High molecular weight polyacrylamide nanoparticles prepared by inverse emulsion polymerization: reaction conditions-properties relationships

摘要

High molecular weight polyacrylamide (PAM) nanoparticle dispersions are products with wide application possibilities, the most important of which is in petroleum industry such as drilling fluid and flooding agent in enhanced oil recovery. For that aim, it is necessary to achieve complete control of the final dispersion and polymer properties during the synthesis step. In this work, PAMs were synthesized by inverse emulsion polymerization of aqueous acrylamide solution in cyclohexane in the presence of emulsifier mixture of Span 20 and Span 80. We present a comprehensive study of the effects of variation of all important reaction conditions (agitation rate, reaction time and temperature, initiator type and concentration, emulsifier HLB ratio and its concentration, and water to oil ratio) on final monomer conversion, reaction kinetics, polymer intrinsic viscosity and molecular weight, particle size and distribution, and colloidal stability. Finally, the relationships between the reaction conditions and the polymer properties were developed, which allowed determination of the ranges of variation of reaction conditions for optimal PAM properties for the oil industry applications: high molecular weight and intrinsic viscosity, nanosized polymer particles with narrow particle size distribution, and improved colloidal stability of the final dispersions.