Complexes polypropylene oxide

Polyethers. Polyethers such as polyethylene oxide (PEO) and polypropylene oxide (PPO) have been used for ESI-MS calibration [10,11,19]. The predominant ions for these calibrants are cation attachments, and sodium attachment is frequently observed, due to traces of sodium in solvents and glassware. The positive-ion ESI mass spectra of PEO and PPO are characterized by abundant [M + nNa]n+ and some [M + ] + species. Macrocyclic polyethers and crown ethers were also used as ESI-MS calibrants [11]. In general, nonderivatized polyethers show the following drawbacks when used as calibrations solutions (1) they are difficult to flush out of the ion source, (2) they generate complex mass spectra resulting from the presence of several different cation sources, and... 

Harada et al. explored the compatibility of CD with various polymeric backbones including polyethylene oxide) (PEG), polypropylene oxide) (PPG), polyisobutylene (PIB), and polyethylene (PE) [77-87]. The corresponding polyrotaxanes (36 to 47) were prepared by Method 2, simply by mixing a solution of CD and the polymer. The cavity size of CD was found to be the main factor in the threading process. While one a-CD (20) was threaded per two repeat units in PEG (m/n=0.50) and every three repeat units for PE (m/n=0.333), it was too small for PIB and PPG. On the other hand, two PPG units complexed per /(-CD (21). Because the upper limit of the min value is controlled by the depth of the CD cavity, the m/n value remained constant for the same type of backbone, irrespective of the end group. However, the nature and concentration, i.e., polymer... 

The 100 MHz H-NMR spectrum of polypropylene oxide is too complex to be analyzed accurately even when decoupled from methyl protons. It is reasonable to ascribe the complexity of the spectrum to the spin coupling between hydrogen atoms linked to contiguous carbon atoms in the main chain. If this interpretation is correct, the spectrum should be simplified by substituting the methine proton by a deuterium atom. In fact, the spectrum of polypropylene oxide-a-d was simpler than that of the undeuterated one. Methyl protons lie at higher field and methylene protons at lower field. The stereoregularity was analyzed on the basis of the spectrum of the methylene proton absorption other than that of the methyl proton absorption. 

A second class of important electrolytes for rechargeable lithium batteries are solid electrolytes Of particular importance is the class known as solid polymer electrolytes (SPEs) SPEs are polymers capable of forming complexes with lithium salts to yield tome conductivity. The best known of the SPEs are the lithium salt complexes of polytethylene oxide) (PEO), -(CH.CH OH 1,-, and polypropylene oxide) (PPO). 

MTX MCC mPEG MA NFX PEO PCS PECs PLA PBLA PLG PPO PEG PCL PBLG PBS PGA Methotrexate Crystalline cellulose Monomethoxypoly(ethylene glycol) Maleic acid Norfloxacin Polyethylene oxide) Photon correlation spectroscopy Poly(electrolyte complexes) Poly(L-lactic acid) Poly( 3-benzyl-L-aspartate) Poly (lactide- co -glycolide) Polypropylene oxide) Polyethylene glycol) Poly(e-caprolactone) Poly(y-benzyl-L-glutamate) Phosphate buffered saline Poly(glycolic acid)... 

The most well-known member of this class is the polyether, polyethylene oxide, whose complexes with lithium perchlorate have been used commercially in lithium batteries.60-62 The good solvating power of polyethylene oxide is attributed to an optimal spacing of the electron-donating ether oxygens along a flexible backbone that allows multiple contacts between the polymer backbone and cations. When this distance is decreased, as in polymethylene oxide, chain flexibility is greatly reduced when it is increased, as in 1,3-polypropylene oxide, the distance between... 

Figure 4. Backbone structures of salt-solvating polymers. The figure shows the similarity of backbone structure, with optimal spacing between electron-donating oxygens, of polymers that form ion-conducting salt complexes. PPL-poly-3-propiolac-tone PEO polyethylene oxide PPO 1,2- polypropylene oxide.18...

The complex with [Li+]/[PO] = 0.10 exhibits a crystalline melting transition followed by a smectic A mesophase. By increasing the salt concentration as in the case of complexes with [Li+]/[PO] = 0.15 0.30, the smectic A phase is suppressed instead, they exhibit a hexagonal columnar mesophase as evidenced by X-ray scattering. The induction of ordered structure in the melt state of the rod—coil molecule by complexation is most probably due to enhanced microphase separation between hydrophobic blocks and polypropylene oxide) block caused by transformation from a dipolar medium to an ionic medium in polypropylene oxide) coil. 

Inhibition Periods of Polypropylene Oxidations. Although the kinetics of BHT-inhibited polypropylene oxidations may be complex, the consumption of the inhibitor seems to follow simple stoichiometry, at least up to 3 X 10 3M BHT. In Figure 5, the tinh values for polypropylene oxidations [PP]0 = 2.5M, [tert-Bu202]0= 1-2 X 10 2M are plotted against the initial BHT concentrations (triangles). The heavy line close to these... 

Materials that promote polymerization may be devided into true catalysts such as metal complexes, metal oxides, and anionic and cationic catalysts and initiators, which appear as end groups in the final polymer. It seems to be clear that the most expensive polymerization catalysts are the single-site metallocene catalysts. Sales has grown from 1 million US in 1994 to 100 million US in 2000. Ziegler catalysts used for polypropylene and polyethylene, and the dibutyl tin and special basic catalysts for polyurethanes are also expensive. 

This methodology enjoys the merits of other approaches and exhibits several additional advantages 1) it has proven applicable to a wide range of transition metal and main group oxides 2) the metal precursors studied so far are readily available, being either alkoxide or halide complexes 3) in many cases, syntheses can be run in alcoholic solvents in essentially nonhydrolytic conditions, which aids in controlling hydrolysis and condensation rates 4) the critical micelle concentrations required for polyethylene-oxide-polypropylene-oxide di- and triblock copolymers are usually much lower than the concentrations needed for ionic surfactants and 5) because of the neutral, nonaqueous conditions used in these preparations, control of pH is not required, and the surfactant can be removed from the mesostructured material by calcination or milder solvent extraction methods with nonpolar solvents. 

Stable double emulsions, based on various block copolymers of polyethylene oxides and polypropylene oxides known as Pluronies, have been used. In a recent example. Cole and Whateley (84) have used complexes of Pluronic F127 PAA (polyaerylie aeid) in the internal aqueous phase. In the oil phase, Span 80 and Pluronie LlOl (5 wt %) were used. The outer interfaee was stabilized by xanthan gum (0.25 wt %) and Tween 80 (1 wt %). Theophylline and I-insulin (iodinated insulin) were ineorporated in the internal aqueous phase of the stabilized multiple emulsion, and the release rates were studied. The release rates were found to be related to the droplet sizes of the emulsion whieh were dependent on the partiele size of the pluronie F127 PAA eomplex in the internal aqueous phase and the type of the lipophilie surfaetant in the oil phase. The authors have used the eomplex between the poloxamer surfactant and PAA that occurred at pH 2 and at low molar ratio as a barrier for the release of active matter from the inner to the outer phase. 

Block copolymers are more complex. Only a few remarks arc made below, and immediately after we revat to the more common surfactants, a plan that is followed in the rest of the book. A hnear hydrophihe polymer such as polyethylene oxide (PEO) is attached at one of its terminals to a more hydrophobic polymer such as polypropylene oxide (PPO). The result is an amphiphile PEO-PPO, called a diblock copolyma-. Similarly, PEO-PPO-PEO is a triblock copolymer, another common block copolymer. The blocks range up to hundreds of repeat units. The insoluble block can crystallize or form glass. Ionic blocks are also available, although the nonionic block copolymers are more common. 

Due to the large size of the calixarene molecules, they were also used for the synthesis of stereoregular polymers. Thus, neodymium complex containing the calixarene 32 was active in the formation of isotactic polypropylene oxide (Scheme 4.20) [80]. 

Electrical properties have been reported on numerous carbon fiber-reinforced polymers, including carbon nanoflber-modified thermotropic liquid crystalline polymers [53], low-density polyethylene [54], ethylene vinyl acetate [55], wire coating varnishes [56], polydimethyl siloxane polypyrrole composites [50], polyacrylonitrile [59], polycarbonate [58], polyacrylonitrile-polycarbonate composites [58], modified chrome polymers [59], lithium trifluoromethane sulfonamide-doped polystyrene-block copolymer [60], boron-containing polyvinyl alcohols [71], lanthanum tetrafluoride complexed ethylene oxide [151, 72, 73], polycarbonate-acrylonitrile diene [44], polyethylene deoxythiophe-nel, blends of polystyrene sulfonate, polyvinyl chloride and polyethylene oxide [43], poly-pyrrole [61], polypyrrole-polypropylene-montmorillonite composites [62], polydimethyl siloxane-polypyrrole composites [63], polyaniline [46], epoxy resin-polyaniline dodecyl benzene sulfonic acid blends [64], and polyaniline-polyamide 6 composites [49]. 

Abstract The optical inversion of poly(propylene oxide) by solvent is not due to a helix-coil transition or any other conformational change. The inversion was observed also in the monomer or the ether of propylene glycol. The variation of rotivity of solvent seems to be caused by change of the polarizability of methyl or methylene group of polypropylene oxide due to the formation of a contact complex with aromatic solvent. 

FURUKAWA T, IMURA M, YURUZUME H (1997), Broad-band conductive spectra of polypropylene oxide complexed with LiClOV,/ / J Appl Phys 1, 36,1119-1125. 

---