The effect of the structure of functional monomers on the resistance of copolymers to Fe2+ and S2-

Abstract

Free radical solution polymerization method was used to preparing copolymers (FAPAM, IAPAM, and MAPAM) by copolymerizing acrylamide (AM) with functional monomers fumaric acid (FA), itaconic acid (IA) and maleic anhydride (MAH) respectively. The basic parameters of the polymer were characterized by fourier transform infrared spectrometer (FTIR), proton nuclear magnetic resonance spectroscopy (1HNMR), elemental analyzer and ubbelohde viscometer. In polymer flooding, the viscosity reduction effect of Fe2+ and S2− in formation water is more serious than that of inert cations, and they have greater impact on oil recovery. Therefore, this paper studied the influence of functional monomers on the structure of polymers and the influence on the resistance to Fe2+ and S2− properties of polymers through rheometer, gel permeation chromatography (GPC) and scanning electron microscope (SEM). The results revealed that the intra-chain or interchain forces can be increased to varying degrees by introducing different functional groups into the polymer molecular chains, as a result, the copolymer had different resistance to Fe2+ and S2−. In addition, the carboxyl groups on MAPAM chain were the most evenly distributed, its configuration was the most regular, and its resistance to Fe2+ was the strongest. Relatively, the carboxyl groups on IAPAM macromolecular chain were evenly distributed on both sides of the main chain, and it had the strongest ability to resist S2−. The results of GPC and SEM further proved that the copolymers had the ability to resist Fe2+ and S2−.