Reversed-phase Suspension Polymerization Research Articles

Hydrogel-based microbeads for Raman-encoded suspension array using the reversed-phase suspension polymerization method and ultraviolet light curing.

A one-step synthesis using the reversed-phase suspension polymerization method and ultraviolet light curing is proposed for preparing the Raman-encoded suspension array (SA). The encoded microcarriers are prepared by doping the Raman reporter molecules into an aqueous phase, and then dispersing the aqueous phase in an oil phase and curing by ultraviolet light irradiation. The multiplexed biomolecule detection and various concentration experiments confirm the qualitative and quantitative analysis capabilities of the Raman-encoded SA with a limit of detection of 52.68pM. The narrow bandwidth of the Raman spectrum can achieve a large number of codes in the available spectral range and the independence between the encoding channel and the fluorescent label channel provides the encoding method with high accuracy. This preparation method is simple and easy to operate, low in cost, and high in efficiency. A large number of hydrogel-based encoding microbeads could be quickly obtained with good biocompatibility. Most importantly, concentrating plenty of Raman reporter molecules inside the microbeads increases the signal intensity and means the molecular assembly is not limited by the functional groups; thus, the types of materials available for Raman encoding method are expanded. Furthermore, the signal intensity-related encoding method is verified by doping different proportions of Raman reporter molecules with our proposed synthesis method, which further increases the detection throughput of Raman-encoded SA. Graphical Abstract.

Noble surface molecularly imprinted polymer modified titanium dioxide toward solanesol adsorption selectivity study

Abstract

Application of the nitrogenous polymeric metal complex in organic synthesis

To research chemical formation of the nitrogenous polymeric metal complex, this paper studies the catalysis of the polymeric metal complex in chemical reaction via the organic combination reaction. In this paper, a series of N-functionalized nitrogenous polystyrene ligands are prepared by making chloromethylate polystyrene resin (CPS) reacting with ethanol amine, 2-mercapto ethylamine (MEA), 8-hydroxyquinoline, anthranilic acid and imidogen oxalic acid (IDA) respectively, and crosslinked polyacrylamide is obtained by adopting solution polymerization and reversed phase suspension polymerization methods. Moreover, the polymeric metal complex is obtained by making nitrogenous polymer acting on the water solutions of FeCl3, 6H2O, CuCl2, 2H2O, CoCl2, 6H2O, NiCl2 and 6H2O at certain pH and temperature, the characteristics of nitrogenous polymeric ligand and nitrogenous polymeric metal complex are presented by adopting elemental analysis, Fourier transform infrared, atomic absorption, thermogravimetric analysis (TGA) and electron spin resonance (ESR) etc., and catalytic performance of the nitrogenous polymeric metal complex on acetal (ketone) reaction and alcohol oxidation is inspected. The results indicate that polymeric metal complex can be really formed by making functionalized polystyrene acting on transition metal salt in certain conditions, and various N-functionalized nitrogenous polystyrene ligands have selectivity to the adsorption of metal ions.

Preparation and drug controlled release of porous octyl-dextran microspheres

In this work, porous octyl-dextran microspheres with excellent properties were prepared by two steps. Firstly, dextran microspheres were synthesized by reversed-phase suspension polymerization. Secondly, octyl-dextran microspheres were prepared by the reaction between dextran microspheres and ethylhexyl glycidyl ether and freezing-drying method. Porous structure of microspheres was formed through the interaction between octyl groups and organic solvents. The structure, morphology, dry density, porosity and equilibrium water content of porous octyl-dextran microspheres were systematically investigated. The octyl content affected the properties of microspheres. The results showed that the dry density of microspheres decreased from 2.35 to 1.21 g/ml, porosity increased from 80.68 to 95.05% with the octyl content increasing from 0.49 to 2.28 mmol/g. Meanwhile, the equilibrium water content presented a peak value (90.18%) when the octyl content was 2.25 mmol/g. Octyl-dextran microspheres showed high capacity. Naturally drug carriers play an important role in drug-delivery systems for their biodegradability, wide raw materials sources and nontoxicity. Doxorubicin (DOX) was used as a drug model to examine the drug-loading capacity of porous octyl-dextran microspheres. The drug-loading efficiency increased with the increase in microspheres/drug ratio, while the encapsulation efficiency decreased. When microspheres/drug mass ratio was 4/1, the drug-loading efficiency and encapsulation efficiency were 10.20 and 51.00%, respectively. The release rate of DOX increased as drug content and porosity increased. In conclusion, porous octyl-dextran microspheres were synthesized successfully and have the potential to serve as an effective delivery system in drug controlled release.

Preparation of Glutathione Molecularly Imprinted Polymer Microspheres by Reversed Phase Suspension Polymerization

Molecularly imprinted polymer microspheres (MIPMs) for Glutathione had been prepared by the reversed phase suspension polymerization method; MIPMs were synthesized by using acrylamide and N-vinyl pyrrolidone as functional monomers. N,N’-methylenebisacrylamide and dimethyl diallyl ammonium chloride were the cross-linkers and H2O2 and Vc were redox initiators, Span-80 was the surfactant used and cyclohexane was the oil phase. Our work can provide a method to obtain ball MIPMs, and in this way, the destruction of acting sites because powdery MIPMs could be avoided. Moreover, the low concentration of cross-linker results in imprinted sites not being formed during the reversed phase suspension polymerization. The double cross-linkers not only solved this problem, but they also enlarged the selection range of the template, monomer and cross-linker. Simultaneously, there’s obviously a significant amount of synergy between the two cross-linkers that perhaps improve the adsorption capacity and selectivity. The conditions were investigated and optimized, and the optimum conditions were obtained as follows: the ratio of nAM/nNVP was 2; the optimum temperature and time were 50°C and 4.5 h; and, the dosage of GSH, DMDAAC and Vc were 0.8 g, 14 g and 0.023 g, respectively, under the optimum conditions, GSH-MIPM was prepared and showed the adsorption capacity was 75 mg · g−1. Also, based on the samples prepared at the starting process and under optimal conditions, the adsorption kinetics and adsorption isotherm were investigated and analyzed, respectively.

Preparation of Novel Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-Grafted Core-Shell Magnetic Chitosan Microspheres and Immobilization of Lactase

Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6–17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization.

Preparation and protein adsorption of porous dextran microspheres

Abstract In present work, porous dextran microspheres with good morphology were synthesized by reversed-phase suspension polymerization. Dextran was used as raw material, epichlorohydrin (ECH) as crosslinker, and dimethyl ether of polyethylene glycol (DMPE) as porogen. And porous dextran microspheres were prepared by freezing–drying method. The morphology of the porous dextran microspheres was characterized by the scanning electronic microscope (SEM). The dry and hydrated densities, average pore volume, porosity, hydroxyl content and equilibrium water content were measured. Micropore structure was found on the dextran microspheres. With the increase of porogen amount, the dry density decreased, the hydrated density, the average pore volume, porosity and equilibrium water content initially increased and then decreased, while the hydroxyl content increased. Bovine serum albumin (BSA) was used as an adsorbate model to examine the adsorption behavior of the porous microspheres. The saturated adsorption capacities of these microspheres ranged from 59.1 mg/g to 138.9 mg/g while the amount of porogen increased from 10% to 50%.

Preparation of Porous Nano-Strontium Titanate and its Application in Removal of Heavy Metals from Environmental Water

Porous nano-strontium titanate (PST) was successfully prepared by the reversed-phase suspension polymerization and sol-gel method using reversed-phase suspension droplets as the template, and characterized by XRD and SEM. The ability of the new adsorption to remove lead, cadmium, zinc, copper and nickel ions from water samples was assessed. The results showed that the sorbents were porous, perovskite strontium titanate, and the average particle diameter of crystalloid was 30 nm. The lead, cadmium, zinc, copper and nickel ions were quantitatively retained at pH 5-8; their adsorption capacities of PST for lead, cadmium, zinc, copper and nickel ions were 145.9 mg•g-1, 4.3 mg•g-1, 25.2 mg•g-1, 19.6 mg•g-1and 3.7 mg•g-1, respectively. The adsorbent can be regenerated completely by elution with 0.5 mol•L-1 HNO3. The adsorbent has a promising prospect in removal or enriching of lead, cadmium, zinc, copper and nickel in water.

CuO Catalysts Supported on Porous TiO2 Microspheres for Low-Temperature CO Oxidation

The porous TiO2 microspheres were prepared by the reversed-phase suspension polymerization and sol-gel method using reversed-phase suspension droplets as the templates. The CO oxidation catalytic properties of the CuO/TiO2 catalysts prepared by hydrothermal method and impregnation method were extensively investigated. The structure of CuO/TiO2 catalysts was determined by TG-DTA, XRD, TEM, and XPS. The results indicated that the redox capacity of CuO/TiO2 was greatly depended on the aqueous solution concentration of Cu(NO3)2 used in the preparation of CuO/TiO2 and the calcination temperature of the CuO/TiO2 catalysts.

Sodium Lignosulphonate-Polyvinyl Alcohol Bioadsorbent: Synthesis, Characterization and Adsorption for Pb (II)

A novel sodium lignosulphonate (SLS)-polyvinyl alcohol (PVA) spherical macroporous bioadsorbent (SLSP) was synthesized by reversed phase suspension polymerization. Comparing with powdery and high water solubility SLS, this new spherical bioadsorbent exhibited relative stability under static force. SEM and FTIR proved the cross-linking of SLS and PVA. TG curves of SLS and SLSP indicated that the thermal property of SLS had been improved by cross-linking modification. Meanwhile, comprehensive adsorption study of Pb (II) on this bioadsorbent was conducted regarding the effects of time, initial PH and initial Pb (II) concentration. 90% of Pb (II) from aqueous solution could be removed by 0.4g of the adsorbent at 25°C for less than 3h. The adsorption process was determined to be consistent with the Langmuir isotherm.

Optimization of Synthesis of Spherical Lignosulphonate Resin and Its Structure Characterization

Calcium lignosulphonate was used to synthesize a spherical lignosulphonate resin in a cheap and non-toxic disperse medium by reversed phase suspension polymerization. The process conditions were optimized by orthogonal experiments. Under the optimal conditions ( T=95°C, c HCl=3 mol·L −1, m HCHO: m CLS=7%, w CLS=50%), globulation took about 20 min and the product was featured with excellent spherical shape, narrow particle size range, 61.20% of water retention capacity, 0.83 mmol·ml −1 of total volume exchange capacity and 3.46 mmol·g −1 of total exchange capacity. The results of Scanning Electron Micrograph and Scanning Probe Micrograph indicate that spherical lignosulphonate resin has a rugged surface with porous microstructure in the gel skeleton. The average pore size of dry samples was determined to be 10.46 nm by the BET method.

Synthesis and characterization of superparamagnetic poly(urea-formaldehyde) adsorbents and their use for adsorption of flavonoids from Glycyrrhiza uralensis Fisch

Superparamagnetic spherical poly(urea-formaldehyde) (PUF) adsorbents were synthesized and their selective adsorption for licorice flavonoids was investigated in this paper. The magnetite (Fe(3)O(4)) nanoparticles were prepared by co-precipitation of ferrous and ferric salts. Then the magnetic adsorbents with PUF shell were synthesized by reversed phase suspension polymerization. The spherical adsorbents have an average diameter of 50 mu m and exhibit superparamagnetic characteristics. The saturation magnetization of the adsorbents was 15.1 emu/g. The sorption and desorption properties of licorice flavonoids on the adsorbents were studied. The result shows that the adsorbents have high adsorption capacity (about 16.7 mg/g (adsorbent)). The adsorption data of flavonoids generally obeys the Langmuir isotherm equation. The adsorption can reach equilibrium rapidly and depends strongly on the pH of the feed solution. The concentration of licorice flavonoids after desorption can reach 25.12% in the desorbed fraction with 75% ethanol solution, which is higher than the 21.9% of commercial macroporous resin XDA-1. HPLC showed that liquiritin, one of main flavonoids in the licorice, was retained in this fraction, while glycyrrhizic acid (GA) can be almost removed from this fraction.

Drug release from α, β-poly( N-2-hydroxyethyl)- dl-aspartamide-based microparticles

Spherical pH-sensitive microparticles have been prepared by reverse phase suspension polymerization technique. Starting polymer has been α, β-poly( N-2-hydroxyethyl)- dl-aspartamide (PHEA) partially derivatized with glycidylmethacrylate (GMA). PHEA-GMA copolymer (PHG) has been crosslinked in the presence of acrylic acid (AA) or methacrylic acid (MA) at various concentration. The obtained microparticles have been characterized by FT-IR spectrophotometry, particle size distribution analysis and scanning electron microscopy. In order to have information about water affinity of the prepared samples, swelling measurements have been carried out in aqueous media which simulate some biological fluids. The possibility to employ the prepared samples as pH-sensitive microparticles has been investigated by performing in vitro release studies. Experimental data have showed that the release rate from these microparticles depends on the environmental pH and the chemical structure of the drug.

Beads of Acryloylated Polyaminoacidic Matrices Containing 5-Fluorouracil for Drug Delivery

Spherical polymeric microparticles have been prepared by a reverse phase suspension polymerization technique. The starting polymer was α, β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), partially derivatized with glycidylmethacrylate (GMA). PHEA-GMA copolymer (PHG) was crosslinked in the presence of N,N'-dimethylacrylamide (DMAA) or N,N'-ethylenebisacrylamide (EBA). 5-fluorouracil was incorporated into PHG-DMAA or PHG-EBA beads both during and after the crosslinking process. Swelling studies revealed a high affinity toward aqueous medium, influenced by the presence of 5-fluorouracil. The in vitro release study showed that the release rate depends on the chemical structure of the beads and the procedure adopted to incorporate 5-fluorouracil into the microparticles.

Synthesis of self-crosslinking sodium polyacrylate hydrogel and water-absorbing mechanism

In this paper, the super-absorbent, self-crosslinking sodium polyacrylate was synthesized by means of reversed-phase suspension polymerization under gamma-ray irradiation and the water-absorbing mechanism of the self-crosslinking hydrogel was revealed. Some physical parameters of such a network were estimated and investigated. The stable suspension polymerization of sodium acrylate was carried out in the presence of a surfactant complex consisting of anionic surfactant dodecylbenzen sulfonic sodium (DSS) and nonionic surfactant Span60 or Span20 with a certain ratio. The dual-electronic structure resulted from such a surfactant complex makes the dispersed monomer solution droplets a stable suspension in organic solvent. The water-sorbability was related to the radiation conditions such as dose, dose rate, and degree of monomer neutralization. Only under high dose and dose rate, some initiated branch side species on the main macromolecular chain can couple each other and cause a self-crosslinking network which may contain a lot of water. The gel dose was about 1.57 kGy (radiation dose unit), and G(X), or G value expressed as crosslinking probability at certain energy of 100 ev, was calculated and found to be 2.46 (1/100 ev). The water-sorbing procedure includes three stages, e.g., sorption on the pore surface, ionization of the fixed charges in the network, and swelling equilibrium. The crosslink chain length in the self-crosslinked sodium polycrylate network, expressed as Mc, can be calculated and related to gel dose.

Facile synthesis of new amine high‐loaded poly(meth)acrylamide‐based resins for solid phase peptide

AbstractTwo methods for the ready preparation of some protected primary amine‐functionalized (meth)acrylamide derivatives from amino halides or amino alcohols are described. The (meth)acryloyl moiety is introduced either in the last step from unsymmetrically N,N′‐disubstituted diamines or, more simply, in the first step, but that demands a special work‐up of the reaction mixture in order to prevent polymerization. Both methods are complementary. Reverse phase suspension polymerization of the title compounds with N‐acryloylpyrrolidine and N,N′‐ethylenebis(acrylamide) directly affords new beaded, high‐loaded aminefunctionalized resins for solid phase peptide synthesis.

POLY‐N‐ACRYLYLPYRROLIDINE A NEW RESIN IN PEPTIDE CHEMISTRY

Entirely beaded poly-N-acrylylpyrrolidine-co-bisacrylyl-1,2-diaminoethane-co-N-acrylyl-1,6-diaminohexane.HCl(PAP), a new resin on which to perform peptide chemistry, has been prepared by reverse phase suspension polymerization in quantitative yield. In addition to being a superior support to polystyrene, albeit readily adaptable to current techniques of peptide synthesis, its versatility has been furthur extended by the introduction and use of new peptide-to-polymer linking groups, which allow the use of the bidirectional approach to peptide chemistry. One such linkage, which connects the side chain of cysteine to PAP via an acid resistant S-carbamoyl bond, was used in a bidirectional synthesis of deamino-oxytocin. PAP solvates and swells in solvents with wide-ranging polarities, including aqueous media. Thus, peptide coupling reactions were performed in organic media of high and of low polarity as well as in aqueous solution.