Study On The Properties Of Associative Copolymers P(AM-NIPAM-NPA) In Aqueous Solution

The associative water-soluble copolymers P(AM-NIPAM-NPA) of acrylamide (AM), N-isopropylacrylamide (NIPAM) and nonylphenyl polyoxyethylene acrylate (NPA) were synthesized by free radical aqueous solution copolymerization, while NPA is the first time to be used as the performance modified monomer. The copolymer structures were characterized via IR spectrum and ¹H-NMR spectrum. The effects of the reaction conditions such as reaction temperature, time, initiator concentration, various monomers concentrations and hydrophobic monomers on the performance of the copolymer solution were studied. The effects of copolymer structure, concentration, temperature, shear rate and different electrolyte on the performance of copolymer solutions were studied.The results show that the conditions of polymerization reaction have notable effect on the performance of the product. The apparent viscosity of the copolymer solution first raises then declines with the initiator concentration increasing. The apparent viscosity of copolymer increases at first then decreases with reaction temperature rising. At properly condition(eg.NPA/NIPAM), the copolymers have excellent viscosification property.Different electrolyte has different effect on polymers solution. With NaCl,KCl and Na₂SO₄ concentration increasing, the apparent viscosity will move up. The MgCl₂ and CaCl₂ haven't notable effect on the viscosity of P(AM-NIPAM-NPA) solution. The saline solution of P(AM-NIPAM-NPA) can keep high viscosity at high temperature. At properly condition, the viscosity of P(AM-NIPAM-NPA) solution increase with the temperature rise.The copolymer of P(AM-NIPAM-NPA) is a type of polymer surfactant. With the copolymer concentration increasing, the surface tension of copolymer solution decreases quickly at first then reaches unchanged. The surface tension of 0.1g/dL P(AM-NIPAM-NPA) aqueous solution is 34.1mN/m. The interface properties of P(AM-NIPAM-NPA) aqueous solution are related with polymer structure and solution component. With the molar concentration of NPA increasing, the surface tension of P(AM-NIPAM-NPA) solution decreases. In the saline solution of copolymer, the surface tension decreases with the temperature rise; decreases at first and then increases with the NaCl concentration rise.The studies of dynamic light scattering show that hydrodynamic diameters distribution consist of two distinct regions: small and big diameters in 0.05-0.3g/dL P(AM-NIPAM-NPA) concentration. The micro-structures of aqueous solution of P(AM-NIPAM-NPA) are related with polymer concentration and salt concentration. The hydrodynamic diameters of copolymer aqueous solution increase with the concentration rise; reduce with the temperature rise; the hydrodynamic diameter increases in the saline solution, with the temperature rise.