Preparation And Properties Of A Zwitterionic Polymer Acid Thickening Agent

A new kind of zwitterions copolymer(AD-1) is designed and synthesized exploringly in this paper, which is synthesized by 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and unsaturation quaternary ammonium cationic monomer through aqueous solution polymerization and inverse phase emulsion polymerization. In aqueous solution polymerization, the reaction conditions that influence molecular weight of copolymer were analyzed by orthogonal test, including the concentration and composition of monomers, concentration of initiators, reaction temperature, reaction time and pH number. A preferable scheme can be attain the intrinsic viscosity of copolymer to 272mL/g by w(monomers):25%, w(cationic monomer): 13%, w(initiator): 0.6%, the reaction tempreture: 45℃, the reaction time: 4h, pH number:7. For increasing the monomers concentration and molecular weight of polymer, the effects of monomers concentration, emulsifer concentration, polymerization temperature and the volume ratio oil to water on intrinsic viscosity of copolymer were discussed, based on the preferable reaction condition of aqueous solution polymerization. The intrinsic viscosity of copolymer can be obtained to 303mL/g by v(oil):v(water)=3:7,w(emulsfier):6%,w(monomers):55%,w(cationic monomer): 13% , w(initiator): 0.6%, pH number:7, the reaction tempreture: 50℃, the reaction time: 6h. The molecular structure of polymer is characterized by means of infrared spectrum.In the indoor experiment, the zwitterions copolymer is estimated as gelling agent in acidizing fluids. Evaluation standard of viscosifier refers to the People Republic of China petroleum natural gas profession standard(SY/T6214-1996). The experimental result shows that this zwitterions copolymer in the acid solution has good properties in viscosity increasing, the appearant viscosity of acids reach 24mPa.s, good shear resistant, the stability of shear is hight to 94.4%, better thermal stability can go to 91%, good compatibility with kinds of acid additive, and good resisting salts. It has a broad researching prospect in petroleum industry and other fields.