Study on the morphology of the novel hydrophobically associative acrylamide‐based terpolymer in aqueous solution by AFM measurements

The synthesized hydrophobically associating water‐soluble polymer P(AM‐BST‐NaAMPS) (PASA) exhibits good viscosification properties in the aqueous and brine solution. To study the viscosifying mechanisms of the polymer in the aqueous solution and brine solution, atomic force microscope (AFM) was applied to observe the micromorphology of the polymer solution. The AFM measurements show that continuous network structures have been formed in the aqueous solution of 0.05 g dL^?1 PASA, and with the increase in PASA concentration, the network structures become much bigger and more condensed. The network structures of PASA are collapsed by the addition of salt, and tree‐like crystals are formed, leading to the decrease in the apparent viscosity of PASA solution. However, by increasing the NaCl concentration or the polymer concentration in the brine solution, the sizes of crystals increase. These results are consistent with the ESEM and viscosity study results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3996–4002, 2006     

十二烷基苯磺酸钠对疏水缔合两性聚合物的性能影响

使用激光光散射仪、流变仪研究了十二烷基苯磺酸钠（SDBS）对疏水缔合两性聚合物的溶液性能影响.结果表明,盐浓度较低时,溶液粘度随表面活性剂浓度的增加出现先增加后下降的过程;盐浓度过高时,表面活性剂在盐水中析出.表面活性剂对聚合物溶液的弹性模量具有较大的影响,对粘性模量的影响较小.表面活性剂对聚合物的流体力学半径＜Rh＞和聚合物的表观重均分子量Mw均有较大影响.     

Flourescent probe and ESEM morphologies of a acrylamide‐based terpolymer in aqueous solution

The terpolymer (PASA) of acrylamide with butyl styrene and sodium 2‐acrylamido‐2‐methylpropane sulfonate was synthesized. The composition and molecular structure were characterized by elemental analysis, UV, FTIR, and ¹H NMR. The aggregation behaviors of PASA were studied by means of the fluorescent probe analysis and environmental scanning electron microscope (ESEM). The flourescent probe analysis indicates that the PASA molecules form excellent hydrophobically associating structures in pure water and with the increase in PASA concentration at low concentrations, the nonpolarity of hydrophobic microdomains and the degree of intermolecular hydrophobic association increase in aqueous and brine solution. ESEM measurements show that gigantic aggregates have been formed in the PASA aqueous solution at the polymer concentration of 0.05 g dL^?1, which is the critical association concentration of the polymer, and excellent solution properties of PASA are attributed to integrated network‐structures formed by PASA in aqueous solution, which are collapsed by the addition of salt, resulting in the decrease in apparent viscosity of PASA in brine solution. However, with the increase in the NaCl concentration or the PASA concentration, the number and size of aggregates increase, leading to the remarkable increase in the apparent viscosity of PASA in brine solution. These results are consistent with the AFM and viscosity study results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:277–286, 2007     

Studies on the self‐assembly behavior of the hydrophobically associating polyacrylamide

Contrasted with partially hydrolyzed polyacrylamide (HPAM), the self‐assembly behavior and microstructure of hydrophobically associating polyacrylamide (HAPAM) in aqueous solution have been studied by means of fluorescence spectrum, transmission electron microscopy (TEM), atomic force microscope (AFM), and apparent viscosity test in this article. The fluorescent probe analysis indicates that the HAPAM molecules will form associating aggregates in pure water. The results show that HAPAM can easily self‐assemble to form an aggregate by hydrophobic driving force in dilute aqueous solution. The association of hydrophobic groups of the HAPAM causes the formation of supermolecule, so there are associating aggregates formed at very low concentration and then leads to the formation of network at a higher concentration. TEM and AFM measurements show that a distinct network structure has been formed in 1000 mg L^?1 of HAPAM solution, indicating the strong association of hydrophobic groups. These results are consistent with the viscosity measurement and reveal that the excellent viscosification of HAPAM is due to the association of hydrophobic groups in the aqueous solution. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A water‐soluble acrylamide hydrophobically associating polymer: Synthesis,characterization, and properties as EOR chemical

A water‐soluble acrylamide hydrophobically associating terpolymer for polymer flooding was successfully synthesized via free radical polymerization using acrylamide (AM), acrylic acid (AA), and N,N‐divinylnonadeca‐1,10‐dien‐2‐amine (DNDA) as raw materials. The terpolymer was characterized by IR spectroscopy and fluorescence spectra. Compared with partially hydrolyzed polyacryamide (HPAM), the terpolymer showed a stronger link and better dimensional network structure under the environmental scanning electron microscope (ESEM). The results of rheology indicated that the terpolymer (AM‐NaAA‐DNDA) showed an excellent shear‐resistance in high shear rate (1000 s^?1) and remarkable temperature‐tolerance (above 110°C). The salt‐resisting experiment revealed that this terpolymer had a better anti‐salt ability. According to the core flooding test, it could be obtained that oil recovery was enhanced more than 15% under conditions of 2000 mg/L terpolymer in the mineralization of 8000 mg/L at 60°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Phase behaviour and solution properties of sulphobetaine polymers

Aqueous polyelectrolytes have been extensively studied and comprehensively described in numerous books and reviews. In contrast, systematic investigations of aqueous polyzwitterions are few. This paper describes the detailed phase behaviour and solution properties of a homopolymer based upon a recently available sulphobetaine monomer, N-(3-sulphopropyl)-N-methacrylooxyethyl-N,N-dimethyl ammonium betaine (SPE). In addition, such properties are probed at the molecular level by static and dynamic light scattering, as well as laser Raman spectroscopy. Poly[N-(3-sulphopropyl)-N-methacrylooxyethyl-N,N-dimethyl ammonium betaine], P(SPE), of 4.35 × 10⁵M_w shows remarkable phase behaviour. It exhibits both an upper critical solution temperature (UCST) and an ‘apparent inverted’ lower critical solution temperature (LCST), i.e. a 1-phase region flanked by two 2-phase regions. Moreover, the UCST occurs at an order of magnitude lower polymer concentration than predicted by theory or demonstrated by experiment with conventional polymers. The aqueous solubility of (SPE) depends upon polymer molecular weight, as well as the concentration and structure of added salts. ‘Soft’ salt anions and cations are more effective solubilizers than ‘hard’ anions and cations. Furthermore, solutions of P(SPE) display ‘antipolyelectrolyte behaviour’, i.e. viscosities which increase with increasing salt concentrations. Static light scattering experiments indicate that the solvent quality for P(SPE) increases with increasing salt concentration. Dynamic light scattering measurements show that the polymer diffusion coefficients decrease and the chain dimensions increase with increasing salt concentrations. Moreover, laser Raman spectroscopy indicates that the local environment around the zwitterion functionalities is also modified by changes in salt concentration. Based upon such molecular level probes, models have been proposed to account for the P(SPE) phase behaviour and solubility. Thus, P(SPE) is depicted as a collapsed coil in water because of intra-group and intra-chain associations. The unusual phase behaviour of P(SPE) in water is rationalized in terms of a shift from intra- to interinteractions. In turn, NaCl breaks up the intra-associations and promotes polymer solubility.     

A novel twin-tailed hydrophobically associating copolymer: synthesis, characterization and solution properties

Novel twin-tailed hydrophobically associating copolymers (DDSPAM) were prepared by micellar copolymerization of acrylamide (AM) and sodium vinylsulfonate with N,N-didecyl-N-methyl-N-(4-vinylbenzyl)ammonium chloride in an aqueous solution. The structure and composition of DDSPAM were characterized by ¹H-NMR and elemental analysis. While the molecular weights of the copolymers were obtained via static light scattering, the hydrodynamic radius of aggregates was investigated using dynamic light scattering. The critical micellar concentration cmc and γ _cmc values of DDSPAM were measured using fluorescence and later correlated with the values obtained from surface tension measurements. In addition, the viscosity stability studies of DDSPAM and hydrolyzed polyacrylamide (HPAM) revealed that DDSPAM, with twin tails of hydrophobic groups, exhibited better salt tolerance as well as temperature resistance compared to HPAM.     

Amphiphilic cycloterpolymers of diallyldimethylammonium chloride,diallyloctadecylammonium chloride,and sulfur dioxide

A hydrophilic monomer (diallyldimethylammonium chloride), a hydrophobic monomer (diallyloctadecylammonium chloride), and sulfur dioxide are cycloterpolymerized in dimethylsulfoxide using azobisisobutyronitrile as the initiator to afford water‐soluble cationic polyelectrolytes having a five‐membered cyclic structure on the polymeric backbone. The molecular weights of the polymers containing varying amounts of the hydrophobic monomer (0–7.5 mol %) are determined by light‐scattering experiments. The solution properties of the series of cationic polyelectrolytes are investigated by viscometric techniques. A polymer concentration (C*_HA) of <1 g/dL is required for the manifestation of hydrophobic associations in these terpolymers containing C₁₈ hydrophobic pendents. This is a notable improvement over the C*_HA values (ca. 15–17 g/dL) for the associating cyclopolymers having a pendant length of C10 to C14. The polymer solutions exhibit a sharp increase in viscosity with increasing polymer concentrations in salt‐free as well as salt‐added solutions. The presence of sodium chloride is shown to enhance the hydrophobic association tremendously. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1298–1306, 2005     

Synthesis and photochromic property of nanoparticles with spiropyran moieties via one-step miniemulsion polymerization

Summary  Photochromic nanoparticles with spiropyran moieties were prepared by a facile one-step miniemulsion polymerization. The nanoparticle dispersion was obtained by mixing the monomers, spiropyran-containing molecules and hydrophobe, dispersing them into an aqueous solution with surfactant, subjecting the dispersion to ultrasonification and polymerizing the monomers by using a water soluble initiator. The shape and size of the nanoparticles was determined with the atomic force microscope (AFM) and dynamic light scattering (DLS), and the determined average diameter of the nanoparticles ranges from 30 nm to 60 nm. The absorption and fluorescence spectra for the nanoparticles dispersions reveal that the spiropyran molecules were successfully incorporated in the polymer nanoparticles. Moreover, the nanoparticle dispersions were found to exhibit enhanced photo-reversibility, photo-stability and relatively fast photo-responsive property compare to the same species in aqueous solution.     

Use of solution crystallization analysis by laser light scattering for studying the solution crystallization of various Ziegler–Natta‐catalysed polypropylenes

Solution crystallization analysis by laser light scattering (SCALLS) involves the observation of the scattering of diode mercury laser lamp light after it passes through a polymer solution. An increase in turbidity occurs when the hot polymer solution is cooled and the polymer starts to crystallize out of solution. This causes a decrease in the amount of laser light that can pass through the solution and an increase in the amount of scattered light. The reverse of this process leads to the turbidity decreasing with an increase in temperature. According to this concept, it is possible to follow the solution crystallization of various polypropylenes under controlled cooling. In this study, SCALLS was able to differentiate between different isotactic and syndiotactic polypropylenes with similar chemical structures, but different tacticity and molecular weights. Furthermore, SCALLS provided good crystallization information that is similar to that from crystallization analysis fractionation and temperature rising elution fractionation. In addition, SCALLS can be used as a quantitative tool for the measurement of weight fractions during dissolution. © 2014 Society of Chemical Industry     

A double‐tailed acrylamide hydrophobically associating polymer: Synthesis,characterization, and solution properties

In order to improve the salt resistant, temperature tolerance, and stability of the acrylamide‐based copolymer, the double‐tailed hydrophobically associating copolymer (DTHAP) was synthesized. The chemical and spatial network structures of the copolymer were characterized by Fourier transform infrared spectroscopy (FT‐IR), nuclear magnetic resonance spectroscopy (NMR), and environmental scanning electron microscope (ESEM). The salt, temperature, aging resistance, and rheological behavior of the copolymer were investigated in detail. The experimental results showed that the performance of DTHAP were influenced by the amount of AA, PETMAM, SDS, and NaCl in the reaction system. Compared with HPAM, DTHAP solution showed excellent temperature resistance and salt tolerance. No matter in the solution varying NaCl or CaCl₂ concentration from 8 to 80 and 1 to 1.8 g/L, respectively, DTHAP behaved an obvious salt‐thickening phenomenon. The simulative tertiary oil recovery tests at 80°C indicated that DTHAP can remarkably enhance 16.9% of the oil recovery ratio. Even at 100 g/L salt solution, DTHAP exhibited an excellent performance which can also enhance 9.9% of oil recovery ratio. The experiment results indicated that DTHAP was superior to HPAM as a kind of oil displacement agent for enhanced oil recovery, especially in high‐temperature and high‐mineralization oil fields. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42569.     

Viscous and Interfacial Behaviors,and AFM Morphologies of a Tetra-Polymer in Aqueous Solutions for Enhanced Oil Recovery

An acrylamide-based tetra-polymer (PAVO) containing a macro-monomer APEO: allyl-capped octylphenoxy poly(ethylene oxide) and vinyl biphenyl (VP), was measured in 30 g/L NaCl with static light scattering. The result shows that the molecular weight is low and the polymer chains are expanded. The apparent viscosities are much higher in 90 g/L NaCl than in water for PAVO at polymer concentrations higher than 1 g/L, the salt-thickening effects induced by the Na⁺, Ca²⁺, and Mg²⁺ ions are exhibited, and both surface and interfacial tensions are low in water and 90 g/L NaCl. In order to reveal the mechanism giving rise to solution properties for this polymer, the effects of polymer concentration on associating behaviors of the polymer chains in water and in 90 g/L NaCl, were investigated by the ultraviolet spectral analysis using pyrene as a probe. Resistance factor and residual resistance factor are remarkably higher in 120 g/L salt for PAVO than for HPAM. Atomic force microscope (AFM) morphologies of PAVO in water show that the expanded polymer chain bundles are formed at the polymer concentrations of 0.5–1.5 g/L, which demonstrates that the introduction of the APEO macro-monomer together with VP can make the polymer chains expanded.     

Superabsorbent polymeric materials. VI. Effect of sulfobetaine structure on swelling behavior of crosslinked poly(sodium acrylate‐co‐sulfobetaines) in aqueous salt solutions

A series of xerogels based on sodium acrylate (SA), N,N‐dimethyl(acrylamidopropyl) ammonium propane sulfonate (DMAAPS) or dimethyl(methacryloyloxy ethyl) ammonium propane sulfonate (DMAPS), and N,N′‐methylene bisacrylamide (NMBA) was prepared by inverse suspension polymerization. The water absorbencies or swelling kinetic behaviors for these xerogels in water or various saline solutions were investigated. The swelling behaviors of these absorbents were related to their chemical structures, their compositions, and the nature of external salt solutions. The water absorbencies of these two copolymeric gel series in deionized water or in various salt solutions would be improved effectively by copolymerizing SA with a small amount of zwitterionic monomer (DMAAPS or DMAPS). The water absorbency of the gel containing DMAPS is larger than that of the gel containing DMAAPS when the amount of zwitterionic monomer in the copolymeric gel is <0.8 mol %, but a contrary result is observed when the zwitterionic monomer content is >0.8 mol %. The tendency of the absorbency for these gels in dilute solution is in the order Cu²⁺ > Zn²⁺ > Co²⁺ > Ni²⁺ for CuCl₂, ZnCl₂, CoCl₂, and NiCl₂ aqueous solution, respectively. The absorbency and initial absorption rate for those gels are related with gel compositions and salt concentrations. Finally, the adsorption of cupric ion by these gels is also investigated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1221–1232, 1999     

Synthesis and properties of hydrophobically modified acrylamide-based polysulfobetaines

Acrylamide-based, hydrophobically modified polysulfobetaines containing 3-[N-(2-methacroyloylethyl)-N,N-dimethylammonio]-propane sulfonate (DMAPS) and varying amounts of the hydrophobic monomer stearyl methylacrylate (SMA) were synthesized by micellar copolymerization. The basic physico-chemical properties of the synthesized copolymers were studied by means of surface tension, dynamic laser light scattering, and rheological measurements. All the copolymers showed surface activity when the copolymer concentration was above 0.07 wt%. The dynamic laser light scattering measurement revealed that both zwitterionic and hydrophobic associations were important in copolymer aggregation. The rheological properties of the copolymers in aqueous solution depended on the content of hydrophobic monomer, the copolymer concentration and the addition of salt, which were characteristic of hydrophobically modified polyacrylamide and acrylamide-based polyzwitterions. The critical aggregation concentration of the copolymers was in the range of 0.07–0.1 wt%.     

Study on the rheological behavior of the hydrophobically modified hydroxyethyl cellulose with 1,2‐epoxyhexadecane*

Through the macromolecule reaction method, the hydrophobically modified hydroxyethyl cellulose (EP16–HAHEC) was synthesized using 1, 2‐epoxyhexadecane as the hydrophobic monomer. The solution properties of EP16–HAHEC were comprehensively investigated, which showed that the polymer with enhanced; viscosification property, thermal stability, shear resistance, and salt resistance was obtained. Amphiphilic structure of EP16–HAHEC molecules contributed to the surface activity of the polymer. By forming complex solution with surfactants or carboxylmethyl cellulose (CMC), the viscosification property of EP16–HAHEC could be enhanced through the interactions of hydrophobic groups and hydrogen bonds. The viscosity‐enhancing mechanism of HAHEC was studied by the environment scan electronic microscope (ESEM) and the fluorescence spectrum measurements, which demonstrated that the formation of the supramolecular aggregation networks was coincident with the increase of the apparent viscosity of HAHEC. With the gradual formation of the complete polymer molecule networks, the apparent viscosity rised dramatically, and the associating aggregations of the polymer molecules appeared far before the great change of the macroproperty of the polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2953–2959, 2006     

Emulsifier‐free synthesis and self‐assembly of an amphiphilic poly(styrene‐co‐acrylic acid) copolymer

A poly(styrene‐co‐acrylic acid) copolymer was synthesized by surfactant‐free polymerization with the assistance of power ultrasound in water. Fourier transform infrared, NMR, and differential scanning calorimetry measurements revealed that the copolymer was random. Atomic force microscopy and laser light scattering were used to investigate the self‐assembly of the copolymer, and it was found that the copolymer chains formed micelles or other self‐assemble structures in solution. Atomic force microscopy also indicated that the self‐assembled structures developed into nanospheres with a poly(acrylic acid)‐rich or polystyrene‐rich surface in a film, depending on the solvent used for the preparation of the film. In particular, a wheel‐like structure could resulted in a film when the copolymer film was prepared in a moist environment; it resulted from heterogeneous aggregates of poly(acrylic acid) at the rim of water bubbles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:3718–3726, 2006     

Bifunctional poly(ethylene glycol) based crosslinked network polymers as electrolytes for all‐solid‐state lithium ion batteries

Polymer electrolyte based lithium ion batteries represent a revolution in the battery community due to their intrinsic enhanced safety, and as a result polymer electrolytes have been proposed as a replacement for conventional liquid electrolytes. Herein, the preparation of a family of crosslinked network polymers as electrolytes via the ‘click‐chemistry’ technique involving thiol‐ene or thiol‐epoxy is reported. These network polymer electrolytes comprise bifunctional poly(ethylene glycol) as the lithium ion solvating polymer, pentaerythritol tetrakis (3‐mercaptopropionate) as the crosslinker and lithium bis(trifluoromethane)sulfonimide as the lithium salt. The crosslinked network polymer electrolytes obtained show low T_g, high ionic conductivity and a good lithium ion transference number (ca 0.56). In addition, the membrane demonstrated sterling mechanical robustness and high thermal stability. The advantages of the network polymer electrolytes in this study are their harmonious characteristics as solid electrolytes and the potential adaptability to improve performance by combining with inorganic fillers, ionic liquids or other materials. In addition, the simple formation of the network structures without high temperatures or light irradiation has enabled the practical large‐area fabrication and in situ fabrication on cathode electrodes. As a preliminary study, the prepared crosslinked network polymer materials were used as solid electrolytes in the elaboration of all‐solid‐state lithium metal battery prototypes with moderate charge–discharge profiles at different current densities leaving a good platform for further improvement. © 2018 Society of Chemical Industry     

Effect of Sodium Salicylate on the Properties of Gemini Surfactant Solutions

In this paper, the effect of sodium salicylate on the solution properties of a gemini surfactant, butylidene-α, ω-bis (cetyl dimethyl ammonium bromide), was investigated through absorbance and dynamic light scattering (DLS) measurement, transmission electron microscope (TEM) observation, and rheology measurement. The DLS experiment showed that the average size of aggregates increases with the addition of sodium salicylate. The TEM experiment showed that the addition of sodium salicylate causes the change of the size and shape of aggregate. With the increase of the concentration of sodium salicylate, the viscosity of the gemini surfactant solution reaches a maximum value and the flow pattern of the gemini surfactant solution also undergoes a great change with a transition from a Newtonian fluid to a non-Newtonian fluid.     

Electrolyte‐ and pH‐responsive polyampholytes with potential as viscosity‐control agents in enhanced petroleum recovery

Low‐charge‐density amphoteric copolymers and terpolymers composed of AM, the cationic comonomer (3‐acrylamidopropyl)trimethyl ammonium chloride, and amino acid derived monomers (e.g., N‐acryloyl valine, N‐acryloyl alanine, and N‐acryloyl aspartate) have been prepared via free‐radical polymerization in aqueous media. These terpolymers with random charge distributions have been compared to terpolymers of like compositions containing the anionic comonomer sodium 3‐acrylamido‐3‐methylbutanoate. Terpolymer compositions determined by ¹³C‐ and ¹H‐NMR spectroscopy, terpolymer molecular weights and polydispersity indices obtained via size exclusion chromatography/multi‐angle laser light scattering, and hydrodynamic dimensions determined via dynamic light scattering have allowed a direct comparison of the fundamental parameters affecting the behavioral characteristics. The solution properties of low‐charge‐density amphoteric copolymers and terpolymers have been studied as functions of the solution pH, ionic strength, and polymer concentration. The low‐charge‐density terpolymers display excellent solubility in deionized water with no phase separation. The charge‐balanced terpolymers exhibit antipolyelectrolyte behavior at pH values greater than or equal to 6.5 ± 0.2. As the solution pH decreases, these charge‐balanced terpolymers become increasingly cationic because of the protonation of the anionic repeat units. The aqueous solution behavior (i.e., globule‐ to‐coil transition at the isoelectric point in the presence of salt and globule elongation with increasing charge asymmetry) of the terpolymers in the dilute regime correlates well with that predicted by the polyampholyte solution theories. An examination of the comonomer charge density, hydrogen‐bonding ability, and spacer group (e.g., the moiety separating the ionic group from the polymer chain) indicates that conformational restrictions of the sodium 3‐acrylamido‐3‐methylbutanoate and N‐acryloyl valine segments result in increased chain stiffness and higher solution viscosities in deionized water and brine solutions. On the other hand, the terpolymers with N‐acryloyl alanine and N‐acryloyl aspartate segments are more responsive to changes in the salt concentration. An assessment of the effects of the terpolymer structure on the viscosity under specified conditions of the ionic strength and pH from these studies should allow for rational design of optimized systems for enhanced petroleum recovery. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007.     

Associations between a hydrophobically modified,degradable, poly(malic acid) and a β‐cyclodextrin polymer in solution

A new associating system has been elaborated from mixing a degradable polymer, poly(β‐malic acid‐co‐β‐ethyladamantyl malate), and a β‐cyclodextrin polymer in aqueous solution. Viscosity and dynamic light scattering measurements have been made on solutions of the single copolyester and of mixtures of both polymers. Studies on copolyesters with different percentages of hydrophobic groups (0–7.5%) show that a small proportion of the chains (less than 5% in weight) are aggregated in large structures (100 nm) which dominate the scattering intensity. The mixtures exhibit slow diffusive relaxation modes which correlate with a large viscosity enhancement at low concentration. These effects, which depend sensitively on pH, are attributed to the presence of polydisperse complexes of copolyester and β‐cyclodextrin polymer. The influence of pH, ionic strength, medium composition, and concentration were examined on the mixture of copolymers. It was found that the association properties are controlled by the net charge on the amphiphilic copolyester. © 2001 Society of Chemical Industry