Poly oxide, silica

As an organic polymer, poly(tetramethylene oxide) was also used for the preparation of ceramers. The mechanical properties in these cases were much improved in comparison with those for hybrids from polysiloxanes. In these poly (tetramethylene oxide)-silica hybrids, the effect of the number of functional triethoxysilyl groups was examined [13]. As shown in Fig. 2, more multifunctional organic polymer produced more crosslinked hybrid networks. This means that the more rigid the structure in the hybrids is, the higher the modulus and the lower swelling property. 

By using a similar procedure for the preparation of hybrids of silica, hybrids materials consisting of other metal oxides were also prepared by the group of Wilkes [15]. For example, titania was incorporated into organic polymers by using the chemically controlled condensation (CCC) method for the preparation of poly(tetramethylene oxide)-silica or poly(dimethylsiloxane)-silica hybrids. Especially, in the case of the hybrid with poly (tetramethylene oxide), the modulus or ultimate strength of the hybrid increased in the presence of titania component, as shown in Table 3. This phenomenon was explained by the catalytic ability of... 

EXPLOSIVES AND PROPELLANTS - PROPELLANTS] (Vol 10) Poly(ethylene oxide)/silica... 

Other oiganic—inoiganic hybrids include poly(eth5ioxazoline)—silica, poly(vinyl alcohol)—silica, poly(arylene ether) ketone—silica, polyimide—silica, polyozoline—silica, poly(eth5iene oxide)—silica, and polymers—modified alkoxysilane. 

Another example of network formation is found in PEO (poly(ethylene oxide))-silica systems [58, 59]. At relatively small-particle concentrations, the elastic modulus increases at low frequencies, suggesting that stress relaxation of these hybrids is effectively arrested by the presence of silica nanoparticles. This is indicative of a transition from liquidlike to solidlike behavior. At high frequencies, the effect of particles is weak, indicating that the influence of particles on stress relaxation dynamics is much stronger than their influence on the plateau modulus. 

Dextran bovine seram albumin/guar-g-poly(l-vinyl-2-pynx)lidinone] and water poly(ethylene oxide)/polystyrene and water poly(ethylene oxide)/silica and water poly(ethylene oxide-co-propylene oxide)/ poly(ethylene oxide-co-propylene oxide)/silica and water polystyrene and water 2009KAU 20050L1 20050L1 20050L1 20050L1... 

Zhang Q, Archer LA (2004) Optical polarimetry and mechanical rheometry of Poly(ethylene oxide) — silica dispersions. Macromolecules 37(5) 1928-1936... 

Zhang Q, Archer LA (2002) Poly(ethylene oxide)/silica nanocomposites structure and rheology. Langmuir 18(26) 10435-10442... 

Kim JH, Lee YM (2001) Gas permeation properties of poly(amide-6-b-ethylene oxide)-silica hybrid membranes. J Membr Sci 193(2) 209-225... 

Sternsteiu S S and Zhu A J (2002) Reinforcement mechanism of nanofilled polymer melts as elucidated by nonlinear viscoelastic behavior. Macromolecules 35 7262-7273. Zhang Q and Archer L A (2002) Poly(ethylene oxide)/silica nanocomposites structure and rheology, Langmuir 18 10435-10442. 

Manaf I and Mascia L (2004) Compatibilization of water born poly(ethylene oxide)-silica hybrids, Adv Polym Technol 23 125-134. 

WANG c, WEI Y, FERMENT G R, LI w and LI T, Poly(ethylene oxide)-silica hybrid materials for hthium battery application . Mater Lett, 1999,39,206-210... 

MACCALLUM J R and SETH s, Conductivity of poly(ethylene oxide)/silica composite films containing hthium trifluorosulphonate , Eur Polym J, 2000, 36, 2337-2341... 

It has been outlined by several authors that the single macromolecule may be irreversibly bound because of the large number of weakly interacting segments. The first papers on the construction of polymer-coated silica adsorbents involved the physical adsorption of water-soluble polymers. Polyethylene oxides [28, 29] and poly-/V-vinylpyrrolidone [30] are examples of the stationary phases of this type. 

Although Fields already mentioned the possible preparation of monolithic silica-based CEC columns, the lack of experimental data leads to the assumption that this option has not been tested [111]. In fact, it was Tanaka et al. who demonstrated the preparation of monolithic capillary columns using a sol-gel transition within an open capillary tube [99,112]. The trick was in the starting mixture that in addition to tetramethoxysilane and acetic acid also includes poly(ethylene oxide). The gel formed at room temperature was carefully washed with a variety of solvents and heated to 330 °C. The surface was then modified with octadecyl-trichlorosilane or octadecyldimethyl-A N-dimethylaminosilane to attach the hy-... 

Titania is being examined for use as a base material for bonded stationary phases because of its stability and its ability to separate bases under normal-phase conditions.Other researchers are investigating silica that has been surface modified with titanium oxide followed by the immobilization of poly(methyloctylsiloxane). These columns show promise for routine chromatographic analyses, but more research needs to be performed to evaluate the best manufacturing methods. 

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