The Influence Of Crosslink Ratio On Rheological Properties And Heat Resistance Ability Of Microspheres

Polyacrylamides microspheres can be applicable to deep profile control because of their excellent water-absorption ability and elastic deformation.While the rheological properties of microspheres affects the ability of seepage and migration.It is significant to explore the influence of the degree of crosslinking.This paper used inverse suspension polymerization with the monomers of 2-acrylamido-2-methylpropanesulfonic acid(AMPS),N-vinyl pyrrolidone(NVP)and acrylamide(AM)to prepare microspheres of different sizes from 1 microns to several tens of microns.Then the impact of the degree of crosslinking of the microspheres on the particle size,swelling behavior and heat resistance ability was studied.Furthermore,the effects of crosslinking ratio on rheological properties of the microspheres were further investigated.In the case of DX-series microspheres,the particle size declined with the increasing degree of crosslinking.While microspheres of the crosslinking degree of 0% and 0.05% cannot exist stably in the water,others absorb water and swell well in the water.The swelling size and swelling times decreased with the increasing of crosslinkingratio.We found that the viscosities of the microspheres solutions with various crosslinking ratio were changed,which decreased with the increasing of the degree of crosslinking.While the concentration of the solution is 0.25%,under low crosslinking ratio(0.25%),the viscosity of the solution decreases with the increase of shear rate.With the increase of crosslinking ratio(0.5%-10%),solution viscosity increase with the increase in shear rate.The elasticity of solution enhanced first with the increase of crosslinking ratio,then it decreased.When tracing the effects of different crosslinking ratio on the stability of the microspheres,we found that the heat resistance ability of microspheres was improved by the increasing of crosslinking ratio,and the temperature effect was very good.