| Acrylamide polymer,a functional polymer of acrylamide homopolymers or copolymers of acrylamide and other functions monomer,exhibits good thickening,rheology and dispersion properties,which is widely used in petrochemical,mineral flotation,water treatment and other industries.Wherein the hydrophobic modified polyacrylamide has been successfully used in many aspects of oil and gas production,such as drilling,fracturing and EOR because of the favourable temperature and salt resistance,anti-shear property.However,the unsatisfactory water solubility of the hydrophobic modified polyacrylamide has limited the extensive application.In this paper,a side chain with lower critical solution temperature(LCST)was introduced into the polymer backbone,which makes the polymer possess excellent water solubility at room temperature.The polymer side chain is hydrophilic at room temperature and hydrophobic at higher temperature,which improves the solubility of the polymer and makes the polymer maintain good temperature and salt resistance.The main research contents are as follows.1.Six allyl alkyl polyoxyethylene ether temperature-sensitive monomers were synthesized by introducing long-chain alkyl groups into allyl polyoxyethylene ether molecular chain with polymerization degree of 10,8 and 6,namely AEO10C16,AEO10C10,AEO10C4,AEO8C10,AEO6C10 and AOP10.The structure of six monomer molecules was confirmed by IR,1H NMR,13C NMR and MS.And their cloud point was determined by measuring transmittance of 1.0%aqueous solution of the monomers at different temperatures.The cloud point of AEO10C16,AEO10C10 and AOP10 were 37?,43? and 28 ?.The cloud of AEO10C4 was above 60 ?,and the cloud of AEO8C10 and AEO6C10 fell below 25?.2.Six kinds of polymers containing alkyl polyoxyethylene side chain with temperature response characteristics were synthesized by copolymerization of acrylamide(AM),acrylic acid(AA)and one of six temperature-sensitive monomers,respectively.Other three kinds of polymers containing polyoxyethylene side chain were synthesized by copolymerization of AM,AA and one of three allyl polyoxyethylene ethers containing the same ethoxy structure with six temperature-sensitive monomers(AEO10,AEO8 and AEO6),respectively.The effect of reaction conditions on the properties of the polymer solution was studied,and the optimal reaction conditions were determined as:n(AM):n(AA):n(functional monomer)was 84.0:15.0:1.0(%),initiator dosage was 0.3 wt%,pH of the reaction system was 7,polymerization temperature was 40 ?,the total concentration of the monomers was 25 wt%.The molecular structure of nine polyoxyethylene polymers was characterized by IR and 1H NMR.The intrinsic viscosity of nine polymers was determined by dilution method.3.The water solubility of polyoxyethylene polymers,HP AM and hydrophobic polymer(AP-P4)were studied in indeionized water at room temperature and 45 ?,and in saline at room temperaturew.It has been found that the dissolution time of polyoxyethylene ether polymers was similar with HP AM or even shorter than HPAM.The result had showed that polyoxyethylene ether polymer have bettter water-solubility than AP-P4.The further studies on the effect of temperature on the dissolution time polyoxyethylene polymers were carried out in indeionized water.It was found that the dissolution time of polyoxyethylene polymers containing alkyl ether on the side chains became longer at about LCST of side chain,which showed that polymers containing alkyl-polyoxyethylene side chain exerted temperature response characteristics.4.The solution behavior of polyoxyethylene ether polymer,HPAM and AP-P4 was studied in different conditions.The polymer containing alkyl-polyoxyethylene side chain had better thickening properties,wherein tackifying of the polymer AM/AA/AEO10C16 and AM/AA/AEO8C10 was best.The apparent viscosity of 2000 mg/L AM/AA/AEO10C16 and AM/AA/AEO8C10 solution could be up to 428.7 mPa s and 438.3 mPa s,respectively.It has been found that the anti-NaCl,anti-CaCl2 ability of polymers containing alkyl-polyoxyethylene side chain was weaker than AP-P4,but much better than HPAM and other polyoxyethylene ether polymer by studying the effect of inorganic salt on the apparent viscosity of the polymer solution.The surface morphology of the polymers were studied by SEM,which has been found that AM/AA/AEO10C16 has distinct network structure in indeionized water and the network structure could be still observed in saline.5.The rheological properties of the polymer solution were studied,which has been found that the polymer containing alkyl-polyoxyethylene side chain has better temperature resistance,shear resistance,shear recovery and viscoelastic.It has been also found that the polymer containing alkyl-polyoxyethylene side chain exerted a significant thermal thickening characteristic and increase phenomenon in viscoelasticity with increasing temperature.The apparent viscosity of AM/AA/AEO10C16,AM/AA/AEO10C10,AM/AA/AEO8C10 and AM/AA/AEO6C10 exhibited temperature response in the range of 20?60?,which showed that the polymers containing alkyl-polyoxyethylene ether having temperature response property.And the study had showed that the polymers containing alkyl-polyoxyethylene side chains exerted the property of shear thickening at a high shear,and the apparent viscosity retention of 2000 mg/L AM/AA/AEO10C16?AM/AA/AEO10C10?AM/AA/AEO8C10 and AM/AA/AEO6C10 solution could be up to 56.3 mPsˇs?34.4 mPaˇs?30.7 mPaˇs and 29.4 mPaˇs.6.The obvious surface activity of the polymers containing alkyl-polyoxyethylene side chains could be observed through studying the change of surface tension of the polymers aqueous solution.And the surface tension of water when adding AM/AA/AEO10C16,AM/AA/AEO10C10,AM/AA/AOP10 AM/AA/AEO8C10 and AM/AA/AEO6C10 could be reduced to 40.6 mN/m,39.9 mN/m,45.1 mN/m,38.6 mN/m and 44.3 mN/m. |
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