Copolymer Beads Research Articles

Composite Copolymer Beads Incorporating Red Mud for Water Amendment by Adsorption—Oxidation Processes

We face significant environmental pollution problems due to various industries, such as the aluminum industry, which generates large amounts of red mud (RM) waste, or agriculture, in which case the use of pesticides creates huge water pollution problems. In this context, the present study offers a better perspective to originally solve both environmental issues. Thus, the main target of the study referred to using RM waste as a filler for preparing composite copolymer beads. Thereafter, this can achieve significant removal of water pollutants due to their adsorption/oxidation characteristics. As evidenced by the changes in chemical structure and composition, thermal stability, morphology, and porosity, RM was homogenously incorporated in poly(acrylonitrile-co-acrylic acid) beads prepared by wet phase inversion. The final assessment for the removal of pesticides by adsorption and oxidation processes was proven successful. In this regard, 2,4-dichlorophenoxyacetic acid was chosen as a model pollutant, for which an adsorption capacity of 16.08 mg/g composite beads was achieved.

Selective Adsorption of Ionic Species Using Macroporous Monodispersed Polyethylene Glycol Diacrylate/Acrylic Acid Microgels with Tunable Negative Charge.

Monodispersed polyethylene glycol diacrylate (PEGDA)/acrylic acid (AA) microgels with a tuneable negative charge and macroporous internal structure have been produced using a Lego-inspired droplet microfluidic device. The surface charge of microgels was controlled by changing the content of AA in the monomer mixture from zero (for noncharged PEGDA beads) to 4 wt%. The macroporosity of the polymer matrix was introduced by adding 20 wt% of 600-MW polyethylene glycol (PEG) as a porogen material into the monomer mixture. The porogen was successfully leached out with acetone after UV-crosslinking, which resulted in micron-sized cylindrical pores with crater-like morphology, uniformly arranged on the microgel surface. Negatively charged PEGDA/AA beads showed improved adsorption capacity towards positively charged organic dyes (methylene blue and rhodamine B) compared to neutral PEGDA beads and high repulsion of negatively charged dye molecules (methyl orange and congo red). Macroporous microgels showed better adsorption properties than nonporous beads, with a maximum adsorption capacity towards methylene blue of 45 mg/g for macroporous PEGDA/AA microgels at pH 8.6, as compared to 23 mg/g for nonporous PEGDA/AA microgels at the same pH. More than 98% of Cu(II) ions were removed from 50 ppm solution at pH 6.7 using 2.7 mg/mL of macroporous PEGDA/AA microgel. The adsorption of cationic species was significantly improved when pH was increased from 3 to 9 due to a higher degree of ionization of AA monomeric units in the polymer network. The synthesized copolymer beads can be used in drug delivery to achieve improved loading capacity of positively charged therapeutic agents and in tissue engineering, where a negative charge of scaffolds coupled with porous structure can help to achieve improved permeability of high-molecular-weight metabolites and nutrients, and anti-fouling activity against negatively charged species.

Preparation of Superabsorbent Beads via Superfast Photopolymerization and Their Characterization

AbstractIn the present work, a superfast and simple photopolymerization process is developed in preparing superabsorbent beads under ambient conditions. Hydrophilic monomers, N,N‐dimethylacrylamide (AM) and 2‐hydroxyethyl methacrylate (HEMA) are photopolymerized in 60 s using phenylbis (2,4,6‐trimethylbenzoyl)phosphine (BAPO) under UV/Vis light. Proton nuclear magnetic resonance spectroscopy (NMR) and Fourier‐transform infrared spectroscopy (FT‐IR) confirmed the successful polymerization of both monomers. Monomer conversions, quantitatively examined with gas chromatography (GC), are over 90% for all homo‐ and copolymerizations. Water absorbance is greatly influenced by the ratio of the two monomers. With the increase of AM in the copolymers, the water absorbance increased. Copolymer beads absorbed less water at 40° than room temperature. Polymeric beads are water soluble when the AM content is equal to or above 90% by weight in the superabsorbent. Without any cross‐linkers, beads prepared with 85/15 weight ratio of AM to HEMA absorbed 84 times their weight of water.

Copolymer-MnO2 nanocomposites for the adsorptive removal of organic pollutants from water.

The copolymer beads prepared by suspension polymerisation were decorated with MnO2 nanoparticles and successfully implemented for the efficient removal of toxic organic contaminants from water. Copolymer-MnO2 nanocomposite was further analysed using XRD, SEM and optical microscope. The SEM images showed the surface characteristics of MnO2 nanoparticles on copolymer beads. The efficiency of the copolymer-MnO2 nanocomposite for the removal of model pollutant methylene blue and rhodamine B is then analysed by changing the concentration of pollutant. The results obtained exhibited 18.45mg/g for methylene blue adsorption and 3.125mg/g for rhodamine B. The adsorption equilibrium results were fitted to Langmuir adsorption isotherm for both methylene blue and rhodamine B adsorption. The desorption studies were performed for five consecutive cycles, and material was showing good regenerating capacity towards both organic pollutants. The obtained results show that copolymer-MnO2 nanocomposite is an efficient material for the removal of organic contaminants from wastewater.

Effect of N-vinylimidazole comonomer on blood plasma protein and endogenous toxin adsorption on mesoporous copolymer beads

N-vinylimidazole-divinylbenzene (VI-DVB) copolymer beads with a N-vinylimidazole (VI) weight content ranging from 7% to 15% were studied as possible adsorbents for hemoperfusion and compared with the cross-linked polystyrene beads from commercial devices. All the beads had a large volume fraction of mesopores with diameters of 2–50 nm, quantified by nitrogen adsorption, and BET areas from 500 to 1000 m²/g. Metal-chelate adsorption of copper (II) ions on VI-DVB was high in 0.15 M NaCl (up to 40 μmol/mL), and low in blood plasma (< 1 μmol/mL). Reversible adsorption of blood plasma proteins was high (> 100 mg/mL beads) on all the bead types. Irreversibly adsorbed proteins eluted by 2% SDS included albumin, fibrinogen, fibronectin, and transferrin. Metal chelating contributed to the irreversible adsorption. Unlike the beads from commercial devices, VI-DVB beads adsorbed the LPS endotoxin from plasma. Adsorption of bilirubin and IL-6 was high on all the beads tested, but VI-DVB beads were better adsorbents of bile acids. VI-DVB are promising as components of multifunctional devices for blood purification applicable to treatment of diseases where conventional devices have lower or negligible adsorption capacity.

Fabrication of Expanded Ethylene–Propylene–Butene-1 Copolymer Bead

Fabrication of Expanded Ethylene–Propylene–Butene-1 Copolymer Bead

Technical Note: Novel Use of CytoSorb™ Haemadsorption to Provide Wound Healing Support in Case of Severe Burn Trauma via Reduction of Hyperbilirubinaemia.

Hyperbilirubinaemia has been shown to compromise wound healing in severely burned patients. The therapy options for patients with impairment of wound healing and subsequent severe liver dysfunction are limited. A novel extracorporeal treatment, CytoSorb® (CytoSorbents Corp, USA), is a whole blood adsorber composed of highly biocompatible and porous polystyrene divinylbenzene copolymer beads covered in a polyvinylpyrrolidone coating. It is capable of extracting mainly hydrophobic middle-sized (up to 55 kDa) molecules from blood via size exclusion, including cytokines and bilirubin. We performed therapy with CytoSorb® on a severely burned (48% Total Body Surface Area-TBSA) patient with secondary sclerosing cholangitis (SCC) to promote the wound healing process by reducing bilirubin concentrations and to bridge the time to spontaneous liver regeneration or eventually to liver transplantation after two skin transplantations had failed to provide wound closure. In the first 6 days the cartridge was changed on a daily basis and later after every 2–4 days. The therapy with six adsorbers decreased a total bilirubin concentration from 14.02 to 4.29 mg/dl. By maintaining a stable bilirubin concentration under 5 mg/dl, debridement of abdomen and upper extremities with autologous skin grafting and, 4 weeks later, autologous skin grafting of the back from scrotum and lower extremities were performed successfully. After wound healing had been achieved, the CytoSorb therapy was discontinued after 57 days and 27 adsorber changes. CytoSorb therapy can be a promising support of wound and skin graft healing in patients with severe burns and liver dysfunction due to a significant reduction of total bilirubin concentration.

Cross‐linked poly(N‐vinylpyrrolidone)‐titanium tetrachloride complex: A novel stable solid TiCl4 equivalent as a recyclable polymeric Lewis acid catalyst for regioselective ring‐opening alcoholysis of epoxides

AbstractCross‐linked poly(N‐vinylpyrrolidone) resin beads were prepared as macromolecular ligand precursors by suspension copolymerization of N‐vinyl‐2‐pyrrolidone and N,N′‐methylenebisacrylamide (MBA) as a crosslinking agent in water. Subsequently, the resulting polymer carrier precursor was readily combined with titanium tetrachloride to form a stable polymeric coordination complex (PNVP/TiCl4), and this novel stable TiCl4 equivalent evaluated as a heterogeneous and reusable solid Lewis acid catalyst for the regio‐and stereoselective nucleophilic ring opening of various epoxides with various alcohols to prepare β‐alkoxy alcohols in excellent yields without generating any waste. The MBA‐cross‐linked PNVP and resultant catalyst were characterized by Fourier transform infrared spectroscopy (FT–IR), field‐emission scanning electron microscope (FE–SEM), energy dispersive X‐ray (EDX), inductively coupled plasma (ICP), and thermogravimetric analysis (TGA) techniques. Moreover, the catalyst is very stable, easily separated, and reused at least five times without significant loss of activity. In terms of scope, yields, the amount of catalyst used, and reaction time, the PNVP‐TiCl4 complex catalyst is an improvement over previously reported heterogeneous catalysts for ring opening of epoxides methods. Further, the experimental outcome revealed that using the copolymer beads as carriers with a high percentage of crosslinking and the high mesh size leads had an adverse effect on the reaction rate.

Fabrication of a novel nitrogen-containing porous carbon adsorbent for protein-bound uremic toxins removal

Protein-bound uremic toxins (PBUTs), the presence of which in the blood is an important risk factor for the progression of chronic kidney disease (CKD), have not been cleared efficiently via traditional hemodialysis methods until now. In this study, biosafe and efficient nitrogen-containing porous carbon adsorbent (NPCA) beads for the clearance of PBUTs were prepared from porous acrylonitrile/divinylbenzene cross-linked copolymer beads followed by pyrolysis. The resulting NPCA beads were characterized via SEM, XPS and nitrogen adsorption/desorption tests. The results demonstrated that the NPCA beads possessed a mesoporous/microporous hierarchical structure with rich nitrogen functional groups on their surfaces and realized efficient PBUTs adsorption in human plasma. More importantly, the efficacy of PBUTs removal was substantially higher than those of commercial adsorbents that are commonly used in clinical uremia treatments. The NPCA beads also exhibited satisfactory removal efficacy towards middle-molecular-weight uremic toxins. The PBUTs removal mechanism of the NPCA beads is ascribed to effective competition between nitrogen-containing NPCA and proteins for PBUT binding. According to hemocompatibility assays, the NPCA beads possessed satisfactory in vitro hemocompatibility. This nitrogen-containing porous carbon adsorbent is an attractive and promising material for blood purification applications in the treatment of clinical uremia.

Effect of N-Vinylimidazole Comonomer on Blood Plasma Protein and Endogenous Toxin Adsorption on Mesoporous Copolymer Beads

Effect of N-Vinylimidazole Comonomer on Blood Plasma Protein and Endogenous Toxin Adsorption on Mesoporous Copolymer Beads

Highly porous polyelectrolyte beads through multiple-emulsion-templating: Synthesis and organic solvent drying efficiency

Thus far, emulsion-templated macroporous hydrogels have mostly been produced as monolithic blocks corresponding to the dimensions of the polymerization vessel, while the number of examples of other shapes and dimensions is as yet fairly small. In this article, we report on the double-emulsion-templated synthesis of spherical, cross-linked polyelectrolyte-based hydrogel beads through the sedimentation polymerization of oil-in-water-in-oil (O/W/O) high internal phase emulsions (HIPEs). When a mixture of 2-acrylamido-2-methyl-1-propanesulfonic acid or (3-acrylamidopropyl)-trimethylammonium chloride (AMPS or AMPTMA, ionic monomers) and acrylamide (AAM, a nonionic monomer) was used, the sedimentation polymerization of O/W/O HIPEs resulted in spherical polymerized high internal phase emulsions (polyHIPE) copolymer beads with a throughout open macroporous morphology. A combination of three-dimensionally-interconnected macroporous morphology and small spherical size remarkably improves the swelling and water absorption properties of the beads as dry beads swell to near-equilibrium size within seconds as opposed to hours in the case of monolithic blocks. PolyHIPE beads have a hygroscopic character due to their inherent charges within the macroporous framework. Therefore, the throughout porous morphology and charged functionality of the polyelectrolyte polyHIPE beads allow reversible and rapid water absorption from the tested organic solvents with a water removal efficiency of up to 95%. This work opens a new path to polyHIPE hydrogel engineering, with extremely fast water-absorption capability, which may have promising applications in various fields such as agriculture, horticulture, hygiene products, and daily chemicals.

Hybrid Beads Bearing Immobilized Bacteria as Advanced Means for the Removal of Acid Blue 93 Dye

This paper describes the preparation of three- component hybrid copolymer beads, with water purification features. These newly developed hybrid beads were prepared starting from a mixture of poly(acrylonitrile- co- methacrylic acid) (PAN-co-PMAA), polyvinyl alcohol (PVA) and magnetite (Fe3O4), respectively. The preparation itself involved a Wet Phase Inversion (WPI) process. A Pseudomonas sp. strain was immobilized onto previously mentioned beads, before and after activation of the beads surface with glutardialdehyde, and afterwards used for the amendment of simulated water bearing an azo- blue dye, i.e. Acid Blue 93. In order to highlight the immobilization of Pseudomonas sp. strain, FTIR spectra and TGA results were recorded. CFU measurements as well as SEM images further provided evidence towards the occurrence of immobilization. The biodegradation studies of Acid Blue 93were carried out by means of UV spectroscopy at various contact times (24; 72 and 144 h) of the hybrid beads with the targeted dye.

Techno-Economic Analysis of Glycerol Valorization via Catalytic Applications of Sulphonic Acid-Functionalized Copolymer Beads.

The design of experiments response surface analysis was employed for the first time to study the effect of divinylbenzene (DVB) (20–80 wt. %), diluent (0–100 wt.%), and mixing (200–900 rpm) on the beads' physical properties and on swelling ability. The beads with the highest performances, in terms of mechanical stability, surface area, and swelling ability, were sulphated, and tested in converting glycerol to a valuable product “solketal.” Process options for glycerol valorization to solketal using synthesized sulphonic acid-functionalized styrene-divinylbenzene (ST-DVB-SO3H) copolymer beads and techno-economic analysis of the processes have been investigated. Three processes were evaluated: two one-stage processes at 8.5 wt.% catalyst and 50°C, based on either 6:1 acetone to glycerol molar ratio (87% conversion) or 12:1 (98% glycerol to solketal conversion), and a two-stage route (two acetone additions), where ≥98% conversion can be achieved with lower overall acetone use (10:1 acetone to glycerol molar ratio and 50°C). Techno-economic analyses of the three solketal options were performed using Aspen (HYSYS), based on a fixed capacity of 100,000 te/y and 20-years lifetime. The techno-economic analyses showed that the net present values for the solketal process options were $707 M for the two-stage, $384 M for the one-stage at 6:1 acetone to glycerol molar ratio, and $703 M for the one-stage at 12:1 acetone to glycerol molar ratio. The break-even prices for these solketal processes were $2,058/ ton for the one-stage at 12:1 of acetone and two-stage and $2,088/ton for the one-stage at 6:1 of acetone, which is lower than the current price of solketal at $3,000/ton. The two-stage process was found to be the most effective method of glycerol valorization production to solketal.

Sorption properties of polymeric beads and films containing tetraoctyl diglycolamide towards europium (III) ions

The article presents results obtained during investigation of Eu(III) ion removal from aqueous solutions using triacetate cellulose films and styrene-divinylbenzene copolymer beads containing tetraoctyl diglycolamide (TODGA). A simple method for manufacturing films containing up to 50 % w/w TODGA is provided. Solution acidity effect on the removal rate of Eu(III) ions was studied. Maximum removal of Eu(III) ions was obtained in nitric acid solutions with concentrations of 1-6 mol/l. Additionally, increase in the europium removal rate is also observed at pH &gt; 2 for beads and in the pH range of 2 to 4 for films. In the former case increase in the removal rate is explained by increase in the nitrate ion concentration in the solution and Eu(NO3)3(TODGA)3 complex formation, and in the latter case – by decrease in TODGA protonation rate with рН growth. Observed trends indicate a high similarity in surface sorption mechanisms between the materials studied. Sorption equilibrium of Eu(III) ions onto the styrene-divinylbenzene copolymer beads impregnated with TODGA is adequately fitted to Langmuir sorption isotherm. The maximum sorption capacity of this material for Eu(III) removal from solutions with nitric acid concentration of 1 mol/l is 7.4 mg/g. It has been found that the maximum removal rate of Eu(III) ions by the triacetate cellulose films is achieved for TODGA content in the films ≥ 40 % w/w. The possibility of selective europium sorption from natural water using both beads and films is shown. Although cations present in natural water do not bind to sorbents studied, there is still slight deterioration in sorption properties when moving from model solutions to natural water. Complete desorption of Eu(III) ions from the film surface is achieved by washing three times with an EDTA solution, рН = 6.8. Prepared films can be reused for Eu(III) ion removal.

Diblock Sodium Alginate Grafted Poly (N-vinylimidazole) in blank copolymeric beads and immobilized algal beads for water treatment

Synthesis of diblock sodium alginate grafted poly (N-vinylimidazole), SA-g-PNVI, was investigated as preliminary step toward preparation of blank copolymeric beads (BCB) and immobilized algal beads (IAB) for the removal of phenol from aqueous solutions. The diblock SA-g-PNVI was self-crosslinked via calcium ions to make BCB, and crosslinked with dead green algae (Chlorella pyrenoidosa) to make the IAB. The diblock SA-g-PNVI was fully characterized using spectroscopic, thermal and optical means. Adsorption optimization parameters like effect of solution pH, dynamics, and adsorption isotherms were investigated; Optimum pH value for phenol removal was found at pH=5.0 for blank copolymer beads (BCB) and immobilized algal beads (IAB). The adsorption kinetics demonstrated pseudo-second order phenol removal with major contribution of intraparticle diffusion mechanism. Adsorption isotherms were fitted to equilibrium data in linear and nonlinear regressions using different objective functions. The low cost, natural origin, biodegradability and environmentally friendly characteristics of the diblock SA-g-PNVI sorbents adapt them to play promising role in recovery of missing ecology and in wastewater management.

Cross-linked polystyrene/titanium tetrachloride as a tightly bound complex catalyzed the modified Mannich reaction for the synthesis of piperidin-4-ones

Cross-linked polystyrene beads were prepared, characterized and the resulting polymer carrier was functionalized with titanium tetrachloride (TiCl4) via complexation of polystyrene with TiCl4 to afford the corresponding cross-linked polystyrene-TiCl4 stable complex (PSt/TiCl4) in an one step reaction and characterized by FT-IR, UV, TGA, DSC, XRD, SEM, BET. This tightly bound coordination complex was used as a water tolerant, heterogeneous, recoverable and reusable Lewis acid catalyst for the synthesis of substituted piperidin-4-ones via the modified Mannich multi-component condensation of ketones, aromatic aldehydes, and ammonium acetate in 1:2:1 M ratio under mild conditions. The rate of reactions was found to decrease with an increasing percentage of crosslinking and the mesh size of the copolymer beads. The catalyst is water tolerant, stable and can be easily recovered and reused at least four times without any loss of activity.

Recoverable polystyrene-supported catalysts for Sharpless allylic alcohols epoxidations

In this work, new heterogeneous catalysts intended for enantioselective Sharpless epoxidation were prepared. The catalysts are based on Ti(IV) complexes of cross-linked swellable spherical copolymer beads of styrene with ethyl-(4-vinylbenzyl)-L-tartrate, or with ethyl-(2R,3R)-2,3-dihydroxy-4-oxo-5-(4-vinylphenyl)pentanoate. These catalysts were tested in epoxidation of cinnamyl alcohols. High conversion (up to 99%) and high enantioselectivity (up to 99% ee) were achieved in the case of catalysts based on copolymers of styrene with ethyl-(4-vinylbenzyl)-L-tartrate (5, 20, 50%). Unfortunately, the copolymers lost their enantioselectivity due to the leaching of L-tartrate, caused by alcoholysis of ester bond. This problem has been overcome by replacing the ester bond by a stable keto bond. The prepared catalyst based on the copolymer of styrene with ethyl-(2R,3R)-2,3-dihydroxy-4-oxo-5-(4-vinylphenyl)pentanoate (20%) achieved a similarly high conversion and enantioselectivity as in the previous case (up to 99%, up to 99% ee) and was successfully recycled.

1, 6-Hexanediol Diacrylate Cross-linked Polystyrene-A novel catalyst support system-Its synthesis, swelling capacity studies and surface morphological analysis

Cross-linked polymers with specific properties are widely used as catalyst support as they are inert, non toxic and non volatile and offer advantageous features of heterogeneous catalysis such as thermal stability selectivity and recyclability to homogeneous system. The ease of separation from the reaction products lead to operational flexibility. Here we report the synthesis, characterisation and comparative study of swelling capacity and surface morphology of different mol % of styrene –HDODA copolymer. Suspension polymerisation is used for the preparation of Styrene - 1, 6-hexanediol diacrylate (HDODA) copolymer beads with different mole percent of HDODA content. They can be used as catalyst support, as the base for the preparation of cation exchangers and anion exchangers. The characterizations of the polymers were done by FTIR spectroscopy and SEM analysis

Effect of Long-term Immersion in Water and Artificial Saliva on the Flexural Strength of Two Heat Cure Denture Base Resins

The aim of the present study was to compare and evaluate the flexural strength of heat-polymerized Lucitone 199 and SR Ivocap denture base resin materials which uses polymerization techniques of compression molding and injection molding respectively and effect of artificial saliva and distilled water on long-term. Ninety specimens each from both the materials measuring 65 × 10 × 3 mm were prepared. After the polymerization, flexural strength was calculated after 24 hours (control group) without immersing in the liquid medium. The test group specimens immersed in saliva and distilled water at 37°C was calculated for the flexural strength at 2 weeks, 1 month, 2 months and 4 months. The flexural strength was measured using a universal testing machine. One-way analysis of variance (ANOVA) method was used to analyze the data, pairwise comparisons were done using Bonferroni post hoc test with a probability of less than 0.05 were considered to be statistically significant. The evaluation showed that, despite the duration of immersion and type of acrylic resin, high flexural strength was seen with specimens immersed in saliva than specimens under distilled water. The higher flexural strength was seen in SR Ivocap compared to that of Lucitone199 with the p value less than 0.05 which showed significant statistically. From the results, we can conclude that the higher flexural strength was shown in specimens of SR Ivocap fabricated through injection molding technique compared to specimens of Lucitone 199 fabricated through compression molding technique after immersion in artificial saliva and distilled water for long term. The homogeneous copolymer beads, the difference in the water sorption and powder to liquid ratios also affect the mechanical properties of the resins other than the type of resin used in the dentures base.

Cross-linked polystyrene-TiCl4 complex as a reusable Lewis acid catalyst for solvent-free Knoevenagel condensations of 1,3-dicarbonyl compounds with aldehydes

Cross-linked polystyrene copolymer beads with the average particle size in the range of (50–80 mesh size) were prepared by a new method, characterized and functionalized with titanium tetrachloride to afford the corresponding polystyrene‑titanium tetrachloride complex in one step reaction and characterized by FT-IR, UV, TGA, DSC, XRD, SEM, BET. This polymer metal complex (PS/TiCl4) was used as a heterogeneous, recoverable, reusable Lewis acid for solvent-free Knoevenagel condensations of 1,3-diketones with aromatic aldehydes under green and mild conditions. The rate of reactions was found to decrease with an increasing percentage of crosslinking and the mesh size of the copolymer beads. This complex showed good stability and catalytic activity in the Knoevenagel reactions.