Styrene-divinylbenzene Copolymer Research Articles

Synthesis and Properties of Anion Exchangers Derived from Chloromethyl Styrene Codivinylbenzene and Their Use in Water Treatment

Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB) copolymers is an effective method for preparation of ion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to copolymerize vinylbenzyl chloride with divinylbenzene to generate the necessary VBC-DVB. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. In this investigation, an improved solvent system was found for the preparation of anion exchange resins by the vinylbenzyl chloride route. The effectiveness of amination of the intermediate VBC-DVB polymers with a variety of trimethylamine reagents was investigated, and ethanolic trimethylamine produced the highest degree of amination. These resulting ion-exchange polymers were characterized by a variety of techniques such as analytical titrations, nitrogen analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads.

Isoelectric Separation of Proteins using Charged Ultrafilter Membranes with Different Functionality under Coupled Driving Forces

A simple membrane process for the protein fractionation under coupled driving forces (pressure and potential difference) has been developed using acidic functionalized (sulphonated, carboxyleted, and phosphorylated) ultrafilter membranes, based on the interpolymer of poly(vinyl chloride) (PVC) and styrene-divinyl benzene (DVB) copolymer. Introduction of the different functional groups was confirmed by Fourier transform infrared (FTIR), CHNS analysis, and ion-exchange capacity measurements. Molecular weight cut off (MWCO) determination of these membranes suggested their ultrafilter nature, while their contact angle values showed hydrophilic characteristics. The apparent pore radius of these membranes was estimated by water permeation studies, while electro-osmotic permeation data was used for the determination of zeta potential under the operating environment. Systematic studies on the effects of pH, or nature of the charge on the casein (CAS) and lysozyme (LYS), on their adsorption characteristic using these charged ultrafilter membranes were carried out. Protein transmission (selectivity) and membrane throughput across both membranes were studied using binary mixture of protein under different gradients at pH points: 2.0, 5.0, 10.7, and 13.0. It was concluded that separation from the binary mixture of CAS−LYS of LYS at pH 5.0 (pI of CAS) using charged ultrafilter membranes was possible with high selectivity and throughput. It was observed that transmission of protein can be governed by varying the nature and extent of charge on the protein (pH) and membrane matrix, polarity of applied potential gradient with an ultrafilter membrane of given pore dimensions. In these novel processes, charge on the protein, nature and extent of the charge on the membrane interfaces, and polarity of the potential gradient all are governing the transport of a given protein across the membrane, which resulted high selectivity and membrane throughput under coupled driving forces.

Optical properties of CdS nanoparticles embedded in polymeric microspheres

Mesoporous microspheres of styrene-divinylbenzene (Sty-DVB) copolymer have been used as template for encapsulation of CdS nanocrystal-quantum-dots (NQDs). Raman, micro-photoluminescence and optical absorption were used to investigate the optical properties of the nanocomposites containing CdS NQDs. When a single microsphere nanocomposite is excited by a laser beam at room temperature, very strong and sharp whispering-gallery mode (WGM) is shown on the background of CdS NQD PL spectra, which confirms that coupling between the optical emission of the encapsulated NQDs and spherical cavity modes was realized. The results show that the microspheres loaded with CdS nanoparticles work as an optical microcavity allowing the observation of WGM. The lasing behavior is achieved at relatively low laser excitation intensity (∼1 mW) at room temperature. High-optical stability and low-threshold value make this optical system promising in visible microlaser applications.

Synthesis and characterization of a polymer/multiwalled carbon nanotube composite and its application in the hydration of ethylene oxide

AbstractMultiwalled carbon nanotubes (MWNTs) were incorporated into the crosslinking network of a styrene–divinylbenzene copolymer (PS–DVB) via suspension polymerization. The prepared crosslinking PS–DVB with MWNTs was first treated with chloromethyl methyl ether to introduce chloromethyl groups through Friedel–Craft reaction; then, the chloromethylation product was reacted with trimethyl amine to obtain the target polymer/carbon nanotube composite: PS–DVB/MWNT ion‐exchange resin. The obtained composite was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, and X‐ray photoelectron spectroscopy. The results show the successful incorporation of MWNTs into the polymer network. The physical and chemical properties of the PS–DVB/MWNT ion‐exchange resin were nearly the same as those of the controlled sample. With its excellent antiswelling properties, the catalytic behavior of the polymer composite was examined in the hydration of ethylene oxide. Also, it demonstrated excellent stability as a catalyst without a decline in conversion and selectivity in a long‐time run. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Acid properties of phosphoric acid activated carbons and their catalytic behavior in ethyl-tert-butyl ether synthesis

Carbon catalysts were prepared by phosphoric acid activation of styrene–divinylbenzene copolymer followed by liquid phase oxidation with nitric acid. Their surface properties were modified by heat treatment at 300–600 °C in an argon atmosphere, and their acid properties were characterized by quasi-equilibrium temperature desorption of ammonia and by acid–base titration. The pore structure was characterized by nitrogen adsorption at −196 °C. Their catalytic activity in the synthesis of ethyl-tert-butyl ether (ETBE) from isobutene and ethanol was investigated. It has been shown that the carbon catalysts are active and selective in ETBE synthesis. The main factor determining the catalytic activity of carbon catalysts is the total number of acid surface sites. A linear correlation between total amount of surface sites and catalytic activity was found.

Determination of Tricyclazole in Water Using Solid Phase Extraction and Liquid Chromatography

A method for determination of tricyclazole in water using solid phase extraction and high performance liquid chromatography (HPLC) with UV detection at 230 nm and a mobile phase of acetonitrile:water (20:80, v/v) was developed. A performance comparison between two types of solid phase sorbents, the C18 sorbent of Supelclean ENVI-18 cartridge and the styrene-divinyl benzene copolymer sorbent of Sep-Pak PS2-Plus cartridge was conducted. The Sep-Pak PS2-Plus cartridges were found more suitable for extracting tricyclazole from water samples than the Supelclean ENVI-18 cartridges. For this cartridge, both methanol and ethyl acetate produced good results. The method was validated with good linearity and with a limit of detection of 0.008 µg L−1 for a 500-fold concentration through the SPE procedure. The recoveries of the method were stable at ∼80% and the precision was from 1.1 − 6.0% within the range of fortified concentrations. The validated method was also applied to measure the concentrations of tricyclazole in real paddy water.

Interaction of apple polyphenols in a multi-compound system upon adsorption onto a food-grade resin

Adsorption of catechin, caffeic acid, chlorogenic acid, phloridzin and rutin from multi-compound model solutions onto Amberlite ® XAD 16HP was studied in laboratory experiments. The adsorption conditions were adapted to those optimal for single compound binding, which were determined in previous studies. The following order of affinity towards the styrene–divinylbenzene copolymer was determined: caffeic acid < catechin < chlorogenic acid < phloridzin < rutin, and the data also reveal significant interactions of the phenolics upon adsorption from multi-compound solutions. The affinity order was successfully derived from differences in the consecutive phases of the adsorption kinetics of individual phenolic compounds. At the very beginning of adsorption polyphenol binding is characterized by processes, which may result in the formation of a subsurface surrounding the resin particles and which precede surface reactions, whereas the final phase is dominated by intraparticle diffusion processes. The results presented in this work contribute to a better understanding of the complexity of adsorption mechanisms and of the influence of adsorption conditions. Thus, detailed evaluation of such complex systems may contribute to optimize the selective recovery of plant secondary metabolites, e.g. by providing phloridzin-enriched extracts with promising health-promoting properties.

Heterogeneous ion-selective membranes: the influence of the inert matrix polymer on the membrane properties

Heterogeneous ion-exchange membranes were prepared by mixing small particles of sulfonated poly(1,4-phenylene sulfide) or sulfonated styrene–divinylbenzene copolymer with a matrix polymer. Four kinds of polymers were tested as a matrix: highly flexible linear polyethylene, medium-flexible fluoroelastomer, rigid polystyrene (all highly hydrophobic) and hydrophilic cellulose prepared by hydrolysis of cellulose acetate butyrate. Membrane morphologies were studied by scanning electron microscopy, IR spectroscopy and density measurements. Subsequently, the membranes were characterised with respect to their swelling in water, electrochemical characteristics and transport properties. Ion-exchange capacity and proton conductivity together with the permeability to hydrogen and methanol were investigated. The important impact of the ion-exchange particles as well as of the polymer matrix used was observed. The increasing rigidity of the polymer matrix resulted in a decrease in membrane permeability, but at the same time in deterioration of its ion-exchange capacity and subsequently of the proton conductivity, too. This was explained in terms of the limited elasticity of the polymer matrix, in each sample under study, which does not allow the ion-exchange particles to swell to an identical degree.

Analytical performance of three commonly used extraction methods for the gas chromatography–mass spectrometry analysis of wine volatile compounds

The analytical performance of three extraction procedures based on cold liquid–liquid extraction using dicloromethane (LLE), solid phase extraction (SPE) using a styrene–divinylbenzene copolymer and headspace solid phase microextraction (SPME) using a carboxen–polydimethylsiloxane coated fibre has been evaluated based on the analysis of 30 representative wine volatile compounds. From the comparison of the three procedures, LLE and SPE showed very good linearity covering a wide range of concentrations of wine volatile compounds, low detection limits, high recovery for most of the volatile compounds under study and higher sensitivity compared to the headspace-SPME procedure. The latter showed in general, poor recovery for polar volatile compounds. Despite some drawbacks associated with the LLE and SPE procedures such as the more tedious sampling treatment and the use of organic solvents, the analytical performance of both procedures showed that they are more adequate for the analysis of wine volatiles.

Ion exchange behavior of plutonium(IV) on imidazolium nitrate immobilized resin

Imidazolium nitrate anchored on poly(styrene-divinylbenzene) co-polymer, Im-NO3, has been synthesized and evaluated for plutonium purification. The results are compared with those obtained using Dowex 1 × 4 anion exchange resin. The distribution coefficient (Kd) of Pu(IV) increased with increase in concentration of nitric acid, reached a maximum at 8 M, followed by decrease in Kd values. Rapid ion exchange of Pu(IV) followed by the establishment of equilibrium occurred within 100 min of equilibration and the data was fitted in to first order rate equation. Variation of distribution coefficient of Pu(IV) as a function of exchange capacity and nitrate ion concentration suggest the involvement of anion exchange mechanism is responsible for extraction. The apparent ion exchange capacity was 310 mg/g at 8 M nitric acid. The performance of the Im-NO3 under dynamic condition was assessed by column breakthrough experiments. Radiolytic degradation of Im-NO3 resin in presence and absence of nitric acid (8 M) was studied and the results are reported in this paper.

Preparative separation and purification of rosavin in Rhodiola rosea by macroporous adsorption resins

Rosavin is one of the main bioactive components in Rhodiola rosea L. with known pharmacological effects. In this study, a simple method for preparative separation and purification of rosavin from R. rosea L. was developed with macroporous adsorption resins. The adsorption isotherms and desorption performances of some resins have been determined and compared. Depending on its hydrophobic force, HPD-200 resin, a styrene-divinylbenzene (SDVB) copolymer, offers the best adsorption and desorption properties for rosavin based on the research results, its adsorption data fit best to the Langmuir adsorption model. Dynamic adsorption and desorption was performed on HPD-200 resin packed in a glass column to obtain optimal parameters for the separation of rosavin. The optimum conditions were as follow. The volume, concentration, bed height and flow rate of loading sample were 4 bed volumes (BV), 0.24 mg/mL, 30 cm and 2 BV/h, respectively, at 25 °C; desorption was performed successively with 30% ethanol of 4 bed volumes, 40% ethanol of 2.5 bed volumes and 60% ethanol of 3 bed volumes. After one run treatment with HPD-200, the rosavin content in the product was increased from 0.69% to 11.02% with a recovery of 82.46%. In this case, the process throughout is 1.34 g rosavin/L adsorbent/day, solvent usage is 7.14 L ethanol/g rosavin. The simple purification scheme avoids toxic organic solvent and thus, increases the safety of the process with a potential industrial application prospect.

Synthesis, characterization, and adsorption properties of phenolic hydroxyl group modified hyper-cross-linked polymeric adsorbent

A kind of phenolic hydroxyl group modified hyper-cross-linked polymeric adsorbent HJ-02 was prepared from macroporous crosslinked chloromethylated styrene-divinylbenzene copolymers by Friedel–Crafts post-cross-linked reaction and esterified reaction. Its chemical structure and pore structure were characterized by chemical analysis, infrared spectroscopy, and N 2 adsorption–desorption experiments. It was thereafter applied to adsorb p-aminobenzoic acid in aqueous solution for its potential application in separation and purification. The p-aminobenzoic acid aqueous solution, pH unadjusted, was the optimum for the adsorption and the salinity posed a positive effect. The adsorption dynamic curves obeyed the pseudo-second-order rate equation and the adsorption was controlled by an intraparticle diffusion model. The adsorption enthalpy was calculated to be negative and decreased with the increase of the p-aminobenzoic acid uptake. The surface character of HJ-02 resin was described with function of the adsorption enthalpy by Do’s model and the result indicated that it exhibited surface energy heterogeneity.

Evaluation of the adsorption behavior of flavonoids and phenolic acids onto a food-grade resin using a D-optimal design

A D-optimal experimental design has been applied to study the single-compound adsorption of caffeic acid, catechin, chlorogenic acid, and phloridzin from aqueous solutions onto a food-grade styrene–divinylbenzene copolymer. Among the parameters determining adsorption the solute concentration, the temperature, the pH value, and the resin amounts were evaluated. Mathematical models were established for each phenolic compound allowing to predict the adsorption behavior under any given condition. Furthermore, determination of the optimal adsorption conditions using the mathematical equations was possible, thus facilitating systematic optimization of the adsorption process. The Langmuir and Freundlich isotherms have been applied to describe the adsorption of the four phenolic compounds and were used to interpret the adsorption behavior. Finally, ΔG, ΔH and ΔS were determined to evaluate polyphenol adsorption based on thermodynamic parameters. The present study contributes to optimize adsorber technology, thus, being a prerequisite for establishing cost-efficient technological processes for the recovery of plant phenolic compounds.

スチレンジビニルベンゼン共重合体樹脂を用いた天然水中における疎水性と親水性の溶存有機物の分画

To characterize dissolved organic matter (DOM) in natural waters, a procedure called dissolved organic carbon (DOC) fractionation analysis is useful, in which DOM is fractionated into hydrophobic-hydrophilic fractions using XAD-8 resin of an acrylic ester polymer, and into acid-neutral-base fractions using ion exchange resins. However, the difficulties in XAD-8 purification and handling have limited the use of the fractionation procedure to a few research groups; thus, we have developed a new fractionation procedure using PS-2 cartridges packed with purified styrene divinylbenzene copolymer resins, instead of XAD-8. Recovery studies of model compounds such as humic and fulvic acids were conducted to compare the fractionation properties of PS-2 with those of XAD-8. The added hydrophobic and hydrophilic compounds were found at recoveries of 81∼103 % in the hydrophobic and hydrophilic fractions, respectively. The results of the recovery tests showed that PS-2 and XAD-8 have the same fractionation properties for hydrophobic DOM and hydrophilic DOM. By using a similar conditioning of PS-2 cartridges in the solid-phase extraction of the water samples, the blank DOC level in this procedure was easily reduced to 0.4∼0.5 mgC · l-1, corresponding to the levels obtained using purified XAD-8. For the repeatability of the fractionated DOC measurement, the relative standard deviation was ca. 10% when the measured DOC level was higher than threefold of the blank DOC; it was ca. 30% when the measured DOC level was between two- and threefold of the blank DOC. It was found from the data for the application to river and lake waters that the obtained composition data of hydrophobic DOM and hydrophilic DOM agreed with the reported composition data obtained using XAD-8. This procedure using PS-2 can be used for the hydrophobic-hydrophilic fractionation of DOM in natural water samples as an alternative to the conventional procedure using XAD-8.

Determination of Bicozamycin in Livestock Products and Seafoods by Liquid Chromatography-Tandem Mass Spectrometry

A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for trace residue determination of bicozamycin (BZM) in livestock products and seafoods. BZM was extracted from a sample with acetonitrile-water (4 : 1), followed by a two-stage SPE enrichment and cleanup. The first stage involved a styrene-divinylbenzene copolymer cartridge (GL-Pak PLS-2), and the second stage involved a divinylbenzene-N-vinylpyrrolidone copolymer cartridge (Oasis HLB). The LC separation was performed on a C18 column using 0.01% formic acid-methanol (8 : 2) as the mobile phase and MS detection with negative ion electrospray ionization. The mean recoveries from swine muscle, liver, yellowtail, and milk fortified at the minimum residue limit (MRL) levels and 0.01 microg/g were >70%, and the relative standard deviations (RSDs) were <20%. Limits of quantitation (LOQs) ranged from 0.002 to 0.005 microg/g.

Biodiesel production from canola oil by using lipase immobilized onto hydrophobic microporous styrene–divinylbenzene copolymer

In this study, the methyl esters of the long chain fatty acids (biodiesel) were synthesized by methanolysis of canola oil by immobilized lipase. Lipase from Thermomyces lanuginosus was immobilized by both physical adsorption and covalent attachment onto polyglutaraldehyde activated styrene–divinylbenzene (STY–DVB) copolymer, which is synthesized by using high internal phase emulsion (polyHIPE). Two different STY–DVB copolymers were evaluated: STY–DVB copolymer and STY–DVB copolymer containing polyglutaraldehyde (STY–DVB–PGA). Lipase from T. lanuginosus was immobilized with 60% and 85% yield on the hydrophobic microporous STY–DVB and STY–DVB–PGA copolymer, respectively. Biodiesel production using the latter lipase preparation was realized by a three-step addition of methanol to avoid strong substrate inhibition. Under the optimized conditions, the maximum biodiesel yield was 97% at 50 °C in 24 h reaction. The immobilized enzyme retained its activity during the 10 repeated batch reactions.

Removal of p-nitrophenol by a water-compatible hypercrosslinked resin functionalized with formaldehyde carbonyl groups and XAD-4 in aqueous solution: A comparative study

Chloromethylated styrene-divinylbenzene copolymers were post-crosslinked through Fredel–Crafts alkylation reaction and a water-compatible hypercrosslinked resin HJ-1 was developed successfully. It can be wetted directly by water and can be used without any wetting process. It was applied to remove p-nitrophenol in aqueous solution in comparison with the commercial Amberlite XAD-4 resin. Their adsorption behaviors for p-nitrophenol were conducted and it was found the adsorption dynamics obeyed the pseudo-second-order rate equation and the intra-particle diffusion was the rate-limiting step. The adsorption isotherms can be correlated to Freundlich isotherm and the adsorption capacity onto HJ-1 resin was much larger than XAD-4. The maximum adsorption capacity of p-nitrophenol for HJ-1 resin was measured to be 179.4 mg/g with the equilibrium concentration at 178.9 mg/l and the maximum removal percentage was predicted to be 98.3%. The adsorption thermodynamic parameters were calculated and the adsorption was mainly driven by enthalpy change. The micropore structure, the size matching between the pore diameter of HJ-1 resin and the molecular size of p-nitrophenol, and polarity matching between the formaldehyde carbonyl groups of HJ-1 resin and p-nitrophenol bring the larger adsorption capacity and higher adsorption affinity.

Water softening by combination of ultrasound and ion exchange

Ion exchange resin used in this work was styrene-divinylbenzene co-polymer with sulfonic acid group as a strong acid cation resin. This resin is particularly well suited for the removal of water hardness. In water treatment, commonly used softening processes are chemical precipitation and ion exchange. In this study, a combination of ultrasound and ion exchange was applied for reducing the hardness of water. The rate of exchange or kinetics of ion exchange is governed by several parameters. Therefore, important variables such as intensity of ultrasound, amount of resin, concentration of ions and contact time were investigated. The experimental data related to the removal of magnesium and calcium ions were fitted properly with Langmuir model. The kinetic of removal for both ions was pseudo-first-order. In point of mechanism, the internal porous and film diffusion were both effective in the process. The capacity of sorption and the velocity of removal were higher in the presence of ultrasound than control method and this is related to the cavitation process.

Adsorption of rutin onto a food-grade styrene–divinylbenzene copolymer in a model system

Adsorption of quercetin-3- O-rutinoside (rutin) onto Amberlite ® XAD 16HP was studied applying a modified D-optimal design. Temperature, pH value, rutin concentration and resin amount were studied as independent factors determining rutin adsorption. Using the mathematical model resulting from the analysis of the D-optimal design the optimal conditions for rutin adsorption onto the styrene–divinylbenzene copolymer were determined. Furthermore, the model equation was successfully applied to calculate the Langmuir and Freundlich isotherm parameters of this particular solute–sorbent system. In addition, the data obtained from the D-optimal design allowed the calculation of Δ G, Δ H and Δ S for the adsorption process. The results presented in this study are of utmost importance for a better understanding of adsorption phenomena. The more detailed knowledge of such sorbent systems is required to improve the cost-effectiveness of industrial processes for the recovery of secondary plant metabolites, such as polyphenols, based on resin adsorption technology.

Modification of styrene-divinyl benzene copolymers using monoacrylates as ter-monomer

Porous styrene-divinyl benzene (St-DVB) copolymers were synthesized by incorporation of cyclohexanol during copolymerization. It led to copolymers of high porosity, high surface area and high % swelling. However these copolymers exhibit very poor compressive strength. Therefore they have been modified by terpolymerization in order to achieve styrene-DVB copolymers of adequate compressive strength with high surface area and % swelling. These terpolymers were synthesized by suspension copolymerization of styrene, DVB and variable amount of monoacrylates in presence of cyclohexanol as a diluent. Methylacrylate, ethyl acrylate, butyl acrylate, methylmethacrylate and glycidyl methacrylate were taken as ter-monomers for the present study and influence of these ter-monomers on formation of porous structure of the copolymer was investigated by % swelling, surface area, bulk density, compressive strength measurement and surface morphology. Incorporation of ter-monomers resulted into increased compressive strength and bulk density with adequate surface area and % swelling with the increased content of monoacrylates. Further at constant ter-monomer concentration, physical properties and thermal stability of the ter-polymers were found to be in the order: MMA > MA > EA > BA > GMA.