The shear stability and degradation mechanism of crosslinked polymer systems comprising of low concentration and high molecular weight partially hydrolyzed polyacrylamides （HPAM） and aluminum citrate （AlCit） were investigated by viscometry

nuclear pore membrane filtration and dynamic light scattering.The results indicated that the filtering rate in 1.2 μm nuclear pore membrane of crosslinked polymer system formed by low concentration HPAM and AlCit increased and the plugging efficiency decreased

while the shear rate became high.The shear stability of this system was not good

so its plugging efficiency was weak under shear.For crosslinked polymer systems formed by the degraded HPAM in high shear rate and AlCit

the plugging efficiency was little affected under low shear rates

but was lowered obviously in the range of high shear rate.The crosslinked polymer system formed by the degraded HPAM in high shear rate was almost not able to plug the 1.2 μm nuclear pore membrane

but was able to plug the 0.4 μm nuclear pore membrane.Low concentration HPAM which had the same concentration with the former could not plug the 0.4 μm nuclear pore membrane

but the pore membrane with a less small pore diameter after shear.The size of crosslinked polymer coils (LPC) in the crosslinked polymer system and the low concentration HPAM and high molecular weight partially hydrolyzed polyacrylamides （HPAM） coils gradually became smaller while the shear rate became high.The reason that the plugging efficiency of crosslinked polymer system after degradation decreased at high shear rate was that the size of LPC and high molecular weight partially hydrolyzed polyacrylamides （HPAM） coils became smaller because of the rupture of crosslinked polymer coils (LPC) and the partially hydrolyzed polyacrylamides （HPAM） molecules.