Biporous polymeric beads fabricated by double emulsification for high-speed protein chromatography

Novel biporous polymeric stationary phase for high-speed protein chromatography

The free radical copolymerization of glycidyl methacrylate (GMA) and octadecyl acrylate (ODA) was carried out at 70 °C in solution using toluene as solvent and 2,2′-azobisisobutyronitrile (AIBN) as initiator. The copolymer compositions were determined using 1H NMR spectroscopy. The monomer reactivity ratios were computed using five linear methods at low conversions, i.e. Mayo–Lewis (ML), Fineman–Ross (FR), inverted Fineman-Ross (IFR), Ezrielev–Brokhina– Roskin (EBR) and Kelen–Tudos (KT). The reactivity ratios resulted from different methods are in agreement with each other and showed higher reactivity for GMA monomer in comparison with ODA monomer (FR: r G = 1.29 and r O = 0.68). Crosslinked GMA–ODA copolymers were also prepared using ethylene glycol dimethacrylate as a crosslinker. Thermal properties and swelling behaviors of crosslinked copolymers in different polar and nonpolar solvents were evaluated. GMA incorporation in the crosslinked copolymers improved T g values, while decreased T m quantities and swelling in nonpolar solvents. The swelling values are in the acceptable range and the prepared functional crosslinked copolymers can be used for nonpolar solvents absorbency applications.

Summary: Inverse gas chromatography under finite surface coverage conditions (IGC‐FC) was used for the investigation of sorption of hexane, benzene, chloroform and tetrahydrofuran on macroporous crosslinked poly[(glycidyl methacrylate)‐co‐(ethylene glycol dimethacrylate)], poly(GMA‐co‐EGDMA), and copolymer modified with ethylene diamine, EDA, poly(GMA‐co‐EGDMA)‐en, in the temperature range 333–363 K. Two poly(GMA‐co‐EGDMA) samples with different porosity parameters were synthesized by suspension copolymerization and modified using a ring‐opening reaction of the pendant epoxy groups with EDA. The specific surface areas of the initial and modified copolymer samples were determined by the BET method from low temperature nitrogen adsorption isotherms (77 K). The adsorption isotherms determined from chromatographic peaks of adsorbates were analyzed using the BET theoretical model and used for estimation of the surface area, isosteric heat of adsorption and the adsorption energy distribution on the surface of the initial and modified copolymer samples. It was observed that the adsorbate nature and the properties of the solid surface of the initial and modified copolymer governed the uptake of adsorbate by the copolymer. The deviations observed for the Sa values obtained by the BET method from the low temperature nitrogen adsorption isotherms and hexane was attributed not only to the difference in molecule size, but also to the specific polymer‐adsorbate interactions. The isosteric heat of adsorption approached a constant value with increasing adsorbate loading. A large variation in the shapes of the qst‐α curves resulted from strong acid‐base interactions, as well as dissolution phenomena. Of the four studied adsorbates, chloroform was shown to have the greatest affinity towards the surface of the investigated polymer samples.Adsorption isotherms of hexane on sample 1 and 1a.magnified imageAdsorption isotherms of hexane on sample 1 and 1a.

This work reports results on phenol adsorption from aqueous solution by porous copolymers based on glycidyl methacrylate: two samples of macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), were synthetized by suspension copolymerisation with ethylene glycol dimethacrylate. In addition, the two copolymer samples were functionalized with ethylene diamine. The amounts of adsorbed phenol were presented in the form of adsorptions isotherms, which were interpreted using Langmuir, Freundlich and Sips' equations. The first was found to express high level of agreement with experimental data. Phenol adsorption indicate the homogeneous distribution of active sites present on the investigated polymers. It was found that adsorption of phenol on copolymers is fast and depends on the presence of amino groups and on the pore size. From the obtained results, it was possible to distinguish macroporous polymer as a material which possesses the capacity for adsorption of phenol comparable to that of activated carbon.

The aim of this work was the preparation of molecularly imprinted membranes by surface modification of microfiltration polyvinylidene fluoride membranes with a thin layer of molecular imprinted polymer by UV irradiation. The flavonoid naringin (4,5,7-trihydroxyflavanone-7-rhamnoglucoside) was used as template molecule. The compound 4-vinylpyridine was used as functional monomer. Benzoin ethyl ether and ethylene glycol dimethacrylate were used as photo-initiator and cross-linker, respectively. Membranes were also modified in the absence of naringin and used as reference (blank). Imprinted membranes prepared in this work could be applied as new separation devices in affinity filtrations aimed to reduce the naringin content in grapefruit and improve its benefit properties. The method used to prepare them offers the advantage of combining the mechanical integrity of the membrane support with the selective recognition properties of the imprinted polymer layer. The recognition properties of all prepared membranes were evaluated by their capability to retain naringin in aqueous solution during filtration tests. Results showed that imprinted membranes exhibited specific binding properties for template molecules. Blank membranes only showed non-specific binding. The selectivity of the naringin-imprinted membranes was tested evaluating their bound property toward the rutin, a structural analogue of naringin.

Crosslinking reaction of polymer by ultraviolet (UV) irradiation has been important in industries. In this work, photocrosslinking of styrene–isoprene–styrene (SIS) triblock copolymer in the presence of benzoin photoinitiator and a dimethacrylate monomer as crosslinking agent was investigated. Curing of samples was initiated under UV irradiation. Benzoin was used as photoinitiator because it contains chromophore group that could absorb UV irradiation. Ethylene glycol dimethacrylate (EGDMA) was used as crosslinking agent, since it has alkene functional groups that could react with the alkene group of SIS. ATR-FTIR spectra of samples show that absorption band of double bond at 1500–1600 cm−1 decreases after UV exposure. Increasing the concentration of benzoin (0.1–1 phr) and EGDMA (1–10 phr) leads to an increase in gel content and hardness, while swelling ratio decreases. After 5 min heating at 150 °C, about 20%wt of the unirradiated compound became insoluble, because heating of compound at 150 °C causes crosslinking reaction without any irradiation.

A polyHIPE is a cross-linked, highly porous polymer from the polymerization of monomers and cross-linking comonomers in the external phase of a high internal phase emulsion (HIPE). Crystallizable polyHIPE were synthesized through the copolymerization of stearyl acrylate (A18) with ethylene glycol dimethacrylate (EGDMA). PolyHIPE synthesized with the more flexible EGDMA were compared to those synthesized with the more rigid divinylbenzene. The polyHIPE densities were around 0.11 g cm-3. EGDMA destabilized the HIPE yielding relatively large voids and a structure whose partial closed-cell nature increased with increasing EGDMA content. The EGDMA cross-linked polyHIPE exhibited higher melting peak temperatures and higher crystallinities than the divinylbenzene cross-linked polyHIPE. Organic phase initiation of the EGDMA cross-linked polyHIPE yielded lower melting temperatures, lower crystallinities, and a highly interconnected porous structure that resulted in a lower modulus.

In order to improve Cu(II) adsorption ability of chelating resins based on a macrocyclic ligand 1,4,8,11-tetraazacyclotetradecane-5,7-dione (L) bound to crosslinked copolymers, the resins were prepared by reaction of L with poly(glycidyl methacrylate)s crosslinked with ethylene glycol dimethacrylate (1G), tetraethylene glycol dimethacrylate (4G) or nonaethylene glycol dimethacrylate (9G). By systematically changing the amounts of each crosslinker (degree of crosslinking) and of isobutyl acetate (IBA) as diluent in the suspension polymerization of the monomers, precursory copolymers with various degrees of crosslinking as well as with different specific surface areas (SSAs) were prepared, and then L was introduced into them. Ligand contents, SSAs, and Cu(II) adsorption abilities of the resulting resins were evaluated, and it was clarified that resins derived from precursors (prepared by using 4G or 9G in the presence of 120–160 vol % of IBA) exhibit high capacities for Cu(II), whereas the capacities of resins crosslinked with 1G are not so high. Further detailed study on the uptake of metal ions using the resins RG4D(10)-140 and RG9D(10)-140 (derived from the precursors prepared by using 10 mol % of the respective crosslinkers 4G and 9G in the presence of 140 vol % of IBA) showed that RG9D(10)-140 is much superior to RG4D(10)-140 in the column-mode adsorption of Cu(II). These results indicate that not only the selection of the suitable crosslinker but also the use of a pertinent amount of the diluent are very important in improving the complexing abilities of the polymer-bound L. © 1996 John Wiley & Sons, Inc.

Functional polymer nanograss and nanotubes with active epoxy groups were synthesized by a surface-initiated photopolymerization pattern transfer method in cylindrical alumina nanopores. The nanograss structures were obtained when the neat glycidyl methacrylate (GMA) monomer or the mixture of GMA monomer and ethylene glycol dimethacrylate (EGDMA) crosslinker solution was injected into the photoinitiator-immobilized template. In contrast, uniform polymer nanotubes that completely follow the contour of the template were generated with the mixture of GMA monomer, EGDMA crosslinker and pre-synthesized poly(glycidyl methacrylate) (PGMA) polymer as the precursor material. The mechanism of the formation of polymer nanograss and nanotubes was discussed in terms of mechanical strength of polymer and polymerization shrinkage. The incorporation of the pre-synthesized polymer into the monomer solution as the precursor material allows for precompensation of the structure shrinkage induced by photopolymerization reactions. Effects of the pre-synthesized PGMA polymer percentage and the amount of the EGDMA crosslinker on the morphology of the formed polymer nanostructures were investigated respectively. FT-IR spectra confirmed the chemically immobilized photoinitiators, and chemical component, poly(GMA-co-EGDMA), of the polymer nanotubes inside the cylindrical alumina nanopores respectively. Finally, an intriguing dendritic-shaped fractal pattern was formed from concentrated crosslinked polymer nanoneedles by self-assembly and droplet evaporation.

Preparation of hydrogels via ultrasonic polymerization

Modification of argon plasma‐pretreated Si(100) surfaces via plasma polymerization of glycidyl methacrylate(GMA), followed by reactive coupling of the epoxide groups of the plasma deposited GMA chains with aniline, and finally by oxidative graft polymerization of aniline was carried out. An alternative approach involved the modification of the argon plasma‐pretreated Si(100) surfaces via plasma polymerization of glycidyl methacrylate(GMA), followed by direct oxidative graft polymerization of aniline and thermal curing. The compositions and chemical states of the modified Si surfaces were characterized by X‐ray photoelectron spectroscopy (XPS). The two methods of surface modification of the Si(100) surfaces produced similar results. The protonation‐deprotonation behavior, the interconvertible intrinsic redox states, and the metal reduction behavior (the electroless plating of Pd from the Pd(II) ion solution) of the grafted polyaniline (PANI) chains on the Si(100) surface were grossly similar to those of the PANI homopolymer. The coupling of PANI to the covalently tethered GMA chains on the Si(100) surface was suggested by the cohesive failure inside the epoxy adhesive that was applied to the modified Si surface in an attempt to peel off the PANI layer from the GMA plasma‐polymerized Si (GMA‐pp‐Si) substrate.

To explore suitable synthesis parameters of efficient graft copolymerization on wool, the disulfide bonds in wool chains were reduced to sulfhydryl groups by the treatment of thioglycolic acid to wool, and then wool-g-poly(glycidyl methacrylate) was prepared by graft copolymerization of wool with glycidyl methacrylate by building a redox system between sulfhydryl groups and ammonium persulfate. The wool-g-poly(glycidyl methacrylate) was characterized by the analyses of Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric and x-ray diffraction. Influences of molar concentrations of monomer and initiator as well as reaction temperature on grafting ratios were investigated. The experimental results showed that the sulfhydryl groups/ammonium persulfate redox system built could effectively initiate graft polymerization of lipophilic glycidyl methacrylate on the wool surface in an aqueous medium. The suitable process parameters of graft copolymerization were: 0.6 mmol/L molar concentration of glycidyl methacrylate, 3.0 mmol/L molar concentration of ammonium persulfate, and reaction temperature of 50 ℃. At the suitable parameters, the grafting ratio of wool-g-poly(glycidyl methacrylate) showed a maximum value of 195.8 %, indicating an efficient graft copolymerization was achieved. The copolymerization could reduce the degree of crystallinity of wool. The wool-g-poly(glycidyl methacrylate) had higher thermal stability than raw wool at a temperature of below 406 ℃ by performing the thermogravimetric analysis. Based on the results, we successfully built new sulfhydryl groups on the wool/ammonium persulfate redox system, prepared the wool-g-poly(glycidyl methacrylate), and this work will lay an important foundation for the application of wool-g-poly(glycidyl methacrylate) in the textile field.

ABSTRACTA beaded polymer with a poly (glycidyl methacrylate) surface shell was prepared in two steps, starting from (3-chloro-2-hydroxypropyl methacrylate-methyl methacrylate (MMA)-ethylene glycole dimethacrylate (EGDMA)) terpolymer beads by using suspension polymerization method and grafting using a concentrated aqueous glycidyl methacrylate solution with a CuBr–Bipyridine complex (1:3). The resulting polymer resin with 300 wt% grafted (glycidyl methacrylate) was reacted with excess of diallylamine, yielding corresponding polymers with diallylamino functions. Cis-dihydroxylation of the allyl groups was performed. The resulting polymeric sorbent has been demonstrated to be an efficient boron-specific sorbent, able to remove boron from solutions at ppm levels.

Comparison of decay resistance of wood and wood-polymer composite prepared by in-situ polymerization of monomers

Amidoxime-based adsorbents are widely investigated as the main adsorbent in the recovery of uranium from seawater. However, the adsorption rate and loading capacity of such adsorbents should be further improved due to the economic viability consideration. In this paper, the adsorption properties of amidoxime-based adsorbent were enhanced through the cografting of amino groups. The acrylonitrile (AN) and glycidyl methacrylate (GMA) were firstly cografted onto polypropylene fibers by preirradiation grafting technique. Then the cografted fibers were treated with ethylenediamine to convert GMA to amino group, following treated with hydroxylamine to convert AN groups to amidoxime (AO) group. Fourier transform infrared spectroscopy, scanning electron microscopy and contact angle measurement were used to characterize the structure of the adsorbent. The results showed that the amidoxime and amino groups had been successfully grafted onto the polypropylene fibers. For AO fiber, high adsorption rate was observed within the first 30 min and the plateau value of 42.3% uranium loading (0.0904mg/g) was reached at around 30 min. The AO/amine fibers exhibited a higher adsorption rate. The adsorption equilibrium for AO/amine fiber was attained within 20 min, resulting in the adsorption of 93.3% uranium loading (0.191mg/g). Additionally, AO/amine fibers can avoid pH reducing for better adsorption efficiency.