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Geng X.F.,Southwest Petroleum University | Hu X.Q.,Southwest Petroleum University | Jia X.C.,BGP Inc. | Luo L.J.,Sichuan Guangya Polymer Chemical Company
Colloid and Polymer Science

Solutions of a novel zwitterionic gemini surfactant, 1,2-bis[N-ethyl-N- (sodium 2-hydroxyl-3-sulfopropyl)-dodecyl-ammonium] ethane betaine (DBA 2-12), in presence of sodium salicylate (NaSal) can form wormlike micelles and thereby show a viscoelasticity. At low molar ratio of NaSal/DBA2-12, R∈≤0.3, the systems behaved like a Newton fluid. However, as the R increased, the systems exhibited shear-thinning behavior. The zero-shear viscosity η ;bsubesub increased dramatically with increasing R and peaked with R∈=∈0.8 at a value of 18.8 Pa s. This was attributed to the formation of long wormlike micelles (1.6∈~≤∈2.9 μm) and network structure confirmed by scanning electron microscopy. Further increase in R beyond 0.8 resulted in a slight decrease in η ;bsubesub, which may be caused by the branched micelles formed at high salt concentration. In addition, the tested systems showed a Maxwellian behavior at lower frequencies, but deviated from the Maxwellian mode at higher frequencies. © 2013 Springer-Verlag Berlin Heidelberg. Source

Bao J.,Southwest Petroleum University | Luo P.,Southwest Petroleum University | Guo Y.,Southwest Petroleum University | Xiong Y.,Sichuan Guangya Polymer Chemical Company
Oilfield Chemistry

Viscosity change regularity of adding novel non-ionic surfactants (GS-1, GS-2 and GS-3) with different hydrophobic chain length to non-crosslinked associative structural fracturing fluid using hydrophobic associative polymer as thickener was investigated. The number of carbon atoms in hydrophobic tail of GS-1, GS-2 and GS-3 was 6, 10 and 14, respectively. GS-3 was selected as the optimal tackifying adjuvant for the fracturing fluid accordingly. The optimum concentration and application temperature range of GS-3 were obtained. And the influence of GS-3 on the viscosity and viscoelasticity of base fracturing fluid was also investigated. The results of experiments showed that the apparent viscosity of fracturing fluid could be greatly increased by adding traces GS-3 (0.03%-0.05%). The optimum concentration of GS-3 was the concentration corresponding to the peak apparent viscosity of complex system and its applicable temperature range was 30-90°C. Within the test concentration range, the apparent viscosity of system increased first and then decreased, the change trend accorded with Biggs's 3 periods model. When the temperature increased from 30°C to 120°C, the apparent viscosity of system also increased first and then decreased. The maximum tackifying rate was 168% at 63°C. The viscoelasticity of fracturing fluid was also enhanced simultaneously. The storage modulus could be increased 1-10 times according to the concentration of thickener. So the dosage of thickener could be greatly decreased by using GS-3 as tackifying adjuvant. © 2015, China International Book Trading Corp. (Guoji Shudian). All rights reserved. Source

Chen Q.-S.,University of Queensland | Kang Q.-J.,Southwest Petroleum University | Kang Q.-J.,Sichuan Guangya Polymer Chemical Company | Li H.-B.,Southwest Petroleum University | Li H.-B.,Sichuan Guangya Polymer Chemical Company
Xinan Shiyou Daxue Xuebao/Journal of Southwest Petroleum University

The new initiating system for synthesis of acrylamide-based polymers has attracted much attention and been the focus of increasing polymer molecular weight in recent years. The performance of polymerization, characteristic and range of application of aqueous azo initiator has been investigated and the aqueous azo initiators can be used for the preparation of high molecular weight acrylamide-based polymers and its derivatives, which demonstrates abroad application prospect. The effect of difunctional initiator and amino functional monomer on molecular weight are also discussed. The initiating system of the new kind of cryogenic compound initiators containing potassium persulfate, ammonia water, urea, azo-(2-amidinopropane) dihydrochloride, functional monomer MP are believed to be able to be used for the preparation of ultrahigh molecular weight acrylamide-based polymers. Source

Feng K.-S.,State Key Laboratory of Oil and Gas Reservoirs Geology and Exploration | Feng K.-S.,Southwest Petroleum University | Guo Y.-J.,State Key Laboratory of Oil and Gas Reservoirs Geology and Exploration | Guo Y.-J.,Sichuan Guangya Polymer Chemical Company | And 6 more authors.
Acta Polymerica Sinica

The hydrophobic association and polyelectrolyte effect of hydrophobically associated water-soluble polymers (HAWSP) were eliminated in solvents containing 50% (volume percent concentration) 1, 3-propylene glycol, 0. 2 mol/L NaCl and water that could make molecules of HAWSP disperse in dilute solutions. Then the polymers of different molecular weights were split through the microporous membrane equipment with different aperture microporous membranes according to the principle of membrane aperture separation. The cumulative percentage of each fraction was calculated through the quantity of each fraction polymer solution which was measured by the curve of percolate quantity-filtration time fitted with a quadratic equation, and the concentration of each fraction polymer solution was measured by spectrophotometry. The Mark-Houwink equation [η] = 0. 182M0.586 of HAWSP which was used to accurately determine the molecular weight of each HAWSP fraction, was calibrated through the static light scattering and capillary tube viscosity methods. The molecular weight distribution curve was determined according to the molecular weight (M) and cumulative percentage (W) of each fraction by using the 4-parameter equation curve. The method of microporous membrane grading to determine the molecular weight distribution of HAWSP was compared with the method of dynamic light scattering for measurement of particle size, the results of the two methods were consistent with each other. Source

Guo Y.,Southwest Petroleum University | Guo Y.,Sichuan Guangya Polymer Chemical Company | Liang Y.,Southwest Petroleum University | Yang X.,Sichuan Guangya Polymer Chemical Company | And 4 more authors.
Journal of Applied Polymer Science

Poly(acrylamide/sodium acrylate/N-dodecyl acrylamide)s [poly(AM/NaAA/C 12AM)s] with different hydrophobic microblock lengths (N H's) were prepared by the micellar copolymerization of acrylamide and sodium acrylate with a low amount of N-dodecyl acrylamide (0.2 mol %), and the molecular structure was characterized by Fourier transform infrared spectroscopy, 1H-NMR, and static light scattering. A combination of experiments involving viscosity measurement, fluorescence, and conductometry was applied to investigate the effect of NH on the interaction strength and binding capacity between poly(AM/NaAA/C12AM)s and C 12H25SO4Na [sodium dodecyl sulfate (SDS)]. The viscosity, I3/I1 (the intensity ratio of the third vibrational band to the first band of pyrene molecules), and conductivity of the mixed system of copolymers with SDS all had different variation trends with the concentration of SDS. The binding capacity of the copolymers with SDS was calculated according to quantitative differences between the critical micelle concentration of the pure SDS solution and the mixed system. All of the results show that the interaction strength of SDS with the copolymers rose, and the binding capacity decreased with increasing NH. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40633. Copyright © 2014 Wiley Periodicals, Inc. Source

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