Synthesis,characterization, and curing of well-defined allyl ether-maleate functional ester oligomers: Linear versus nonlinear structures

A series of allyl ether-maleate functional star-shaped esters with from one to four arms has been synthesized. The structures that have been made are an analogous series with increasing molecular weight and functionality where the increase in molecular weight has been made nonlinear, i.e., star-shaped. The resins are monodisperse in the sense that each arm has a well-defined structure and that, within a certain sample, only one type of molecule exists. The viscosity and rheological behavior of the resins have been studied. The curing kinetics of the star-shaped (branched) resins and the properties of the films formed have also been studied. These properties have been related to differences in functionality and to differences in the molecular architecture of the resins. © 1992 John Wiley & Sons, Inc.     

Urea-formaldehyde resins characterized by thermal analysis and FTIR method

Urea-formaldehyde (UF) resins are the most used polycondensation resins today, in manufacturing particleboards. UF resins possess some advantages such as fast curing, good performance in the panel, water solubility and low price. However, the main chemical bonds of the UF resins macromolecules are hydrolysis sensitive. This causes low water and mositure resistance performance and subsequent formaldehyde release from the UF-bonded panels. A multitude of pathways have been explored for the improvement of UF resins’ behavior relating either to their synthesis procedure or application parameters during panel manufacture. In this study, two UF resins (a conventional and an innovative one produced at very low pH and temperature conditions) were analyzed for their specifications and characterized with TG-DTA technique in dynamic heating conditions and FTIR measurements both in their pre-polymer and cured state.     

Heavy metal ion uptake properties of polystyrene-supported chelating polymer resins

Metal ion uptake properties of polystyrene-supported chelating polymer resins functionalized with (i) glycine, (ii) hydroxy benzoic acid, (iii) Schiff base and (iv) diethanol amine have been investigated. The effects of pH, time and initial concentration on the uptake of metal ions have been studied. The uptake of metal ion depends on pH. The resins are more selective at pH 10 for Pb(II) and Hg(II), whereas at pH 6 they are found to be Cd(II) and Cr(VI) selective. Metal ion uptake properties of resins follow Freundlich’s equation. The resins are recyclable and are therefore employed for the removal of heavy metal pollutants from industrial waste water.     

Separation and determination of some metal ions on new chelating resins containing N, N donor sets

Two new stable chelating resins have been synthesized incorporating the imidazolylazobenzene and 1,4-bis(imidazolylazo)benzene as functional group into Merrifield polymer through CN covalent bond and characterized by elemental analyses, IR and thermal study. A comparison of sorption capacity of newly formed resins towards the cations Ag(I), Cu(II), Zn(II), Cd(II), Hg(II) and Pb(II) as a function of pH has been studied. Kinetic studies show the time for the completeness of metal ion saturation with the resin phase. Cd(II) in trace quantities has been successfully separated and determined in different biological samples and Zn(II) in medicinal samples. It is also found that Cd(II) can be removed from water at usual pH of natural water. Both the resins can be employed for water purification as the resins reveal sorption ability towards toxic metal ions and exhibit no affinity to alkali or alkaline earth metal ions.     

Exit reactor Thetis/Ghent (1967–2003): A recollection of its significant contribution to NAA and its leading role in the development of the k<Subscript>0</Subscript>-standardization

Resins with monoamides as functional groups have been synthesized and their fundamental adsorption behaviors have been examined for selective recovery of uranium(VI) from nitric acid media. The resins synthesized with porous silica support showed greatly different adsorptions for U(VI) depending on the chemical structures of the functional group. Some resins show little or no adsorption for U(VI) from 0.1 to 6 mol/dm³ HNO₃. While, resins consisting of dimethylacrylamide (DMAA) showed an increasing adsorption with an increasing concentration of HNO³ up to 9 to 12 mol/dm³. Other ions were not found to be adsorbed onto Silica-DMAA under similar solution conditions, which means that the resin is selective for U(VI) in HNO₃ media.     

Uptake of alkanes and alcohols by ion-exchange resins in aqueous solution.

Uptake of alkane (C5-C9) and alcohol (C4-C7) solutes by both strong acid cation exchange resins and strong base anion exchange resins in aqueous medium has been studied. The amount of solute taken up by resins is directly proportional to the solute concentration equilibrium with resins. Hydrophobic interaction between the solute and the resin matrix appears to play an important role in the uptake phenomenon.     

Natural resins and balsams from an eighteenth-century pharmaceutical collection analysed by gas chromatography/mass spectrometry

Historical nomenclature has not always been unequivocally associated with the botanical origin of natural resins. The availability of natural resins has changed throughout the centuries and so have their trade names. Furthermore, adulterations and lack of knowledge have led to variations in the composition of the products traded under the same name. This investigation aims at a new understanding of the interrelation between the historical and modern terms for natural resins. Different Pinaceae and Pistacia resins, mastic, sandarac, copaiba balm and burgundy pitch from Vigani’s Cabinet, a 300-year-old pharmaceutical collection owned by Queens’ College, Cambridge (UK) were investigated. Related reference materials from modern collections were analysed together with natural resins derived from reliable botanical sources. The analytical method was gas chromatography/mass spectrometry (GC-MS) with and without derivatisation with trimethylsulfonium hydroxide. This technique provided detailed molecular compositions of the studied materials, which in turn led to particular data profiles of the materials. Marker molecules of Copaifera, Pinaceae, Cupressaceae and Pistacia resins were identified. By comparing the GC-MS data profiles to the reference samples, a clearer picture of the connection between nomenclature and botanical origin was obtained. With the aid of the marker molecules and data profiles, it was then possible to clarify the nomenclature of the aged resins sampled from Vigani’s Cabinet.     

Synthesis and characterization of thiocarbonohydrazone-based epoxy resins

Novel epoxy resins of various thiocarbonohydrazones have been synthesized by reacting the aldehyde or ketone derivatives of thiocarbohydrazide with excess of epichlorohydrin. The resins have been characterized by elemental analyses, epoxy equivalents, ¹H-NMR and IR spectra, thermal analyses, and viscosity measurements. Curing of the resins has been carried out by mixing with thiocarbohydrazide or ethylenediamine and heating at 80°C for 48 h. A comparison of the thermal stability of the cured resin samples has been made.     

新型含氮、硫纤维素螯合树脂的合成及其吸附性能

将稻壳纤维素的氯化产物(CDC)分别与水合肼、乙二胺、二乙烯三胺、三乙烯四胺、丁二胺和己二胺反应,合成了6种含氮纤维素螯合树脂(ADC-1～ADC-6);在碱性条件下用环硫氯丙烷交联ADC合成了6种新型含氮、硫纤维素螯合树脂(TADC-1～TADC-6),研究了合成条件和ADC,TADC树脂对金属离子的吸附性能.结果表明,ADC树脂对Cu²⁺,Cr³⁺,Ni²⁺,Hg²⁺,Zn²⁺等离子有较好的吸附性,对Hg²⁺吸附容量可达0.5mmol/g左右;TADC树脂对Ag⁺,Cu²⁺,Hg²⁺等离子有较好的吸附性,对Hg²⁺和Ag⁺吸附容量可达1.1mmol/g和1.9mmol/g左右;强酸性条件下,ADC和TADC树脂的吸附容量都降低,它们对金属离子的吸附顺序分别为Hg²⁺>Cu²⁺>Ni²⁺和Ag⁺>Hg²⁺>Cu²⁺,树脂用10%的氨水解吸附可重复使用.     

Macroreticular p-(omega-sulfonic-perfluoroalkylated) polystyrene ion-exchange resins: a new type of selective solid acid catalyst

Macroreticular p-(omega-sulfonic-perfluoroalkylated) polystyrene (FPS) cation-exchange resins have been synthesized by sequential p-perfluoroalkylation of macroreticular polystyrene (PS) with omega-fluorosulfonylperfluorodiacyl peroxide 2, hydrolysis and acidification; the fluorinated mesoporous resins exhibited higher activity and selectivity than commercial Amberlyst 36 and Nafion NR50 in the cyclization of pseudoionone.     

丙烯腈系大孔螯合树脂的合成及研究——Ⅰ.大孔PSA树脂的制备及结构研究

氰基树脂是氮配位及氮氧协同配位型螯合树脂的重要母体之一,也可制备专一性吸附树脂和弱酸树脂,故丙烯腈系大孔树脂的合成及结构研究具有一定的理论与实际意义。线型高分子致孔时可得更大孔径的树脂,但因丙烯腈(AN)的沉淀聚合特性,聚丙烯腈(PAN)不能用于丙烯腈系树脂的致孔。 本文选用线型聚苯乙烯(PS)、PS-环己     

Synthesis, characterization, and cure properties of phosphorus-containing epoxy resins for flame retardance

An organophosphorus compound, 10-(2,5-dihydroxyl phenyl)-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DHPDOPO), was synthesized through the reaction of 9,10-dihydro-9-oxa-10-phosphaphnanthrene-10-oxide (DOPO) and p-benzoquinone, and characterized by elemental analysis, Fourier transform infrared spectrum (FTIR), and ¹H-NMR and ³¹P-NMR spectroscopes. Consequently, the phosphorus-containing epoxy resins with phosphorus content of 1 and 2 wt.% were prepared via the reaction of diglycidyl ether of bisphenol-A with DHPDOPO and bisphenol-A, and confirmed with FTIR and gel permeation chromatography (GPC). Phenolic melamine, novolak, and dicyanodiamide (DICY) were used as curing agents to prepare the thermosetted resins with the control and the phosphorus-containing epoxy resins. Thermal properties and thermal degradation behaviors of these the thermosetted resins were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Phenolic melamine-cured resins exhibited higher glass transition temperatures than the other cured resins due to the high rigidity of their molecular chain. TGA studies demonstrated that the decomposition temperatures of the novolak-cured resins were higher than those of the others. A synergistic effect from the combination of the phosphorus-containing epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermosetted resins.     

Photopatternable thin films from silyl hydride containing silicone resins and photobase generators

The photopatternability of various silyl hydride containing organosilicone resins containing the photobase generators N‐methylnifedipine or O‐(2‐nitrobenzyl)‐N‐octyl carbamate have been examined, with the goal of identifying potential photopatternable compositions with high thermal stability after cure. Two different categories of silicone resins have been prepared from combinations of diphenylsiloxane and methyl and hydrogen silsesquioxane units and a combination of phenyl and hydrogen silsesquioxane monomer units. The photobase generators were incorporated into these resins at concentrations up to 10 weight percent. UV‐irradiation of micrometer thick silicone resin‐photobase films through a photomask, under an air atmosphere, yielded micrometer scale features after development. Photopatternable compositions have been identified with photosensitivities of less than 50 mJ/cm2. The photopatterning process is believed to proceed by base‐catalyzed reaction of resin‐based silanol groups with neighboring silyl hydride groups to yield thermally stable siloxane crosslinks. Copyright © 1999 John Wiley & Sons, Ltd.     

Extraction of palladium from nitric acid medium by commercial resins with phosphinic acid,methylene thiol and isothiouronium moieties attached to polystyrene-divinylbenzene

Summary Commercially available polystyrene-divinylbenzene (PS-DVB) resins functionalized with isothiouronium (Tulsion CH-95), phosphinic acid (Tulsion CH-96) and methylene thiol (Tulsion CH-97) moieties have been used for separating palladium from nitric acid medium. Extraction of palladium has been studied as a function of time, concentration of nitric acid and palladium. The distribution coefficients (K_d, ml/g) of palladium on sulfur based resins (Tulsion CH-95 and Tulsion CH-97) are higher (5000-10⁴ml/g in 0.1M nitric acid) than on Tulsion CH-96 resin and decrease with increasing concentration of nitric acid. The initial rate of extraction of palladium by Tulsion CH-95 and Tulsion CH-97 resins was very rapid and the time required for the establishment of equilibrium was a function of palladium concentration in the aqueous phase. The rate data could be fitted by a second order rate equation and the magnitude of rate constant for the extraction of palladium by these resins (~10²M^-1. min^-1) decreased in the order of: Tulsion CH-95 > Tulsion CH-97 > Tulsion CH-96. The extraction isotherms of Tulsion CH-95 were fitted by Langmuir adsorption model and the coefficients were obtained by regression. The extraction capacity of palladium on Tulsion CH-95 was found to be ~20 mg/g at 3M nitric acid. Column experiments have been conducted and the data were fitted using Thomas model. A column utilization of 75% was achieved for the extraction of palladium by Tulsion CH-95 resin.     

Synthesis of Davankov‐type hypercrosslinked resins using different isomer compositions of vinylbenzyl chloride monomer,and application in the solid‐phase extraction of polar compounds

Two different gel‐type resins have been prepared by suspension polymerization using 2 wt % divinylbenzene (DVB) with either p‐vinylbenzyl chloride (pVBC) or a mixture of VBC isomers (～ 70% m‐; ～ 30% p‐). Significant difference in the chlorine content was observed, which was attributed to a more favored hydrolysis process when p‐VBC was used. The presence of hydroxyl groups has been confirmed by elemental microanalytical data and solid‐state ¹³C cross‐polarization/magic angle spinning (CP‐MAS) nuclear magnetic resonance (NMR) spectra. Hypercrosslinked resins were prepared from both gel‐type precursors by treatment with FeCl₃ in 1,2‐dichloroethane (DCE) at 80 °C. The resultant resins showed differences in specific surface area and degree of hydrophilicity. The performance of the hypercrosslinked resins was evaluated in solid‐phase extraction (SPE) of polar compounds, and better results were obtained for the hypercrosslinked resin prepared from p‐VBC that combines a relatively high specific surface area (908 m² g^?1) and somewhat higher oxygen content (3.96 wt % O). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1718–1728, 2005     

Epoxy resins from rosin acids: synthesis and characterization

A series of multifunctional cycloaliphatic glycidyl ester and ether epoxy resins were synthesized by reaction of condensed rosin acid‐formaldehyde resins with epichlorohydrin. The chemical structure of the produced resins was determined by IR and ¹H‐NMR analysis. The molecular weight of the produced resins was determined by gel permeation chromatography (GPC). A series of poly‐ (amide‐imide) hardeners were prepared from condensation of Diels–Alder adducts of rosin acid‐maleic anhydride and acrylic acid with triethylene tetramine and pentaethylene hexamine. These amines were also condensed with Diels–Alder adducts of rosin ketones. The curing exotherms of the produced epoxy resins with poly(amide‐imide) hardeners were investigated. The data of mechanical properties, solvent and chemical resistance indicate the superior adhesion of the cured epoxy resins. Copyright © 2004 John Wiley & Sons, Ltd.     

Thermosetting characteristics of some new polymethylol epoxy resins

Several new polymethylol epoxy resins have been synthesised in a one pot reaction system and characterised. The new resins are derived from epichlorohydrine, formaldehyde and several aromatic phenols: phenol, biphenylol, bisphenol-A, bisphenol-S, sulphone, and DDT. The rate of crosslinking has been studied at different temperatures (120–180°C) by determining the amount of H₂O evolved from the crosslinking reaction using a DuPont moisture evolution analyser; the activation energy of setting has been determined from Arrhenius plots. The results are 57.1, 50.0, 42.9, 75.2, 11.3 and 74.3 kJ mol⁻¹ for resins I–VI respectively. The set resins show good thermal stability and are resistant toward chemicals and solvents; these resins also set catalytically at room temperature.     

Polyaryläther-Kondensationsprodukte des 4,4′-bis(chloromethylphenyl) äthers mit manchen diphenolen

Poly(aryl ethers) as products of the polycondensation of 4,4′-bis(chloromethylphenyl) ether with sodium salts of various phenols have been prepared in the Williamson reaction. The reaction was carried out at three different temperatures (78, 140, and 185°C.) in ethanol, xylene, and tetralin, respectively. The effect of the polycondensation and the nature and composition of initial components on the properties of the products has been studied. The molecular weights and the melting temperature of the synthesized resins increased with increasing reaction temperature. The structure and molecular weight have a pronounced effect on the properties of the resins. Resins prepared from 4,4′-dihydroxydinaphthyl had the highest melting temperature and were practically insoluble, while the resins prepared from 2,2′-dihydroxydinaphthlmethane had the lowest melting temperature and were soluble in practically all organic solvents. On the basis of the experimental data a reaction scheme appropriate for the synthesis of poly(aryl ethers) from the phenolates as well as from the free phenols in the presence of NaOH has been proposed. Some thermal and mechanical properties of poly(aryl ethers) have been determined. Thermal treatment of the resins above theri softening temperature resulted in an elevated softening point too. This is explained by the supplementary condensation of both chlorine or hydroxyl endgroups in the molten resins.     

Uricase-like catalytic activity of ion-exchange resins modified with metalloporphyrins

The uricase-like catalytic activity of the ion-exchange resins modified with metalloporphyrins has been investigated through the oxidation of uric acid. The anion-exchange resins modified with Mn(3+)-tetrakis(sulfophenyl)porphine and the cation-exchange resin modified with Mn(3+)-tetrakis(1-methylpyridinium-4-yl)porphine exhibited the highest uricase-like activity among the modified resins tested. The fact that these resins accelerated the oxidation of uric acid even after ten cycles of use indicates that the modified resins act as catalysts in the reaction catalysed by uricase. Some of the modified resins may be effectively used for the determination of uric acid in place of uricase.     

Cross-linked polystyrene resins containing triorganotin-4-vinylbenzoates: Assessment of their catalytic activity in transesterification reactions

Three new resins are synthesized by radical co-polymerization of triorganotin-4-vinylbenzoates (substituent at tin = Me, Bu or Ph) with styrene and 1,4-divinylbenzene. The products prepared have been characterized by FT-IR and NMR spectroscopy both in the solid state and as swollen samples, showing a predominantly tetracoordinated tin atom. The catalytic activity of the above resins in a transesterification reaction has been tested using ethyl acetate and primary, secondary or tertiary alcohol, showing good results with the former, but not with the latter ones. Focussing on the different triorganotin substituents, a comparison between the prepared resins and low molecular weight analogues evidences a lower activity of the resins, due to their inhomogeneous operating conditions. However, the triphenyltin functionalized resin shows a transesterification activity comparable to the corresponding model compound. The reaction mechanism and the effects of Lewis acidity of the different groups linked to tin have been investigated by ¹H and ¹¹⁹Sn hr-MAS NMR.