Intermolecular Hydrophobic Associations Research Articles

Reverse cationic flotation of low-grade phosphate ore using quaternary ammonium salt as a collector and its adsorption mechanism

A novel quaternary ammonium salt collector, LH-01, was employed for the reverse cationic flotation of a magnesium-depleted concentrate (P2O5 grade of 19.72wt%, SiO2 content of 44.26wt%). We achieved an outstanding phosphate concentrate with a P2O5 grade of 35.16wt%, a SiO2 content of 6.06wt%, and a P2O5 recovery of 75.88%. This process was accomplished through two sequential reverse cationic flotation processes designed for quartz removal. Importantly, the quartz removal by LH-01 reached 94.17%, far superior to that by dodecyltrimethylammonium chloride, achieving highly selective separation of quartz and apatite. To understand the adsorption mechanism and kinetics of the collector LH-01 on quartz and apatite surfaces, various techniques, such as quartz crystal microbalance with dissipation, atomic force microscopy, and X-ray photoelectron spectroscopy, were employed. Results revealed that the adsorption layer of LH-01 on the apatite surface was thin and rigid, with a significantly lower hydrophobic effect than that of the viscoelastic multiple adsorption layer formed by LH-01 on the quartz surface. This disparity was identified as the primary factor contributing to the selective flotation separation of apatite and quartz. Moreover, the adsorption of LH-01 on the quartz surface was the result of multiple forces, including electrostatic adsorption, multiple-hydrogen-bond adsorption, and intermolecular hydrophobic association.

Enhancing Oil Recovery in Low-Permeability Reservoirs Using a Low-Molecular Weight Amphiphilic Polymer.

Polymer flooding has achieved considerable success in medium-high permeability reservoirs. However, when it comes to low-permeability reservoirs, polymer flooding suffers from poor injectivity due to the large molecular size of the commonly used high-molecular-weight (high-MW) partially hydrolyzed polyacrylamides (HPAM). Herein, an amphiphilic polymer (LMWAP) with a low MW (3.9 × 106 g/mol) was synthesized by introducing an amphiphilic monomer (Allyl-OP-10) and a chain transfer agent into the polymerization reaction. Despite the low MW, LMWAP exhibited better thickening capability in brine than its counterparts HPAM-1800 (MW = 1.8 × 107 g/mol) and HPAM-800 (MW = 8 × 106 g/mol) due to the intermolecular hydrophobic association. LMWAP also exhibited more significant shear-thinning behavior and stronger elasticity than the two counterparts. Furthermore, LMWAP possesses favorable oil-water interfacial activity due to its amphiphilicity. The oil-water interfacial tension (IFT) could be reduced to 0.88 mN/m and oil-in-water (O/W) emulsions could be formed under the effect of LMWAP. In addition, the reversible hydrophobic association endows the molecular chains of LMWAP with dynamic association-disassociation transition ability. Therefore, despite the similar hydrodynamic sizes in brine, LMWAP exhibited favorable injectivity under low-permeability conditions, while the counterpart HPAM-1800 led to fatal plugging. Furthermore, LMWAP could enhance oil recovery up to 21.5%, while the counterpart HPAM-800 could only enhance oil recovery by up to 11.5%, which could be attributed to the favorable interfacial activity of LMWAP.

Residue-Free and Recyclable Starch-Based Flocculants for Dye Wastewater Flocculation.

Flocculants are crucial agents in wastewater treatment because they can remove oppositely charged impurities effectively and swiftly. However, flocculation also inevitably causes secondary contamination due to the residual properties, nonreusability, and nondegradability of traditional flocculant molecules. Herein, an ecofriendly starch-based flocculant, i.e., 2,4-bis(dimethylamino)-[1,3,5]-triazine-6-starch, was synthesized via a preactivation-etherification strategy. The large molecular weight property of the flocculant produced by this method enhances the intermolecular hydrophobic association, achieving complete phase separation of all flocculant molecules from water and residue-free flocculation for the first time. Importantly, a large molecular weight tertiary amine starch-based flocculant (LMTS) exhibits a remarkable flocculation capacity of over 1800 mg·g-1 for dye wastewater, which is significantly higher than that of traditional polyacrylamide and polyaluminum chloride flocculants. Furthermore, the LMTS flocculant could be recycled by pH adjustment, and its structural stability ensured sustained reusability. This high-performance residue-free biomass-based flocculant offers a green advance for wastewater treatment.

The characteristics and flocculation performance of hydrophobic association poly‐(3‐methacryloylamido propyl trimethyl ammonium chloride)

AbstractThe cationic polymer plays a crucial role in the flocculation process for solid–liquid separation. A hydrophobic‐associated cationic polymer was prepared through micellar free‐radical polymerization of cationic monomer 3‐methyl acrylamide propyl trimethyl ammonium chloride (MAPTAC) and hydrophobic monomer Poly (ethylene glycol) Octadecyl methacrylate (OEMA). The Poly‐MAPTAC‐OEMA can form network structure through intermolecular hydrophobic association in aqueous solution, which leads to the solution viscosity increase and the salt thickening property. The critical associating concentrations (CACs) of Poly‐MAPTAC‐OEMA are 5818–6992 mg/L in aqueous solution. For the diatomite suspensions, at the dosage above about 5 mg/L, the Poly‐MAPTAC‐OEMA can show higher flocculation efficiency compared with Poly‐MAPTAC. Specifically, at the dosage of 8 mg/L, the enhancement rate of sedimentation rate can reach 7.27%–32.31%. Meanwhile, the hydrophobic association mainly enhances the bridging ability but has no significant effect on the improvement of the electric neutralization ability of Poly‐MAPTAC‐OEMA. The flocculation performance‐enhanced dosage of Poly‐MAPTAC‐OEMA is obviously lower than the CAC of Poly‐MAPTAC‐OEMA; this may be because during the flocculation process, the Poly‐MAPTAC‐OEMA first absorb and deeply concentrate on the particle surface, and then the hydrophobic association and bridging enhancement of Poly‐MAPTAC‐OEMA can occur more easily on the particle surface.

Preparation, characterization, and evaluation of suspension stabilizer for low‐density cement slurry for cementing

AbstractA low‐density cement slurry system is commonly used in low‐pressure and leakage‐prone cementing. However, the suspension stability of the system is more difficult to control because of the addition of lightning material. Especially under the condition of large temperature differences, the relative motion between solid particles with large density differences increases, which will aggravate the instability of the slurry and affect the cementing quality. Therefore, to effectively control the suspension stability of the low‐density cementing slurry system, the suspension stabilizer PAND was synthesized by free radical solution polymerization withN‐vinyl caprolactam (NVCL); 2‐acrylamide‐2‐methyl propane sulfonic acid (AMPS),N, N‐dimethyl acrylamide (DMAA) as monomers. The effect of PAND on the stability of low‐density cement slurry under a large temperature difference (40 ~ 120°C) was evaluated. The results showed that under 40 ~ 120°C, adding 0.8% PAND can control the water separation of the cement slurry to 0; the density difference between the upper and lower parts of the cement stone column after curing is less than 0.01 g/cm3. The mechanical properties of cement stone are improved, which shows that it has a good suspension stability effect on low‐density cement slurry systems. The analysis of UV spectroscopy and scanning electron microscopy showed that PAND formed an intermolecular hydrophobic association network structure with the increase in temperature, which could maintain the viscosity of the solution system, thus playing an influential suspension stability role.

A novel hydrophobically associating water-soluble polymer used as constant rheology agent for cement slurry.

During the process of well cementing in deep water, the cement slurry experiences a wide range of temperature variation from low temperature at seabed to high temperature in downhole. The elevated temperature affects the rheology of cement slurry. The change of rheology of cement slurry could influence the safety of cementing operation. The aim of this paper is to develop a new kind of hydrophobically associating water-soluble polymer (NHAWP) as an additive to prepare a constant rheology oil well cement slurry, which can be used at temperature range from 4°C to 90°C. The acrylamide, 2-acrylamide-2-methylpropionic acid and stearyl methylacrylate were applied to synthesize the NHAWP by the inverse microemulsion polymerization. Test results indicate that the critical association temperature of NHAWP is 45°C. The critical association temperature is independent of NHAWP concentration, salt concentration and alkalinity of solution. When the temperature is below 45°C, NHAWP shows little influence on the viscosity of solution. When the temperature is above 45°C, the NHAWP forms spatial network structure by intermolecular hydrophobic association and thus increases the viscosity of solution significantly. The NHAWP also displays good thermal stability and excellent salt and alkali resistance properties. In addition, the NHAWP shows nearly no negative influence on the basic properties of cement slurry, which indicates that the NHAWP can be used as a constant rheology agent to prepare a cement slurry with constant rheology in the temperature range of 4°C to 90°C.

A quinoline alkaloid potentially modulates the amyloidogenic structural transitions of the biofilm scaffolding small basic protein

Bacterial biofilm formation by communities of opportunistic bacterial pathogens like Staphylococcus epidermidis is regarded as the primary virulence mechanism facilitating the spread of detrimental nosocomial and implant-associated infections. An 18-kDa small basic protein (Sbp) and its amyloid fibrils account for strengthening the biofilm architecture and scaffolding the S. epidermidis biofilm matrix. Our study reports systematic analysis of the amyloidogenic structural transitions of Sbp and predicts the amyloid core of the protein which may trigger misfolding and aggregation. Herein, we report the novel amyloid inhibitory potential of Camptothecin, a quinoline alkaloid which binds stably to Sbp monomers and redirects the formation of unstructured regions further destabilizing the protein. Molecular dynamics simulations reveal that Camptothecin averts β-sheet transitions, interrupts with electrostatic interactions and disrupts the intermolecular hydrophobic associations between the exposed hydrophobic amyloidogenic regions of Sbp. Collectively, our study puts forward the first report detailing the heteromolecular associations and amyloid modulatory effects of Camptothecin which may serve as a structural scaffold for the tailored designing of novel drugs targeting the S. epidermidis biofilm matrix. Communicated by Ramaswamy H. Sarma

Hydrophobically Modified Alginate Derivatives via the Ugi Multicomponent Reaction for the Development of Hydrophobic Pharmaceutical Formulations

AbstractIn this work, the hydrophobically modified alginate derivative (HMAD) was synthesized by using sodium alginate, cyclohexyl isocyanide, octylamine and propionaldehyde instead of formaldehyde, based on previous explorations of the Ugi reaction for the modification of alginate. Experimental results revealed that the successful grafting of the hydrophobic chains onto the alginate molecular backbone via the Ugi reaction had weakened and destroyed the intramolecular hydrogen bonds, thus enhancing the molecular flexibility of alginate, which endowed the HMAD with good amphiphilic property with the critical aggregation concentration (CAC) of 0.44 g/L. Moreover, the resultant HMAD could form the stable self‐aggregated micelles with the spherical shape due to the intra or intermolecular hydrophobic associations. Its average hydrodynamic diameter and zeta potential were 458 nm (PDI=0.26) and −61.4 mV, respectively, which was able to achieve the loading and sustained‐release of hydrophobic ibuprofen. Meanwhile, HMAD had no significant cytotoxicity to the murine macrophage RAW264.7 cells. Based on the above merits, the synthesized HMAD could exhibit great potential for the development of hydrophobic pharmaceutical formulations.

Esterification of Alginate with Alkyl Bromides of Different Carbon Chain Lengths via the Bimolecular Nucleophilic Substitution Reaction: Synthesis, Characterization, and Controlled Release Performance.

To extend the alginate applicability for the sustained release of hydrophobic medicine in drug delivery systems, the alkyl alginate ester derivative (AAD), including hexyl alginate ester derivative (HAD), octyl alginate ester derivative (OAD), decyl alginate ester derivative (DAD), and lauryl alginate ester derivative (LAD), were synthesized using the alkyl bromides with different lengths of carbon chain as the hydrophobic modifiers under homogeneous conditions via the bimolecular nucleophilic substitution (SN2) reaction. Experimental results revealed that the successful grafting of the hydrophobic alkyl groups onto the alginate molecular backbone via the SN2 reaction had weakened and destroyed the intramolecular hydrogen bonds, thus enhancing the molecular flexibility of the alginate, which endowed the AAD with a good amphiphilic property and a critical aggregation concentration (CAC) of 0.48~0.0068 g/L. Therefore, the resultant AAD could form stable spherical self-aggregated micelles with the average hydrodynamic diameter of 285.3~180.5 nm and zeta potential at approximately −44.8~−34.4 mV due to the intra or intermolecular hydrophobic associations. With the increase of the carbon chain length of the hydrophobic side groups, the AAD was more prone to self-aggregation, and therefore was able to achieve the loading and sustained release of hydrophobic ibuprofen. Additionally, the swelling and degradation of AAD microcapsules and the diffusion of the loaded drug jointly controlled the release rate of ibuprofen. Meanwhile, the AAD also displayed low cytotoxicity to the murine macrophage RAW264.7 cells. Thanks to the good amphiphilic property, colloidal interface activity, hydrophobic drug-loading performance, and cytocompatibility, the synthesized AAD exhibited a great potential for the development of hydrophobic pharmaceutical formulations.

Chemically modified phytoglycogen: Physicochemical characterizations and applications to encapsulate curcumin

Phytoglycogen (PG), a water-soluble glycogen-like α-d-glucan, exists as natural dendritic nanoparticles which are known as a promising solubility enhancer and delivery vehicle for lipophilic compounds. However, the practical applications of PG in food and pharmaceutical fields are limited by their high hydrophilicity and relatively low encapsulation efficiency compared with other delivery systems. The objectives of this work were to chemically modify native PG nanoparticles with hydrophobic groups and to characterize their physicochemical properties, as well as to evaluate the application feasibility of modified PG (mPG) nanoparticles as a carrier for hydrophobic bioactive compounds. The surface hydroxyl groups of PG nanoparticles were capped with various anhydrides, e.g., acetic, valeric, and N-caprylic, to obtain the PG nanoparticles with different hydrophobicity. Successful modification by acyl groups was evidenced by both Fourier-transform infrared and nuclear magnetic resonance spectroscopies. The mPG nanoparticles exhibited a more compact structure and homogeneous size distribution as revealed by dynamic light scattering measurement and visualized by transmission electron microscope, while their size slightly increased with the chain length of anhydride. Rheological measurement revealed that the viscosity of mPG at low shear rate was increased with the increase of degree of substitution due to the intermolecular hydrophobic association. A novel pH-driven method to load curcumin showed significantly higher encapsulation efficiency and greater antioxidant activity compared with traditional ethanol mediated loading method. Hydrophobic modification of natural dendritic PG nanostructures demonstrates promising potential to develop food-grade nanocarriers for lipophilic bioactive compounds with improved bioactivity.

Hydrophobic modification of cationic microblocked polyacrylamide and its enhanced flocculation performance for oily wastewater treatment

In this study, a novel amphiphilic flocculant TP-ADL was synthesized using acrylamide, methacryloxyethyltrimethyl ammonium chloride and lauryl acrylate as monomers through UV-light-initiating template copolymerization technology. Copolymerization conditions were optimized towards higher intrinsic viscosity and conversion rate. The Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectroscopy (NMR) analysis confirms the functional groups composition in TP-ADL, and the thermogravimetric (TGA) analysis indicates its good thermal stability. Furthermore, the detailed 1H NMR and TGA analysis confirms the microblock structure in polymer chain. The amphiphilic rheological characteristics of copolymer were detected according to apparent viscosity. TP-ADL displayed superior flocculation efficiency towards oily wastewater in terms of oil and turbidity removal rate, and zeta potential. The median floc size (d50) and fractal dimension (Df) results indicate a large and compact floc structure. The synergistic effect between cationic microblock structure and inter-molecular hydrophobic association is the main reason for the better treatment efficiency.

Synthesis, Characterization, and Aqueous Properties of an Amphiphilic Terpolymer with a Novel Nonionic Surfmer

A series of surfactive amphiphilic polymer PAADs were prepared from the copolymerization of sodium acrylate, dodecyl polyoxyethylene acrylate (DPA, a surfmer), and acrylamide under the action of a mixed initiating agent consisting of ammonium persulfate-sodium bisulfite/2,2′-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride. The aggregative behaviors of PAADs were explored by 13C nuclear magnetic resonance, a viscometer, and a surface tension instrument. It was found that the apparent viscosity and surface activity of PAADs were significantly improved by the increase of average sequence length of hydrophobic micro blocks, strong intermolecular hydrophobic association, or the formation of mixed micelles between hydrophobic micro blocks and micromolecular surface-active agent. The introduction of long-chain alkyls on molecular chains prolonged the average sequence length of hydrophobic micro blocks in molecular chains and enhanced the hydrophobic association between molecular chains and the tight arrangement of molecular chains on water surfaces, thereby increasing the surface activity. Moreover, the anionic monomer sodium acrylate on molecular chains, via electrostatic repulsion, promoted the conversion from intrachain association to intermolecular association and thereby facilitated the formation of dense interfacial films, enhancing the surface activity of water solutions. Then, the anion surfmer sodium dodecylbenzenesulfonate interacted with the hydrophobic micro blocks on the molecular chains to form mixed micelles, which accelerated the interchain association and enhanced the polymer surface activity. The novel polymeric micelle with higher viscosifying ability and surface activity was expected to be a promising oil drive agent for tertiary oil recovery.

Preparation and evaluation of supramolecular fracturing fluid of hydrophobically associative polymer and viscoelastic surfactant

A novel fracturing fluid (NAF) comprising of self-synthesized β-cyclodextrin-functionalized hydrophobically associative polymer (HMPAM) and viscoelastic surfactant (VES) was developed. The apparent viscosity of NAF was several times more than that of HMPAM and VES alone. The supramolecular complex gel was achieved by weak physical attractive forces, including intermolecular hydrophobic association, host-guest inclusion, and self-assembly between hydrophobic chains and wormlike micelles. NAF possessed favorable temperature tolerance, shearing resistance, and proppant suspension ability due to its multiple supramoelcular behaviors and high viscoelasticity. Moreover, the gel could be completely broken with no residue, and the broken fluid was easy to flow back. The results indicated that NAF is an effective fracturing fluid and might have favorable application during hydraulic fracturing.

Synthesis and characterization of carboxymethylcellulose grafted with thermoresponsive side chains of high LCST: The high temperature and high salinity self-assembly dependence

Graft copolymers based on carboxymethylcellulose (CMC) and thermosensitive polyetheramines (ethylene oxide/propylene oxide = 33/10 and 1/9) were prepared in water, at room temperature, by using a carbodiimide and N-hydroxysuccinimide as activators. SLS was applied to obtain Mw, A2 and Rg of CMC and its derivatives. Amide linkages were evidenced by FTIR and grafting percentage was determined by 1H NMR. TGA demonstrated that copolymers were thermally more stable than their precursors. DLS, UV-vis and rheological measurements revealed that properties were salt- and thermo-responsive and linked to the polysaccharide/polyetheramine ratio and the hydrophobicity of the graft. None of the copolymers showed cloud point temperature (Tcp) in water, but they turned turbid in saline media when heated. Copolymers exhibited thermothickening behaviour at 60 °C (>Tcp) in saline media. Below their Tcp, they showed the ability of keeping constant viscosity or even slight increase it, which was interpreted in terms of intermolecular hydrophobic associations.

An autonomous self‐healing hydrogel based on surfactant‐free hydrophobic association

ABSTRACTSelf‐healing hydrogels are attractive for a variety of applications including wound dressings and coatings. This paper describes the facile preparation and characterization of an autonomous self‐healing hydrogel system comprising surfactant‐free hydrophobic associations. The hydrogel comprised a copolymer of benzyl methacrylate (B), octadecyl methacrylate (O), and methacrylic acid (MA). The hydrogels were prepared via a controlled dehydration procedure to achieve the formation of strong intermolecular hydrophobic associations of the octadecyl groups above a critical polymer concentration. Fractured hydrogels healed within 30 min without any external intervention. Increasing hydrogel polymer content from 31 wt % to 39 wt % resulted in a threefold increase in the shear modulus and 50% reduction of the relaxation time. Addition of 4 mM NaCl to a hydrogel of 31 wt % polymer content resulted in 2.5 times longer relaxation time and 24% decrease in shear modulus. The hydrogels swelled up water by up to four times its weight, which corroborates the robustness of the hydrophobic association crosslinks. The bulk properties of the hydrogels are discussed in terms of the hydrophobic associations of the O‐groups and the electrostatic interaction of the MA‐groups in the polymer chains. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44800.

Thermo-reversible sol–gel transition of aqueous solutions of patchy polymers

Aqueous solutions of an amphiphilic thermoreversible patchy polymer show abrupt gelation upon cooling by the combined effect of percolation and transition from intra to intermolecular hydrophobic associations.

Study on the self-assembly properties of surface active hydrophobically associating polyacrylamide with nonionic surfmer units

A novel class of hydrophobic associated copolymers (PASC) with nonionic surfmer was synthesized. These copolymers are the copolymerization product of acrylamide (AM), 2-(acrylamido)-2- methyl propane sulfonic acid (AMPS) and different contents of nonionic surfmer (CP). Macroscopic and microscopic self-assembly associative properties in solutions of PASC, as well as the effects of salt and temperature on the associative behavior were studied via viscosimetry, scanning electron microscope (SEM), atomic force microscope (AFM), rheology and fluorescence spectroscopy (FS). The results show that the introduced nonionic surfmer along polymer chain can lead to a strong intermolecular hydrophobic association in water. The viscosity and surface activity increased with the increase of polymer concentration and nonionic surfmer concentration. Additionally, the polymer showed a good thermal stability and good salt tolerance. Contact angle studies shows that PASC solution has good potential on change of wettability from oil-wet to water-wet. All of these properties indicate that the polymer is an excellent chemical for chemical enhanced oil recovery.

Rheological evaluation of synthesized template‐hydrophobically modified acrylamide based copolymers in brine

ABSTRACTThe newly hydrophobically modified associating acrylamide‐based copolymers were prepared by the inverse miniemulsion polymerization method in order to investigate the copolymers rheological and associating properties in water and brine solutions. Dimethyldodecane (2‐acrylamidopropyl) ammonium bromide (DDPAB) was synthesized and used as a hydrophobic monomer and was later copolymerized with acrylamide in the presence of poly(acrylic acid‐co‐maleic acid) and various molecular weights of poly(acrylic acid) as templates. The chemical compositions and functional groups of the resulting hydrophobic monomer and copolymers were characterized using the 1H nuclear magnetic resonance and Fourier transform‐infrared spectroscopy. According to the studies on the solutions viscosity behavior, incorporation of small amount of hydrophobic monomer improved the thickening properties due to the intermolecular hydrophobic association. The apparent viscosity of the copolymers with a template was much greater than those prepared without a template. The molecular weight of the template strongly influenced the thickening behaviors of the copolymers. A template copolymer with 1 mol % of a hydrophobic monomer was the one most efficient. The addition of electrolyte saline improved the polarization of the solutions and enhanced the thickening ability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43588.

Self-assembling transition behavior of a hydrophobic associative polymer based on counterion and pH effects

Abstract The hydrophobically associating cationic polyacrylamides (C-HAPAM), containing a major part of hydrophilic polyacrylamide backbones and a minor part of ionic hydrophobic groups, i.e. N,N′-dimethyl octadeyl allyl ammonium chloride (DOAC), were synthesized. The self-assembling behaviors of the C-HAPAM molecules in water under different concentrations and pH values were investigated in detail and disclosed by rheological tests, dynamic light scattering (DLS), zeta potential, scanning electron microscope (SEM), and atomic force microscope (AFM). The critical aggregate concentration (CAC) for C-HAPAM was about 0.42 wt% and a solution-sol–gel appearance transition has been observed for C-HAPAM aqueous solutions with increasing concentration. Rheological tests demonstrated a pH reversible sol–gel transition when the pH was regulated from its original value of 7.45 to the weak alkaline value of 9.87 by adding NaOH and then switched back to 5.28 by adding HCl. The SEM, AFM and DLS results revealed that the sol–gel transition was actually attributed to the fiber-network aggregate structure transition. The mechanism of above pH responsive self-assembling behavior transition was explained by the remarkable counterion effect of OH−. Specifically, OH− was additionally capable of H-bonding with surrounding water molecules which promoted the solvation of C-HAPAM and induced thick hydration layer. Then, the hydrated layer led to the increment of zeta potential and volume expansion of C-HAPAM molecule which in turn strongly enhanced the viscosity of the solution. The strong counterion effect of OH− and the inter-molecular hydrophobic association interactions of C-HAPAM collectively triggered the formation of joints and hence the network structure transition, i.e. sol–gel transition.

Synthesis and characterizations of hydrophobically associating water‐soluble polymer with nonionic surfmer

ABSTRACTIn this article, a hydrophobically associating copolymer (2‐acrylamido)‐2‐methylpropanesulfonic acid (AMPS)/AA‐EO25C12 was synthesized by AMPS and nonionic surfmer AA‐EO25C12 through free radical copolymerization. The structure of copolymer was characterized by FT‐IR and 1H‐NMR. The properties of copolymer were studied and the results indicated that the copolymer exhibits good thickening ability due to intermolecular hydrophobic associations as the apparent viscosity of the copolymer solution increases sharply with increasing polymer concentration. Compared with homopolymer PAMPS, the rheological test indicates that the copolymer solution shows shear thickening behavior at low shear rate region. Besides, the copolymer exhibits interfacial activity as it can reduce the interfacial tension to 10° level, and ability to form emulsion with good stability, which is due to successfully introducing the structure of nonionic surfmer AA‐EO25C12 to the polymer chain. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43195.