Macroporous Polymer Beads Research Articles

An approach for the scalable production of macroporous polymer beads

A tubular co-flow reactor to produce macroporous polymer beads by polymerization of medium and high internal phase emulsion (M/HIPE) templates was developed. This reactor allows for improved production rates compared to tubing based microfluidic devices. Water-in-oil (W/O) M/HIPEs, containing methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) monomers in the continuous phase, were injected into a re-circulating carrier phase. The continuous phase of the emulsion droplets was UV polymerized in situ, resulting in polyM/HIPE beads. The emulsion composition was adjusted to produce poly(MMA-co-EGDMA) porous polymer beads with a protective crust and an interconnected internal pore structure. HCl loaded beads were produced by adding the active ingredient into the dispersed emulsion phase, leading to HCl encapsulation in the porous structure of the beads after polymerization. Even after exposure to ambient conditions for 24 h, 60% of the HCl remained in the beads, indicating good encapsulation efficiencies. Thus, it is possible to use such macroporous beads as delivery vehicles.

Chelating Polymers for Hereditary Hemochromatosis Treatment

Hemochromatosis (iron overload) encompasses a group of diseases that are characterized by a toxic hyperaccumulation of iron in parenchymal organs. Currently, only few treatments for this disease have been approved; however, all these treatments possess severe side effects. In this study, a paradigm for hemochromatosis maintenance/preventive therapy is investigated: polymers with negligible systemic biological availability form stable complexes with iron ions in the gastrointestinal tract, which reduces the biological availability of iron. Macroporous polymer beads are synthesized with three different iron-chelating moieties (benzene-1,2-diol, benzene-1,2,3-triol, and 1,10-phenanthroline). The polymers rapidly chelate iron ions from aqueous solutions in vitro in the course of minutes, and are noncytotoxic and nonprooxidant. Moreover, the in vivo biodistribution and pharmacokinetics show a negligible uptake from the gastrointestinal tract (using 125 I-labeled polymer and single photon emission computed tomography/computed tomography), which generally prevents them from having systemic side effects. The therapeutic efficacy of the prepared polymers is successfully tested in vivo, and exhibits a significant inhibition of iron uptake from the gastrointestinal tract without any noticeable signs of toxicity. Furthermore, an in silico method is developed for the prediction of chelator selectivity. Therefore, this paradigm can be applied to the next-generation maintenance/preventive treatment for hemochromatosis and/or other diseases of similar pathophysiology.

Magnetic Hierarchically Macroporous Emulsion-Templated Poly(acrylic acid)-Iron Oxide Nanocomposite Beads for Water Remediation.

Tainting of waterbodies with noxious industrial waste is the gravest environmental concern of the day that continues to wreak inevitable havoc on human health. To cleanup these hard-to-remove life-threatening water contaminants, we have prepared hierarchically porous poly(acrylic acid) beads by emulsion templating. These emulsion-templated macroporous polymer beads not only mediate the synthesis of Fe3O4 nanoparticles inside their porous network using a coprecipitation approach but, in turn, create diverse anchoring sites to immobilize an additional poly(acrylic acid) active layer onto the nanocomposite beads. These post-synthetically modified nanocomposite beads with macropores and abundant acrylic acid moieties offer the ready mass transfer and fair advantage of relatively higher overall negative charge to efficiently adsorb lead [Pb(II)] and crystal violet with impressive performance-even superior to many of the materials explored in this regard so far. Furthermore, the strong entanglement of nanoparticles in the porous polymeric scaffolds tackles the curb of trade-off between all-round effective remediation and secondary pollution and the millimeter size eases their processing and recovery during the adsorption tests, thereby making these materials practically worthwhile.

Preparation of magnetic macroporous polymer sphere for biofilm immobilization and biodesulfurization

Immobilized sulfate reducing bacteria have been widely investigated in the field of bioremediation of sulfate containing wastewater. To enhance the biofilm loading and shorten the start-up stage, a series of magnetic macroporous polymer beads were prepared in this work by using a novel co-stabilized Pickering high internal phase emulsions (HIPEs) template method. The effect of the addition of magnetic particles on both the morphology of the polymer support and the performance of the biofilm at the start-up stage were investigated. The results showed that the addition of magnetic particles could restrain the enrichment phenomenon of silicone and, hence, increase the loading amount of the biofilm. At the start-up stage under 3000 mg SO42−·L−1 concentration, the sulfate reducing efficiencies on the magnetic support reached a maximum of 39.90%, which was higher than that of other systems that exhibit efficiencies of approximately 30%. For the long-term stage, due to the decomposition of the ferriferous oxide, the sulfate reducing efficiencies of the biofilm on the magnetic poly(St-MTQ)HIPE (MPSMH) and poly(St-MTQ)HIPE (PSMH) supports did not show a significant difference.

Green synthesis and in situ immobilization of gold nanoparticles and their application for the reduction of p-nitrophenol in continuous-flow mode.

A green and facile method has been developed for the preparation of in situ immobilized gold nanoparticles (AuNPs) using agarose as a reducing and stabilizing agent. The size of the synthesized AuNPs ranges between 10 and 100 nm, and their average size can be controlled by the concentrations of the agarose and gold salt. The agarose matrix as a mild and green reaction medium can provide a good dispersion environment for forming AuNPs, and the hydrogel can be well homogenized with polyacrylic macroporous microbeads as well, which can adsorb and stabilize the particles leading to the simultaneous synthesis and immobilization of AuNPs avoiding harmful inorganic compounds or organic solvents. The supported gold nanocatalyst was successfully applied as a catalyst in packed bed reactors for efficient NaBH4-mediated reduction of p-nitrophenol in continuous-flow mode.

Macroporous polymer beads derived from a novel coporogen of polyethylene/dichlorobenzene

AbstractMacroporous poly(divinylbenzene) (PDVB) beads were prepared by traditional suspension polymerization in the presence of dichlorobenzene (DCB) and polyethylene (PE) as coporogen. Two types of PE with different molecular weights were used as polymer porogen, and the weight percent of PE in DCB varied from 0 to 8.0 wt%. Effects of PE concentration and PE molecular weight on the pore structure of PDVB beads were investigated. As expected, the highest surface area was achieved by the beads prepared with DCB as the sole porogen. Applying coporogen with PE with low molecular weight (LPE) content, the surface area of PDVB beads declined because of early phase separation induced by the cooperation of LPE and DCB. However, the value increased abruptly when 5 wt% LPE in DCB was used as coporogen. Subsequently, the values again decreased when LPE amount further increased. Overall, the molecular weight of PE and the concentration of PE in coporogen had a significant effect on the pore structure and surface morphology of PDVB beads.

Double emulsion droplets as microreactors for synthesis of magnetic macroporous polymer beads

An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads (MMPBs). Waterin- oil high internal phase emulsion (HIPE) is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers. The HIPE is introduced into a simple microfluidic device to fabricate monodisperse (water-in-oil)-in-water double emulsion droplets. The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs. The prepared MMPBs display uniform size, interconnected porous structure, superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix. The MMPBs are characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM). We believe that this method is a universal technique in preparing macroporous nanocomposite beads.

Evaporation Kinetics in Swollen Porous Polymeric Networks

NMR is a fast, nondestructive, and noninvasive technique that can provide information about the pore structure of macroporous polymer beads and the dynamics of liquids confined in them. In this work, we describe the study of the pore structure of the macroporous polymer of ethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate [poly(EGDMA-co-HEMA)] in the dry but also in the swollen state by measuring relaxation times of liquids contained in the polymer network. The results show that the pore architecture differs from the dry to the soaked state. The behavior of polar liquids during evaporation and deswelling dynamics is monitored and described. An internal migration of water from the swollen polymer mesh into expanding pores takes place. With this procedure it is possible to obtain information about the microscopic morphology behavior of the matrix during evaporation and deswelling. This information is of great interest with the aspect of possible and future applications for these types of materials.

Immobilization of steapsin lipase on macroporous immobead-350 for biodiesel production in solvent free system

Commercially available steapsin lipase was immobilized on macroporous polymer beads (IB-350) and further investigated for biodiesel production under solvent free conditions. The fatty acid methyl ester (biodiesel) synthesis was carried out by the methanolysis of fresh and used cooking sunflower oil. The enzymatic reaction for biodiesel synthesis was optimized with various reaction parameters and the obtained reaction conditions were 1: 6 molar ratio (oil: methanol), 50 mg biocatalyst and 20% water content at 45°C for 48 h under solvent free conditions. It was observed that 94% of biodiesel was produced under the optimized reaction conditions. The four step addition of methanol at the interval of 12 h was found to be more effective. Moreover the biocatalyst was effectively reused for four consecutive recycles and was appreciably stable for 90 days. The results obtained highlight potential of immobilized steapsin lipase for biodiesel production.

Macroporous Polymer Beads and Monoliths From Pickering Simple, Double, and Triple Emulsions

AbstractVarious polymeric materials based on simple, double, and triple emulsions stabilized solely by dichlorodimethylsilane (DCDMS)‐modified amorphous silica nanoparticles of well‐controlled surface hydrophobicities or organo‐modified Laponite clay nanoparticles are described. Magnetic and fluorescent polymer beads having different morphologies are fabricated from double‐emulsion templates. Polymer foams based on Pickering emulsions are fabricated and functionalized using different materials such as sporopollenin and zinc metal particles. Suspension polymerization of both oil phases of a novel Pickering triple emulsion results in the formation of new porous hierarchical structures. Polymer foams and beads based on novel nonaqueous Pickering simple and double emulsions are fabricated.

Lutetium-177 and iodine-131 loaded chelating polymer microparticles intended for radioembolization of liver malignancies

We describe the synthesis, characterization and radiochemical studies on macroporous chelating polymer beads as carriers of beta-emitters lutetium-177 and iodine-131 intended for radioembolization of liver tumors. The starting poly(glycidyl methacrylate- co-ethylene dimethacrylate) (bead size 20–40 μ) was reacted with ammonia or methylamine to introduce primary and secondary amino groups, respectively. The primary amino groups containing polymer was used for the attachment of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) moieties, while quinoline-8-ol or 8-hydroxyquinoline-5-sulfonic acid moieties, respectively, were introduced onto the secondary amino groups containing polymer. All the polymers were labeled quantitatively by lutetium-177 in ammonium acetate buffer, DOTA containing beads however required heating to 80 °C while the quinoline-8-ol or 8-hydroxyquinoline-5-sulfonic acid moieties containing polymers were quantitatively radiolabeled within 1 h at room temperature. The quinoline-8-ol groups containing polymer was radioiodinated in 95% yield by a chloramine method. Both lutetium-177 and iodine-131 radiolabels were stable in an in vitro study in rat blood plasma. Quinoline-8-ol or 8-hydroxyquinoline-5-sulfonic acid moieties are thus more suitable for the radiolabeling of macroporous beads with lutetium-177 for radioembolization purposes than well-established DOTA moieties and in addition, quinoline-8-ol also allows radiolabeling with iodine-131.

Preparation of pore size controllable macroporous polymer beads

Macroporous polymer beads have been used in various fields, for example as solid supports in solid-phase organic synthesis and heterogeneous catalysts and as adsorbents in column chromatography. Their broad applications have stimulated many researchers to develop various kinds of macroporous polymer beads. However, despite all the efforts, it is still hard to control the porosity and pore size distributions within the polymer beads. In this study, we prepared pore size controllable macroporous poly(methyl methacrylate-co-methyl methacrylic acid) (PMMA-co-PMAA) beads. First, we prepared silica submicron particles embedded PMMA beads by the polymerization of methyl methacrylate monomer with mono-dispersed silica particles. Then, the silica NP embedded PMMA beads were hydrolyzed with sodium hydroxide to obtain a macroporous structure by removing the embedded silica particles. At the same time, part of the methyl methacrylate turned into methacrylic acid, which caused the PMMA beads to become PMAA-co-PMMA beads. Through this method, two types of beads having different pore sizes were prepared as a model study. The pore size of the beads could be easily controlled by adjusting the size of the silica particles.

The influence of crosslinking density on the pore morphology of copolymer beads prepared with a novel pore-forming agent

Macroporous styrene–divinylbenzene (St–DVB) copolymer beads are prepared with a novel pore-forming agent, 1-chlorodecane. Copolymer beads with high specific surface area are obtained although 1-chlorodecane is a typical incompatible solvent of polystyrene. The unexpected behavior of 1-chlorodecane during preparation of copolymer beads is discussed. It is found that the excellent compatibility between the chloro substituents in 1-chlorodecane and phenyl rings in copolymer could be responsible for the unexpected behavior. In addition, the effect of crosslinking density on the pore morphology of the copolymer beads is systematically investigated. The results indicate that the specific surface area, the total pore volume and the average pore diameter of the copolymer beads strongly depend on the crosslinking agent concentration. Overall, the present study provides a novel route to prepare macroporous polymer beads with controllable pore morphology.

Synthesis of Hydroxylated Macroporous Polymer Beads for Microwave-Assisted Desorption of Nonpolar Volatile Organic Compounds

Opperman and Brown reported a microwave-assisted volatile organic compounds (VOCs) recovery system with polymer bead adsorbents, with emphasis on significant advantages over the conventional granulated activated carbon-based systems in terms of cost and energy efficiency, but details on their experimental results were not included.

Preparation of macroporous monoliths based on epoxy-bearing hydrophilic terpolymers and applied for affinity separations

This work reports the synthesis and characterization of poly( N-acryloyl-tris(hydroxymethyl)aminomethane-co-glycidyl methacrylate-co- N, N′-methylenebisacrylamide) [poly(NAT-GMA-BIS)] discs using different porogenic solvents. The macroporous polymer obtained with PEG 6000 as co-porogen showed the best porous properties of the series. End-point immobilization of heparin (Hep, as ligand) was then carried out on the products through reductive amination. Thus, the products were reacted with ethylenediamine (EDA) and hexamethylenediamine (HMDA) in order to introduce amine groups and to analyze the length of the spacer on the immobilization of heparin. Then, the highest value of amine groups [1.280 and 0.919 mmol amine/g dry support for poly(NAT-GMA-BIS)-EDA and poly(NAT-GMA-BIS)-HMDA, respectively] was obtained at 40 °C after 48 h of reaction. Finally, the amount of ligand coupled to discs was not influenced by the two length spacers assayed. The amount of Hep coupled on discs [591.50 and 489.90 μg Hep/g dry polymer for poly(NAT-GMA-BIS)-EDA-Hep and poly(NAT-GMA-BIS)-HMDA-Hep, respectively] was similar to that obtained using macroporous polymer beads reported by other authors. The supports yielded were used to assay the retention of antithrombin III (AT-III). The retention was greater for the EDA-containing product with a larger amount of heparin. These novel heparin-containing macroporous poly(NAT-GMA-BIS) discs could be used as potential affinity chromatography supports.

Thiol-ene and thiol-yne chemistry in microfluidics: a straightforward method towards macroporous and nonporous functional polymer beads

Thiol-ene and thiol-yne reactions are explored as efficient pathways towards rapid production of diverse monodisperse macroporous and nonporous functional beads. In a straightforward method, polymer beads containing amine, hydroxyl and carboxyl groups have been prepared by reacting a tetrafunctional thiol with a range of mono and/or multifunctional -enes/-ynes containing the desired functional groups. The thiol-ene and thiol-yne reactions have been performed in a simple home-made microfluidic device utilizing thiol and ene/yne monomers at a 1 : 1 ratio of thiol to π-bond. The porous functional beads were prepared making use of a porogen in combination with a photoinitiator. The optical and scanning electron microscopy images demonstrated monodispersity of the beads with a spherical shape ranging in size from 210 to 600 μm. The beads were characterized in terms of glass transition temperature, surface area measurement and composition. The accessible amine and hydroxyl loading in the beads ranges from 0.23 to 0.69 mmol g−1 and 0.24 to 0.64 mmol g−1 respectively, as determined by the Fmoc method. This work demonstrates the applicability of thiol-ene and thiol-yne reactions in microfluidics as a powerful tool for the rapid design of functional beads for diverse applications.

IgG adsorption on a new protein A adsorbent based on macroporous hydrophilic polymers: II. Pressure–flow curves and optimization for capture

Pressure–flow curves are obtained for a new protein A adsorbent matrix based on macroporous hydrophilic polymer beads with average diameter of 57 μm and a narrow particle size distribution. Experimental data are obtained in a 1 cm diameter laboratory column and in preparative scale columns with diameters of 20, 30, and 45 cm. The results are consistent with a model that assumes a linear relationship between bed compression and relative flow velocity. Surprisingly, the packing compressibility is essentially independent of column diameter for the preparative columns. As a result, after accounting for the variation in extraparticle porosity caused by compression, the column pressure drop is accurately predictable using the Carman–Kozeny equation. A model is also developed to predict productivity for IgG capture as a function of operating conditions based on dynamic binding capacity data presented in Part I of this work. For typical conditions, the model predicts maximum productivity at low residence times, between 1 and 1.5 min, when the dynamic binding capacity is at about 70–80% of the maximum. Combining the two models for column pressure and for dynamic binding capacity allows the design of preparative scale columns that maximize productivity while meeting specified pressure constraints.

Preparation and Evaluation of Uniform-size (-)-Ephedrine-imprinted Polymeric Microspheres by Multi-step Swelling and Suspension Polymerization

Ephedrine-imprinted polymeric microspheres have been prepared in an aqueous system by multi-step swelling and suspension polymerization, using methacrylic acid (MAA) as a functional monomer, and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Scanning electron microscopy (SEM) was used as a means to identify the structure features of the obtained polymers. Further, we examined the recognition mechanism of the polymers and the influences of some chromatographic conditions, such as the mobile-phase composition, flow-rate, column temperature and sample amount on the retentivity and selectivity for (-)-ephedrine and (+)-ephedrine. The results reveal that stable macroporous polymer beads with good size monodispersity were obtained, the average size of which was 3-5 microm. Baseline chiral separation of the template isomers was achieved on a short column (50 mmx4.6 mm i.d.) when the prepared polymer beads were used as a stationary phase, while the non-imprinted polymers (NIPs) did not show such ability. The optimized chromatographic condition was as follows: acetonitrile-acetic acid (99.8/0.2, v/v) as the mobile phase; sample amount, 40-80 microg; flow rate, 1.0 ml min-1; and column temperature, room temperature, respectively. It is assumed that two classes of binding sites exist in the porous polymers, one being hydrophilic binding sites, the other being hydrophobic binding sites.

Preparation of highly selective stationary phases for high-performance liquid chromatographic separation of enantiomers by direct copolymerization of monomers with single or twin chiral ligands

Uniformly sized macroporous polymer beads, which can be used as chiral stationary phase (CSP), have been prepared by the staged templated suspension polymerization process using chiral monomer as one of the copolymerization components. This approach enables the preparation of CSPs for which properties such as pore size, pore volume, surface area, chemistry, and chiral ligands can be tuned over a broad range. Several types of well-defined chiral monomers were prepared and allowed to assess synergistic effect of multiple selectors attached to a branched linker as well as the effect of the length and chemistry of the linker. Microscale batch screening was used for simple and rapid evaluation of selectivity. The most promising candidate CSPs were prepared on a larger scale and packed into HPLC columns. Their performance was demonstrated on the separation of racemic N-(3,5-dinitrobenzoyl)-α-amino acid alkylamides. The highest separation factors α of up to 27 were observed for CSPs prepared from monomers containing the branched spacer. These highly selective CSPs also enabled the separation of larger amounts of the target racemates upon column overload conditions.

Synthesis of Macroporous Polymer Beads by Suspension Polymerization Using Supercritical Carbon Dioxide as a Pressure-Adjustable Porogen

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis of Macroporous Polymer Beads by Suspension Polymerization Using Supercritical Carbon Dioxide as a Pressure-Adjustable PorogenColin D. Wood and Andrew I. CooperView Author Information Donnan and Robert Robinson Laboratories, Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K. Cite this: Macromolecules 2001, 34, 1, 5–8Publication Date (Web):December 26, 2000Publication History Received30 August 2000Revised6 November 2000Published online26 December 2000Published inissue 1 January 2001https://doi.org/10.1021/ma001514lCopyright © 2001 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views982Altmetric-Citations71LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (182 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Monomers,Polymerization,Polymers,Porosity,Solvents Get e-Alerts