Microstructural evolution of a silicon oxide phase in a perfluorosulfonic acid ionomer by an in situ sol-gel reaction. 1. Infrared spectroscopic studies

Mauritz, Kenneth A.; Warren, R. M.

doi:10.1021/ma00194a038

Cited by 151 publications

(111 citation statements)

References 1 publication

(1 reference statement)

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“…Such composites are usually formed by either dispersing inorganic particles in a solution of the ionomer, followed by film casting and solvent elimination, or by precipitation of inorganic particles within a pre-existing membrane. The latter procedure was first used by Mauritz 247 to precipitate SiO 2 particles in Nafion using in situ hydrolysis of tetraethoxysilane (TEOS). Although SiO 2 does not show measurable proton conductivity itself, other inorganic compounds, such as diverse zirconium phosphates and phosphonates or heteropolyacids, 245,248 have recently been used as fillers.…”

Section: Compositesmentioning

confidence: 99%

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Kreuer¹,

Paddison²,

Spohr³

et al. 2004

ChemInform

126

193

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Section: Compositesmentioning

confidence: 99%

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Kreuer¹,

Paddison²,

Spohr³

et al. 2004

ChemInform

126

193

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“…If the polymer chains in a material resist movement at T g , then the tan d peak will be broad. [21][22][23][24] For the case of the 20 and 25% POSS polyimides, the increased breadth of the tan d peak may be a consequence of the additional volume occupied by the POSS molecules which leads to an increased steric barrier for the cooperative chain movements at T g . The decrease in the intensity of the tan d peak indicates that the material is not effective in dissipating energy and thus would be a poor impact-resistant material.…”

Section: Dynamic Mechanical Thermal Analysis (Dmta) Of Poss Polyimidesmentioning

confidence: 99%

Properties and Improved Space Survivability of POSS (Polyhedral Oligomeric Silsesquioxane) Polyimides

et al. 2004

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Kapton polyimide (PI) is widely used on the exterior of spacecraft as a thermal insulator. Atomic oxygen (AO) in lower earth orbit (LEO) causes severe degradation in Kapton resulting in reduced spacecraft lifetimes. One solution is to coat the polymer surface with SiO 2 since this coating is known to impart remarkable oxidation resistance. Imperfections in the SiO 2 application process and micrometeoroid / debris impact in orbit damage the SiO 2 coating, leading to erosion of Kapton.A self passivating, self healing silica layer protecting underlying Kapton upon exposure to AO may result from the nanodispersion of silicon and oxygen within the polymer matrix. Polyhedral oligomeric silsesquioxane (POSS) is composed of an inorganic cage structure with a 2:3 Si:O ratio surrounded by tailorable organic groups and is a possible delivery system for nanodispersed silica. A POSS dianiline was copolymerized with pyromellitic dianhydride and 4,4?-oxydianiline resulting in POSS Kapton Polyimide. The glass transition temperature (Tg) of 5 to 25 weight % POSS Polyimide was determined to be slightly lower, 5 -10 %, than that of unmodified polyimides (414 ºC). Furthermore the room temperature modulus of polyimide is unaffected by POSS, and the modulus at temperatures greater than the Tg of the polyimide is doubled by the incorporation of 20 wt % POSS.To simulate LEO conditions, POSS PI films underwent exposure to a hyperthermal O-atom beam. Surface analysis of exposed and unexposed films conducted with X-ray photoelectron spectroscopy, atomic force microscopy, and surface profilometry support the formation of a SiO 2 self healing passivation layer upon AO exposure. This is exemplified by erosion rates of 10 and 20 weight % POSS PI samples which were 3.7 and 0.98 percent, respectively, of the erosion rate for Kapton H at a fluence of 8.5 x 10 20 O atoms cm -2 . This data corresponds to an erosion yield for 10 wt % POSS PI of 4.8 % of Kapton H. In a separate exposure, at a fluence of 7.33 x 10 20 O atoms cm -2 , 25 wt % POSS Polyimide showed the erosion yield of about 1.1 % of that of Kapton H. Also, recently at a lower fluence of 2.03 x 10 20 O atoms cm -2 , in going from 20 to 25 wt % POSS PI the erosion was decreased by a factor of 2 with an erosion yield too minor to be measured for 25 wt % POSS PI.

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“…In some cases, hybrid membranes were prepared by sol-gel techniques [32][33][34][35]. The same approach was used to synthesize tailored organic-modified silica bearing a variety of functional groups, with a preference for hydrophilic fragments.…”

Section: Introductionmentioning

confidence: 99%

Precipitated silica as filler for polymer electrolyte based on poly(acrylonitrile)/sulfolane

Kurc

2014

J Solid State Electrochem

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The aim of the present work was to perform a preliminary study of the physicochemical properties of hybrid organic-inorganic gel electrolytes for Li-ion batteries based on the PAN/TMS -poly(acrylonitrile)/sulfolane -polymeric matrix and surface-modified precipitated silicas. Modifications were done by means of the so-called dry method using silane U-511 3-methacryloxypropyltrimetoxysilane. Scanning electron microscopy (SEM), noninvasive back scattering method (NIBS), specific surface area (BET), the degree of modification of the silica fillers-Fourier-transform infrared spectroscopy (FT-IR), impedance analysis, and charging/ discharging were carried out. It is found that the silica fillers were homogeneously dispersed in the polymeric matrix, which enhanced conductivity and electrochemical stability of porous polymer electrolytes. Applicability of the prepared gel electrolytes for the Li-ion technology was estimated on the basis of specific conductivity measurements. It was shown that modification of the silica surface by the silane causes an increase in the gel-specific conductivity by about 2 orders of magnitude as compared to gel with unmodified silica.

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Microstructural evolution of a silicon oxide phase in a perfluorosulfonic acid ionomer by an in situ sol-gel reaction. 1. Infrared spectroscopic studies

Cited by 151 publications

References 1 publication

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Properties and Improved Space Survivability of POSS (Polyhedral Oligomeric Silsesquioxane) Polyimides

Precipitated silica as filler for polymer electrolyte based on poly(acrylonitrile)/sulfolane

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