Synthesis And Properties Of Thermosensitive Amphiphilic Compolymer HPAM-g-P(NIPA-co-DMAM-co-C₁₂AM)

The graft copolymers HPAM-g-P(NIPA-co-DMAM-co-C₁₂AM) with different side chain composition and molecular mass were synthesized by macromonomer method. Firstly, amino-end P(NIPA-co-DMAM-co-C₁₂AM) was prepared by copolymerization of N-dodecylacrylamide(C₁₂AM), N-isopropylacrylamide (NIPA) and N,N-dimethylacrylamide(DMAM) by using 2-aminoethanethiol hydrochloride as chain transfer agent and then macromonomers P(NIPA-co-DMAM-co-C₁₂AM) 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 side chain polymers were studied as a function of composition, concentration and added salt concentration.The rheological characters of the graft copolymers were studied by RS600 Rheometer under different temperature, shear rate, polymer and salt concentrations. The results show that the graft copolymers have significant thermothickening properties when their concentration above 1.0g/L, the concentration of NaCl is at 0.25mol/L.The association temperature of graft copolymers is very close to the temperature of cloud point. The thermothickening extent is improved by the increase of polymer concentration, graft ratio and the molecular mass of main chain. It was also impacted by salt concentration and the composition of side chains. These thermothickening amphiphilic graft copolymers are expected to be used in oil recovery industry as a novel temperature-and salt-resistance polymer flooding agent varying with the composition of side chains.