Abolhasan hashemi sohi - Department of Chemical Engineering, Iran University of Science and Technology, Tehran, Iran
Mohamadreza moghbeli - Department of Chemical Engineering, Iran University of Science and Technology, Tehran, Iran
Emad Roayaei - National Iranian Oil Company, Research and Technology Directorate, Tehran, Iran

Acrylamide microspheres are synthesized by inverse suspension method to investigate swelling and rheological properties. In addition, impact of crosslinking density on gel behaviors are studied. Typical image of products showed that gel with fine spherical morphology and sufficient size distribution are prepared. The results demonstrated that swelling capacity decreased with increasing salt concentrations due to the osmotic pressure differential between the inside and outside of the swollen gel. The equilibrium swelling and the swelling rate of the individual samples are fitted into the Voigt-based viscoelastic model to find the values of the rate and power parameters. The results show that the microspheres had large elastic modulus. Degree of expansion of microspheres at different temperature confirmed that swelling capacity will increase with the increase of temperature. It was found that microspheress were stable in brines with 25,000 ppm salt at 80 oC for 6 months.

microspheres, hydrogel, acrylamide, inverse suspension polymerization, swelling