Modified Suspension Polymerization Research Articles

Modified suspension polymerization of styrene-divinylbenzene for application in size exclusion chromatography

Macromolecular SymposiaVolume 151, Issue 1 p. 399-405 Article Modified suspension polymerization of styrene-divinylbenzene for application in size exclusion chromatography Fernanda M.B. Coutinho, Fernanda M.B. CoutinhoSearch for more papers by this authorGizelda M. Alves, Gizelda M. AlvesSearch for more papers by this authorMárcia A.F.S. Neves, Márcia A.F.S. NevesSearch for more papers by this authorMarcos L. Dias, Marcos L. DiasSearch for more papers by this authorBeatriz S. Chagas, Beatriz S. ChagasSearch for more papers by this author Fernanda M.B. Coutinho, Fernanda M.B. CoutinhoSearch for more papers by this authorGizelda M. Alves, Gizelda M. AlvesSearch for more papers by this authorMárcia A.F.S. Neves, Márcia A.F.S. NevesSearch for more papers by this authorMarcos L. Dias, Marcos L. DiasSearch for more papers by this authorBeatriz S. Chagas, Beatriz S. ChagasSearch for more papers by this author First published: 14 November 2000 https://doi.org/10.1002/1521-3900(200002)151:1<399::AID-MASY399>3.0.CO;2-1Citations: 4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume151, Issue1February 2000Pages 399-405 RelatedInformation

Heparin‐immobilized poly(2‐hydroxyethylmethacrylate)‐based microspheres

Poly(2-hydroxyethylmethacrylate) (PHEMA)-based microspheres (150–200 µm in diameter) were produced by a modified suspension polymerization of different type of comonomers—namely, acrylic acid, dimethylaminoethyl-methacrylate, and methylmethacrylate. These microspheres were activated with cyanogen bromide (CNBr) at pH 11.5, and heparin molecules were then immobilized through covalent bonds. The amount of immobilized heparin was controlled by changing the initial concentration of CNBr and heparin. The increase in the initial concentrations of both CNBr and heparin caused an increase in the amount of heparin immobilized onto microspheres for all polymer surfaces. The maximum heparin immobilization was observed on the PHEMA homopolymer microspheres (180 mg/g). The plain and heparin-immobilized microspheres were contacted with blood in in vitro systems and in ex vivo animal experiments. Loss of the blood cells and clotting times were followed. Anticoagulant effect of the immobilized heparin was clearly observed with blood coagulation experiments. Loss of cells in the blood contacting with heparin-immobilized microspheres was significantly lower than those observed with the plain microspheres. Bovine serum albumin adsorption onto the microspheres containing heparin on their surfaces was also studied. High albumin adsorption values (up to 127 mg/g) were observed in which the heparin-immobilized PHEMA microspheres were used. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 655–662, 1999

Heparin-immobilized poly(2-hydroxyethylmethacrylate)-based microspheres

Poly(2-hydroxyethylmethacrylate) (PHEMA)-based microspheres (150–200 µm in diameter) were produced by a modified suspension polymerization of different type of comonomers—namely, acrylic acid, dimethylaminoethyl-methacrylate, and methylmethacrylate. These microspheres were activated with cyanogen bromide (CNBr) at pH 11.5, and heparin molecules were then immobilized through covalent bonds. The amount of immobilized heparin was controlled by changing the initial concentration of CNBr and heparin. The increase in the initial concentrations of both CNBr and heparin caused an increase in the amount of heparin immobilized onto microspheres for all polymer surfaces. The maximum heparin immobilization was observed on the PHEMA homopolymer microspheres (180 mg/g). The plain and heparin-immobilized microspheres were contacted with blood in in vitro systems and in ex vivo animal experiments. Loss of the blood cells and clotting times were followed. Anticoagulant effect of the immobilized heparin was clearly observed with blood coagulation experiments. Loss of cells in the blood contacting with heparin-immobilized microspheres was significantly lower than those observed with the plain microspheres. Bovine serum albumin adsorption onto the microspheres containing heparin on their surfaces was also studied. High albumin adsorption values (up to 127 mg/g) were observed in which the heparin-immobilized PHEMA microspheres were used. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 655–662, 1999

New chelate-forming polymer microspheres carrying dyes as chelators for iron overload

Dye-incorporated [poly(EGDMA-HEMA)] microspheres were investigated as a new chelate-forming polymer for iron overload. Poly(EGDMA-HEMA) microspheres, in the size range of 150-200 μm, were produced by a modified suspension polymerization of EGDMA and HEMA. The reactive dye-ligands (i.e. Cibacron Blue F3GA, Alkali Blue 6B and Congo Red) were covalently incorporated to the microspheres. The maximum dye incorporations were 16.5 μmol Cibacron Blue F3GA g-1, 23.7 μmol Alkali Blue 6B g-1, and 14.5 μmol Congo Red g-1. The maximum Fe(III) adsorptions on the dye-incorporated microspheres from aqueous solutions containing different amounts of Fe(III) ions were 51.0, 37.3, and 25.1 mg g-1 for the Cibacron Blue F3GA, Alkali Blue 6B, and Congo Red carrying microspheres, respectively. The maximum Fe(III) adsorptions were observed at pH 4.0 in all cases. Fe(III) removal from human plasma was also investigated. The maximum adsorption capacities of Fe(III) ions from human plasma for Cibacron Blue F3GA, Alkali Blue 6B, and Congo Red, were of 12.0, 7.5, and 3.8 mg g-1 polymer, respectively. It was observed that Fe(III) could be repeatedly adsorbed and desorbed without significant loss in adsorption capacity.

Copolímeros de estireno-divinilbenzeno para aplicação em cromatografia de exclusão por tamanho

Copolímeros de estireno-divinilbenzeno para a aplicação em cromatografia de exclusão por tamanho foram sintetizados através de polimerização em suspensão aquosa modificada pela presença de diluentes. Na síntese dos copolímeros foram variados os seguintes parâmetros reacionais: tipo de diluente, grau de diluição e teor de divinilbenzeno. Os copolímeros obtidos como partículas esféricas com tamanho médio em torno de 10 µm foram caracterizados quanto à porosidade no estado seco e às propriedades de inchamento. Os copolímeros foram utilizados como material de empacotamento de colunas para cromatografia de exclusão por tamanho (SEC). O aumento do grau de diluição na síntese do copolímero aumentou o limite de exclusão da cromatografia, porém a redução do poder solvatante do diluente teve um efeito mais pronunciado sobre esse parâmetro.

Dye-incorporated poly(EGDMA-HEMA) microspheres as specific sorbents for aluminum removal

Aluminum [Al(III)] adsorption onto dye-incorporated poly(ethylene glycol dimethacrylate-hydroxyethyl methacrylate) [poly(EGDMA-HEMA)] microspheres was investigated. Poly(EGDMA-HEMA) microspheres, in the size range of 150–200 μm, were produced by a modified suspension polymerization of EGDMA and HEMA. The reactive dyes (i.e., Congo Red, Cibacron Blue F3GA and Alkali Blue 6B) were covalently incorporated to the microspheres. The maximum dye load was 14.5 μmol Congo Red/g, 16.5 μmol Cibacron Blue F3GA/g and 23.7 μmol Alkali Blue 6B/g polymer. The maximum Al(III) adsorption on the dye microspheres from aqueous solutions containing different amounts of Al(III) ions were 27.9 mg/g, 17.3 mg/g and 12.2 mg/g polymer for the Congo Red, Cibacron Blue F3GA and Alkali Blue 6B, respectively. The maximum Al(III) adsorption was observed at pH 7.0 in all cases. Non-specific Al(III) adsorption was about 0.84 mg/g polymer under the same conditions. High desorption ratios (95%) were achieved in all cases by using 0.1 M HNO 3. It was possible to reuse these dye-incorporated poly(EGDMA-HEMA) microspheres without significant losses in the Al(III) adsorption capacities.

Porous structure and swelling properties of styrene-divinylbenzene copolymers for size exclusion chromatography

Small spherical particles of styrene–divinylbenzene copolymers have been synthesized by modified suspension polymerization. The effects of divinylbenzene (DVB) contents, dilution degree of the monomers and diluent composition on the porous structure and swelling properties of the copolymers were investigated. Toluene uptakes of macroporous copolymers were considered as a result of three contributions: filling of the fixed pores, expansion of the fixed or collapsed pores, and nuclei swelling and heptane uptakes as a result of the two first contributions. The increase of DVB content in the copolymers synthesized in presence of a solvating diluent (toluene) provoked a decrease on the nuclei swelling. The increase of dilution degree with solvating diluents changed the toluene and heptane uptakes, and when the diluent–copolymer affinity was reduced, the fixed pore volume increased. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1257–1262, 1997

Nonswellable and swellable poly(EGDMA) microspheres

In this study, nonswellable and swellable poly(ethylene glycol-dimethacrylate) microspheres, in the size range of 20–177 μm, were produced by conventional and modified suspension polymerizations of ethylene glycol-dimethacrylate (EGDMA) in an aqueous medium. Poly(vinyl alcohol) and benzoyl peroxide were used as the stabilizer and the initiator. A diluent, i.e., toluene, was included in the polymerization recipe of the modified suspension polymerization. The microspheres were characterized by optical microscopy, FTIR, and FTIR-DRS. Highly crosslinked, transparent, and nonswellable poly(EGDMA) microspheres were obtained with the conventional suspension polymerization procedure. While the modified suspension polymerization provided swellable, opaque, and crosslinked copolymer microspheres. © 1996 John Wiley & Sons, Inc.

Nonswellable and swellable ethylene glycol dimethacrylate-acrylic acid copolymer microspheres

In this study, nonswellable and swellable poly(ethylene glycol dimethacrylate/acrylic acid) copolymer microspheres, in the size range of 50–150 μm, were produced by conventional and modified suspension copolymerizations of the respective monomers, i.e., ethyleneglycol dimethacrylate (EGDMA) and acrylic acid (AA) 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 polymerization recipe of the modified suspension polymerization. The microspheres were characterized by optical microscopy, FTIR, and FTIR-DRS, and potentiometric titrations. Highly crosslinked, transparent, and nonswellable poly(EGDMA/AA) microspheres were obtained with the conventional suspension polymerization procedure. The modified suspension polymerization provided swellable, opaque, and crosslinked copolymer microspheres. Acrylic acid incorporation into the copolymeric microspheres were significantly higher in the modified procedure, relative to the conventional procedure. © 1996 John Wiley & Sons, Inc.

Spherical gradient-index polymer lens with low spherical aberration

A sphere lens with a spherical gradient index (GRIN) was prepared by the modified suspension polymerization technique. GRIN spheres with quadratic- and linear-index distributions were obtained by two different methods to confirm the effect of the GRIN profile on the focusing property of the sphere lens. It was confirmed in both theory and experiment that the spherical aberration of such GRIN spheres was remarkably decreased compared with that of a homogeneous sphere.

Preparation of photooxidized magnetic polystyrene beads for enzyme immobilization

Magnetic polystyrene beads were synthesized by a modified suspension polymerization technique. The beads consisted of iron powder entrapped in the polymer backbone. The photooxidation of the magnetic polystyrene beads was achieved under UV irradiation in order to obtain functionalized solid support matrices to be used for the immobilization of urease (EC 3.5.1.5). Enzyme immobilization experiments revealed that unirradiated beads were not suitable for direct coupling reactions. Under similar immobilization conditions, direct covalent linkage of enzyme occurred on photooxidized magnetic polystyrene beads. It is found that this immobilized enzyme is efficient in catalyzing decomposition of urea and the photooxidized magnetic polystyrene beads might bring several interesting applications to downstream separations processes.

Gradient‐Index polymer materials and their optical devices

AbstractA gradient‐index (GRIN) plastic optical fiber was prepared by a heat‐drawing process of the GRIN preform rod obtained by a new interfacial‐gel copolymerization technique. The attenuation loss of the GRIN fiber was 179 kB/km at 650‐nm wave‐length and its numerical aperture was 0.20‐0.25. To attain low loss and highly dense integrated circuits, steric radial‐GRIN optical waveguide components such as GRIN branching, star coupler, multi‐coupler, and a 2‐D GRIN lens array, were monolithically fabricated by this technique. A novel spherical GRIN sphere lens, whose index function is symmetrical about the center of the sphere, with a low spherical aberration, was prepared by a modified suspension polymerization technique. A W‐shaped GRIN sphere has been newly proposed to further reduce the spherical aberration, compared with the parabolic GRIN sphere previously proposed.

Spherical gradient-index sphere lens

The sphere lens with a spherical gradient-index (GRIN) was prepared for the first time by two modified suspension polymerization techniques. The index change of the 0.05–3.0-mm diam GRIN sphere was 0.02–0.04, and the index profile was almost quadratic. The optimum condition minimizing the spherical aberration of the GRIN sphere embedded in a certain substrate was confirmed. Furthermore, 1-D and 2-D GRIN sphere lens arrays were fabricated.

Structural heterogeneities of suspension poly(vinyl chloride). I. Compact glassy particles

AbstractBy using the modified suspension polymerization of vinyl chloride, samples of poly(vinyl chloride) (PVC) were prepared with a high content of unprocessible particles which were isolated and subjected to a morphological investigation. Their structure was examined viscometrically, by the light‐scattering method, GPC, IR spectroscopy, and X‐ray analysis; the specific surface area of the particles was measured, and their heat stability was determined. The results lead to a conclusion that the unprocessibility of the particles compared with the usual particles of suspension PVC is not caused by differences on the level of molecular structure, but ensues from the difference in their morphology.