Synthesis of a hydrosoluble reversible addition‐fragmentation chain transfer agent and application in the preparation of micro/nano‐polyacrylamide gel dispersions

Abstract

AbstractA hydrosoluble reversible addition‐fragmentation chain transfer (RAFT) agent named S‐(2‐propionic acid)‐S′‐(2‐methylpropionic acid) trithiocarbonate (PAMPATTC) is successfully synthesized. Then the micro/nano‐polyacrylamide gel dispersions are prepared via one‐pot RAFT polymerization in water to solve the problems of complicated preparation process and particle size control of common profile‐controlling and flooding agents. The structure of the RAFT agent is characterized and confirmed by fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H‐NMR). The effects of different reaction conditions on the properties of polyacrylamide gel dispersions are studied. The polymer dispersity index (PDI) of the polyacrylamide gel dispersions is tested by aqueous gel permeation chromatography, confirming the activity characteristics of RAFT polymerization. The rheological characteristics of the polyacrylamide gel dispersions and liner polyacrylamide are characterized. Compared with the liner polyacrylamide at similar viscosities, it is confirmed that the polyacrylamide gel dispersions were closer to Newtonian fluid, especially at high shear rates and the increasing amount of RAFT agent. The viscoelasticity tests under frequency scanning further confirm that the polyacrylamide gel dispersions are successfully synthesized via aqueous RAFT polymerization. The particle sizes are measured to show that the particle size of the polyacrylamide gel dispersions is micro/nano‐scale. The micromorphology of polyacrylamide gel dispersions is determined to indicate the irregular spherical structure, confirming that the micro‐particles are indeed formed by the aggregation of nano‐particles.