Copolymerization Of Ethylene Glycol Dimethacrylate Research Articles

The roles of template complexation and ligand binding conditions on recognition in bupivacaine molecularly imprinted polymers.

A model for the molecular basis for ligand recognition in bupivacaine imprinted methacrylic acid-ethylene glycol dimethacrylate co-polymers has been developed based upon a series of (1)H-NMR studies in conjunction with HPLC and radioligand binding analyses. (1)H-NMR studies indicated that functional monomer-template complexes survive the polymerisation process, at least up until the stage of gelation. Polymers were synthesised and characterised by surface area analysis (BET), FT-IR and SEM. A combination of zonal and frontal chromatographic studies in aqueous and non-polar media indicate that selectivity arises from a combination of hydrophobic and electrostatic interactions. However, in the concentration regime employed for LC-based studies, ligand recognition in aqueous media was shown to be predominantly non-specific and hydrophobic in character. Radioligand binding studies, in lower ligand binding concentration regimes, permitted closer examination of the higher affinity binding sites. It was shown that the presence of a polar modifier in a non-polar solvent, or an organic modifier in water, produced enhanced selectivity. Variable temperature studies showed that the temperature of binding influences selectivity as well as the apparent number of sites available and that this effect is different in organic and aqueous environments. This indicates that the system studied is more complex in character than is generally appreciated. A comparison of the techniques employed here indicates that although chromatographic studies provide a valuable first-round screen for polymer-ligand selectivities, the level of detail obtainable using radioligand binding studies (lower concentrations and true equilibrium binding) makes them superior for detailed evaluations of molecularly imprinted polymers.

Soluble hyperbranched polymer through initiator-fragment incorporation radical copolymerization of ethylene glycol dimethacrylate and α-ethyl β- N-(α ′-methylbenzyl) itaconamate in benzene

The copolymerizations of ethylene glycol dimethacrylate (EGDM) with α-ethyl β- N-(α ′-methylbenzyl) itaconamates (RS- and S-EMBIs) derived from (RS)- and (S)-α-methylbenzylamines were conducted at 70 and 80 °C in benzene using dimethyl 2,2 ′-azobisisobutyrate (MAIB) of high concentration as initiator. The copolymerization of EGBM (0.20 mol/l) and RS-EMBI (0.50 mol/l) with MAIB (0.50 mol/l) proceeded homogeneously without any gelation in benzene to give benzene-soluble copolymer in a yield of 55% based on the total weight of EGDM, RS-EMBI and MAIB. The copolymer was soluble in acetone, ethyl acetate, chloroform, tetrahydrofuran (THF), toluene, N, N-dimethylformamide and insoluble in n-hexane, methanol, dimethyl sulfoxide, and water. The copolymerization system involved ESR-observable propagating radicals derived from EGDM and RS-EMBI, of which the total concentration increased with time in spite of the homogeneous system. The copolymer consisted of EGDM unit (25 mol%), RS-EMBI unit (45 mol%), and methoxycarbonylpropyl group as MAIB-fragment (30 mol%). Such a large number of initiator fragments were incorporated into the copolymer as terminal groups through initiation and primary radical termination, leading to a conclusion that the copolymer was of hyperbranched structure (initiator-fragment incorporation radical copolymerization). Radius of gyration ( R g) and M w of the copolymer by light scattering measurements in THF were 17.8 nm and 7.7 × 10 5, respectively. Comparison of these values with those ( R g=27.6 nm and M w=2.9×10 5) of linear polystyrene also supported the above conclusion. Reflecting the compact hyperbranched structure, the intrinsic viscosity ([ η]) of the copolymer was very low, [ η]=0.075 dl/g at 25 °C in THF. The individual copolymer molecules were observed as a nanoparticle by TEM. The copolymerization of EGDM and S-EMBI with MAIB in benzene also gave similar results.

A Chloro-Bridged (Arene)Ru Complex with a Polymerizable Side Chain

An [(arene)RuCl2](2) complex with a methacrylate side chain (2) has been prepared in two steps using commercially available starting materials. This complex reacts with PPh3, pyridine, or toluidine to give the corresponding mononuclear adducts (3-5). The structure of 4 was determined by single-crystal X-ray diffraction. Complex 2 and the PPh3 adduct 3 were immobilized by copolymerization with divinylbenzene (DVB) or ethyleneglycol dimethacrylate (EGDMA). The resulting EGDMA copolymer was tested as a catalyst in asymmetric transfer hydrogenations. Using (1R,2R)-(-)-N-p-tosyl-1,2-diphenylethylenediamine as the chiral ligand and azeotropic NEt3/HCO2H as the reducing agent, aromatic ketones were converted to the corresponding alcohols with selectivities between 87 and 97% ee.

Molecular recognition through the exact placement of functional groups on non-covalent molecularly imprinted polymers

To investigate the extent of the placement of functional groups in the non-covalent molecularly imprinted polymers contributing to selectivity, three kinds of molecularly imprinted methacrylic acid–ethylene glycol dimethacrylate copolymers were prepared at higher polymerization temperature (60 °C) using 2- l-phenylalanylamino-pyridine, 3- l-phenylalanylamino-pyridine, or 4- l-phenylalanylamino-pyridine as a template molecule, respectively. The enantiomeric recognition performance of these molecularly imprinted polymers (MIPs) in the high-performance liquid chromatography (HPLC) mode was investigated. The polymers exhibited efficient enantiomeric resolution of the racemic mixture of their printing molecules and could hardly resolve the enantiomers of other substrates that were structurally analogous to the imprinting molecules, but different from spatial interaction sites on the polymer with the methacrylic acid residues. Our results showed that the shape and spatial orientation of functionality of imprinted binding sites were critical for recognition and the recognition properties of MIPs were greatly influenced by the minor difference of N position on the pyridine ring and caused by the distance accuracy of functional groups in the binding sites. The implication of these findings with respect of the mechanism of recognition was discussed.

A cobalt(II)—porphyrin complex as a regulator of cross-linking radical copolymerization

The additions of a porphyrin cobalt complex diminished the rate of cross-linking copolymerization of ethylene glycol dimethacrylate (EGDMA) and styrene, shifted the autoacceleration process towards higher degrees of monomer conversions and modified the structure and properties of resulting cross-linked copolymers owing to catalytic chain transfer reaction, catalytic inhibition reaction and chain regeneration as a result of the reversible breakdown of a Co–C bond.

The preparation of the chronic hyper-endotoxemia experimental animal model by means of a drug delivery system

A drug delivery system (DDS) consisting of lipopolysaccharide (LPS) as a drug and 2-hydroxyethyl methacrylate (HEMA)-diethylene glycol dimethacrylate (2G) or –polyethylene glycol dimethacrylate (4G, 9G) copolymer was prepared, and used for the efficient preparation of an experimental animal model of chronic hyper-endotoxemia. The release profiles of LPS in the in-vitro test were greatly influenced by the composition of HEMA-2G, 4G, 9G in the copolymer. It was found that LPS release from the DDS continued gradually and constantly throughout 2 weeks. In the in-vivo experiment with rats, the DDS maintained a high blood concentration level of LPS for 3 days. These results strongly suggest the possibility of convenient and reproducible preparation of a chronic hyper-endotoxemia animal model.

On the thermal and chemical stability of molecularly imprinted polymers

The thermal and chemical stability of a theophylline imprinted methacrylic acid–ethylene glycol dimethacrylate co-polymer has been investigated. Radioligand binding studies have been used to study the changes in theophylline recognition characteristics of this and a non-imprinted, reference polymer arising from exposure to elevated temperatures and a range of chemical environments. Polymers were shown to withstand exposure to temperatures of up to 150°C (for 24 h) without loss of affinity for the template. Temperatures above this point induced a rapid loss in binding capacity and a concomitant mass loss. FT-IR indicated that this arises from decarboxylation of the polymer. The polymers exhibited remarkable resistance to extremes of pH, organic base and to autoclave treatment. This study provides an indication as to the limits of polymer stability, which is of significance for the practical use of this type of polymer, e.g. in sensor-based applications.

Hollow‐particle latexes: Preparation and properties

AbstractHollow‐particle latexes were prepared according to the following stages: (1) the preparation of the methyl methacrylate–methacrylic acid (MAA)–ethylene glycol dimethacrylate copolymer (I) latex, (2) the preparation of a shell (II) based on polystyrene or styrene–acrylonitrile–divinyl benzene copolymer polymerized onto copolymer (I) particles, and (3) the neutralization of the core (I) carboxyl groups with a base (NH4OH or NaOH) at temperatures close to the glass‐transition temperature of the polymer (II). The neutralization resulted in the expansion of the particles and formed water‐filled hollow particles. The microspheres had an overall diameter of 460–650 nm and a hollow diameter of 300–450 nm. Rheological studies and particle size measurements by transmission electron microscopy and dynamic light scattering of the copolymer (I) latex indicate that the maximum particle swelling occurred at an approximately equimolar MAA/base ratio. It was found that even without the neutralization of the MAA units, a small hollow formation in the latex particles occurred during stage 2 because one volume of the copolymer (I) retained about 8 volume parts of water. It was also discovered that the final hollow‐particle geometry after neutralization depends on the shell copolymer thickness and type as well as on the conditions during stage 3, that is, the time, temperature, base type, and concentration. The opacifying ability of the synthesized hollow particles was investigated in latex coatings. The opacifying ability values were generally in agreement with the hollow‐particle geometry. The only exception was related to the copolymer (I)/copolymer (II) ratio. The maximum hollow volume was obtained at this value equal to 1/8, whereas the highest opacifying ability was observed at 1/10. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1435–1449, 2001

Synthesis of strongly basic anion exchange resins based on glycidyl methacrylate-ethylene glycol dimethacrylate copolymer. Effect of amount and nature of diluent, and the degree of crosslinkage on the resins properties

A number of hydrophilic copolymers based on glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDM) were synthesized using the technique of suspension polymerization. A number of diluents such as dimethylpthalate (DMT), diethylpthalate (DET), dibutylpthalate (DBT) and bis-2-ethylhexylpthalate (diocylphthalate, DOT) were used. The resulting polymers were modified into strongly basic anion exchange resins using 50% aqueous trimethylamin hydrochloride solution. In this study, the effects of amount and nature of diluents on resin properties, i. e. porosity, density, mechanical properties and capacities, were investigated. The effect of amount of crosslinking agent, i.e. the amount of EGDM, was also studied. It was found that resin become porous as the number of methylene groups in diluents increases. The pore volume changes from 0.05 to 1.35 ml/g as the diluent change from DMT to DOT. The mechanical strength of the resin decreases on increasing the number of methylene groups in the diluent. However, the chloride capacity shows no significant change. By varying the amount of crosslinking agent (from 10 to 50%) the chloride capacity changes from 3.46 to 1.2 meq/g, respectively. The effect of crosslinking on porosity was also investigated. It was found that porosity of the resin increases on increasing the amount of EGDM. This is the first time that strongly basic anion exchange resin based on GMA-co-EGDM using different and varying amounts of diluents, as well as various degrees of crosslinkage, were synthesized and characterized. The important aspect of this study is that it provides a guideline for the synthesis of a resin with specific properties by selection of a diluent and varying its ratio with respect to the monomer.

Synthesis of strongly basic anion exchange resins based on glycidyl methacrylate-ethylene glycol dimethacrylate copolymer. Effect of amount and nature of diluent, and the degree of crosslinkage on the resins properties

A number of hydrophilic copolymers based on glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDM) were synthesized using the technique of suspension polymerization. A number of diluents such as dimethylpthalate (DMT), diethylpthalate (DET), dibutylpthalate (DBT) and bis-2-ethylhexylpthalate (diocylphthalate, DOT) were used. The resulting polymers were modified into strongly basic anion exchange resins using 50% aqueous trimethylamin hydrochloride solution. In this study, the effects of amount and nature of diluents on resin properties, i. e. porosity, density, mechanical properties and capacities, were investigated. The effect of amount of crosslinking agent, i.e. the amount of EGDM, was also studied. It was found that resin become porous as the number of methylene groups in diluents increases. The pore volume changes from 0.05 to 1.35 ml/g as the diluent change from DMT to DOT. The mechanical strength of the resin decreases on increasing the number of methylene groups in the diluent. However, the chloride capacity shows no significant change. By varying the amount of crosslinking agent (from 10 to 50%) the chloride capacity changes from 3.46 to 1.2 meq/g, respectively. The effect of crosslinking on porosity was also investigated. It was found that porosity of the resin increases on increasing the amount of EGDM. This is the first time that strongly basic anion exchange resin based on GMA-co-EGDM using different and varying amounts of diluents, as well as various degrees of crosslinkage, were synthesized and characterized. The important aspect of this study is that it provides a guideline for the synthesis of a resin with specific properties by selection of a diluent and varying its ratio with respect to the monomer.

A new bonded porous polymer PLOT U column with increased polarity.

The separation features of a new type of PLOT U column are presented through many applications. This type of PLOT U column is coated with a divinylbenzene-ethylene glycol dimethacrylate copolymer. It has an increased polarity when compared with a conventional PLOT Q type column. The stationary phase of the PLOT U column is truly bonded, thus providing column rinsability and low column bleed.

Enantioselective Tröger's Base Synthetic Receptors

Synthetic receptors selective for the enantiomers of Tröger's base (1), a compound containing chiral nitrogen atoms, have been prepared by the molecular imprinting of 1 in methacrylic acid–ethylene glycol dimethacrylate copolymers. Spectroscopic evaluation of the self-assembly phase, prior to polymerization, demonstrated the formation of template-functional monomer adducts of Kdiss 0.7 ± 0.1 mM at 293 K in chloroform. The synthetic receptors demonstrated enantioselectivity when used as HPLC chiral stationary phases; enantioseparation factors (α) of up to 4.8 ± 0.2 are reported. Baseline resolution of racemic 1 was readily achieved. Furthermore, the influence of water on polymer–ligand selectivity was examined, which yielded insights into the molecular basis for ligand selectivity in these synthetic receptors.

The optical properties of some dimethacrylic composites

One series of composites based on 2,2-bis-4(2-hydroxy-3-methacryloyloxy propoxy)phenyl propane (BisGMA), ethylene glycol dimethacrylate (EGDMA) and colloidal silica, quartz or titanium dioxide filler were formulated and investigated by UV-visible spectroscopy and optical microscopy. Also the FTIR spectrum of BisGMA–EGDMA copolymer was reported and discussed to offer adequate information for identification purpose. The investigation was centred on the evaluation of some important effects of the filler level and nature on such composites opacity by comparison with unfilled dimethacrylic resin. The composite opacities were determinated in terms of visible light transmission through the thickness of composites. The visible transmission spectra within the range 350–850 nm wavelength show that transmittance values decrease with increasing wt% of filler incorporated in composites. It was found that the filler nature influences the transmission degree of such composites. The feature of the visible absorption spectra has been discussed by taking into account light scattering phenomena, filler size and the degree of mismatch of the refractive indices of the filler and resin.

Heterogeneity of segmental dynamics aroundtg and nanoscale compositional inhomogeneity in polyurethane/methacrylate interpenetrating networks as estimated by creep rate spectroscopy

Segmental relaxations in a series of poly(propylene oxide)-based polyurethane/butyl methacrylate-triethylene glycol dimethacrylate copolymer interpenetrating networks (IPNs) of various compositions, as compared to those in the pure constituent networks, were studied by an original laser-interferometric Creep Rate Spectroscopy (CRS) technique. The spectra, obtained over the range from 150 K to 360 K, confirmed the CRS superiority in resolution to generally utilized relaxation spectrometry techniques and allowed to characterize in detail the heterogeneity of segmental dynamics within or near the extraordinarily broad glass transition range in these IPNs. Up to eight creep rate peaks have been registered which were shown to be associated just with the predicted kinds of segmental motions, cooperative and partly- or noncooperative; thereby, molecular assignments could be done for these peaks. The relative peak contributions to dynamics around Tg as a function of IPN composition were approximately estimated that provided also some information on nanoscale compositional inhomogeneity of the networks. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 429–441, 1999

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 HNO 3 . 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.

Selection of phage display combinatorial library peptides with affinity for a yohimbine imprinted methacrylate polymer

α2-Adrenoreceptor mimics, prepared by molecular imprinting of yohimbine, were used to select ligands from a phage display hexapeptide library. Phages with affinity for the yohimbine imprinted methacrylic acid–ethylene glycol dimethacrylate copolymer were selected. Phage affinities were estimated using an enzyme immunoassay. The selected library showed three-fold higher affinity for the imprinted polymer compared with the primary library. Eighty-two of ninety characterized phage clones from the selected library showed low affinity for the polymer. The hexapeptides on eight of these low binding phage clones consisted of mainly hydrophobic amino acid residues, and four clones were identical. The hexapeptides on five of the eight high affinity phage clones contained positively charged amino acids. Identical hexapeptides were expressed on four of these five clones. The results of this study suggest that the majority of the selected phages form hydrophobic and/or ionic interactions with the polymer framework rather than specific interactions only with the yohimbine imprinted sites. Furthermore, a direct correlation can be seen between hexapeptide sequence affinity and the number of positively charged amino acid residues they contain.

Porous thiiranyl polymers: Newer supports for immobilization of penicillin G acylase

Spherical and macroreticular epithiopropyl methacrylate-ethylene glycol dimethacrylate (thiiranyl) and glycidyl methacrylate-ethylene glycol dimethacrylate (glycidyl) copolymer beads of two differing copolymer compositions were synthesized. Particle size was estimated to be in the range 250–420 μm for both sets of copolymers. The anomalous increase in both surface area and pore volume with crosslinking density reflects a bimodal distribution of the internal porous structure in both these copolymers. These reactive copolymer beads were investigated for the binding and expression of a biocatalyst, penicillin G acylase. The activity of immobilized penicillin G acylase obtained, 191 IU/g, compares well with established industrial immobilized enzymes.

Redox polymerization of acrylamide by polymer supported vanadium (V) ion

Macroreticular glycidyl methacrylate-ethylene glycol dimethacrylate (GMA-EGDM) copolymers of controlled particle size were synthesized by suspension polymerization. The copolymer beads were derivatized to incorporate di- and tetracarboxylic acid functionalities. Vanadium (V) ion was chelated on the modified copolymers. The vanadium chelated copolymers were used in combination with cyclohexanone as redox reagent for the free radical polymerization of acrylamide at 30°C. The molecular weights of the polyacrylamide were significantly higher than that prepared by a soluble vanadium (V) ion — cyclohexanone homogeneous redox initiator pair.

4-Vinylpyridine-Ethylene Glycol Dimethacrylate Copolymers. Formation of Porous Structure by Using Cyclohexanone and Toluene as Diluents in Suspension Polymerization

A series of porous copolymer beads were synthesized by suspension copolymerization of 4-vinylpyridine (4VP) with ethylene glycol dimethacrylate (EGDM) in the presence of diluents, cyclohexanone (CHN), and toluene (TOL). The resulting copolymer beads were characterized for their density, porosity, surface area, mechanical strength, and Cl− ion capacity. It was observed that the apparent density of the copolymer beads decreases with the decrease in CHN of a given mixture of diluents, % cross-linking agent (EGDM) and with the increase in solvent fraction (Fs). It was also observed that the porosity and surface area of the copolymer beads increase with the decrease in CHN of a given mixture of diluents, % cross-linking agent and with the increase in solvent fraction. The mechanical strength of the copolymer beads decreases with the increase in solvent fraction. The Cl− ions capacity of the copolymer beads decreases with the increase in % cross-linking agent whereas it is almost independent of the change of one component of a given mixture of diluents and solvent fraction.

Swellable ethylene glycol dimethacrylate-hydroxyethylmethacrylate copolymer beads

In this study, Swellable poly(EGDMA/HEMA) beads in the size range of 30–170 μm with different size distributions were produced by suspension copolymerization of ethylene glycol dimethacrylate (EGDMA) and hydroxyethylmethacrylate (HEMA) in aqueous media. Poly(vinyl alcohol) and benzoyl peroxide were used as the stabilizer and the initiator. The diluent, i.e. toluene was included in the recipe of the second group of copolymerizations. The beads were characterized by optical microscopy, FTIR and FTIR-DRS. Crosslinked, transparent, nonporous and Swellable (up to a swelling ratio of 31.2%) poly(EGDMA/HEMA) beads were obtained in which there was no toluene in the recipe. While copolymerizations with toluene provided Swellable (up to a swelling ratio of 57.1%), opaque, porous and crosslinked copolymer beads. In the polymerization (without toluene) HEMA is mainly incorporated on the outer layers (near surface) of the beads. In this case, increase in the EGDMA/HEMA ratio resulted larger beads with wider size distributions, and with lower swellabilities. The porosity of the dry copolymer beads were studied with mercury pycnometric method. Incorporation of toluene within the recipe (in the modified polymerization) caused pronounced effects both on bead size and swellability. Larger beads with broader size distributions, with higher swellabilities were obtained when the relative amount of toluene increased.