Effects of amphoteric copolymer structure on the properties of barium titanate suspensions

The effect of the molecular structure of an amphoteric copolymer, i.e., poly[acrylamide/(α‐N,N‐dimethyl‐N‐(3‐(β‐carboxylate)acrylamino)propyl)ammonium ethanate)] (PAD) on the interactions with BaTiO₃ (BT) particles in water and on the stability of BT suspensions was examined by means of adsorption, ζ potential, sedimentation, and viscosity measurements. The results indicate that the adsorption of PAD onto BT particles follows the Langmuir adsorption isotherm. As the added PAD containing greater ionic group fraction, both the saturated amount of adsorbed polymer and the amount of the polymer required to reach the minimal ζ potential decrease. Whatever the ionic group fraction in PAD, BT suspensions become stable and less viscous when saturated amount of the polymer was adsorbed on particle surface. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Dispersion properties of BaTi4O9/Ba2Ti9O20 colloids with amphoteric polyelectrolytes

An amphoteric water-soluble copolymer, i.e., polyacrylamide/(α-N,N-dimethyl-N-(3-(β-carboxylate)acrylamino)propyl) ammonium ethanate (PAM/DAE) was synthesized and used as a dispersion agent for BaTi₄O₉/Ba₂Ti₉O₂₀ (BT₄/B₂T₉) particles. PAM/DAE was prepared from acrylamide and (α-N,N-dimethyl-N-(3-(β-carboxylate)acrylamino)propyl) ammonium ethanate in a basic condition through a free radical polymerization. The dispersing property of this copolymer was examined by means of rheology, particle size, and leached Ba²⁺ concentration measurements. The results indicate that PAM/DAE could reduce the viscosity of slurries greatly, and cause BT₄/B₂T₉ particle sizes a shift to smaller values. Compared with a commercial dispersant, ammonium salt of poly(methacrylic acid) (PMAA–NH₄), PAM/DAE is as effective in preparing dispersed suspensions. More importantly, PAM/DAE could lessen the leached Ba²⁺ concentration.     

Amphibious water‐soluble copolymer. I. Its synthesis and dispersing ability on barium titanate

An amphibious water‐soluble copolymer, polyacrylamide/(α‐N,N‐dimethyl‐N‐acryloyloxyethyl) ammonium ethanate (PAAM/DAAE), was synthesized and used as a dispersion agent for BaTiO₃ particles. PAAM/DAAE was prepared from acrylamide and (α‐N,N‐dimethyl‐N‐acryloyloxyethyl) ammonium ethanate under basic conditions through a free‐radical polymerization. The structure of this copolymer was verified with IR and ¹H‐NMR spectra. The dispersing effects of PAAM/DAAE were examined through the measurement of the viscosity and sedimentation of BaTiO₃ suspensions and the green density. The results indicated that this copolymer could uniformly disperse the particles, reduce the viscosity, stabilize the suspensions, and produce high‐density green compacts. In comparison with a commercial dispersant, the ammonium salt of poly(methylacrylic acid), PAAM/DAAE was clearly more effective. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2232–2239, 2004     

Dispersion of nanoscale BaTiO3 suspensions by a combination of chemical and mechanical grinding/mixing processes

The colloidal stability of aqueous nanometer‐ and micrometer‐scale barium titanate (BaTiO₃) utilizing poly (methacrylic acid) (PMAA‐Na) and polyacrylamide/(α‐N,N‐dimethyl‐N‐acryloyloxyethyl)ammonium ethanate (PDAAE) was investigated. In addition to chemical dispersants, the effects of mechanical milling using either conventional ball milling or nanogrinding/‐mixing on the dispersion of BaTiO₃ suspensions were also studied. Characterization of the particle size distribution (d₅₀), viscosity, and morphology of BaTiO₃ particles in the suspensions revealed that a sole chemical dispersant or mechanical milling was insufficient to achieve nanometer‐scale dispersion. The best dispersion results were obtained with a combination of PMAA‐Na dispersant and nanogrinding/‐mixing, which could provide sufficient electronic repulsive force and shear force to disperse the 80‐nm BaTiO₃ powders uniformly in the aqueous suspension. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

An amphoteric water‐soluble copolymer. II. Effect of its molecular weight on the dispersion of barium titanate in water

An amphoteric water‐soluble copolymer, that is, polyacrylamide/(α‐N,N‐dimethyl‐N‐acryloyloxyethyl)ammonium ethanate (PAAM/DAAE) was synthesized and it showed the ability to disperse BaTiO₃ (BT) particles in aqueous solutions. In this work, the effect of molecular weight of this polymer on the dispersing properties was further examined. The results indicate that the effectiveness of three polymer samples with different molecular weights in the dispersion of BT particles is P2 (M_w = 1.1 × 10⁵) > P1 (M_w = 1.2 × 10⁴) > P3 (M_w = 3.0 × 10⁵). Apparently, P2 is most effective in dispersing the particles, reducing the viscosity of the suspensions, and obtaining highest green and sintered densities. This is attributed to the highest adsorption of this polymer onto BT powder, and causes strongest electrostatic and steric repulsions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 886–891, 2006     

Synthetic amphoteric copolymer as a dispersant for aqueous barium titanate slurries

An amphoteric water‐soluble copolymer, i.e., poly(methacrylate‐co‐N‐(4‐vinylbenzyl)‐N,N‐dimethylglycinate) (PMV) was synthesized and used as a dispersion agent for barium titanate (BaTiO₃) (BT) particles. PMV was prepared from methacrylic acid and N‐(4‐vinylbenzyl)‐N,N‐dimethylglycinate in basic conditions through free radical polymerization. The structure of this copolymer was verified by its IR and ¹H‐NMR spectra. The dispersing effects of PMV were examined and evaluated through viscosity and sedimentation measurements. The results indicate that this copolymer could uniformly disperse the particles, make the resulting suspensions less viscous and more stabilized. The dispersing ability of PMV is better than that of a commercial dispersant, ammonium polymethacrylate (PMAAN). Accordingly, the BT compacts with PMV exhibit higher dielectric constant values than those with PMAAN. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Poly(sulfobetaine)s and corresponding cationic polymers. IX. Synthesis and aqueous solution properties of zwitterionic poly(sulfobetaine) derived from a styrene–N,N‐dimethylaminopropyl maleamidic acid copolymer

A styrene–N,N‐dimethyl(maleamidic acid)propyl ammonium propane sulfonate (SDMMAAPS) copolymer was synthesized through an amidoacidation reaction of a styrene–maleic anhydride alternating copolymer with N,N‐dimethylaminopropylamine (ring‐opening reaction) and then reacted with propane sultone. The cloud point and minimum salt concentration (msc) of this ampholytic SDMMAAPS copolymer were determined in aqueous salt solutions. The effects of counterions on the cloud point and msc of SDMMAAPS were not entirely the same as those of other zwitterionic poly(sulfobetaine)s. The greatest difference from other poly(sulfobetaine)s, such as styrene–N,N‐dimethyl(maleimido propyl)ammonium propane sulfonate copolymers, was the carboxylic group on the polymer chain unit of SDMMAAPS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1884–1889, 2003     

Poly(sulfobetaine)s and corresponding cationic polymers. X. Viscous properties of zwitterionic poly(sulfobetaine) derived from styrene–(N,N‐dimethylaminopropyl maleamidic acid) copolymer in aqueous salt solutions

A styrene–[N,N‐dimethyl (maleamidic acid) propyl ammonium propane sulfonate] (SDMMAAPS) copolymer was synthesized through an amidoacidation reaction of styrene–maleic anhydride (SMA) alternating copolymer with N,N‐dimethylaminopropylamine (ring‐opening reaction), which was then reacted with propane sultone. The effect of various salt solutions on the intrinsic viscosity of this ampholytic ADMMAAPS copolymer was investigated. The results showed that the effect of counter ions on the intrinsic viscosity of SDMMAAPS was not entirely similar to that of other zwitterionic poly(sulfobetaine)s. The greatest difference from other poly(sulfobetaine)s is the carboxylic group on the polymer chain unit of SDMMAAPS. The Huggins constants for SDMMAAPS in aqueous salt solutions, however, were also quite different from those of other sulfobetaine copolymers, such as styrene–N,N‐dimethyl (maleimido propyl) ammonium propane sulfonate] (SDMMAPS) copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 726–734, 2004     

Synthesis and application of an anionic water‐soluble copolymer as a dispersant for barium titanate slurries

An anionic water‐soluble copolymer, poly(acrylamide/4‐carboxylamino‐4‐oxo‐2‐butenate) (PAAM/COB), was synthesized and used as a dispersion agent for BaTiO₃ particles. PAAM/COB was prepared from acrylamide and 4‐carboxylamino‐4‐oxo‐2‐butenate in basic conditions through free‐radical polymerization. The structure of this copolymer was verified by IR and ¹H‐NMR spectra. We examined the dispersion effects of PAAM/COB by measuring the viscosity and sedimentation of BaTiO₃ suspensions and by analyzing the particle sizes. The results indicate that this copolymer was indeed effective in dispersing the particles, for the resulting suspensions were less viscous, more stabilized, and contained powder with smaller particle sizes. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 109–115, 2005     

Study of polymerization kinetics and copolymerization behavior of N-[3-(dimethylamino)propyl]methacryamide and cationic surfmers

Gas flotation is one of the important technologies for oily wastewater treatment and the surface-active polymer is an important kind of developing flotation agents. In this article, the flotation performance, polymerization kinetics, and copolymerization behavior of surface-active copolymer of N-[3-(dimethylamino) propyl] methacrylamide (DMAPMA) and dodecyl dimethyl propenyl ammonium chloride (C₁₂DM) and copolymer of DMAPMA and decyl dimethyl vinylbenzyl ammonium chloride(C₁₀MVBA) were investigated. The flotation experiment showed that both copolymers had an oil removal of 97% at the concentration of 30 mg/L. The result of polymerization kinetics showed that the polymerization initiation rate was influenced by the monomer concentration and the polymerization termination was dominated by bimolecular termination and accompanied by unimolecular termination. The activation energy of DMAPMA-C₁₂DM copolymerization (89.64 kJ/mol) was smaller than that of DMAPMA-C₁₀MVBA (91.65 kJ/mol) copolymerization. The reactivity ratios of DMAPMA and C₁₂DM were 0.46 and 15.52, respectively, as well as the reactivity ratios of DMAPMA and C₁₀ MVBA were 1.19 and 35.77, respectively. These results are meaningful for the oily wastewater flotation and the copolymerization mechanism of DMAPMA-based copolymer.     

Spontaneous Vesicle Formation in Mixtures of Quaternary Ammonium Compounds with Carbamate and Sodium Dodecylbenzene Sulfonate

Spontaneous vesicles formation in the aqueous mixtures of 2,3‐bis (dodecylcarbamoyloxy)‐N, N‐dimethyl‐N‐(2‐hydroxyalkyl) propyl ammonium chloride (C₁₂PAC) and sodium dodecylbenzene sulfonate at different mixing molar ratios have been investigated. The characterizations are demonstrated by electrical conductivity measurements, dynamic light scattering and zeta (ζ) potential measurements. The ζ‐potential results indicate the C₁₂PAC/SDBS systems are stable. The shapes of the catanionic vesicles are observed by negative‐staining transmission electronic microscopy. Meanwhile, from the viewpoint of molecular geometry structure, the electrostatic interaction between anionic and cationic molecules is regarded as the main driving force for spontaneous formation of vesicles.     

An investigation of the flocculation characteristics of polyacrylamide‐grafted chitosan

To investigate the flocculation characteristics of polyacrylamide (PAM)‐grafted chitosan, a series of PAM‐grafted chitosan copolymer (Chito‐g‐PAM1 to Chito‐g‐PAM4) have been synthesized by ceric ammonium nitrate‐induced solution polymerization technique in nitrogen atmosphere. The flocculation characteristics of the polymer samples (PAM, grafted and ungrafted chitosan) were studied by settling test and jar test methods in the colloidal suspensions of kaolin, iron ore, silica, and bentonite powder. It was found that the settling performance of Chito‐g‐PAM3 is best among the polymer samples. The jar test results indicate that the ungrafted chitosan has better water clarifying performance than both the PAM and grafted chitosan. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Functional polymers for colloidal applications. XIV. Syntheses of styrene–maleic anhydride copolymers with different charges and their ability to disperse kaolinite particles

Four kinds of styrene/maleic–anhydride (SMA) copolymer‐derived dispersants with different charged forms were synthesized and characterized with ¹H‐NMR. These four different dispersants contained carboxylic acid groups and exhibited characteristics indicative of anionic, cationic, zwitterionic, or nonionic surfactants as pH was changed. The charge properties of these copolymers changes with pH, and their ability to disperse clay particles under low and high pH were assessed by measuring viscosity or sedimentation, as well as Scanning Electron Microscopy (SEM). The results showed that the dispersing abilities are functions of pH of the system. It was found that SMA‐N [Poly(styrene‐co‐β‐N,N‐dimethylpropylamino) maleic acid, sodium salt)] exhibits the best dispersing ability, the fastest rate of sedimentation, and the smallest sedimentation volume at pH = 2, and SMA‐Na [poly(styrene‐co‐maleic acid, disodium salt)] exhibits the better dispersing ability at pH = 7 and 12. In addition, the aggregation behavior of the dispersants characterized by fluorescence spectroscopy revealed that the degree of aggregation for all dispersants at high concentration increases in the order: SMA‐Na < SMA‐B [poly(styrene‐co‐B‐imino‐propyl‐N‐trimethylammonium acetate) maleic acid, disodium salt)] < SMA‐N < SMA‐Q [poly(styrene‐co‐β‐imino‐propyl‐N‐trimethylammonium sulfate) maleic acid, sodium salt)]. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 592–602, 2000     

Resins containing amino and carboxylic acid groups. Synthesis,characterization, and metal ion retention properties

The crosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide], P(MAPDSA), and poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐acrylic acid], P(MAPDSA‐co‐AA), were synthesized by radical polymerization. The resins were completely insoluble in water. Due to the lower metal ion retention of P(MAPDSA), the metal ions investigated under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) ions by batch and column equilibrium procedures were carried out only for P(MAPDA‐co‐AA), particularly for Hg(II). The resin–Hg(II) ion equilibrium was achieved before 15 min. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.89 meq/g. The resin showed a high selectivity to Hg(II) ions. The recovery of the resin was investigated at 25°C with different concentrations of HNO₃ and HClO₄. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 525–530, 2005     

Cationic starch iodophores

Cross‐linked cationic starches N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch chloride (CQS chloride), N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch iodide (CQS iodide), and N‐(2‐hydroxyl)propyl‐3‐trimethyl ammonium starch iodide–iodine (CQS triiodide) with the degree of substitution (DS) according to cationic groups from 0.04 to 0.62, as well as cross‐linked starch–iodine complexes were synthesized and tested as potential antibacterial agents. Cationic starch iodine derivatives were obtained during ion exchange reaction between CQS chloride and iodide or iodide–iodine anions in aqueous solutions. CQS_DS≤0.3 chloride can form several types of iodine complexes, such as the blue amylose–iodine inclusion complex and ionic CQS⁺I^?·(I₂)_m complex (m ≥ 1). The antibacterial activity of modified starches–iodine samples against different pathogenic bacterial cultures and contaminated water microorganisms was evaluated. CQS chloride and CQS iodide were found to be bacteriostatic. A strong antibacterial activity was characteristic of CQS triiodides in which molecular iodine is present in both ionic and inclusion complexes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of metal ions and pH values on the conformational transition of the copolymer chain in aqueous solutions

A novel salts‐ and pH‐responsive copolymer, poly(acrylic acid‐co‐ethyl 1‐(4‐chlorophenyl)‐5‐acrylamino‐1,2,3‐triazol‐4‐carboxylate), poly(AA‐co‐ECATC), was prepared by radical polymerization in methanol at room temperature with L ‐ascorbic acid (Vc) and peroxide hydrogen (H₂O₂) as initiators. The copolymer was characterized by Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). The copolymer possessed excellent fluorescence properties. The effects of metal ions with different charges, radius and outer‐layer electron constructions and pH values on the conformation transition of copolymer chains were systematically investigated by the fluorescence intensity and the fluorescence anisotropy. It was found that fluorescence intensity and fluorescence anisotropy curves waved with the change of metal ions concentrations and pH values. Additionally, FTIR Subtraction spectroscopy was also carried out to confirm our results. The work provided a theory basis for the study of salts‐ and pH‐sensitive smart hydrogels, which were always used in the slow‐ or controlled‐release drugs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1714–1722, 2007     

Comparative studies on the flocculation characteristics of polyacrylamide grafted guar gum and hydroxypropyl guar gum

The synthesis of two polysaccharide‐based graft copolymers with acrylamide, guar gum grafted polyacrylamide (GG‐g‐PAM) and hydroxypropyl guar gum grafted polyacrylamide (HPG‐g‐PAM) is described. The graft copolymers have been characterized by viscometry, infrared spectroscopy and thermal analysis. The flocculation characteristics of the graft copolymers have been studied in kaolin, iron ore, and silica suspensions. For the base polysaccharides guar gum (GG) and hydroxypropyl guar gum (HPG), it is observed that GG exhibits better performance than HPG in all three suspensions. For the graft copolymers, HPG‐g‐PAM shows better performance than GG‐g‐PAM. The flocculation characteristics of the best performing graft copolymer (HPG‐g‐PAM) are compared with various commercially available flocculants in the three suspensions mentioned above. © 2001 Society of Chemical Industry     

Synthesis of an amide/carboxylate copolymer for barium titanate suspensions. I. As a dispersant

An anionic copolymer, that is, poly[methacrylamide‐co‐(ammonium methacrylate)] (PMMN), was synthesized for the purpose of application to barium titanate (BT) suspensions. The chemical structure of the prepared polymer was verified with IR and ¹H‐NMR spectra. PMMN has the potential to have a double function of dispersant and binder for BT suspensions because it contains both amide groups, which are expected to bring a binder contribution, and carboxylate groups, which are expected to bring a dispersant contribution. In this article, the dispersion effects of PMMN with different monomer ratios are examined and evaluated through viscosity and sedimentation measurements. The results indicate that this polymer could uniformly disperse the particles and make the resulting suspensions less viscous and more stabilized. PMMN with a methacrylamide/ammonium methacrylate ratio of 60/40 appears to be most effective, as this polymer induces sufficient electrostatic forces among particles when it is adsorbed onto BT powder. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Chemical Synthesis of Rare Natural Bile Acids: 11α‐Hydroxy Derivatives of Lithocholic and Chenodeoxycholic Acids

A method for the preparation of 11α‐hydroxy derivatives of lithocholic and chenodeoxycholic acids, recently discovered to be natural bile acids, is described. The principal reactions involved were (1) elimination of the 12α‐mesyloxy group of the methyl esters of 3α‐acetate‐12α‐mesylate and 3α,7α‐diacetate‐12α‐mesylate derivatives of deoxycholic acid and cholic acid with potassium acetate/hexamethylphosphoramide; (2) simultaneous reduction/hydrolysis of the resulting △¹¹‐3α‐acetoxy and △¹¹‐3α,7α‐diacetoxy methyl esters with lithium aluminum hydride; (3) stereoselective 11α‐hydroxylation of the △¹¹‐3α,24‐diol and △¹¹‐3α,7α,24‐triol intermediates with B₂H₆/tetrahydrofuran (THF); and (4) selective oxidation at C‐24 of the resulting 3α,11α,24‐triol and 3α,7α,11α,24‐tetrol to the corresponding C‐24 carboxylic acids with NaClO₂ catalyzed by 2,2,6,6‐tetramethylpiperidine 1‐oxyl free radical (TEMPO) and NaClO. In summary, 3α,11α‐dihydroxy‐5β‐cholan‐24‐oic acid and 3α,7α,11α‐trihydroxy‐5β‐cholan‐24‐oic acid have been synthesized and their nuclear magnetic resonance (NMR) spectra characterized. These compounds are now available as reference standards to be used in biliary bile acid analysis.     

Fluidizing effects of polymers with various anchoring groups in cement pastes and their sensitivity to environmental temperatures

We synthesized various polymers with different functional groups of ─COO⁻, ─SO₃⁻, and ≡N⁺─ to study the impact of the environmental temperature (25, 50, and 80 °C) on the dispersing capability by measuring the fluidity of fresh cement paste, total organic carbon, ζ potential, and isothermal calorimetry. The results show that no adsorption was observed for the cement pastes containing acrylic acid, 2-acrylamido-2-methyl propane sulfonic acid, and [3-(methacryloylamino)propyl] trimethyl ammonium chloride, probably because of the trace amount of adsorption, whereas the fluidity of the pastes was indeed improved by the addition of these chemicals. Generally, for the polymers containing various functional groups, the adsorption capability was in the order ─COO⁻ > ─SO₃⁻ > ≡N⁺─. The dispersing capability for the carboxylate superplasticizer was robust to the change in the temperature, whereas it was dramatically weakened by the increase in temperature for sulfonate superplasticizer, although the adsorption amount increased along with the temperature rise. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47494.