pH‐sensitive uniform gel beads for DNA adsorption

Uniform gel beads 3 mm in diameter were obtained by the suspension polymerization of an amine functionalized monomer, N‐3‐(dimethyl amino)propylmethacrylamide (DMAPM). The polymerization of DMAPM in the form of uniform droplets could be achieved at room temperature in an aqueous dispersion medium by using Ca–alginate gel as the polymerization mold. In this preparation, potassium persulfate/tetramethyl ethylenediamine and sodium alginate/calcium chloride were used as the redox initiator and the stabilizer systems, respectively. The crosslinked DMAPM gel beads exhibited pH‐sensitive, reversible swelling–deswelling behavior. The uniform gel beads were also obtained by the copolymerization of DMAPM and acrylamide (AA) in the same polymerization system. Although copolymer gel beads with higher pH sensitivities were obtained with increasing feed concentration of DMAPM, the total monomer conversion decreased. Crosslinked DMAPM and DMAPM–AA copolymer gel beads were utilized as sorbents for DNA adsorption. The gel beads produced with higher DMAPM feed concentration exhibited higher equilibrium DNA adsorption capacity. The DNA equilibrium adsorption capacities up to 50 mg DNA/g dry gel could be achieved with the crosslinked DMAPM gel beads. This value was reasonably higher relative to the previously reported adsorption capacities of known sorbents. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3154–3161, 2000     

A novel approach for albumin determination in aqueous media by using temperature‐ and pH‐sensitive N‐isopropylacrylamide‐co‐N‐[3‐(dimethylamino)‐propyl]methacrylamide random copolymers

Random copolymers of N‐isopropylacrylamide (NIPA) and N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPM) were synthesized by solution polymerization using azobisizobutyronitrile as the initiator in 1,4‐dioxane at 60°C. NIPA‐co‐DMAPM copolymer exhibited both temperature and pH sensitivity. Thermally reversible phase transitions were observed both in the acidic and the alkaline pH regions for copolymers produced with different DMAPM/NIPA feed ratios. The pH dependency of the lower critical solution temperature (LCST) was stronger for copolymers produced with higher DMAPM feed concentrations. NIPA‐co‐DMAPM random copolymer was also sensitive to the albumin concentration. In the presence of albumin, thermally irreversible phase transitions were observed in slightly acidic and neutral media. However, reversible transitions were obtained in aqueous media containing albumin at basic pH. The phase‐transition temperature of NIPA‐co‐DMAPM copolymer significantly decreased with increasing albumin concentration at both acidic and alkaline pH values. This behavior was explained by albumin binding onto the copolymer chains by means of H‐bond formation between the dimethylamino groups of the copolymer and the carboxyl groups of albumin. For a certain range of albumin concentration, the phase‐transition temperature exhibited a linear decrease with increasing albumin concentration. By utilizing this behavior, a simple albumin assay was developed. The results indicated that NIPA‐co‐DMAPM copolymer could be utilized as a new reagent for the determination of albumin concentration in the aqueous medium. The proposed method was valid for the albumin concentration range of 0–4000 μg/mL. The protein concentrations commonly utilized in biotechnological studies fall in the range of the proposed method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2060–2071, 2002; DOI 10.1002/app.10503     

Superabsorbent polymeric materials. XI. Effect of nonionic monomers on the swelling behavior of crosslinked poly(sodium acrylate‐co‐nonionic monomers) in aqueous salt solutions

A series of xerogels based on sodium acrylate, nonionic monomers such as 2‐hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methacrylate (PEGMA), and N,N′‐methylene bisacrylamide were prepared by inverse suspension polymerization. The results indicate that the water absorbencies for these two gel series were effectively improved by the addition of a small amount of nonionic monomer (HEMA or PEGMA). The initial absorption rates in deionized water were faster for the PEGMA gels than for the HEMA gels. Scanning electron microscopy showed that the spherical particle size was smaller for the PEGMA gels than for the HEMA gels. In addition, the water absorbency of the gels in various salt solutions decreased with increasing ionic strength, especially for the multivalent salt solutions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3666–3674, 2004     

Radiation synthesis and characterization of 2‐hydroxyethyl‐methacrylate‐based hydrogels containing di‐ and tri‐protic acid and its application on wastewater treatment

Radiation‐crosslinked 2‐hydroxyethylmethacrylate/citric acid (HEMA/CAc), 2‐hydroxyethylmethacrylate/tartaric acid (HEMA/TA), and 2‐hydroxyethylmethacrylate/succinic acid (HEMA/Sc) copolymers were prepared by using ⁶⁰Co γ‐rays. The gel fraction yield and the swelling behavior of the prepared hydrogels were studied. It was shown that increasing irradiation doses was accompanied by an increase in yield of gel fraction and a decrease in swelling degree. The parameters of equilibrium swelling, maximum swelling, initial swelling rate, swelling exponent, and diffusion coefficient of the hydrogels were determined by studying the swelling behavior of the hydrogels prepared. It was seen that the equilibrium swelling degree increases as the content of acid increases, as a result of introducing more hydrophilic groups. When the hydrophilic polymer (acids) varies in the content range of 40–80 mg, swelling exponents (n) decreases, thereby indicating a shift in the water‐transport mechanism from the anomalous (non‐Fickian)‐type to the Fickian‐type. Characterization and some selected properties of the prepared hydrogels were studied, and accordingly the possibility of its practical use in the treatment of industrial wastes such as dyes and heavy metals (Fe, Ni, Co, and Cu) were also studied. The effect of treatment time, pH of feed solution, initial feed concentration, and temperature on the dye and heavy metals uptake was determined. The uptake order for a given metal was HEMA/TA hydrogel > HEMA/CAc > HEMA/Sc hydrogel. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Specific sorbents for bilirubin removal from human plasma: Congo red-modified poly(EGDMA/HEMA) microbeads

Congo Red-modified poly(EGDMA–HEMA) microbeads were investigated as a specific sorbent for bilirubin removal from human plasma. Poly(EGDMA–HEMA) microbeads were prepared by a modified suspension copolymerization technique. Congo Red was covalently incorporated into the poly(EGDMA–HEMA) microbeads via condensation reactions between the aromatic amine groups of the dyes and the hydroxyl groups of the HEMA, under alkaline conditions. Bilirubin adsorption was investigated from hyperbilirubinemic human plasma on the poly(EGDMA–HEMA) microbeads containing different amounts of attached Congo Red (between 2.5 and 14.6 μmol/g). The nonspecific bilirubin adsorption on the unmodified poly(EGDMA–HEMA) microbeads were 0.32 mg/g from human plasma. High adsorption rates were observed at the beginning, and the adsorption equilibrium was then gradually achieved in about 30–60 min. Much higher bilirubin adsorption values, up to 11.7 mg/g, were obtained with the Congo Red-modified microbeads especially at 37°C. The numbers (as μmol) of bilirubin molecules to albumin molecules adsorbed on the sorbent microbeads were in the range of 15–20, which showed that bilirubin molecules were preferentially adsorbed to the Congo Red-modified microbeads. Bilirubin adsorption increased with increasing temperature. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:373–380, 1998     

Synthesis and Characterization of Oriented Glyco‐Capturing Macroligand

An oriented glyco‐capturing macroligand was synthesized by site‐specific immobilization of an O‐cyanate chain‐end‐functionalized boronic acid containing polymer (boropolymer) onto an amine surface. The O‐cyanate chain‐end‐functionalized boropolymer was synthesized by arylamine‐initiated cyanoxyl‐mediated free‐radical polymerization in a one‐pot fashion. The chain‐end O‐cyanate was confirmed by ¹³C NMR spectroscopy. The specific carbohydrate‐binding capacity of the boropolymer was evaluated by an alizarin red S assay. Oriented and covalent immobilization of the O‐cyanate chain‐end‐functionalized boropolymer onto the amine‐modified solid surfaces and its specific glyco‐capturing capacity were confirmed by the quartz crystal microbalance (QCM) and atomic force microscopy (AFM) techniques. The oriented multivalent glyco‐capturing ligand can be used for efficient carbohydrate and glycoconjugate purification and identification, and thus is expected to constitute a core strategy of glycomics and glycoproteomics and carbohydrate‐sensing applications.     

Preparation and characterization of 2‐hydroxyethyl methacrylate–chitosan functionalized multiwall carbon nanotubes nanocomposites

Surface of chitosan (CS) functionalized multiwall carbon nanotubes (MWCNTs) was modified by using 2‐hydroxyethyl methacrylate (HEMA) monomers and the composites were synthesized under microwave irradiation. In this approach, multiwalled carbon nanotubes were functionalized with HEMA and CS in two steps. Firstly, CS was grafted onto the surface and side wall of carbon nanotubes by using microwave irradiation. At the second step, HEMA monomers were grafted onto the polymeric matrix surface. The modified surface of CS functionalized multi‐walled carbon nanotube composites are confirmed by Fourier transform infrared spectroscopy. Moreover, Transmission electron microscopic and scanning electron microscopic images show the morphological changes of the carbon nanotubes. Thermal gravimetric analysis shows content of HEMA–CS functionalized MWCNTs in the composites. Dispersibility of pristine MWCNTs was compared with dispersibility of resultant composites in aqueous phase as well. Results show that composites have higher dispersibility in aqueous phase. Considering the biomedical importance of HEMA monomers and CS polymer, in future, these materials are expected to be useful in the pharmaceutical industry as novel biomaterials composites with potential applications in drug delivery. POLYM. COMPOS., 35:495–500, 2014. © 2013 Society of Plastics Engineers     

Synthesis and characterization of a surface imprinting silica gel polymer functionalized with phosphonic acid groups for selective adsorption of Fe(III) from aqueous solution

A Fe(III) ion‐imprinted silica gel polymer functionalized with phosphonic acid groups (IIP‐PA/SiO₂) was prepared with surface imprinting technique by using Fe(III) ion as template ion, grafted silica gel as support, and vinylphosphonic acid as functional monomer. The polymer was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller, and thermogravimetric analysis. The synthesized imprinted silica gel polymer was used as a sorbent for Fe(III) adsorption. The adsorption properties, such as the effect of solution pH, adsorption kinetic, adsorption isotherm, adsorption selectivity as well as the regeneration of sorbent were studied. The results showd that the prepared sorbent (IIP‐PA/SiO₂) had a short adsorption equilibrium time (12 min) and high adsorption capacity (29.92 mg g^?1) for Fe(III) at the optimal pH of 2.0. The selectivity coefficients of the sorbent for Fe(III) in presence of Cr(III), M_n (II), and Zn(II) were 51.76, 27.86, and 207. 76, respectively. Moreover, the adsorption capacity of the prepared sorbent did not decrease significantly after six repeated use. Thus, the prepared ion‐imprinted silica gel polymer was a promising candidate sorbent for the selective adsorption of Fe(III) from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45165.     

Iminodiacetic acid‐containing polymer brushes grafted onto silica gel for preconcentration and determination of copper(II) in environmental samples

Silica gel has been modified by silylation with 3‐mercaptopropyltrimethoxysilane followed by graft polymerization of dimethylacrylamide and (N,N‐bis‐carboxymethyl)amino‐3‐allylglycerol‐co‐dimethylacrylamide, synthesized via the reaction of allyl glycidyl ether with iminodiacetic acid. The sorbent, poly(AGE/IDA‐co‐DMAA)‐grafted silica gel, has been characterized by FTIR, elemental analysis, thermogravimetric analysis (TGA), FT‐Raman, and scanning electron microscopy and studied for the preconcentration and determination of trace amounts of Cu(II) ion in environmental water samples. The optimum pH value for quantitative sorption of Cu(II) in batch mode was 5.5 and desorption was achieved, using 0.5 mol L^?1 nitric acid. The sorption capacity of functionalized sorbent is 32.3 mg g^?1. The chelating sorbent was reused for 15 sorption–desorption cycles without any significant change in sorption capacity. The profile of copper uptake by the sorbent reflected good accessibility of the chelating sites in the poly(AGE/IDA‐co‐DMAA)‐grafted silica gel. Scatchard analysis demonstrated homogeneous nature of binding sites. The equilibrium adsorption data of Cu(II) on modified sorbent were analyzed by Langmuir, Freundlich, Temkin, and Redlich–Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined as 0.0665, 4.26, and 8.34, respectively, at pH 5.5 and 20°C. Adsorption isotherms were analyzed at different temperatures to obtain free energy, enthalpy, and entropy of adsorption. The method was applied for Cu(II) determination in sea water samples. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of bimodal porous copolymer containing β‐cyclodextrin and its inclusion adsorption behavior

A novel insoluble bimodal porous polymer containing β‐cyclodextrin (β‐CD) was prepared to adsorb aromatic amine compound. The process involved copolymerization of styrene and methyl methacrylate with a maleic acid derivative of β‐CD, subsequently, above formed copolymer was foamed by supercritical CO₂. The chemical properties and physical structure of obtained copolymer was analyzed using Fourier transform infrared spectra, Thermal gravimetric analysis, X‐ray diffraction, scanning electron microscope, and N₂ adsorption techniques. The inclusion adsorption of aromatic amine compounds on β‐CD copolymer was carried out in a batch system. The quantities of aromatic amine compounds adsorbed on β‐CD copolymer reached equilibrium within 60 min. The adsorption kinetic could be fitted to a pseudo‐second‐order kinetic equation, and the linear correlation coefficients varied from 0.9828 to 0.9935. With the influence of molecular structure and hydrophobicity of the aromatic amine compound, the sequence of quantity of aromatic amine compounds adsorbed on β‐CD copolymer is p‐toluidine > aniline > benzidine > o‐toluidine. The adsorption equilibrium data of aromatic amine compound adsorbed on β‐CD copolymer were fitted to Freundlich and Langmuir models, respectively. The linear correlation coefficients of Langmuir model varied from 0.9516 to 0.9940, and the linear correlation coefficients of Freundlich varied from 0.9752 to 0.9976. It is concluded that Freundlich model fits better than Langmuir model, because the adsorption of aromatic amine compound on β‐CD copolymer is a chemical process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Functional,uniform, and macroporous latex particles: Preparation,electron microscopic characterization,and nonspecific protein adsorption properties

A series of uniform, macroporous particles with different surface chemistries were prepared with different acrylic comonomers [methyl methacrylate (MMA), butyl methacrylate (BMA), epoxypropyl methacrylate (EPMA), 2‐hydroxyethyl methacrylate (HEMA), and methacrylic acid (MAA)] with styrene–divinylbenzene (S–DVB) in a multistep seeded polymerization. In the synthesis, uniform polystyrene seed particles 6.2 μm in size were swollen first with a low molecular weight organic agent and then with a monomer phase including an S–DVB mixture and a relatively polar acrylic monomer. Final macroporous particles approximately 10 μm in size were obtained by the repolymerization of the monomer phase in the swollen seed particles. Surface and bulk morphologies were investigated with scanning and transmission electron microscopy, respectively. Although highly porous particles could be achieved with relatively hydrophobic monomers such as styrene, BMA, MMA, and EPMA, the use of hydrophilic monomers such as HEMA and MAA led to the synthesis of uniform particles with lower macroporosity. A comparison of Fourier transform infrared and Fourier transform infrared/diffuse reflectance spectroscopy spectra indicated that the concentration of polar acrylic monomer on the surface was higher than in the bulk structure. The nonspecific protein adsorption behavior of uniform, macroporous particles was investigated with albumin as a model protein. The highest nonspecific albumin adsorption was observed with plain poly(styrene‐co‐divinylbenzene) [poly(S–DVB)] particles. The particles produced with MMA and EPMA also exhibited albumin adsorption capacities very close to that of plain poly(S–DVB). Reasonably low nonspecific albumin adsorption was observed with the particles produced in the presence of MAA, HEMA, and BMA. Poly(S–DVB) particles functionalized with poly(vinyl alcohol) provided nearly zero nonspecific albumin adsorption. For nonspecific albumin binding onto the particles via a physical adsorption mechanism, desorption ratios higher than 80% could be achieved. The desorption ratio with the EPMA‐carrying particles was only 5% because the albumin adsorption onto EPMA‐carrying particles occurred predominantly with covalent‐bond formation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 414–429, 2002; DOI 10.1002/app.10412     

Prolonged zero‐order BSA release from pH‐sensitive hydrogels of poly(AAc‐co‐DMAPMA) having rich nano through micro scale morphology

New variety of pH‐sensitive hydrogels, having macroporous interior with honey‐comb type architecture and continuous skin at the surface, have been developed by single step aqueous copolymerization of acrylic acid (AAc) and N‐[3‐(dimethylamino)propyl]‐methacrylamide (DMAPMA) in different feed ratios at 41 ± 1°C. Interlocked nanogels of ～ 300 nm were identified as the building blocks in all of these cylindrical poly(AAc‐co‐DMAPMA) matrices (PDMAAc). The gels showed good compressive strength even at a swelling as high as 4330% (mass) at pH 7.0. Morphology of McCoy fibroblast cell line remained unchanged in direct contact with different PDMAAc gels, and cell viability (±SD) was recorded to be in the range of 105 (±3)% to 87 (±8)% after 72 h. Bovine serum albumin (BSA) loaded gels were prepared by means of equilibrium partitioning. Loading efficiency of PDMAAc gels has been found to be in the range of 210–277 mg/g dry gel. BSA release from PDMAAc gels at 37°C has been found to follow non‐Fickian diffusion mechanism in simulated gastric juice (pH 1.2), and Case II transport in simulated intestinal juice (pH 7.4). In vitro study showed that the gels are capable of retaining >95% of the loaded BSA in gastric medium through average gastric emptying period. Again, ～ 56% BSA release was recorded in 24 h at pH 7.4, indicating prolonged BSA diffusion in intestinal condition. Constant rate of BSA diffusion was reflected from the release profiles at both the pH. Diffusion exponents also supported the same and indicated for absolute zero‐order kinetics at pH 7.4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of layered membranes constructed by sequential redox‐initiated grafting onto polyacrylonitrile ultrafiltration membranes

Layered membranes were prepared by sequential grafting—by means of redox initiators—of water‐soluble monomers, with oppositely charged ionic groups, onto ultrafiltration (UF) polyacrylonitrile (PAN) membranes at room temperature. Grafting of a single layer of 2‐hydroxyethylmethacrylate (HEMA) onto a PAN membrane gave a highly grafted membrane with a relatively high water flux. Bilayered membranes with various properties containing poly‐2‐(dimethylamino)ethyl methacrylate (p‐2DMAEMA) as the bottom layer and polymethacrylic acid or polystyrenesulfonic acid (p‐SSA) as the upper layer were prepared and compared—by means of infrared spectroscopy and electron microscopy—with single‐layered membranes of grafted polyhydroxyethylmethacrylate. Layered membranes exhibited a significant decline in water flux in comparison with the initial UF membranes. The flux could, however, be manipulated by controlling the concentration of monomers, the time of grafting, and the number of layers. When four layers of p‐2DMAEMA and p‐SSA were sequentially grafted onto a PAN membrane, pure water fluxes were stable over a wide range of pH values and did not change over long storage times. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 509–520, 2005     

Copolymers of N‐isopropylacrylamide,HEMA‐lactate and acrylic acid with time‐dependent lower critical solution temperature as a bioresorbable carrier

Copolymers of N‐isopropylacrylamide (NIPAAm), 2‐hydroxyethyl methacryl lactate (HEMA‐lactate) and acrylic acid (AAc) were prepared, with varying mole ratios of monomers, to develop a bioresorbable in‐situ‐gelling material with a time‐dependent lower critical solution temperature (LCST). The synthesized copolymers were characterized by nuclear magnetic resonance, gel permeation chromatography and differential scanning calorimetry. In 0.1 M phosphate‐buffered saline solution of pH 7.4, these copolymers had an LCST below body temperature. The LCST decreased as the HEMA‐lactate content of the copolymers was increased. Furthermore, in these conditions, the LCST of the copolymers exhibited time‐dependent properties, due to hydrolysis of the HEMA‐lactate. As the HEMA‐lactate hydrolyzed, the copolymers became more hydrophilic, thereby leading to an increase in LCST. This hydrophilicity caused copolymers of approximately 6 mol% of AAc to exhibit an LCST above body temperature after hydrolysis. In neutral solution, copolymers with varying mol% of AAc saw their LCST rise above 37 °C within one to ten days, depending upon the HEMA‐lactate/NIPAAm ratio, due to the complete hydrolysis of the HEMA‐lactate. The above properties indicate that these copolymers would be useful for drug delivery because their variable LCST makes them bioresorbable. Copyright © 2004 Society of Chemical Industry     

Synthesis and swelling properties of 2‐hydroxyethyl methacrylate‐co‐1‐vinyl‐3‐(3‐sulfopropyl)imidazolium betaine hydrogels

A series of 2‐hydroxyethyl methacrylate/1‐vinyl‐3‐(3‐sulfopropyl)imidazolium betaine (HEMA/VSIB) copolymeric gels were prepared from various molar ratios of HEMA and the zwitterionic monomer VSIB. The influence of the amount of VSIB in copolymeric gels on their swelling behavior in water and various saline solutions at different temperatures and the drug‐release behavior, compression strength, and crosslinking density were investigated. Experimental results indicated that the PHEMA hydrogel and the lower VSIB content (3%) in the HEMA/VSIB gel exhibited an overshooting phenomenon in their dynamic swelling behavior, and the overshooting ratio decreased with increase of the temperature. In the equilibrium water content, the value increased with increase of the VSIB content in HEMA/VSIB hydrogels. In the saline solution, the water content for these gels was not affected by the ion concentration when the salt concentration was lower than the minimum salt concentration (MSC) of poly(VSIB). When the salt concentration was higher than the MSC of poly(VSIB), the deswelling behavior of the copolymeric gel was more effectively suppressed as more VSIB was added to the copolymeric gels. However, the swelling behavior of gels in KI, KBr, NaClO₄, and NaNO₃ solutions at a higher concentration would cause an antipolyelectrolyte phenomenon. Besides, the anion effects were larger than were the cation effects in the presence of a common anion (Cl^?) with different cations and a common cation (K⁺) with different anions for the hydrogel. In drug‐release behavior, the addition of VSIB increased the drug‐release ratio and the release rate. Finally, the addition of VSIB in the hydrogel improved the gel strength and crosslinking density of the gel. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2888–2900, 2001     

Synthesis and characterization of poly[(R,S)‐3‐hydroxybutyrate] telechelics and their use in the synthesis of poly(methyl methacrylate)‐b‐ poly(3‐hydroxybutyrate) block copolymers

Poly[(R,S)‐3‐hydroxybutyrate] oligomers containing dihyroxyl (PHB‐diol), dicarboxylic acid (PHB‐diacid) and hydroxyl‐carboxylic acid (a‐PHB) end functionalities were obtained by the anionic polymerization of β‐butyrolacton (β‐BL). Ring opening anionic polymerization of β‐BL was initiated by a complex of 18‐Crown‐6 with γ‐hydroxybutyric acid sodium salts (for PHB‐diol and a‐PHB) or succinic acid disodium salt (for PHB‐diacid). Dihydroxyl functionalization was formed by the termination of polymerization with bromo‐ethanol or bromo‐decanol while the others were done by protonation. Hydroxyl and/or carboxylic acid functionalized PHB oligomers with ceric salts were used to initiate the polymerization of methylmethacrylate (MMA). PHB‐b‐PMMA block copolymers obtained by this way were purified by fractional precipitation and characterized using ¹H‐NMR and ¹³C‐NMR, gel permeation chromatography (GPC), and thermal analysis (DSC and TGA) techniques. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 965–973, 2002     

Synthesis,characterization, and antimicrobial properties of novel quaternary amine methacrylate copolymers

A novel amine methacrylate monomer trimethylolpropane trimethacrylate–piperazine–ethyleneglycol dimethacrylate (TMPTMA‐PPZ‐EGDMA) was synthesized by amination of trimethylolpropane trimethacrylate (TMPTMA) with excess of piperazine (PPZ) followed by reaction with ethyleneglycol dimethacrylate (EGDMA). Copolymerization of TMPTMA‐PPZ‐EGDMA with 2‐hydroxyethyl methacrylate (HEMA) was carried out by free radical polymerization using ammonium persulfate (APS) and N,N,N′,N′‐tetramethyl ethylenediamine (TEMED) as a redox initiator. The copolymers obtained were then quaternized with 1‐iodooctane. The monomers were characterized by FTIR and ¹H NMR spectral studies. The molecular weights and polydispersity values of the monomers were determined with gel permeation chromatography. Quaternized copolymers containing more than 20% amine methacrylate monomer showed microporosity in the range of 9.9–10.4 μm. The antibacterial activity of the quaternized copolymers against Escherichia coli and Staphylococcus aureus was studied using UV–vis spectrophotometer and scanning electron microscopy. Quaternized copolymers showed broad‐spectrum contact‐killing antibacterial properties without releasing any active agent as checked by iodide selective ion meter. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Microporous gel electrolyte for quasi‐solid‐state dye‐sensitized solar cell

The extension of electrocatalytic reaction of I^?/I₃^? from counter electrode/gel electrolyte interface to gel electrolyte can significantly enhance the redox kinetics and therefore conversion efficiency of dye‐sensitized solar cells. Microporous gel electrolyte from polypyrrole integrated poly(hydroxyethyl methacrylate/cetytrimethylammonium bromide) [PPy‐integrated poly (HEMA/CTAB)] is successfully synthesized by in‐situ polymerization of pyrrole monomers in three‐dimensional framework of porous poly(HEMA/CTAB) matrix. An ionic conductivity of 12.72 mS cm^?1 and activation energy of 8.65 kJ mol^?1 are obtained from PPy‐integrated poly(HEMA/CTAB) gel electrolyte. Tafel polarization and electrochemical impedance spectroscopy are employed to characterize the electrocatalytic behaviors of the gel electrolytes. The resultant quasi‐solid‐state dye‐sensitized solar cell shows a light‐to‐electrical conversion efficiency of 6.68%. POLYM. ENG. SCI., 54:2531–2535, 2014. © 2013 Society of Plastics Engineers     

Metal chelating properties of Cibacron Blue F3GA‐derived poly(EGDMA‐HEMA) microbeads

Metal chelating properties of Cibacron Blue F3GA‐derived poly(EGDMA‐HEMA) microbeads have been studied. Poly(EGDMA‐HEMA) microbeads were prepared by suspension copolymerization of ethylene glycol dimethacrylate (EGDMA) and hydroxy‐ethyl methacrylate (HEMA) by using poly(vinyl alcohol), benzoyl peroxide, and toluene as the stabilizer, the initiator, and the pore‐former, respectively. Cibacron Blue F3GA was covalently attached to the microbeads via the nucleophilic substitution reaction between the chloride of its triazine ring and the hydroxyl groups of the HEMA, under alkaline conditions. Microbeads (150–200 μm in diameter) with a swelling ratio of 55%, and carrying 16.5 μmol Cibacron Blue F3GA/g polymer were used in the adsorption/desorption studies. Adsorption capacity of the microbeads for the selected metal ions, i.e., Cu(II), Zn(II), Cd(II), Fe(III), and Pb(II) were investigated in aqueous media containing different amounts of these ions (5–200 ppm) and at different pH values (2.0–7.0). The maximum adsorptions of metal ions onto the Cibacron Blue F3GA‐derived microbeads were 0.19 mmol/g for Cu(II), 0.34 mmol/g for Zn(II), 0.40 mmol/g for Cd(II), 0.91 mmol/g for Fe(III), and 1.05 mmol/g for Pb(II). Desorption of metal ions were studied by using 0.1 M HNO₃. High desorption ratios (up to 97%) were observed in all cases. Repeated adsorption/desorption operations showed the feasibility of repeated use of this novel sorbent system. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1397–1403, 1999     

Preparation of recyclable polybutadiene rubber based on acid–base complexation

Thermoreversible polybutadiene (PB) rubber is prepared by the self‐assembly of thiol‐ene functionalized PB oligomers containing amine and carboxylic acid groups, respectively, via acid–base reaction. The as‐formed ionic hydrogen bonds between the amine and carboxylic acid groups function as the crosslinking points to construct the polymer network. By controlling the crosslinking density, a series of materials ranging from soft gel to stiff solid with different physical properties can be obtained. The thermal reversibility of the ionic hydrogen bonds is evidenced by rheometry and temperature‐dependent FTIR spectra. In contrast to conventional covalently crosslinked rubbers, the thermoreversible PB rubbers prepared exhibit the capability of thermally reshaping and recycling. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45280.