Efficient preparation of novel fluoroalkyl end‐capped oligomers/titanium dioxide nanocomposites

Novel fluoroalky end‐capped oligomers/titanium dioxide nanocomposites were prepared by the hydrolysis of titanium isopropoxide in the presence of fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide oligomer [R_F‐(DOBAA)_n‐R_F], fluoroalkyl end‐capped N,N‐dimethylacrylamide oligomer [R_F‐(DMAA)_n‐R_F], and fluoroalkyl end‐capped acrylic acid oligomer [R_F‐(ACA)_n‐R_F] in tetrahydrofuran under mild conditions. In these fluorinated oligomers, R_F‐(ACA)_n‐R_F oligomer is more effective for the preparation of the corresponding oligomers/titanium dioxide nanocomposites, and this oligomer can afford the expected fluorinated titanium dioxide nanocomposites in higher isolated yields. In addition, R_F‐(ACA)_n‐R_F/titanium dioxide composites are nanometer size‐controlled very fine nanoparticles (14–48 nm), and exhibited a good dispersibility not only in water but also in traditional organic solvents. Fluoroalkyl end‐capped oligomers/titanium dioxide nanocomposites were also applied to the surface modification of the common organic polymers such as poly(methyl methacrylate) to exhibit a good oleophobic and hydrophilic characteristics on the surface. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.     

Synthesis and gelation of novel fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide copolymers containing triol segments—Interaction of these fluorinated gels with various hydrophilic compounds

Fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide (DOBAA) copolymers containing triol segments were prepared by the reactions of fluoroalkanoyl peroxide with the corresponding monomer and N‐tris(hydroxymethyl)methylacrylamide (NAT). These obtained fluorinated copolymers [R_F‐(DOBAA)_x‐(NAT)_y‐R_F] were found to cause gelation in water, dimethyl sulfoxide, and N,N‐dimethylformamide under the non‐crosslinked conditions, although the corresponding nonfluorinated DOBAA–NAT copolymer [‐(DOBAA)_x‐(NAT)_y‐] could cause no gelation in these solvents. This gelation is governed by the synergistic interaction of strong aggregations of end‐capped fluoroalkyl segments and intermolecular hydrogen bonding between triol segments. We also studied the uptake and release of a variety of hydrophilic compounds such as methylene blue, methyl orange, 4‐hydroxyazobenzene‐4′‐sulfonic acid sodium salt, 2,4‐dihydroxyazobenzene‐4′‐sulfonic acid sodium salt, acriflavine hydrochloride, acridine hydrochloride, lucigenin, and fluorescein by this fluorinated copolymer gel and fluoroalkyl end‐capped NAT homopolymer gel [R_F‐(NAT)_n‐RF] for comparison. It was demonstrated that the uptake and release ratios of these hydrophilic compounds by R_F‐(DOBAA)_x‐(NAT)_y‐R_F gel become generally lower than those of R_F‐(NAT)_n‐R_F gel. Interestingly, R_F‐(DOBAA)_x‐(NAT)_y‐R_F gel has no releasing power toward methylene blue, acridine hydrochloride, lucigenin, and fluorescein, although R_F‐(NAT)_n‐R_F gel has a good releasing power toward these compounds. Additionally, R_F‐(DOBAA)_x‐(NAT)_y‐R_F gel was applied to the controlled release of anticancer drugs such as methotrexate (MTX), and the releasing ratios of MTX became higher with increasing pH values (from pH 4.3 to 9.1). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88:3212–3217, 2003     

Preparation and applications of novel fluoroalkyl end‐capped sulfonic acid oligomers–silica gel polymer hybrids

Fluoroalkyl end‐capped 2‐methacryloxyethanesulfonic acid homo‐oligomer [R_F–(MES)_n–R_F] and 2‐methacryloxyethanesulfonic acid–N,N‐dimethylacrylamide co‐oligomers [R_F–(MES)_x–(DMAA)_y–R_F] reacted with tetraethoxysilane (TEOS) under acidic conditions to afford R_F–(MES)_n–R_F homo‐oligomer–SiO₂ polymer hybrid and R_F–(MES)_x–(DMAA)_y–R_F co‐oligomer–SiO₂ polymer hybrid, respectively. Thermogravimetric–mass spectra showed that the thermal stability of R_F–(MES)_n–R_F homo‐oligomer–SiO₂ polymer hybrid was superior to that of traditionally well‐known perfluorinated ion exchange polymers such as Nafion 112 (TR). The sol solutions of the fluorinated co‐oligomer–SiO₂ polymer hybrid were applied to the surface modification of glass to exhibit not only a strong oleophobicity imparted by fluorine but also a good hydrophilicity on the glass surface. On the other hand, R_F–(MES)_x–(DMAA)_y–R_F co‐oligomer reacted with TEOS in the presence of a variety of silica nanoparticles (mean diameters: 11–95 nm) under alkaline conditions to afford fluoroalkyl end‐capped oligomers–silica nanoparticles (mean diameters: 32–173 nm) with a good dispersibility and stability in methanol. Similarly, a variety of fluorinated oligomers containing sulfo groups–silica nanoparticles were prepared by the homo‐ and co‐oligomerizations of fluoroalkanoyl peroxides with 2‐methacryloxyethane sulfonic acid (MES) and comonomers such as N,N‐dimethylacrylamide (DMAA) and acryloylmorpholine (ACMO) in the presence of silica nanoparticles. Interestingly, these isolated fluorinated particle powders were found to afford nanometer size‐controlled colloidal particles with a good redispersibility and stability in aqueous and organic media such as methanol. These fluorinated nanoparticles containing sulfo groups were also applied to an excellent heterogeneous catalyst for Bronsted acid‐catalyzed transformations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 110–117, 2007     

Synthesis and gelation of fluoroalkyl end‐capped copolymers containing glucosyl segments: Application to new fluorinated conductive polymer electrolytes

Fluoroalkyl end‐capped copolymers containing glucosyl segments were prepared by the copolymerizations of fluoroalkanoyl peroxides with 2‐glucosyoxyethyl methacrylate (GEMA) and comonomers such as acrylic acid (ACA) and methacrylate monomer‐containing poly(oxyethylene) units (PME). Under the non‐cross‐linked conditions, fluoroalkyl end‐capped GEMA–ACA and GEMA–PME copolymers were found to cause a gelation in dimethyl sulfoxide (DMSO), where the aggregations of end‐capped fluoroalkyl segments and the hydrogen‐bonding interaction between hydroxyl segments are involved in establishing a physical gel network, although the corresponding nonfluorinated GEMA copolymers could cause no gelation in DMSO. More interestingly, it was demonstrated that these fluorinated polymeric gelling electrolytes containing lithium salts exhibit a considerably high ionic conductivity of 10^?3 S/cm level at room temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2833–2838, 2002     

Reactions of copper ions with amines in the presence of self‐assembled fluorinated oligomeric aggregates

Copper acetylacetonate reacted with N,N‐diethylmethylamine and 4,4′‐thiobis(6‐t‐butyl‐o‐cresol) in the presence of self‐assembled fluorinated oligmeric aggregates formed by fluoroalkyl end‐capped 2‐[3‐(2H‐benzotriazol‐2‐yl)‐4‐hydroxyphenyl]ethyl methacrylate–N,N‐dimethylacrylamide cooligomer [R_F–(BTRI)_x–(DMAA)_y–R_F; R_F = CF(CF₃)OCF₂CF(CF₃)OC₃F₇] to afford stable fluorinated aggregates–copper ions nanocomposites. These fluorinated oligomeric aggregates–copper ions nanocomposites thus obtained were applied to the dispersion of copper ions nanocomposites above the traditional organic polymeric materials such as poly(methyl methacrylate) (PMMA) surface. On the other hand, copper (II) chloride reacted with hydrazine hydrate in the presence of fluorinated oligomeric aggregates formed by fluoroalkyl end‐capped N,N‐dimethylacrylamide homooligomer to afford stable copper nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1328–1334, 2006     

Hydrophobically modified acrylamide‐based polybetaines. I. Synthesis,characterization, and stimuli‐responsive solution behavior

Acrylamide‐based, hydrophobically modified (HM) polybetaines containing N‐butylphenylacrylamide (BPAM) and varying amounts of the sulfobetaine monomer 3‐(2‐acrylamido‐2‐methylpropanedimethylammonio)‐1‐propanesulfonate (AMPDAPS) or the carboxybetaine monomer 4‐(2‐acrylamido‐2‐methylpropyldimethylammonio)butanoate (AMPDAB) were synthesized by micellar copolymerization. The corresponding control (co)polymers lacking BPAM or betaine comonomers were also prepared. The terpolymers were characterized by ¹³C‐NMR and UV spectroscopy, classical light scattering, and potentiometric titration. Low charge density polymers contained 3.9–8.6 mol % betaine, whereas the high charge density systems contained 17–25 mol % betaine; the HM polymers contained up to 1.0 mol % BPAM as the hydrophobe. The weight‐average molecular weights of the polymers ranged from 4.19 × 10⁵ to 1.29 × 10⁶ g/mol, and most HM polymers exhibited negative second virial coefficients. The pK_a of the carboxybetaine moieties was found to increase with increasing levels of hydrophobic and betaine comonomer incorporation. The response of aqueous polymer solutions to various external stimuli, including changes in solution pH and electrolyte concentration, was investigated using rheological analysis. The solution behavior of the polymers was characteristic of HM polyacrylamides and acrylamide‐based polyzwitterions. The high charge density HM polycarboxybetaine exhibited unusual solution behavior that can be explained in terms of electrostatic, hydrophobic, and hydrogen‐bonding associations. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 647–657, 2004     

Fluoroalkyl end‐capped oligomer possessing a nonflammable characteristic in silica gel matrices even at 800°C under atmospheric conditions

We succeeded in observing the similar solid‐state NMR spectra (¹H‐magic‐angle spinning NMR spectra) of fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide oligomer [R_F‐(DOBAA)_n‐R_F]/silica gel nanocomposite before and even after calcinations at 800°C. This finding suggests that R_F‐(DOBAA)_n‐R_F oligomer in R_F‐(DOBAA)_n‐R_F/silica gel nanocomposite can afford a nonflammable characteristic to exhibit no weight loss behavior even at 800°C under atmospheric conditions. In addition, we had good oleo‐ and hydrophobic characteristics on the modified glass surface treated with R_F‐(DOBAA)_n‐R_F/silica gel nanocomposite even after calcination at 800°C as well as those before calcinations. Especially, R_F‐(DOBAA)_n‐R_F/silica gel nanocomposite‐encapsulated cetylpyridinium chloride (CPC) possessing no weight loss characteristic even at 800°C exhibited a clear UV–vis absorption band around 260 nm related to the presence of CPC before and even after calcinations at 800°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and properties of novel fluoroalkyl end‐capped oligomers containing phosphorus segments

New fluoroalkyl end‐capped oligomers containing pendant phosphoric acid groups wereprepared by the reactions of the corresponding monomer with fluoroalkanoyl peroxides. It was demonstrated that not only strong aggregations of fluoroalkyl segments but also hydrogen bonding could interact synergistically to form the highly viscoelastic fluids (gel‐like fluids) in aqueous solutions of these new fluoroalkyl end‐capped oligomers containing pendant phosphoric acid groups. Furthermore, these oligomers were able to reduce the surface tension of water effectively to exhibit a clear breakpoint resembling a CMC, and the modified stainless‐steel surface treated with these oligomers was shown to possess an excellent property imparted by fluorine. More interestingly, these oligomers were found to be potent and selective inhibitors against HIV‐1 replication in vitro. New fluoroalkyl end‐capped phosphonic acid and phosphonate oligomers were also prepared by the reactions of the corresponding phosphonic acid and phosphonate monomers, respectively, by the use of fluoroalkanoyl peroxides. These new fluoroalkyl end‐capped phosphonic acid and phosphonate oligomers were found to have a higher solubility in not only water but also in common organic solvents than that of the corresponding fluorinated oligomers containing pendant phosphoric acid groups, and these new oligomers were able to reduce the surface tension of these solvents quite effectively. Thus, these oligomers are expected to develop as new fluorinated oligosurfactants. Moreover, the modified poly(methyl methacrylate) surface treated with these phosphonate oligomers was clarified to exhibit a good oil‐repellency imparted by fluorine. In addition, fluoroalkyl end‐capped phosphonate homo‐ and cooligomers were found to form monomolecular films at the air–water interface. Therefore, these fluorinated oligomers are suggested to have high potential for new functional materials through not only their excellent properties imparted by both fluorine and phosphorus, but also through their biological properties. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 228–245, 2001     

Synthesis and applications of silicone oil–soluble fluoroalkyl end‐capped cooligomers

Fluoroalkyl end‐capped cooligomers containing polydimethylsiloxane and polyoxyethylene segments were prepared under very mild conditions by the cooligomerizations of fluoroalkanoyl peroxides with methacrylate monomers containing the corresponding segments and comonomers such as dimethylacrylamide and acryloylmorpholine. These obtained fluorinated cooligomers exhibited amphipathic characteristics and became soluble in water and common organic solvents. In particular interest, fluoroalkyl end‐capped cooligomers containing polyoxyethylene units were soluble not only in poly(methylphenylsiloxane) (silicone oil) but also in water, including common organic solvents except for hexane. Additionally, these fluorinated cooligomers were able to reduce the surface tension of water and m‐xylene quite effectively, to around 15 and 20 mN/m levels, respectively. In these fluorinated cooligomers, fluoroalkyl end‐capped acryloylmorpholine cooligomers containing polyoxyethylene segments were applicable as a novel emulsifying agent against water and silicone oil. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1467–1476, 2005     

Hydrophobically modified acrylamide‐based polybetaines. II. Interaction with surfactants in aqueous solution

The interaction of hydrophobically modified (HM) polybetaines with selected small molecule surfactants in aqueous solution was investigated using rheological and surface tension analyses. The polymers included acrylamide‐based, HM polybetaines containing N‐butylphenylacrylamide (BPAM) and specified amounts of sulfobetaine, 3‐(2‐acrylamido‐2‐methylpropanedimethylammonio)‐1‐propanesulfonate (AMPDAPS), or carboxybetaine, 4‐(2‐acrylamido‐2‐methylpropyldimethylammonio)butanoate (AMPDAB); corresponding control (co)polymers lacking BPAM and/or betaine comonomer(s) were also examined for comparative purposes. Low charge density terpolymers exhibited greater viscosity enhancement with the addition of surfactant compared to the high charge density terpolymers. The addition of sodium dodecyl sulfate (SDS) produced the largest increase in solution viscosity, while N‐dodecyl‐N,N,N‐trimethylammonium bromide (DTAB), N‐dodecyl‐N,N‐dimethylammonio‐1‐propanesulfonate (SB3–12), and Triton X‐100 enhanced polymer solution viscosity to a lesser degree. In most cases, the high charge density carboxybetaine terpolymer exhibited diminished solution viscosity upon surfactant addition. The polymers lacking hydrophobic modification showed no detectable viscosity enhancement in the presence of surfactants. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 658–671, 2004     

Characterization of acrylamide polymers for enhanced oil recovery

Four different copolymers, of acrylamide and acrylic acid, acrylamide and 2‐acrylamido‐2‐methyl propane sulfonic acid, N,N‐dimethylacrylamide and acrylic acid, and N,N‐dimethylacrylamide and 2‐acrylamido‐2‐methyl propane sulfonic acid (sodium salts), were prepared. The copolymers were characterized by their intrinsic viscosities and monomer ratios and with IR, ¹H‐NMR, and X‐ray diffraction (XRD) spectroscopy. No crystallinity was observed by differential thermal analysis, and this was well supported by XRD. All the polymers showed low decomposition temperatures. A number of decomposition temperatures were observed in differential thermogravimetry thermograms because of the elimination of gases such as CO₂, SO₂, CO, and NH₃. The replacement of the acrylate group with a sulfonate group produced polymers that were more compatible with brine, whereas the replacement of acrylamide with a more hydrophobic group such as N,N‐dimethylacrylamide produced a more shear‐resistant polymer. A N,N‐dimethylacrylamide‐co‐sodium‐2‐acrylamido‐2‐methyl propane sulfonate copolymer was better with respect to thermal stability when the polymer solution was aged at 120°C for a period of 1 month. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1869–1878, 2003     

Synthesis and properties of novel fluoroalkyl end‐capped oligomers containing silsesquioxane segments

Fluoroalkyl end‐capped homo‐ and co‐ oligomers containing silsesquioxane segments were prepared by the reactions of fluoroalkanoyl peroxides with the corresponding methacrylate monomer‐bearing silsesquioxane unit (Si‐MMA) and comonomers such as N,N‐dimethylacrylamide (DMAA) and acrylic acid (ACA). These new fluorinated Si‐MMA oligomers were easily soluble in various organic solvents and were able to reduce the surface tension of m‐xylene effectively. The modified poly(methyl methacrylate) [PMMA] and glass surface treated with fluorinated Si‐MMA homo‐oligomers exhibited a strong oleophobicity, although these fluorinated oligomers possess high oleophilic silsesquioxane segments. In contrast, the modified PMMA surface treated with fluorinated Si‐MMA–DMAA cooligomers exhibited a good hydrophilicity with a strong oleophobicity. In a series of fluorinated Si‐MMA oligomers, fluorinated Si‐MMA homo‐oligomers had a relatively high thermal stability. Therefore, these fluoroalkyl end‐capped Si‐MMA oligomers are suggested to have high potential for new functional materials through their unique properties such as a high solubility and surface active properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3486–3493, 2002     

Synthesis of fluoroalkyl‐modified polyester and its application in improving the hydrophobicity and oleophobicity of cured polyester coatings

The fluoroalkyl‐modified polyester (PE‐F_n) was synthesized by the reaction of polyester resin (PE) and fluorinated isocyanate, and the structure of the synthesized product was characterized by proton nuclear magnetic resonance (¹H‐NMR) and fluorine nuclear magnetic resonance (¹⁹F‐NMR). The water and oil wettability of the cured PE coatings with PE‐F_n as additives was investigated by contact angle meter. The results showed that the introduction of an extremely low concentration of PE‐F_n into PE led to the increase in contact angle of water and diiodomethane on cured PE coatings, and the decrease in the surface free energy. The X‐ray photoelectron spectroscopic (XPS) analysis showed that the F/C molar ratio in the outer few nanometers was significantly higher than that in the bulk, indicating that the fluoroalkyl groups in PE‐F_n had enriched on the coating surface. It was also found that longer fluoroalkyl groups and fluoroalkyl groups with ? CF₃ at its end had the higher tendency to aggregate on the coating surface. The topological structures of the cured coatings were recorded by an atomic force microscope under tapping mode and the results revealed that there was a strong surface segregation of fluorinated species. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39812.     

pH‐responsive polyzwitterions: A comparative study of acrylamide‐based polyampholyte terpolymers and polybetaine copolymers

A comparative study of pH‐responsive polyzwitterions (PZs) with polyampholyte or polybetaine architectures was conducted with well‐defined model polymer systems. Low‐charge‐density PZs, including ampholytic terpolymers composed of acrylamide (AM), sodium 3‐acrylamido‐3‐methylbutanoate, and (3‐acrylamidopropyl)trimethylammonium chloride and carboxybetaine copolymers composed of AM and 3‐(3‐acrylamidopropyldimethylammonio)propionate, were prepared via free‐radical polymerization in 0.5M NaCl to yield ter‐ and copolymers with random termonomer and comonomer distributions. Sodium formate was used as a chain‐transfer agent during the polymerizations to eliminate the effects of the monomer feed composition on the degree of polymerization (DP) and to suppress gel effects and broadening of the molecular weight distributions. The polymer compositions were determined via ¹³C‐NMR spectroscopy, and the residual counterion content was determined via elemental analysis for Na⁺ and Cl^?. The molecular weights (MWs) and polydispersity indices (PDIs) were determined via size exclusion chromatography/multi‐angle laser light scattering (SEC–MALLS); the polymer MWs ranged from 1.4 to 1.5 × 10⁶ g/mol, corresponding to DPs of 1.6–1.9 × 10⁴ repeat units, with all the polymers exhibiting PDIs less than or equal to 2.1. The intrinsic viscosities determined from SEC–MALLS data and the Flory–Fox relationship agreed with the intrinsic viscosities determined via low‐shear dilute‐solution viscometry. Data from the SEC–MALLS analysis were used to analyze the radius of gyration/molecular weight (R_g–M) relationships and the Mark–Houwink–Sakurada intrinsic viscosity/molecular weight ([η]–M) relationships for the PZs. The R_g–M and [η]–M relationships and viscometric data revealed that under size exclusion chromatography conditions, the poly[acrylamide‐co‐3‐(3‐acrylamidopropyldimethylammonio)propionate] betaine copolymers had more open, random‐coil conformations and greater polymer–solvent interactions than the ampholytic poly[acrylamide‐co‐sodium 3‐acrylamido‐3‐methylbutanoate‐co‐(3‐acrylamidopropyl)trimethylammonium chloride] terpolymers. The pH‐ and salt‐responsive dilute‐solution viscosity behavior of the PZs was examined to assess the effects of the polymer structure and composition on the solution properties. The polyampholyte terpolymers had greater solution viscosities and more pronounced stimuli‐responsiveness than the polybetaine copolymers because of their stronger intramolecular interactions and increased chain stiffness. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 24–39, 2004     

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     

Novel water‐soluble acryloylmorpholine copolymers: Synthesis,characterization, and metal ion binding properties

Poly(4‐acryloylmorpholine), poly(4‐acryloylmorpholine‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid), and poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) were synthesized by radical polymerization. The water‐soluble polymers obtained, containing tertiary amino, amide, and sulfonic acid groups, were investigated, in view of their metal binding properties, as polychelatogens by using the liquid‐phase polymer‐based retention technique, under different experimental conditions. The metal ions investigated were Ag(I), Cu(II), Co(II), Ni(II), Cd(II), Pb(II), Zn(II), Cr(III), and Al(III). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 180–185, 2006     

Removal of metal ions by water‐soluble polymacromonomers in conjunction with ultrafiltration membrane

The macromonomer polyethylene glycol methylether methacrylate was homo‐ and copolymerized with 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid under three feed monomer ratios. The initiator used was ammonium peroxydisulfate (0.2 mol %). All the polymers were completely soluble in water. The copolymer composition was determined by elemental analysis. The metal ion interaction capability of the three polymers was investigated through the liquid‐phase polymer‐based retention (LPR) technique at different values of pH and filtration factor Z. The highest metal ion retention ability was observed at pH 5.0. The homopolymer showed a high selectivity for Ni(II) ions at pH 3.0. The copolymers (PEGMEM)_1.51‐co‐(APSA)_1.00 and (PEGMEM)_1.00‐co‐(APSA)_1.95 showed a high selectivity for Cr(III) ions at pH 3.0. The maximum retention capacity, in general, was similar for the homo‐ and copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2955–2960, 2004     

Polymer gel electrolytes prepared from P(EG‐co‐PG) and their nanocomposites using organically modified montmorillonite

Polymer gel electrolytes were prepared by thermal crosslinking reaction of a series of acrylic end‐capped poly(ethylene glycol) and poly(propylene glycol) [P(EG‐co‐PG)] having various geometries and molecular weights. Acrylic end‐capped prepolymers were prepared by the esterification of low molecular weight (M_n: 1900–5000) P(EG‐co‐PG) with acrylic acid. The linear increase in the ionic conductivity of polymer gel electrolyte films was observed with increasing temperature. The increase in the conductivity was also monitored by increasing the molecular weight of precursor polymer. Nanocomposite electrolytes were prepared by the addition of 5 wt % of organically modified layered silicate (montmorillonite) into the gel polymer electrolytes. The enhancement of the ionic conductivity as well as mechanical properties was observed in the nanocomposite systems. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 894–899, 2004     

New fluorous bipyridine ligands for copper‐catalyzed atom transfer radical polymerization of methyl methacrylate in the thermomorphic mode

The atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) is often carried out under homogeneous conditions, so the residual metal catalyst in the polymer often influences the quality of the polymer and causes environmental pollution in the long run. Novel CuBr/4,4′‐bis(R_fCH₂OCH₂)‐2,2′‐bpy complexes (R_f = n‐C₉F₁₉, n‐C₁₀F₂₁, or n‐C₁₁F₂₃; 2,2′‐bpy = 2,2′‐bipyridine) are insoluble in toluene at room temperature yet readily dissolve in toluene at elevated temperatures to form homogeneous phases for use as catalysts in the ATRP reaction, and the Cu complexes precipitate again upon cooling. The CuBr/4,4′‐bis(n‐C₉F₁₉CH₂OCH₂)‐2,2′‐bpy system produced the best results (e.g., polydispersity index by gel permeation chromatography = 1.26–1.41), in that the residual Cu content in the polymer was as low as 19.3 ppm when the ATRP of MMA was carried out in the thermomorphic mode. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Study of a new titanium dual initiator for the synthesis of poly(ε‐caprolactone)‐b‐polystyrene block copolymers by the combination of coordination and nitroxide mediated polymerizations

Poly ε‐caprolactone‐polystyrene block‐copolymers (PCL‐b‐PSt) were synthesized using a modified titanium catalyst as the dual initiator. Alcoholysis of Ti(OPr)₄ by 4‐hydroxy 2,2,6,6 tetramethyl piperidinyl‐1‐oxyl (HO‐TEMPO) gave a bifunctional initiator Ti(OTEMPO)₄. Poly ε‐caprolactone prepolymer end‐capped with the nitroxide group was first prepared by ring opening polymerization of ε‐caprolactone with this initiator at high conversion. The nitroxide‐end‐capped structure and molar mass (M_n) of the polymers were demonstrated by typical UV absorption band. This analytical technique indicates a near‐quantitative nitroxide functionality and a M_n in good agreement with size exclusion chromatography (SEC) ones. This polyester prepolymer was used to further initiate the radical polymerization with styrene and reach the block copolymers (PCL‐b‐PSt). All the prepolymers and block copolymers were characterized by SEC and NMR spectroscopy. Additionally, the preparation of star polymers bearing two kinds of arms (PCL and PSt) was envisaged and a preliminary result was given. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008