Solid Polymers Doped with Neodymium. Complex Formation and Morphology in NdCl3 and Nd(DPM)3-Poly(Ethylene Oxide) Systems

1990 ◽  
Vol 210 ◽  
Author(s):  
Conor J. Twomey ◽  
Shaw H. Chen
Keyword(s):  
Complex Formation ◽  
Prolonged Exposure ◽  
Salt Content ◽  
Molar Ratio ◽  
Stoichiometric Ratio ◽  
Oxide Systems ◽  
Residual Moisture ◽  
Polymer Backbone ◽  
Hygroscopic Nature ◽  
Poly Ethylene

AbstractThe complex formation and morphology of the NdCI3—PEO system are presented together with some preliminary results on the Nd(DPM)3 \Nd—tris—2,2,6,6—tetramethyl —3,5—heptane dionate]—PEO system. Although the NdCl3—PEO complex is found to be highly hygroscopic, it is shown that residual moisture can be removed reversibly, thereby permitting the role of water in affecting the morphology of the solid to be examined. It is concluded that complexation is a competitive process between the ether oxygens on the polymer backbone and water. Under anhydrous conditions the resultant complex is amorphous at a \EO]/\NdCl3] molar ratio approximately less than ca. 8, but above this critical value the PEO in excess of the stoichiometric ratio presents a second partially crystalline phase. The glass transition temperatures were found to increase sigmoidally with increasing salt content. Despite the hygroscopic nature of Nd(DPM)3 the resultant complexes were found to be moisture resistant upon prolonged exposure to the atmosphere.

On the Properties of an Ion Conductive System Incorporated in Hybrid Films

2000 ◽  
Vol 628 ◽  
Author(s):  
G. González ◽  
P. J. Retuert ◽  
S. Fuentes
Keyword(s):  
Electrochemical Impedance ◽  
Ternary Phase Diagram ◽  
Lithium Perchlorate ◽  
Molar Ratio ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
Poly Ethylene Oxide ◽  
Ion Conducting ◽  
Poly Ethylene ◽  
High Degree

ABSTRACTBlending the biopolymer chitosan (CHI) with poly (aminopropilsiloxane) oligomers (pAPS), and poly (ethylene oxide) (PEO) in the presence of lithium perchlorate lead to ion conducting products whose conductivity depends on the composition of the mixture. A ternary phase diagram for mixtures containing 0.2 M LiClO4 shows a zone in which the physical properties of the products - transparent, flexible, mechanically robust films - indicate a high degree of molecular compatibilization of the components. Comparison of these films with binary CHI-pAPS nanocomposites as well as the microscopic aspect, thermal behavior, and X-ray diffraction pattern of the product with the composition PEO/CHI/pAPS/LiClO4 1:0.5:0.6:0.2 molar ratio indicates that these films may be described as a layered nanocomposite. In this composite, lithium species coordinated by PEO and pAPS should be inserted into chitosan layers. Electrochemical impedance spectroscopy measurements indicate the films are pure ionic conductors with a maximal bulk conductivity of 1.7*10-5 Scm-1 at 40 °C and a sample-electrode interface capacitance of about 1.2*10-9 F.

Investigating the Effect of Thermoelectric Processing on Ionic Aggregation in Thermoplastic Ionomers

2017 ◽  
Author(s):  
Prasant Vijayaraghavan ◽  
Vishnu-Baba Sundaresan
Keyword(s):  
Mechanical Properties ◽  
Electrostatic Field ◽  
Thermal Studies ◽  
Effect Of Temperature ◽  
Self Healing ◽  
Polymer Backbone ◽  
Ionic Dissociation ◽  
Dissociation Temperature ◽  
Aggregate Morphology ◽  
Poly Ethylene

Ionomers are a class of polymers which contain a small fraction of charged groups in the polymer backbone. These ionic groups aggregate (termed ionic aggregates) to form temporary cross-links that break apart over the ionic dissociation temperature and re-aggregate on cooling, influencing the mechanical properties of these polymers. In addition to enhanced mechanical properties, some ionomers also exhibit self-healing behavior. The self-healing behavior is a consequence of weakly bonded ionic aggregates breaking apart and re-aggregating after puncture or a ballistic impact. The structure and properties of ionomers have been studied over the last several decades; however, there is a lack of understanding of the influence of an electrostatic field on ionic aggregate morphology. Characterizing the effect of temperature and electric field on the formation and structure of these ionic aggregates will lead to preparation of ionomers with enhanced structural properties. This work focuses on Surlyn 8940 which a poly-ethylene methacryclic acid co-polymer in which a fraction of the carboxylic acid is terminated by sodium. In this work, Surlyn is thermoelectrically processed over its ionic dissociation temperature in the presence of a strong electrostatic field. Thermal studies are performed on the ionomer to study the effect of the thermoelectric processing. It is shown that the application of a thermoelectric field leads to increase in the ionic aggregate order in these materials and reduction in crystal size distribution. Thermal Analysis is performed using a Differential Scanning Calorimeter and the resulting thermogram analysis shows that thermoelectric processing increases the peak temperature and onset temperature of melting by 4 C and 20 C respectively. The peak width at half maximum of the melting endotherm is reduced by 10 C due to thermoelectric processing. This serves as a measure of the increased crystallinity. A parametric study on the effect of field duration and field strength is also performed.

Micellization of pH-sensitive poly(butadiene)-block -poly(2 vinylpyridine)-block -poly(ethylene oxide) triblock copolymers: Complex formation with anionic surfactants

2017 ◽  
Vol 134 (38) ◽  
pp. 45313 ◽  
Author(s):  
Leonard Ionut Atanase ◽  
Jean-Philippe Lerch ◽  
Simona Caprarescu ◽  
Camelia Elena Iurciuc Tincu ◽  
Gerard Riess
Keyword(s):  
Complex Formation ◽  
Ethylene Oxide ◽  
Anionic Surfactants ◽  
Triblock Copolymers ◽  
Ph Sensitive ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Control the Surface Wettability of Thermo-Responsive Poly(Ethylene Glycol Methyl Ether methacrylate-co-Triethylene Glycol Methyl Ether Methacrylate) Thin Film by Varying Temperature

2021 ◽  
Vol 873 ◽  
pp. 53-58
Author(s):  
Yang Yi Chen ◽  
Min Pan ◽  
Shan Hong Hu ◽  
Qi Huan ◽  
Chu Yang Zhang
Keyword(s):  
Thin Film ◽  
Ethylene Glycol ◽  
Methyl Ether ◽  
Triethylene Glycol ◽  
Surface Wettability ◽  
Molar Ratio ◽  
Poly Ethylene Glycol ◽  
Vis Spectroscopy ◽  
Poly Ethylene ◽  
Glycol Methyl Ether

The surface wettability of thermo-responsive random poly (ethylene glycol methyl ether methacrylate-co-triethylene glycol methyl ether methacrylate), abbreviated as P(MEOMA-co-MEO3MA), was investigated in thin film. UV-Vis spectroscopy shows that the LCST of P(MEOMA-co-MEO3MA) with molar ratios of 0:20, 6:14 and 9:11 were 43°C, 32 oC and 25 oC, respectively. LCST shifts towards lower temperature when molar ratio of MEOMA increases. ATR-FTIR indicates that P(MEOMA-co-MEO3MA) thin film experienced a collapse when the temperature passes its LCST. The contact angle of the paraffin oil on the film decreases 15o when the temperature is above its LCST, which confirms the surface wettability can be controlled. Atomic force microscopy shows the surface of the swollen thin film becomes rougher when above it LCST.

Tracing the transport of organic colloids in porous media using tailored poly(ethylene glycol)

2021 ◽  
Author(s):  
Thomas Ritschel ◽  
Katharina Lehmann ◽  
Michaela Brunzel ◽  
Jürgen Vitz ◽  
Ivo Nischang ◽  
...  
Keyword(s):  
Porous Media ◽  
Ethylene Glycol ◽  
Water Solubility ◽  
Size Range ◽  
Large Fraction ◽  
Colloid Interface ◽  
Poly Ethylene Glycol ◽  
Polymer Backbone ◽  
Colloidal Transport ◽  
Poly Ethylene

<p>A large fraction of organic matter in natural aqueous soil solutions is given by molecules in sizes above one nanometer, which classifies them as colloids according to the IUPAC definition. Such colloids feature discernable mobility in soils and their transport is decisive for the cycling of carbon as well as the migration of nutrients or contaminants. Yet, their size-dependent hydrodynamics and functional diversity result in transport phenomena that are specific to colloids and, thus, largely differ from those observed for smaller substances. Still, tracers that appropriately represent small organic colloids are not available and the investigation of their transport in laboratory column experiments, in dependence of size and chemistry, remains difficult. To overcome this limitation, we tested if well-defined synthetic polymers in the colloidal size range are suitable as non-conventional tracers of colloidal transport. As polymer backbone, we selected poly(ethylene glycol) (PEG) due to its high water-solubility and established pathway of synthesis that permits tailoring of functional moieties to the fullest extent. An easy and sensitive detection in the aqueous phase became possible by using a fluorophore as starting group. After full characterization, we studied PEG adsorption to quartz, illite, goethite, and their mixtures in batch and column transport experiments. In numerical simulations, we successfully reconstructed and predicted PEG transport based on its physicochemical as well as hydrodynamic properties and, thus, show that PEG transport can be comprehensively and quantitatively studied. Considering also its low adverse effect on the environment, functional PEG therefore presents as promising candidate to be used as organic tracer, designable in the size range of natural organic (macro-)molecules (Ritschel et al., 2021).</p><p>References</p><p>Ritschel, T., Lehmann, K., Brunzel, M., Vitz, J., Nischang, I., Schubert, U., Totsche, K. U. (2021) <strong>Well-defined poly(ethylene glycol) polymers as non-conventional reactive tracers of colloidal transport in porous media</strong>.<em> J. Colloid Interface Sci.</em> 548, 592-601, doi: 10.1016/j.jcis.2020.09.056.</p>

scholarly journals Biological Study of Transition Metal Complexes with Adenine Ligand

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 77 ◽  
Author(s):  
Hamad M. I. Hasan ◽  
Aaza I. Yahiya ◽  
Safaa S. Hassan ◽  
Mabrouk M. Salama
Keyword(s):  
Metal Complexes ◽  
Molar Conductance ◽  
Molar Ratio ◽  
Biological Study ◽  
Ratio Method ◽  
Spectroscopic Techniques ◽  
Stoichiometric Ratio ◽  
Metal Contents ◽  
Molar Ratio Method

Adenine complexes were prepared with some of the first series transition metals in a stoichiometric ratio of 1: 2 (Mn+: L), where Mn+ = Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ ions. The Complexes were characterized by the physicochemical and spectroscopic techniques as electric conductivity, metal contents, IR, UV–Visible, and molar conductance techniques. The stoichiometric ratios of the synthesized complexes were confirmed by using molar ratio method. The dissociation constant of adenine ligand was determined spectrophotometrically. Solvent effect on the electronic spectra of the adenine ligand was examined using solvents with different polarities. The biological activity of adenine ligand and its metal complexes were tested in vitro against some selected species of fungi and bacteria. The results showed a satisfactory spectrum against the tested organisms.

scholarly journals Crystallization of Poly(ethylene)s with Regular Phosphoester Defects Studied at the Air–Water Interface

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2408
Author(s):  
Nazmul Hasan ◽  
Karsten Busse ◽  
Tobias Haider ◽  
Frederik R. Wurm ◽  
Jörg Kressler
Keyword(s):  
Surface Pressure ◽  
Repeat Unit ◽  
Isothermal Condition ◽  
Chloroform Solution ◽  
Epifluorescence Microscopy ◽  
Polymer Backbone ◽  
Lb Films ◽  
Polar Groups ◽  
Poly Ethylene ◽  
Crystalline Domains

Poly(ethylene) (PE) is a commonly used semi-crystalline polymer which, due to the lack of polar groups in the repeating unit, is not able to form Langmuir or Langmuir–Blodgett (LB) films. This problem can be solved using PEs with hydrophilic groups arranged at regular distances within the polymer backbone. With acyclic diene metathesis (ADMET) polymerization, a tool for precise addition of polar groups after a certain interval of methylene sequence is available. In this study, we demonstrate the formation of Langmuir/LB films from two different PEs with regular phosphoester groups, acting as crystallization defects in the main chain. After spreading the polymers from chloroform solution on the water surface of a Langmuir trough and solvent evaporation, the surface pressure is recorded during compression under isothermal condition. These π-A isotherms, surface pressure π vs. mean area per repeat unit A, show a plateau zone at surface pressures of ~ (6 to 8) mN/m, attributed to the formation of crystalline domains of the PEs as confirmed by Brewster angle and epifluorescence microscopy. PE with ethoxy phosphoester defects (Ethoxy-PPE) forms circular shape domains, whereas Methyl-PPE-co-decadiene with methyl phosphoester defects and two different methylene sequences between the defects exhibits a film-like morphology. The domains/films are examined by atomic force microscopy after transferring them to a solid support. The thickness of the domains/films is found in the range from ~ (2.4 to 3.2) nm depending on the transfer pressure. A necessity of chain tilt in the crystalline domains is also confirmed. Grazing incidence X-ray scattering measurements in LB films show a single Bragg reflection at a scattering vector qxy position of ~ 15.1 nm−1 known from crystalline PE samples.

Preparation and Properties of Polycarboxylate Superplasticizer with Hydroxy Terminated Side Chains

2012 ◽  
Vol 455-456 ◽  
pp. 600-605
Author(s):  
Sheng Hua Lv ◽  
Jian Ping Duan ◽  
Fang Li
Keyword(s):  
Maleic Anhydride ◽  
Ethylene Oxide ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
Side Chains ◽  
Polycarboxylate Superplasticizer ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Maleic anhydride modified polycarboxylates superplasticizes (MPC) was synthesized from allylic poly (ethylene oxide ether) (APEG), maleic anhydride (MAH), sodium methylallyl sulfonate (SMAS) using ammonium persulfate (APS) as initiator. The optimal MPC with best fluidity was got at 90 °C when molar ratio of MAH, APEG, SAMA was 2.75∶1∶0.4 in the present of 4.5 mol% APS of all the monomer molars. MPC which possessed hydroxyl terminated side chains shows some difference in fluidity retarding related to the conventional superplasticizers possessed methoxy terminated side chains.

Synthesis of zirconocene silsesquioxane complexes and their ethene polymerization activity in systems with methylaluminoxane

2010 ◽  
Vol 75 (1) ◽  
pp. 105-119 ◽  
Author(s):  
Vojtech Varga ◽  
Jiří Pinkas ◽  
Róbert Gyepes ◽  
Petr Štěpnička ◽  
Michal Horáček ◽  
...  
Keyword(s):  
Ir Spectra ◽  
Elemental Analysis ◽  
Molar Ratio ◽  
Stoichiometric Ratio ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Xps Spectra ◽  
Zirconocene Dichloride ◽  
Order Of Magnitude ◽  
Ethene Polymerization

Protocols for obtaining defined zirconocene complexes with polyhedral oligomeric silsesquioxanes with mono-, di-, and trisilanol functionality (SIPOSS, DIPOSS, and TRIPOSS) were established. The TRIPOSS silanolates binding one zirconocene and one chlorozirconocene moiety, [{(c-C5H9)7Si7O9O3}Zr2Cl(η5-C5H4R)4] (1, R = Bu; 2, R = H), were obtained by reacting the silanol with the respective zirconocene dichloride and triethylamine in CH2Cl2 in a 1.0:3.0:3.0 molar ratio, an excess of the zirconocene dichloride being required to suppress intramolecular dehydration of TRIPOSS. The related SIPOSS complex, [{(c-C5H9)7Si8O12O}2Zr(η5-C5H4Bu)2] (3), was prepared similarly at the stoichiometric ratio of [ZrCl2(η5-C5H4Bu)2]/ SIPOSS/NEt3 equal to 1.0:2.0:2.0. When employed in the 1.0:1.0:1.0 ratio, the same reagents afforded only the impure complex [{(c-C5H9)7Si8O12O}ZrCl(η5-C5H4Bu)2] (4), contaminated with 3 and unreacted [ZrCl2(η5-C5H4Bu)2]. Finally, the zirconocene complexes with SIPOSS and DIPOSS moiety, [{(c-C5H9)7Si8O12O}2Zr(η5-C5H5)2] (5) and [(c-C5H9)7Si7O9(OSiMe3)O2}- Zr(η5-C5H5)2] (6), respectively, were obtained by reacting [ZrMe2(η5-C5H5)2] with stoichiometric amounts of the appropriate silanols. All complexes were characterized by 1H, 13C, 29Si NMR and IR spectra, and by elemental analysis from XPS spectra. Preliminary ethene polymerization experiments showed that compounds 5 or 6 when combined with an excess of methylaluminoxane were nearly as active as [ZrCl2(η5-C5H5)2] whereas compound 2 was by about one order of magnitude less active.

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