Swelling properties of particles in amphoteric polyacrylamide dispersion

Abstract

AbstractSwelling properties of amphoteric polyacrylamide (AmPAM) dispersions were investigated by measurements of apparent viscosity and particle morphology. AmPAM dispersion was prepared by dispersion polymerization in aqueous solution of ammonium sulphate. Changes of particles during dispersion polymerisation of AmPAM were simulated and compared with anionic and cationic polyacrylamide (APAM and CPAM, respectively). Sample viscosity and particle morphology were obtained using a rotational viscometer and optical microscope. It was found that small molecules or ions enter and swell particles in the AmPAM dispersion when (NH4)2SO4 concentration decreases. Similarly, monomers, including acrylamide, acrylic acid, and methacrylatoethyl trimethyl ammonium chloride, have the same effects on the AmPAM dispersion but the effect degree is different. Swelling properties of the AmPAM dispersion were different from those of the APAM and CPAM dispersions due to their different ionic nature, type of stabiliser, media, etc. Particles in the APAM or CPAM dispersions were swelled less than those in the AmPAM dispersion.