Synthesis, characterization and ionic conductivity of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Three comb polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type -O(CH2CH2O)(n)CH3 were synthesized and characterized, and the ionic conductivity of CP/salt complexes is reported. The conductivity of these complexes was about 10(-5)-10(-6) S cm(-1) at room temperature. The conductivity, which displayed non-Arrhenius behaviour, was analysed using the Vogel-Tammann-Fulcher equation. The conductivity maxima appear at lower salt concentration, when CP has longer side chains. Infrared (i.r.) was used to study the cation-polymer interaction. I.r. results also indicate that the ester in CP might decompose at 140 degrees C and reproduce the maleic anhydride ring. (C) 1997 Elsevier Science Ltd.

Ion-conducting polymers based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CPs) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo(oxyethylene) side chains of the type -O(CH2CH2O)(n)CH3 were synthesized and characterized, and complexed with lithium salts to form amorphous polymer electrolytes. Maximum conductivity close to 1.38 x 10(-4) S/cm was achieved at room temperature and at a [Li]/[EO] ratio (EO = ethylene oxide) of about 0.066. The temperature dependence of ionic conductivity suggested that the ion transport was controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulcher plots. The ionic conductivity maximum moved to a higher salt concentration as the temperature increased, indicating that a larger number of charge carriers can be transferred through polymer chains, of which free volume is increased at higher temperature. IR results indicated that the ester in CPs might decompose at 140 degrees C and reproduce the maleic anhydride ring.

Ionic conductivity of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type -O(CH2CH2O)(n)CH3 have been synthesized and characterized, and complexed with lithium salts to form amorphous polymer electrolytes. CP/salt complexes showed conductivity up to 10(-5)Scm(-1) at room temperature. The temperature dependence of ionic conductivity suggests that the ion transport is controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulcher plots. The ionic conductivity maximum moves to a higher salt concentration as the temperature increases. IR results indicate that the ester in CP might decompose at 140 degrees C and reproduce the maleic anhydride ring.

Studies on water-swellable elastomers .2. Thermal properties and crystalline behavior of amphiphilic graft copolymers with poly(ethylene glycol) side chains

The thermal properties and crystalline structure of the amphiphilic graft copolymers CR-g-PEG600, CR-g-PEG2000, and CR-g-PEG6000 using chloroprene rubber (CR) as the hydrophobic backbone and poly(ethylene glycol) (PEG) with different molecular weights as the hydrophilic side chains were studied by DSC and WAXD. The results showed that a distinct phase-separated structure existed in CR-g-PEGs because of the incompatibility between the backbone segments and the side-chain segments. For all the polymers studied, T-m2, which is the melting point of PEG crystalline domains in CR-g-PEG, decreased compared to that of the corresponding pure PEG and varied little with PEG content. For CR-g-PEG600 and CR-g-PEG2000, T-m1, which is the melting point of the CR crystalline domains, increased with increasing PEG content when the PEG content was not high enough, and at constant PEG content, the longer were the PEG side chains the higher was the T-m1. The crystallite size L-011 of CR in CR-g-PEGs increased compared to that of the pure CR and decreased with increasing PEG content. (C) 1997 John Wiley & Sons, Inc.

The synthesis of dendrimers bearing alkyl chains and their behavior at air-water interface

A new kind of amphiphilic polyether dendrimer bearing eight alkyl chains at the periphery were synthesized step by step using the convergent method. Their structures were confirmed by FT-IR spectra, H-1 NMR spectra and mass spectra etc. The pi-A isotherms, hysteresis and molecular area-time curves at air water interface were reported. These results showed that they could form stable monolayers at water surface.

Synthesis and ionic conductivity studies of solid polymer electrolytes based on modified alternating maleic anhydride copolymer with oligo(oxyethylene) side chains

Comb-like polymers (CP) based on modified alternating methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene side chains of the type-O(CH2CH2O)(n)CH3 have been synthesized and characterized, and complexed with LiNO3 to form an amorphous polymer electrolyte. CP/salt complexes showed conductivity up to 10(-5) S/cm at room temperature. The temperature dependence of ionic conductivity suggests that the ion transport is controlled by segmental motion of the polymer, shown by linear curves obtained in Vogel-Tammann-Fulcher plots. The ionic conductivity maximum moves to a higher salt concentration as the temperature increases. IR results also indicate that the ester in CP might decompose at 140 degrees C and reproduce the maleic anhydride ring.

Laser light scattering studies of soluble high-performance polyimides: Solution properties and molar mass distributions

Two soluble high-performance polyimides, poly(BCPOBDA/DMMDA) and poly(ODPA/DMMDA), in CHCl3 at 25 degrees C have been studied using laser light scattering. We found that the z-average radius of gyration ([R(g)]) can be scaled to the weight-average molecular weight (M(w)) as [R(g)] (nm) = 4.95 x 10(-2)M(w)(0.52) and [R(g)] (nm) = 1.25 x 10(-2)M(w)(0.66) respectively for poly(BCPOBDA/DMMDA) and poly(ODPA/DMMDA), indicating that poly(ODPA/DMMDA) in CHCl3 at 25 degrees C has a more extended chain conformation than poly(BCPOBDA/DMMDA). Using the wormlike chain model approach, we found that the Flory characteristic ratios (C*) of poly(BCPOBDA/DMMDA) and poly(ODPA/DMMDA) are similar to 20 and similar to 31, respectively, indicating that both of them have a slightly extended chain conformation in comparison with typical flexible polymer chains, such as polystyrene, whose C-infinity is similar to 10. A combination of the weight-average molar mass (M(w)) with the translational diffusion coefficient distributions (G(D)) has led to D (cm(2)/s) = 3.53 x 10(-4)M(-0.579) and D (cm(2)/s) = 4.30 x 10(-4)M(-0.613) respectively for two soluble high-performance polyimides, poly(BCPOBDA/DMMDA) and poly(ODPA/DMMTA), in CHCl3 at 25 degrees C. Using these two calibrations, we have successfully characterized the molar mass distributions of the two polyimides from their corresponding G(D)s. The exponents of these two calibrations further confirm that both of the polyimides have a slightly extended coil chain conformation in CHCl3. The chain flexibility difference between these two polyimides has also been discussed.

Lithium ion conducting polymer electrolytes based on alternating maleic anhydride copolymer with oligo-oxyethylene side chains

A comb polymer with oligo-oxyethylene side chains of the type -(CH2CB2O)(12)CH3 was prepared from methyl vinyl ether/maleic anhydride copolymer and poly (ethylene glycol) methyl ether. The polymer can dissolve LiClO4 salt to form homogeneous amorphous polymer electrolyte. The ac ion conduction was measured using the complex impedance method, and conductivities were investigated as functions of temperatures and salt concentration. The complexes were first found to have two classes of glass transition which increase with increasing salt content, The optimum conductivity attained at 25 degrees C is in the order of 5.50 x 10(-6)Scm(-1). IR spectroscopy was used to study the cation-polymer interaction.

EXTENDED SOLUBILITY AND SPIN-GLASS BEHAVIOR IN A AG-GD SOLID-SOLUTION PREPARED BY MECHANICAL ALLOYING

The effects of mechanical alloying on the solubility in a Ag-Gd solid solution have been investigated. The study shows that the solubility of Gd in Ag can be extended to about 5 at. % Gd by mechanical alloying from the equilibrium solubility of less than 0.95 at. % Gd. Ag85Gd15 prepared by mechanical alloying exhibits a spin-glass-type transition at similar to 5 K. A Curie-Weiss behavior at higher temperatures and x-ray patterns of the material indicate that Gd atoms are either dissolved in the Ag matrix or in the form of small clusters of diameters of a few nanometers;

IONIC-CONDUCTION OF A NOVEL COMB POLYMER ELECTROLYTE BASED ON MALEIC-ANHYDRIDE COPOLYMER WITH OLIGO-OXYETHYLENE SIDE-CHAINS

A comb-shaped polymer (BM350) with oligo-oxyethylene side chains of the type -O(CH2CH2O)(7)CH3 was prepared from methyl vinyl ether/maleic anhydride copolymer. Homogeneous amorphous polymer electrolyte complexes were made from the comb polymer and LICF(3)SO(3) by solvent casting from acetone, and their conductivities were measured as a function of temperature and salt concentration. Maximum conductivity close to 5.08 X 10(-5) Scm(-1) was obtained at room temperature and at a [Li]/[EO] ratio of about 0.12. The conductivity which displayed non-Arrhenius behaviour was analyzed using the Vogel-Tammann-Fulcher equation and interpreted on the basis of the configurational entropy model. The results of mid-IR showed that the coordination of Li+ to side chains made the C-O-C band become broader and shift slightly. X-ray photoelectron spectroscopy analysis indicated that the oxygen atoms in the two situations could coordinate to Li+ and this coordination resulted in the reduction of the electron orbit binding energy of F and S.

EXTENDED ADJACENCY MATRIX INDEXES AND THEIR APPLICATIONS

In this paper, new topological indices, EA Sigma and EAmax, are introduced. They are based on the extended adjacency matrices of molecules, in which the influences of factors of heteroatoms and multiple bonds were considered. The results show that EA Sigm

PREPARATION AND CHARACTERIZATION OF LANGMUIR-BLODGETT-FILMS OF PORPHYRINS WITHOUT LONG ALKYL CHAINS

A number of synthetic and natural source porphyrins without long alkyl chains have been examined in the form of monolayers and multilayers on solid substrates. These compounds formed stable solid condensed films with measured molecular areas compatible with a vertical or tilted orientation of these molecules on the substrate. Spectral study and fluorescence lifetime measurement, in particular, revealed the formation of aggregates as the main species in these films.

MONOLAYER FORMATION OF A NOVEL AMPHIPHILIC POLYMER PAMC16S

Poly(2-acrylamido-hexadecylsulfonic acid) (PAMC16S) forms a stable monolayer on a pure water surface. More closely packed monolayers can be obtained when the subphase contains Cd2+ or Ca2+. Self-assembled monolayers have been formed on gold surfaces and characterized by contact angle measurement, XPS and electrochemical analysis. The results show that the monolayers are hydrophobic with the hydrophilic sulfonic acid groups adjacent to the metal surfaces and with the hydrocarbon chains extended from the surfaces. The monolayers exhibit great adsorption stability during the faradaic reactions, illustrating the advantage of polymeric LB films in potential applications.

FROM DIMER TO POLYMER .2. EXTENDED TO SYSTEMS POSSESSING 2-FOLD SCREW AXIS OR GLIDE PLANE

The approach for constructing the qualitative band structure of a polymer from corresponding dimer has been extended to the system possessing two-fold screw axis or. glide plane. The classification of energy levels of the dimer in the present case depends on pseudo-symmetry/antisymmetry instead of psendo-in-phase/out-of-phase property of the orbitals. Several typical conductive polymers are then discussed follow this approach. Among them are cis-polyacetylene, polyparaphenylene with a twist ang...