High molecular weight poly(ethylene oxide)/silica hybrids by the sol-gel process

Wójcik, Anna; Ting, Alvin; Klein, Lisa C.

doi:10.1016/s0928-4931(98)00047-2

Cited by 16 publications

(8 citation statements)

References 22 publications

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“…It is known that optical appearance can be used as an initial criterion for the formation of a homogeneous phase in hybrids [28,32]. Our observations show increasing TEOS content favors macroscopic phase separation, in agreement with the previous results [23,33].…”

Section: Discussionsupporting

confidence: 93%

“…The improved thermal stability for the hybrids than pure PMMA may be induced by the interactions between the polymer chains and SiO 2 , and hydrogen bonding should be the main source of such interactions. Another possible reason could be the entrapping of PMMA chains within the SiO 2 , thereby increasing the energy barrier for decomposition [17,32].…”

Section: Discussionmentioning

confidence: 99%

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Characterization and optical properties of sol–gel processed PMMA/SiO2 hybrid monoliths

Sun

Akdoğan

Klein

et al. 2007

Journal of Non-Crystalline Solids

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Characterization and optical properties of sol–gel processed PMMA/SiO2 hybrid monoliths

Sun

Akdoğan

Klein

et al. 2007

Journal of Non-Crystalline Solids

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“…The preparation of PEO/silica16, 19–21 and PCL/silica13, 22–24 hybrid materials by sol–gel method has already been reported. It is widely accepted13, 22, 25 that the presence of alkoxysilane groups on the polymeric chains increase the reactivity/miscibility with the metal alkoxide and promote a better interconnection between organic and inorganic phases.…”

Section: Resultsmentioning

confidence: 99%

Electrical behavior of PET films coated with nanostructured organic–inorganic hybrids

Saccani¹,

Toselli²,

Messori³

et al. 2006

J of Applied Polymer Sci

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Hybrid coatings, based on poly(ethylene oxide) (PEO) or polycaprolactone (PCL) and silica (SiO 2 ), at different organic-inorganic compositions have been used to coat PET films employed in the electric industry to produce capacitors. The overall electrical behavior of the coated films has been investigated. The electrical strength of the coated films increases up to 10-15% of the uncoated ones regardless of polymer type (PEO/PCL) and amount of inorganic phase, as far as the thickness of the coating is below 5 mm. A systematic increase of surface electrical conductivity is found in all coated samples which however still behave as insulators. Permittivity and loss factor also increase particularly at low frequencies (< 10 Hz) on account of the presence of ions deriving from the sol-gel process and on the presence of interfacial polarization probably related to the coatings nanostructurated morphology which leads to phase separation.

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“…The morphology and properties of these nano-materials can be tuned by changing the experimental framework related either to the building of the inorganic network (the nature of the alkoxide precursor, [1] the chelating stabilizer, [1] the low shrinkage process using alkoxides bearing reactive vinylic functionalities released during the hydrolysis step, [2] catalysis, [3] the amount of water [4] ) or to the building of the organic polymer chains or network (preformed or in situ formed polymer, if any, the nature of the grafted coupling agent, [5] the grafting ratio, [6] ). Silica-based hybrids have been studied much more frequently than titania-based or zirconia-based hybrids.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Study of the Effect of a Sol‐Gel Inorganic Network on Polymeric Relaxation Dynamics in Acrylic/Titania Hybrids

Perrin

Nguyen

Vernet

2005

Macro Chemistry & Physics

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In this research, poly[(methyl methacrylate)-co-(butyl methacrylate)-co-(methacrylic acid)]/TiO 2 hybrids were prepared by the sol-gel process. The copolymer composition was 16 mol-% methyl methacrylate (MMA), 80 mol-% butyl methacrylate (BMA) and 4 mol-% methacrylic acid (MA). The dielectric properties of the hybrids with varying titania content were measured over the frequency range 0.1 Hz to 100 kHz and between 25 and 160 8C. In addition, the hybrids were investigated using differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). In the given frequency range, a single relaxation peak was observed both by dielectric relaxation spectroscopy (DRS) and DMTA. The single relaxation observed by DRS behaves in the manner of an a-relaxation, with the frequency-temperature locus showing non-Arrhenius behavior (curved downwards like a VTF law). The change in the DRS and DMTA characteristics in hybrids compared to the pure polymer reflect the presence of antagonistic mechanisms controlling the dynamics of the polymer chains: nanodomains with enhanced and restricted mobilities are suggested to be responsible for the broadening of the isochronal dielectric loss curve toward, respectively, the low and the high temperature sides. Combining the DSC and DRS results, it can be inferred that the domains with enhanced mobility result from internal and external plasticization effects that reduce the intermolecular hydrogen bonds between the polymer chains. Besides, the motion of polymer chains is found to be significantly hindered by the titania network, due to the presence of iono-covalent bonds between the polymer and titania and geometrical restrictions in high junction-point density and titania-rich microphases. From the Arrhenius plot, it is also shown that the addition of sol-gel titania more severely hinders the segmental motion of the macromolecular chains than the local motion of the lateral groups (b relaxation).Simplified schematic morphology for the poly(MMA-co-BMA-co-MA)/TiO 2 hybrids.

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High molecular weight poly(ethylene oxide)/silica hybrids by the sol-gel process

Cited by 16 publications

References 22 publications

Characterization and optical properties of sol–gel processed PMMA/SiO2 hybrid monoliths

Characterization and optical properties of sol–gel processed PMMA/SiO2 hybrid monoliths

Electrical behavior of PET films coated with nanostructured organic–inorganic hybrids

Dielectric Study of the Effect of a Sol‐Gel Inorganic Network on Polymeric Relaxation Dynamics in Acrylic/Titania Hybrids

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