Polyethylene oxide intercalation

Intercalation of Cjq with lithium has been achieved by solid-state electrochemical doping [125]. In this technique, metallic lithium was used as the negative electrode and a polyethylene oxide lithium perchlorate (P(E0)8liCl04) polymer film served as electrolyte. The formation of stoichiometric phases Li Cgg (n = 0.5, 2, 3, 4, and 12) has been observed. 

Lead and mercury are deposited as micron-sized clusters, predominantly at intercrystallite boundaries [105] so does lithium from the polyethylene oxide solid electrolyte. What is more, Li intercalates into the sp2-carbon [22, 138], Thus, observations on the Li intercalation and deintercalation enable one to detect non-diamond carbon on the diamond film surface. Copper is difficult to plate on diamond [139], There is indirect evidence that Cu electrodeposition, whose early stages proceed as underpotential deposition, also involves the intercrystallite boundaries [140], We note that diamond electrodes seem to be an appropriate tool for use in the well-known electroanalytical method of detection of traces of metal ions in solutions by their cathodic accumulation followed by anodic stripping. The same holds for anodic deposition, e.g. of, Pb as PbCh with subsequent cathodic reduction [141, 142], Figure 30 shows the voltammograms of anodic dissolution of Cd and Pb cathodically predeposited from their salt mixtures on diamond and glassy carbon electrodes. We see that the dissolution peaks are clearly resolved. The detection limit for Zn, Cd, and Pb is as low as a few ppb [143]. 

Recent advances in this technology include the use of 2 1 clays converted to hydrophobic forms through the introduction of surfactants in the interlayer. For example, Boyd et al. (1991) introduced cationic chain surfactants into 2 1 clay minerals. Such clays were demonstrated to have high affinity for hydrophobic organic chemicals. Additionally, polyethylene oxides (PEOs) have been intercalated into aluminum-pillared montmorillonite (Montarges et al., 1995). Because PEOs have a... 

Recently, Moad et al. [288,289] designed and prepared novel copolymer intercalant/dis-persant/exfoliant systems that are effective with unmodified clays at low levels (<20% with respect to clay), can be combined with commercial PP and clay in a conventional melt-mixing process, and do not require the use of additional compatibilizers. PP-clay nanocomposites prepared by direct melt mixing using unmodified MMX clays and a copolymer additive added at a level of only 1 wt.% with respect to PP for 5wt.% clay Authors investigated the following two classes of dispersants (1) polyethylene oxide-based nonionic surfactants... 

Liquid organic eIectroI)des consist of a solvent and a salt propylene carbonate (PC) for carbon electrodes, ethylene carbonate and dimethyl carbonate (EC and DMC) for graphite electrodes. LiPF is the usual conductivity salt. A poorly understood process is the formation of a solid electrolyte interface (SEI) on the anode, starting the intercalation process, probably via Li carbonate. Efficiency losses during the formation depend on the carbons or graphites gas is the result of decomposition reactions. To reduce the hazards of flammability "solid polymer electrolytes" originally polyethylene oxide —PEO— and "doped polymer" electrolyte with some "plasticizers" were introduced. Valence first used irradiation for additional crosslinking. 

An example of this discussed earlier is the comparison of polyethylene oxide (PEO) and PVP. The PEO forms intercalated systems almost... 

A quite unexpected influence of the background electrolyte anion on the (85/15) composite (fullerenes plus acetylene black plus polyethylene oxide) in propylene carbonate was reported by Yazami and Cherigui [160]. Their voltammograms were recorded in the potential limits 3-1.5 V vs. Li+/Li, i.e., where, according to most studies, three or four reversible intercalations occur. These processes were not well resolved in Yazami and Cherigui s study [160], and the authors determined only the number of lithium atoms... 

Data are available for cathodic intercalation of tetraalkylammonium (TAA+) cations into C60/C70/ polyethylene oxide composite [160] in propylene carbonate. The total number of the TAA" " cations intercalated per C o upon the first two reductions was 1.5 for the TBAI and 1 for the tetrapropylammo-nium iodide (TPAI) and TEAI supporting electrolytes. Cathodic intercalation processes were also studied for fluorinated C o [H5] as well as for C60(MoF6)9 [171]. 

Figure 7.29. Voltammograms of the first reduction/oxidation cycle of pure Ceo in a solid polymer eleetrolyte (polyethylene oxide/LiC104) in different potential ranges. C o mass 3.16 mg (top) 3.67 mg (bottom). A, B, C, D, E denote consecutive intercalations. Dots are the current averaged over the 1 h duration of each 10 mV step. (Reprinted with permission Ifom ref 163. Copyright 1992, American Chemical Society.)...

A recent solid state battery design, lithium composite cathode batteries, developed at Harwell, features a lithium ion conducting polymer electrolyte (e.g., polyethylene oxide) and a solid intercalation cathode. The battery is made up of a sandwich of lithium foil (50 pm), polymer-electrolyte (50 pm), composite cathode (various types have been studied including VsOis, TiS2, MoOj, etc., plus 5% carbon black) (56 ym) and a nickel foil current collector (10 pm). Thus total cell thickness is 150-200 pm and areas can range from cm to m. ... 

Both natural clays and their alnminium oxide pillared analogues have also been tested for the catalytic cracking of polyethylene [49-51]. The clays investigated include mont-morillonite and saponite. They possess a layered structure which can be converted into a two-dimensional network of interconnected micropores by intercalation of molecular moieties. In the case of alnmininm pillared clays, these materials show a mild acidity... 

Thermal and Thermal-oxidative Degradation of Polyethylene Nanocomposite Prepared by Intercalation Polymerization... 

Keywords Catalysis intercalation polymerization kinetics layered clay nanocomposite oxidation polyethylene thermal degradation... 

In the last decade, considerable progress was observed in the field of PO/compatibil-izer (predominantly on the base of PO-g-MA)/organo-surface-modified clay nanocomposites. Polyethylene (PE), polypropylene (PP), and ethylene-propylene (EP) rubber are one of the most widely used POs as matrix polymers in the preparation of nanocomposites [3,4,6,30-52]. The PO silicate/silica (other clay minerals, metal oxides, carbon nanotubes, or other nanoparticles) nanocomposite and nanohybrid materials, prepared using intercalation/exfoliation of functionalized polymers in situ processing and reactive extrusion systems, have attracted the interest of many academic and industrial researchers because they frequently exhibit unexpected hybrid properties synergisti-cally derived from the two components [9,12,38-43]. One of most promising composite systems are nanocomposites based on organic polymers (thermoplastics and thermosets). 

Durmus, A., Woo, M., Kasgoz, A., Macosko, C. W., and Tsapatsis, M. 2007. Intercalated linear low density polyethylene LLDPE)/clay nanocomposites prepared with oxidized polyethylene as a new type compatibilizer Structural, mechanical and barrier properties. European Polymer Journal 43 3737-3749. 

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