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     

Amphoteric water‐soluble copolymer for barium titanate slurries. I. Synthesis and dispersing ability

An amphoteric water‐soluble copolymer, polyacrylamide/[α‐N,N‐dimethyl‐N‐(3‐(β‐carboxylate)acrylamino)propyl] ammonium ethanate (PAM/DAE) was synthesized and used as a dispersion agent for BaTiO₃ 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 structure of this copolymer was verified by IR and ¹H‐NMR spectra. The dispersing effects of PAM/DAE were examined by measuring the viscosity and sedimentation of BaTiO₃ suspensions, and by analyzing the particle size. The results indicate that this copolymer could uniformly disperse the particles, and the resulting suspensions were less viscous, more stabilized, and contained powder with smaller particle size. The dispersing/stabilizing ability of PAM/DAE is close to, or slightly better than, that of a commercial dispersant, ammonium salt of poly(methacrylic acid). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1443–1450, 2005     

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     

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 BaTiO3 Colloids with Amphoteric Polyelectrolytes

An amphoteric water-soluble copolymer, i.e., poly(acrylamide/(α- N,N -dimethyl- N -acryloyloxyethyl) ammonium ethanate) (PAAM/DAAE), was evaluated as a novel dispersant for aqueous BaTiO₃ (BT) slurries. The dispersing property of this copolymer was examined by means of rheology, sedimentation, particle size, green density, zeta potential, and leached Ba²⁺ concentration measurements. The results indicate that PAAM/DAAE could reduce the viscosity of slurries greatly, cause BT particle sizes to shift to smaller values, and make green compacts more consolidated. Compared with a commercial dispersant, ammonium salt of poly(methacrylic acid) (PMAA-NH₄), it is as effective or even better in preparing stabilized suspensions. More importantly, PAAM/DAAE could lessen the leached Ba²⁺ concentration. This is related to the adsorption behavior of this copolymer onto BT particles, and the interaction between the adsorbed dispersant and dissolved barium ions.     

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     

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     

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.     

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     

Self‐assembled acrylamide‐based copolymer/surfactant with high‐temperature resistance for enhanced oil recovery

In this article, we report on a water‐soluble self‐assembled system that consisted of an acrylamide (AM)‐based copolymer and a nonionic surfactant for enhancing oil recovery. The copolymer, denoted as poly(acrylamide–acrylic acid–diallyl dimethyl ammonium chloride–N ‐allyl benzamide) (PMADN), was synthesized with AM, acrylic acid, diallyl dimethyl ammonium chloride, and N ‐allyl benzamide, and the nonionic surfactant was Tween 40. The results of our investigation of the ratio of the copolymer to Tween 40 show that the optimal concentrations of PMADN and Tween 40 were 1000 and 500 mg/L, respectively. When it was heated to 115–120 °C for 15 min, the apparent viscosity of the self‐assembly system increased 19.2%, and its viscosity retention rate remained at 11.6% under 1000 s^?1. When the system was dissolved in 12,000 mg/L NaCl, 2000 mg/L CaCl₂, and 2000 mg/L MgCl₂ solutions, the viscosity retention rates were 22.3%, 12.1%, and 17.6%, respectively. In addition, a 2000 mg/L PMADN–Tween 40 solution dramatically enhanced the oil recovery up to 13.4%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45202.     

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     

Effect of inorganic salts on viscosity of acrylonitrile‐N‐vinylpyrrolidone copolymer solutions

Effects of inorganic salts on viscosities of dimethyl sulphoxide (DMSO) solutions of acrylonitrile(AN)/N‐vinylpyrrolidone(N‐VP) copolymer are discussed. Viscosity was determined by the rotary viscosimeter. It was shown that the solution viscosity decreases quickly with addition of KCl and NaCl and the effect of NaCl is more prominent than that of KCl. As concentration of KCl and NaCl went beyond 0.025 mol/L, the viscosity showed a trend of increase. The viscosity increased considerably with addition of FeCl₃ and CuCl₂. Changes in solution viscosity became less obvious with addition of ZnCl₂. As temperature increased, the viscosity of the copolymer solution containing NaCl decreased most quickly and the copolymer solution consisting of FeCl₃ showed the slowest decrease. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3492–3495, 2003     

Rheological behavior of acrylonitrile/ammonium acrylate copolymer solutions

Ammonium acrylate was first used as a comonomer to copolymerize with acrylonitrile. The viscosity behavior of dimethyl formamide solutions of acrylonitrile/ammonium acrylate copolymer was studied, and the rheological kinetics of the solutions were studied for comparison. It was shown that the solutions behaved the same as a Newtonian flow as the rotor speed increased beyond 12 rpm. With an increase in temperature, the apparent viscosity of acrylonitrile/ammonium acrylate copolymer solutions showed a trend of decreasing. The changes in the apparent flow‐activation energy of solutions (E_η) calculated by the Arrhenius equation became less prominent along with the changes in the molecular weight of the acrylonitrile/ammonium acrylate copolymers. E_η increased continuously with an increase in copolymer concentration. The viscosity of copolymer solutions decreased continuously as the concentrations of KCl and NaCl increased up to 0.015 mol/L, and then it increased. The E_η showed an obvious trend of decreasing with the addition of alkali salts, and the changes in the E_η containing NaCl were more prominent than those of solutions containing KCl. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2320–2324, 2007     

Viscosity behavior of acrylonitrile–ammonium itaconate copolymer solutions in dimethyl sulfoxide

The viscosity behavior of dimethyl sulfoxide (DMSO) solutions of acrylonitrile–ammonium itaconate copolymer is discussed. The intrinsic viscosity was determined by an Ubbelohde viscometer. It is shown that an increase in the viscosity of acrylonitrile–ammonium itaconate copolymer solutions with time is considerably reduced by mechanical mixing. The viscosity of copolymer solutions with dimethyl formamide as an additive decreases monotonically. The viscosity of copolymer solutions decreases with the addition of H₂O, and as the content of H₂O in DMSO goes beyond 3 wt %, the viscosity shows a trend toward increase. The intrinsic viscosity decreases quickly with the addition of NaCl. As the concentration of NaCl goes beyond 0.015 mol/L, the viscosity increases solwly. The viscosity of copolymer solutions containing sodium ethoxide and sodium hydroxide appears to increase after an initial drop. The viscosity of copolymer solutions upon the addition of diethylamine increases continuously with time and changes in viscosity become less prominent after a period of a few hours. The effects of bases on the tacticity of highly isotactic copolymers follow the order of base strength. Diethylamine is more effective for moderating the stabilization exotherm of highly isotactic copolymers compared to sodium ethoxide and sodium hydroxide. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2622–2626, 2004     

Poly(sulfobetaine)s and corresponding cationic polymers. XI. Synthesis and aqueous solution properties of a cationic poly(methyl iodide quaternized ethyl vinyl ether/N,N‐dimethylaminopropyl maleamidic acid) copolymer

A copolymer prepared by the copolymerization of ethyl vinyl ether and maleic anhydride underwent amidoacidation with N,N‐dimethylaminopropylamine. The obtained ethyl vinyl ether/dimethylaminopropyl maleamidic acid copolymer was then reacted with methyl iodide to yield poly(methyl iodide quaternized ethyl vinyl ether/N,N′‐dimethylaminopropyl maleamidic acid) (MIQEDMAPMA). The greatest difference from other polyelectrolytes was the carboxylic group on the polymer chain unit of MIQEDMAPMA. Its aqueous solution properties in various salts and at various pH values were studied by measurements of the reduced viscosity and intrinsic viscosity. The reduced viscosity and intrinsic viscosity of this cationic polyelectrolyte were related to the types and concentrations of the added salts. The tendency of the salt effect was similar to that of other polyelectrolytes; that is, soft salt anions were more easily bound to the quaternary ammonium (R₄N⁺) of MIQEDMAPMA than hard salt anions. Some salt ions strongly attracted the quaternary ammonium of the cationic polymeric side chain for the agglomeration of the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2261–2269, 2003     

Studies of precipitated polymerization of acrylamide with quaternary ammonium cationic comonomer in potassium citrate solution

Copolymer particles consisting of acrylamide (AM) and cationic comonomer 2‐methyl acryloyloxyethyl trimethyl ammonium chloride (DMC) were prepared by precipitation polymerization in an solution of potassium citrate using ammonium persulfate ((NH₄)₂S₂O₈) and sodium sulfite (Na₂SO₃) as an initiator. The product poly(acrylamide‐2‐methyl acryloyloxyethyl trimethyl ammonium chloride) [Poly(DMC‐AM)] is a water‐soluble cationic polyelectrolyte. The solubility of DMC, AM and Poly(DMC‐AM) in potassium citrate solution were measured, combined with the theory of solubility parameter, and the experiment results indicate that the solubility of DMC and AM is much higher than that of Poly(DMC‐AM), and also the mechanism of copolymer precipitated in salt solution was discussed. The factors influencing the conversion of comonomers were examined, such as salt mass fraction, polymerization temperature, monomers mass fraction, initiator mass fraction, and so on. The results of experiments indicate that the best conditions are salt mass fraction = 57%, monomers mass fraction = 3%, m(DMC) : m(AM) = 3 : 1, initiator mass fraction = 0.08%, polymerization temperature = 50°C, reaction time = 2 h, and the conversion is 86.4%. And the qualitative analysis experimental method for copolymer by infrared absorption spectrum show that [Poly(DMC‐AM)] was successfully synthesized by precipitation polymerization. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Soap‐free cationic emulsion copolymerization of styrene and butyl acrylate with comonomer in the presence of alcohols

Preparation of a cationic polymer latex of styrene and butyl acrylate with comonomer N,N‐dimethyl, N‐butyl,N‐methacryloloxylethyl ammonium bromide (DBMEA) was carried out by soap‐free emulsion polymerization. The effect of reaction conditions such as the ratio of methanol to water, DBMEA concentration, AIBA concentration and ionic strength on properties of copolymer particles was studied. The results showed that the average diameter (D_w) decreased with increasing of AIBA and DBMEA concentration; D_w decreased first then increased with increasing of methanol content; variation of the ionic strength led to a variation in the particle number (N_p) and D_w because of the competition of two kinds of nucleation mechanisms. The same trend was found in the polymerization taking in pure water. The MWD was bimodal during the particle growth period. These results suggest that the particles can be generated through two particle‐formation mechanisms, micelle nucleation and homogeneous nucleation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2791–2797, 2003     

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     

Particle morphology and NMR structure of polymethylmethacrylate/polystyrene emulsifier‐free core–shell cationic latices in the presence of DBMEA

In the absence of emulsifier, we prepared stable emulsifier‐free polymethylmethacrylate/polystyrene (PMMA/PSt) copolymer latex by batch method with comonomer N,N‐dimethyl, N‐butyl, N‐methacryloloxylethyl ammonium bromide (DBMEA) by using A1BN as initiator. The size distribution of the latex particles was very narrow and the copolymer particles were spherical and very uniform. Under the same recipe and polymerization conditions, PMMA/PSt and PSt/PMMA composite polymer particle latices were prepared by a semicontinuous emulsifier‐free seeded emulsion polymerization method. The sizes and size distributions of composite latex particles were determined both by quasi‐elastic light scattering and transmission electron microscopy (TEM). The effects of feeding manner and staining agents on the morphologies of the composite particles were studied. The results were as follows: the latex particles were dyed with pH 2.0 phosphotungestic acid solution and with uranyl acetate solution, respectively, revealing that the morphologies of the composite latex particles were obviously core–shell structures. The core–shell polymer structure of PMMA/PSt was also studied by ¹H, ¹³C, 2D NMR, and distortionless enhancement by polarization transfer, or DEPT, spectroscopy. Results showed that PMMA/PSt polymers are composed of PSt homopolymer, PMMA homopolymer, and PMMA‐g‐PSt graft copolymers; results by NMR are consistent with TEM results. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1681–1687, 2005     

Toward green three‐phase composites with enhanced dielectric permittivity

This work aims to investigate the dielectric potential of microcrystalline cellulose, a green biosourced material, as a third constituent in the three‐phase composites based on ethylene vinyl acetate‐vinyl ester of versatic acid (EVA‐VeoVa) terpolymer and BaTiO₃. For that, new green three‐phase composites were prepared using an economic and green process, with simple implementation at room temperature and using water as a solvent. Compared with the binary composite EVA‐VeoVa/BaTiO₃, the three‐phase composite EVA‐VeoVa/BaTiO₃/microcrystalline cellulose showed an improvement of the BaTiO₃ particles dispersion, enhanced relative permittivity, and reduced dielectric loss, which explains the significance of this study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46147.