Synthesis And Properties Of Thermosensitive Amphiphilic Copolymer Hpam-G-P(NIPA-Co-DMAM)

The graft copolymers HPAM-g-P(NIPA-co-DMAM) with different side chain composition and molecular mass were synthesized by macromonomer method. Firstly, amino-end functionalized P(NIPA-co-DMAM) was prepared by copolymerization of N-isopropylacrylamide(NIPA) and N,N-dimethylacrylamide (DMAM) by using 2-aminoethanethiol as chain transfer agent, then macromonomers P(NIPA-co-DMAM) with acrylamido-end group were obtained by reacting with acryloyl chloride; Secondly, macromonomers were copolymerized with acrylamide and then hydrolysized under base condition. The compositions of the side chain and graft copolymers were characterized by 1H-NMR. The cloud point temperatures of these polymers were studied as a function of composition, concentration and added salt concentration by spectrophotometer. The rheological characters of the graft copolymers were studied by RS600 Rheometer under different temperature, shear rate and polymer and salt concentrations. The results show that the graft copolymers have significant thermothickening properties when their concentration above 2 g/L, and the thermothickening extent is improved by the increase of polymer concentration and graft ratio, and impacted by the side chain length and salt concentration. These thermothickening amphiphilic graft copolymers are expected to be used in oil recovery industry as a novel temperature- and salt-resistance polymer flooding agent.