On the basis of previous investigation of concentration dependence of cryogenic gelation for aqueous solution of poly (vinyl alcohol) (PVA)

the physical hydrogels with high water content were prepared by freezing and thawing to the PVA aqueous solution. The properties of the hydrogels in distilled water have been investigated. A swelling kinetic equation was proposed:Qt= Qe-(Qe- Qo) /eldThis equation fits the experimental results. A quantitative relationship between equilibrium swelling ratio and the solution concentration was also obtained:Qe=60.3-4.45×102C.It was found that equilibrium swelling ratio Qe

dissolution amount W of the hydrogels and the times N of freezing-thawing cycles followed the power lawa:QeN-a; W N-β

as N≤5.By comparing the results of this work with that of previous paper

we found that Qe

reflected the intermolecular hydrogen bonding cohesional entanglemet of concentrated soloution of PVA and [η]

described the intramolecular hydrogen bonding cohesional entanglement in dilute solution of PVA are equal in value.