Crosslinked Polystyrene Beads Research Articles

Evolving Role of Ca2+ on the Long-Term Phosphate Adsorption-Regeneration Performance of Nanoconfined Hydrated Lanthanum Oxides: Short-Term Enhancement and Long-Term Inhibition

Phosphorus (P) advanced treatment by adsorption reduces the risk of eutrophication in natural waters and reservoirs. The impact of ubiquitous Ca2+ on long-term P removal is critical in assessing the regeneration efficiency of one adsorbent, which is a vital indicator for cost-effectiveness. Given the critical role of lanthanum (La)-based composite materials in P removal, in this study, we unravel the long-term evolving role of Ca2+ on phosphate removal by nanosized hydrated lanthanum oxides (HLO) confined in cross-linked polystyrene beads (HLO@201) over 20 adsorption-regeneration cycles and fixed-bed column runs, with a combination of macroscopic adsorption experiments, microscopic structural investigation, and theoretical calculations. The role of Ca2+ gradually evolves from positive (5–70% higher than Ca2+-free group) to negative (18–41% lower than the Ca2+-free group) with ongoing cyclic runs of HLO@201, which is distinctive from the bulky HLO. The presence of Ca2+ enhances P uptake by HLO@201 possibly through ≡La–P–Ca–P multiple complexation and Ca–P precipitation (i.e., hydroxyapatite, HAP) inside the polymeric host, which creates an antagonistic effect with HLO over time. The formed Ca–P precipitates may accumulate and encapsulate on the surface of HLO nanoparticles, which induce the formation of irreversible LaPO4·xH2O under nanoconfinement that deplete the active adsorptive sites. A two-step (acid wash + NaOH) regeneration method can partially recover the P removal performance of HLO@201. We envision that this study could be a cautionary tale for advanced treatment of P by adsorption, to inspire re-evaluation on the long-term performance of adsorption processes.

A Solid Alkylation: Highly Recyclable, Flow Chemistry‐Ready, Resin‐Supported Thioimidazoliums Alkylate Sulfur‐Centered Nucleophiles

AbstractA series of readily regenerable thioimidazolium‐based ionic liquids, which can transfer alkyl groups to nucleophiles, are immobilized on crosslinked polystyrene beads. Different alkyl groups can be loaded onto the resin, highlighting the tunability of the material. The efficiency of these materials is demonstrated by their screening against a series of nucleophiles, showing a particular preference for thiols. Finally, these materials were evaluated for use under continuous flow conditions. The flexibility, ease of use, safety, and recyclability of these alkylating resins shows promise for their use in large scale and automated applications.

A Nonaqueous Redox-Matched Flow Battery with Charge Storage in Insoluble Polymer Beads.

We describe the nonaqueous redox‐matched flow battery (RMFB), where charge is stored on redox‐active moieties covalently tethered to non‐circulating, insoluble polymer beads and charge is transferred between the electrodes and the beads via soluble mediators with redox potentials matched to the active moieties on the beads. The RMFB reported herein uses ferrocene and viologen derivatives bound to crosslinked polystyrene beads. Charge storage in the beads leads to a high (approximately 1.0–1.7 M) effective concentration of active material in the reservoirs while preventing crossover of that material. The relatively low concentration of soluble mediators (15 mM) eliminates the need for high‐solubility molecules to create high energy density batteries. Nernstian redox exchange between the beads and redox‐matched mediators was fast relative to the cycle time of the RMFB. This approach is generalizable to many different redox‐active moieties via attachment to the versatile Merrifield resin.

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.

Use of Bead Mixtures as a Novel Process Optimization Approach to Nanomilling of Drug Suspensions.

We aimed to evaluate the feasibility of cross-linked polystyrene (CPS)-yttrium-stabilized zirconia (YSZ) bead mixtures as a novel optimization approach for fast, effective production of drug nanosuspensions during wet stirred media milling (WSMM). Aqueous suspensions of 10% fenofibrate (FNB, drug), 7.5% HPC-L, and 0.05% SDS were wet-milled at 3000-4000rpm and 35%-50% volumetric loading of CPS:YSZ bead mixtures (CPS:YSZ 0:1-1:0 v:v). Laser diffraction, SEM, viscometry, DSC, and XRPD were used for characterization. An nth-order model described the breakage kinetics, while a microhydrodynamic model allowed us to gain insights into the impact of bead materials. CPS beads achieved the lowest specific power consumption, whereas YSZ beads led to the fastest breakage. Breakage followed second-order kinetics. Optimum conditions were identified as 3000rpm and 50% loading of 0.5:0.5v/v CPS:YSZ mixture from energy-cycle time-heat dissipation perspectives. The microhydrodynamic model suggests that YSZ beads experienced more energetic/forceful collisions with smaller contact area as compared with CPS beads owing to the higher density-elastic modulus of the former. We demonstrated the feasibility of CPS-YSZ bead mixtures and rationalized its optimal use in WSMM through their modulation of breakage kinetics, energy utilization, and heat dissipation.

Improved stability of CdSeS/ZnS quantum dots against temperature, humidity, and UV-O3 by encapsulation in crosslinked polystyrene beads

Improved stability of CdSeS/ZnS quantum dots against temperature, humidity, and UV-O3 by encapsulation in crosslinked polystyrene beads

Impact of media material and process parameters on breakage kinetics–energy consumption during wet media milling of drugs

While crosslinked polystyrene (CPS) beads and yttrium-stabilized zirconia (YSZ) beads have been commonly used as media for wet milling of poorly soluble drugs and their dissolution enhancement, no first-principle rationale exists for selecting the bead material. The aim of this study is to investigate the impact of stirrer speed (2000–4000 rpm) and CPS bead loading (~20–60%) on the breakage kinetics–energy consumption during milling of griseofulvin, a model poorly soluble drug, and compare the performance of CPS vs. YSZ at the highest bead loading. Laser diffraction, SEM, rheological analysis, and XRPD were used for characterization. The milling was most effective at the highest bead loading–stirrer speed. A microhydrodynamic model suggests that an increase in stirrer speed led to faster breakage due to more frequent and forceful CPS bead–bead collisions. Despite causing slight decrease in maximum contact pressure, an increase in CPS bead loading caused a dramatic increase in average frequency of drug particle compressions, which dominated the faster breakage observed. While YSZ generally required higher specific energy consumption than CPS, it achieved the same product fineness faster than CPS. The microhydrodynamic model rationalized the favorable use of YSZ over CPS beads within the experimental domain studied.

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.

Perovskite Quantum Dots: Enhancing the Stability of Perovskite Quantum Dots by Encapsulation in Crosslinked Polystyrene Beads via a Swelling–Shrinking Strategy toward Superior Water Resistance (Adv. Funct. Mater. 39/2017)

Perovskite Quantum Dots: Enhancing the Stability of Perovskite Quantum Dots by Encapsulation in Crosslinked Polystyrene Beads via a Swelling–Shrinking Strategy toward Superior Water Resistance (Adv. Funct. Mater. 39/2017)

Enhancing the Stability of Perovskite Quantum Dots by Encapsulation in Crosslinked Polystyrene Beads via a Swelling–Shrinking Strategy toward Superior Water Resistance

AbstractOrganic/inorganic hybrid lead halide perovskites are promising optoelectronic materials due to their unique structure, excellent properties, and fascinating potential applications in lighting, photovoltaic, etc. However, perovskite materials are very sensitive to moisture and polar solvent, which greatly hinders their practical applications. Here, highly luminescent perovskite–polystyrene composite beads with uniform morphology are prepared via a simple swelling–shrinking strategy. This process is carried out only in nonpolar toluene and hexane without the addition of any polar reagents. As a result, the as‐prepared composite beads not only retain high luminescence but also exhibit superior water‐resistant property. The composites emit strong luminescence after being immersed into water over nine months. Moreover, even in some harsh environments such as acid/alkali aqueous solution, phosphate buffer solution, and Dulbecco's modified eagle medium biological buffers, they still preserve high luminescence. The applications in light‐emitting diodes and cellular labeling agents are also carried out to demonstrate their ultrastability.

Polymer-Supported Aminomethylphosphinate as a Ligand with a High Affinity for U(VI) from Phosphoric Acid Solutions: Combining Variables to Optimize Ligand–Ion Communication

ABSTRACTAminomethylphosphinic acid (AMPA) is immobilized onto cross-linked polystyrene beads and found to have a high affinity for the uranyl ion, especially from solutions as acidic as 6 M H3PO4. The trend in uranyl affinity by different ligands is AMPA > phosphinic > phosphonic > sulfonic. For example, the percent sorbed from 6 M H3PO4 is 89.5% (AMPA), 44.8% (phosphinic), 5.38% (phosphonic), and 2.60% (sulfonic). The high affinity shown by AMPA is due to the decreased hydrogen bonding in the phosphinic acid ligand as well as synergistic coordination of the uranyl ion by a proximate P=O of a second phosphinate ligand. AMPA contacted with synthetic wet process phosphoric acid solution sorbed 72.2% uranium compared to 0.14% for a commercially available sulfonic acid.

Macrocycle-functionalized polystyrene beads as specific absorbers

Crosslinked polystyrene beads were first functionalized with phenacyl ester linkers, and a series of four macrocycles with different ring sizes were synthesized from these linkers. The macrocycles were built from amide-linked monomers coupled by conventional peptide-synthesis methods. Annulation was achieved by copper(I)-catalyzed intramolecular azide–alkyne cycloaddition to give triazole linked macrocycles. The macrocycles were cleaved from the polymer beads with hydrazinolysis or saponification. The structures of macrocycles were confirmed by high-resolution nuclear magnetic resonance (NMR) and liquid chromatography–mass spectrometry (LC–MS) analysis. The ability of the polymers to selectively bind compounds from a mixture of aromatic derivatives in ethanol was tested. The prepared polystyrene supported macrocycles were found to selectively bind bromophenol blue and bromocresol green non-covalently with an association constant of 160–490M−1.

Crosslinked polystyrene beads modified with sulfonyl groups and their application in aromatic/aliphatic hydrocarbons separation

The separation of aromatic hydrocarbons from aromatic/aliphatic mixtures was investigated with cross-linked polystyrene(CPS) beads modified with sulfonyl groups. Three sulfonating agents, i.e. benzenesulfonyl chloride( BsCl), 4-toluene sulfonyl chloride(TsCl) and methanesulfonyl chloride(MsCl) were used to prepare sulfonyl CPS beads by Friedel-Crafts reaction. The CPS beads modified with BsCl exhibited higher sulfonation rate than those modified with MsCl and TsCl and obtained optimum selectivity in the experiments of toluene/n-heptane separation. Further separation tests with various other aromatic/aliphatic mixtures were carried out at an initial aromatic concentration of 13%(mass fraction) with the results showing that the modified beads have preferential selectivity for aromatic hydrocarbons in all aromatic/aliphatic mixtures, and especially a separation factor of 8.21 and a swelling ratio of 30% for toluene/cyclohexane system. The thermal stability and regeneration test indicate that the used polystyrene beads can be recovered through heat-drying and reused effectively.

Synthesis of Crosslinker Containing Sulfone Group and its Crosslinking with Styrene

A new crosslinker containing sulfone group was synthesized by polymerization of 4,4’-dihydroxydiphenyl-sulphone and methacryloyl chloride. Using this kind of crosslinker, the crosslinked polystyrene beads were prepared by suspension polymerization and UV-light polymerization, respectively. The synthesized crosslinker and crosslinked polystyrene beads were characterized by nuclear magnetic resonance spectra and fourier transform infrared spectroscopy. The effect of crosslinker amount on sulfonation rate of beads was studied. Polystyrene beads made by suspension polymerization possess higher sulfonation rate when the crosslinker amount is lower than 6%. When the content of crosslinker is higher than 6%, the reaction still can be carried out by UV-light polymerization, but the coagulation occurred during suspension polymerization because of the extremely high polarity of crosslinker.

Crosslinked polystyrene beads modified with polar groups for the separation of aromatic/aliphatic hydrocarbons

ABSTRACTCrosslinked polystyrene (CPS) beads modified with polar groups for the separation of aromatic/aliphatic hydrocarbons were successfully prepared. The synthesized beads were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. The effects of the crosslinking agents and polar groups on the swelling and selectivity performances toward n‐heptane/toluene mixtures were studied. Impressively, the results indicated that the sulfone‐modified CPS beads obtained a high toluene selectivity. Further adsorption tests with a variety of aromatic/aliphatic hydrocarbons were carried out at 50°C with initial aromatic concentrations of 13 wt %, and the results showed that the beads had a preferential selectivity for aromatic hydrocarbons, in particular, a higher separation factor of 6.76 for benzene/cyclohexane mixtures. We expect that modified CPS beads will serve as an effective material for the selective separation of aromatic/aliphatic hydrocarbons in chemical and petrochemical fields. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40156.

An investigation into the constriction flow of a particle reinforced polystyrene melt using a combination of flow visualization and finite element simulations

This paper investigates the flow of a particle filled polystyrene melt through a constriction zone using a combination of experimental techniques and computer simulation. A special blend, containing cross-linked polystyrene beads mixed into a polydispersed polystyrene matrix, was produced for this study. This closely refractive index matched blend allowed visualization of the flow birefringence up to an equivalent particle loading of around 15 vol %. Flow birefringence through a 10:1.4 contraction, measured using a multi-pass rheometer (MPR), was compared with that predicted from finite element simulations, in a similar way to that already published for unfilled polymer melts [Collis et al., J. Rheol. 49(2), 501–522 (2005)]. Numerical predictions were obtained using the finite element solver “EUFLOW” and ranked against the experimental processing data from the MPR. An extensive study of the rheology of the particle filled polystyrene blend was conducted which provided the input to the simulations. The addition of the particles was seen to enhance the shear thinning of the melt, while debonding between the particles and the polystyrene melt during extension testing had the effect of reducing strain hardening. EUFLOW was used to evaluate how these two important aspects could affect the flow birefringence of the filled polystyrene melt.

Preparation of tethered half-titanocene complex on cross-linked polystyrene beads for using in syndiospecific polymerization of styrene

In this work the cross-linked polystyrene beads were functionalized with silyl hydride groups. Two synthetic procedures were employed to tether of indenyltrichlorotitanium (IndTiCl 3) on the functionalized polystyrene beads. In one approach (method A), the half-titanocene catalyst bearing an allyl group (1-allylindenyltrichlorotitanium) was synthesized and covalently anchored on the functionalized polystyrene by using of hydrosilylation chemistry. In the second approach (method B), the half-titanocene complex was synthesized on the functionalized polystyrene beads. The polymer-supported catalysts were tested for styrene polymerization using methylaluminoxane (MAO) as a cocatalyst. The obtained results revealed that the supported catalyst prepared with method (A) has higher catalytic activity and syndiotacticity than the supported catalyst obtained by method (B). In addition the scanning electron microscopy (SEM) images showed that the polymer particle replicates the shape of the carrier. Furthermore, the 13C NMR and differential scanning calorimetry (DSC) studies confirmed the high syndiotacticity of obtained polymers.

Controllable Route to Solid and Hollow Monodisperse Carbon Nanospheres

An effective mechanism to prepare monodisperse carbon nanospheres with a regular round-ball-like shape is introduced. The route involves three steps: first, to synthesize monodisperse cross-linked polystyrene beads (CLPBs) by soap-free emulsion polymerization; second, to increase the cross-linking degree of CLPBs via Friedel−Crafts alkylation as a post-cross-linking reaction; third, to carbonize the reaction product. Both solid and hollow carbon spheres can be produced by adjusting the post-cross-linking reaction time. Fourier transform infrared spectra demonstrated the occurrence of a Friedel−Crafts alkylation reaction, and X-ray diffraction results showed that the carbon nanospheres are amorphous in structure. Typically, nitrogen adsorption/desorption measurements indicate that solid and hollow carbon nanospheres have a Brunauer−Emmett−Teller surface area as high as 498 and 451 m2/g, respectively. So it indicates that this method is novel in the field of preparation of carbon microspheres.

Preparation of fluorescent polystyrene microspheres by gradual solvent evaporation method

Highly cross-linked polystyrene beads of 9.2 μm were synthesized by seed polymerization with styrene as monomer and divinylbenzene as cross linker. Other sized monodisperse PS microspheres were also prepared by varying seed particle diameter and proportion of swelling agents. Furthermore, the polystyrene beads were stained by gradual solvent evaporation method using dyes such as rhodamine 101 and acridine orange. Gradual solvent evaporation method facilitates a high concentration of fluorescent dyes on beads. This is the key to obtain fluorescent beads with high intensity. The results showed that the fabricated fluorescent microspheres could be excited to various wavelengths (such as yellow, green, red and scarlet). Our synthesized microspheres offer high fluorescence emission efficiency compared to commercial fluorescent microspheres in the mean time have other properties in common.

Swelling of cross-linked polystyrene beads in toluene

Ultraviolet light irradiation of PS microbeads can be used for controlling the solvent uptake and release upon exposure to its vapor. The irradiation leads to additional fracture and crosslinking o...