of crosslinker. When the ratio of crosslinker to PVA equals 10 %

the elasticity and swelling property of PVA hydrogel are the best. The swelling ratio of PVA hydrogel gradually increases with the swelling time increase

and reaches swelling equilibrium in aqueous solution within 40h. The swelling ratio of PVA hydrogel reduces with the increase of salinity in aqueous solution; however

its resistance to salinity is quite strong. It can swell twice its size in water of 10% salinity

so it is applicable to high salinity reservoirs. The swelling ratio and elasticity of PVA hydrogel are not sensitive to temperature; there is hardly any change with the increase of temperature. Consequently

PVA hydrogel is applicable in reservoir temperature.