Macroporous Styrene Divinylbenzene Research Articles

Fluorescence probes for the evaluation of diffusion of ionic reagents through network polymers: chemical quenching of the fluorescence emission of the Dansyl probe in macroporous styrene-divinylbenzene and styrene-diisopropenylbenzene copolymers

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFluorescence probes for the evaluation of diffusion of ionic reagents through network polymers: chemical quenching of the fluorescence emission of the Dansyl probe in macroporous styrene-divinylbenzene and styrene-diisopropenylbenzene copolymersK. J. Shea, G. J. Stoddard, and D. Y. SasakiCite this: Macromolecules 1989, 22, 11, 4303–4308Publication Date (Print):November 1, 1989Publication History Published online1 May 2002Published inissue 1 November 1989https://doi.org/10.1021/ma00201a027RIGHTS & PERMISSIONSArticle Views128Altmetric-Citations25LEARN 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 PDF (728 KB) Get e-Alerts Get e-Alerts

Extraction Chromatographic Performance of Uranium Using XAD-4 Loaded with Di-2-ethylhexylphosphoric Acid and Nitrate Solutions

Chromatographic extraction of uranium from nitrate medium using di-2-ethythexylphosphoric acid (HDEHP) loaded on XAD-4 (macroporous styrene divinylbenzene) is investigated. Parameters affecting column performance including flow rate, HDEHP concentration and column dimensions are studied in terms of height equivalent to theoretical plate and break-through capacity. The experimental results are analysed based on Van Deemter equation. The different constants representing the longitudinal diffusion of the solute in the mobile phase, packing irregularities of the column and rate of transfer of solute between the stationary and aqueous phases are evaluated and discussed. Optimum conditions for uranium removal from comparable simulated high active waste nitrate solution are studied.

Fischer-Tropsch synthesis catalyzed by iron catalyst supported on porous polymers: I. Synthesis of the supported catalyst and study of the repartition of the catalyst in the polymeric support

Macroporous styrene-divinylbenzene and 4-vinylpyridine divinylbenzene polymers were used as supports for an iron Fischer-Tropsch catalyst. The catalyst was based on iron in the zero-valent state. Two methods of preparation were tested: reduction of the catalyst after or before introduction into the polymeric support. In both cases, the dispersion of the catalytic species in the polymeric support was determined by electron probe X-ray microanalysis. It was shown that reduction of the catalyst after diffusion into the polymeric support gives a homogeneous distribution of the catalyst in the beads, whereas the diffusion of already reduced catalyst into the support leads to a heterogeneous mixture of species.

Chemical modification of styrene-divinylbenzene copolymers by dialkyl phosphites

Chloromethylated styrene-divinylbenzene copolymers were treated with dialkyl phosphites to obtain cation exchangers with phosphorus-containing acid groups. The gel and macroporous styrene-divinylbenzene (St-DVB) copolymers of Wofatit type were used. The influence of the phosphite (R=CH 3, C 2H 5) as well as of the copolymer structure (gel, macroporous) on the course of the phosphorylation and of the ester bond hydrolysis was investigated. The cation exchangers with -PO(OH)(OR) functional groups were obtained and their main properties (density, swelling, ion exchange capacity, p K a , thermal stability, i.r. spectra) were determined.

A spectral study of transition-metal complexes on a chelating ion-exchange resin containing aminophosphonic acid groups

The coordination mode of a commercial chelating ion-exchange resin, ES 467, containing aminomethylphosphonic acid groups anchored on a macroporous styrenedivinylbenzene copolymer, with several metal ions, such as chromium(III), cobalt(II), nickel(II), copper(II) and zinc(II) has been studied with the aid of IR, ligand field and ESR spectra. The chelating group of ES 467, aminomethylphosphonic acid, appears to bind different metal ions mainly through oxygen atoms of the phosphonic acid group, though, in the case of those species containing low-loading of metal ions, the secondary amine nitrogen atom also appears to take part in coordination. Most of the metal ions studied seem to be present as six-coordinated species in the polymeric matrix, whereas cobalt(II) species show electronic spectra which are consistent with the presence of both four-coordinated (tetrahedral) and six-coordinated (octahedral) structures of these species. The distribution coefficients for cobalt(II), nickel(II), copper(II) and zinc(II) have been determined and it appears that the resin ES 467 binds copper(II) ions selectively. An attempt has been made to find a possible relationship between the selectivity of the chelating resin and the stereochemistry of the adsorbed metal ions.

Relationships between the synthesis conditions and the characteristics of anion exchangers

AbstractSeveral macroporous styrene–divinylbenzene copolymers were prepared using different diluents. The copolymers were chloromethylated with monochlor methyl ether and aminated with N,N‐dimethyl‐2‐hydroxyethylamine in order to perform strongly basic anion exchanger, type II. It was established that the network morphology of anion exchanger determines its ion‐exchange rate. It was, also established, by means of transmission electron microscopy, that chloromethylation reaction led to the morphological changes in the macromolecular network of the copolymers.

Mechanical behavior and structure of single beads of homogeneous and macroporous styrene–divinylbenzene copolymers

The stress–stain and ultimate behavior in compression of homogeneous and macroporous beads of styrene–divinylbenzene copolymers has been investigated in the dry state or in equilibrium with toluene, acetone, methanol, and water. The penetration modulus A indicates sensitively the transition from the glassy into the rubbery state induced by an increase in temperature or swelling. For macroporous copolymers, A of the glassy polymers is mainly determined by the porosity P, while in the rubbery region it primarily depends on the matrix structure (degree of crosslinking and concentration and composition of the diluent). The high value of the slope s of the A vs. P dependence (s ∼ −3) for macroporous copolymers is evidence of the complex deformation mechanism (bucking of pore walls). The relative compression at break, eb=0.3–0.4, is independent of the composition, and the compressive strength is roughly proportional to the penetration modulus.

The effect of cross-linking on catalytic properties of macroporous styrene-divinylbenzene ion exchangers

Gas-phase dehydration of 1-propanol at 130 °C has been studied on a series of differently cross-linked sulfonated macroporous styrene-divinylbenzene copolymers. The degree of cross-linking of the catalysts influences the values of the constants of the Langmuir-Hinshelwood kinetic equation and brings about changes in total dehydration rate as well as in the ratio of the products formed by parallel reactions, propene and dipropyl ether. These phenomena are probably due to the extensive and fast permeation of 1-propanol into the polymer mass of the ion exchangers and the slow permeation of both reaction products from the polymer mass; during permeation the ether is transformed to a different extent into propene, which results in changes in selectivity. These conclusions were supported by measurements of 1-propanol dehydration on an ion exchanger containing functional groups only on the polymer surface, by the study of partial poisoning of the ion exchangers with nitrogen-containing bases, and by measurements of the relative sorption ability of the reaction components.

Structural parameters of network of macroporous copolymers of styrene and divinyl-benzene determined from their equilibrium swelling in toluene and acetone

The swelling of macroporous styrene divinylbenzene copolymers, containing 20, 40, 50, and 70% by weight of divinylbenzene was investigated in toluene and acetone at 25 °C. From the swelling equilibria between the copolymers and the two solvents possessing knownFlory-Huggins interaction parameterχ average isotropic dilatation factor of a dry network\(\left\langle {\bar \alpha ^2 } \right\rangle _0 \) and the concentration of elastically efficient chains in dry gelν* were determined. Crosslinking uniformity in the gel phase of the copolymers was assumed.

33. Solvent-modified polymer networks. Part I. The preparation and characterisation of expanded-network and macroporous styrene–divinylbenzene copolymers and their sulphonates

33. Solvent-modified polymer networks. Part I. The preparation and characterisation of expanded-network and macroporous styrene–divinylbenzene copolymers and their sulphonates