Arylene‐modified siloxanes

Breed, L. W.; Elliott, Richard L.; Whitehead, M. E.

doi:10.1002/pol.1967.150051103

Cited by 48 publications

(25 citation statements)

References 6 publications

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“…It was revealed that the melt polycondensation and simultaneous cross-linking reaction were effective to obtain the polysilarylenesiloxanes which have high thermal degradation temperature and high thermomechanical stability. [doi:10.1295/polymj.PJ2006004] KEY WORDS Polysilarylenesiloxane / Melt Polycondensation / Thermal Stability / Glass Transition / Thermomechanical Stability / Polysilarylenesiloxanes 1,2 and their copolymers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have been investigated as high temperature elastomers. The common characteristics of these polymers are their high thermal degradation temperatures (T d 's) and low glass transition temperatures (T g 's), which are attributed to their flexible tetramethyldisiloxane units in the main chain.…”

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confidence: 99%

“…The common characteristics of these polymers are their high thermal degradation temperatures (T d 's) and low glass transition temperatures (T g 's), which are attributed to their flexible tetramethyldisiloxane units in the main chain. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] These characteristics are desirable for an elastomer, and are, however, undesirable for the heat-resistant materials such as a high-temperature coating and a low dielectric insulation material in semiconductor devices because the thermomechanical stability of these polymers is not enough at high temperature. Therefore, polysilarylenesiloxanes and their copolymers have never been used nothing but elastomers.…”

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confidence: 99%

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Preparation of Fully Aromatic Polysilarylenesiloxanes by Melt Polycondensation and Their Thermal Properties

Ichikawa

Akiyama

et al. 2006

Polym J

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ABSTRACT:The melt polycondensation of the two kinds of the bis(hydroxydiphenylsilyl)arylene monomers, 1,4-bis(hydroxydiphenylsilyl)benzene and 4,4 0 -bis(hydroxydiphenylsilyl)biphenyl, was investigated. The thermal properties of the obtained polymers were studied by using a thermogravimetry analysis, a differential scanning calorimetry and a thermomechanical analysis. The IR spectra and the XRD patterns of the polymers indicated that the melt polycondensation occurred in the temperature range from 290 C to 400 C. The 5% weight loss temperatures of the polymers synthesized at above 350 C was around or over 500 C, so that these polymers exhibited high thermal stability. All the polymers which were obtained by the melt polycondensation of 1,4-bis(hydroxydiphenylsilyl)benzene exhibited the glass transition temperatures. On the contrary, the polymers obtained from 4,4 0 -bis(hydroxydiphenylsilyl)biphenyl at above 350 C showed no phase transitions in the DSC measurements. From the analysis of the volatile compounds generated during the melt polycondensation of 4,4 0 -bis(hydroxydiphenylsilyl)biphenyl by using a gas chromatograph mass spectrometry and the comparison of the 13 C CP-MAS NMR spectra of the polymers, it was shown that the cross-linking reaction resulting from the thermal decomposition of the monomers and the produced oligomers took place simultaneously. It was revealed that the melt polycondensation and simultaneous cross-linking reaction were effective to obtain the polysilarylenesiloxanes which have high thermal degradation temperature and high thermomechanical stability. have been investigated as high temperature elastomers. The common characteristics of these polymers are their high thermal degradation temperatures (T d 's) and low glass transition temperatures (T g 's), which are attributed to their flexible tetramethyldisiloxane units in the main chain. 2-18 These characteristics are desirable for an elastomer, and are, however, undesirable for the heat-resistant materials such as a high-temperature coating and a low dielectric insulation material in semiconductor devices because the thermomechanical stability of these polymers is not enough at high temperature. Therefore, polysilarylenesiloxanes and their copolymers have never been used nothing but elastomers. If a new type of polysilarylenesiloxane with a high T g is obtained, it is possible that the polysilarylenesiloxane is applied to such heat-resistant materials.On the other hand, we reported that the fully aromatic polysilarylenesiloxanes, which were synthesized via the solution polymerization, poly(tetraphenyl-p-silphenylenesiloxane) (polyPS) and poly(tetraphenyl-p,p 0 -silbiphenylenesiloxane) (polyBS), showed no weight loss in air below 500 C and had high melting temperatures (T m 's) of 323 C and 391 C, respectively 19 (Figure 1). It was revealed that these polymers were candidates for new heat-resistant materials. Unfortunately, these polymers were obtained as insoluble powder, therefore, these polymers had a drawback to a practical use. I...

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Preparation of Fully Aromatic Polysilarylenesiloxanes by Melt Polycondensation and Their Thermal Properties

Ichikawa

Akiyama

et al. 2006

Polym J

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“…This may result in a predominant SiPh or SiMe bond rupture and subsequent recombinations, which would result in a highly crosslinked network. This phenomenon may be analogous to the increased thermal stability observed for dimethylsiloxy/silarylene copolymers 3, 22–24. The char yields of II – V in N 2 were between 45 and 57% when they were heated to 800 °C.…”

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Improvement of anode oxidation reaction of a fuel cell using ammonium formate with Pt‐Ir catalysis

Ohyama

Sugino

Nitta

et al. 2010

Electrical Engineering Japan

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SUMMARYWe have attempted to develop high-performance and safe fuel cells by using ammonium formate as a solid (powder) fuel. This solid fuel has the potential of safer transportability than liquid fuels such as methanol from the viewpoint of toxicity and flammability. In order to make use of some of the advantages of ammonium formate, we investigated the oxidation characteristics of ammonium formate with respect to a Pt electrode. Cyclic voltammograms indicate that ammonium formate has high oxidation activity with respect to a Pt electrode. We have also found that the oxidation of ammonium formate can be improved by the addition of Ir to Pt catalysts. It is highly likely that ammonium formate will be useful as a solid (powder) fuel for polymer electrolyte membrane (PEM) fuel cells. This new fuel will promote the development of safe fuel cells for PEM.

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“…This phenomenon may be analogous to the increased thermal stability observed for dimethylsiloxy/silarylene copolymers. 3,[22][23][24] The char yields of II-V in N 2 were between 45 and 57% when they were heated to 800 8C.…”

Section: Resultsmentioning

confidence: 99%

Preparation, characterization, and thermal properties of alt‐copoly[1,9‐decaphenylpentasiloxanylene/1,3‐bis(ethylene)permethyloligosiloxanylene]s

Lee

Gädda

Weber

2005

J. Polym. Sci. A Polym. Chem.

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alt‐Copoly[1,9‐decaphenylpentasiloxanylene/1,3‐bis(ethylene)tetramethyldisiloxanylene], alt‐copoly[1,9‐decaphenylpentasiloxanylene/1,5‐bis(ethylene)hexamethyltrisiloxanylene], alt‐copoly[1,9‐decaphenylpentasiloxanylene/1,7‐bis(ethylene)octamethyltetrasiloxanylene], and alt‐copoly[1,9‐decaphenylpentasiloxanylene/1,9‐bis(ethylene)decamethylpentasiloxanylene] were synthesized by Pt‐catalyzed hydrosilylation reactions of 1,9 divinyldecaphenylpentasiloxanes with a series of oligodimethylsiloxanes. The molecular weights of these copolymers were determined by gel permeation chromatography. Their glass‐transition temperatures (Tg's) were obtained by differential scanning calorimetry. The thermal stabilities of the copolymers were measured by thermogravimetric analysis. The structures of the copolymers were verified by 1H, 13C, and 29Si NMR as well as IR and UV spectroscopy. The copolymers displayed high thermal stabilities and a single Tg, indicating that phase separation between the two short blocks did not occur. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6146–6152, 2005

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Arylene‐modified siloxanes

Abstract: synopsis Polyarylenepolysiloxanes with varied structure can be obtained in condensation reactions of arylenediilanols and N-methylsiloxazanes. Molecular weights, viscometric properties, glsss transition temperatures, and thermogravimetric analysis data are reported.

Cited by 48 publications

References 6 publications

Preparation of Fully Aromatic Polysilarylenesiloxanes by Melt Polycondensation and Their Thermal Properties

Preparation of Fully Aromatic Polysilarylenesiloxanes by Melt Polycondensation and Their Thermal Properties

Improvement of anode oxidation reaction of a fuel cell using ammonium formate with Pt‐Ir catalysis

Preparation, characterization, and thermal properties of alt‐copoly[1,9‐decaphenylpentasiloxanylene/1,3‐bis(ethylene)permethyloligosiloxanylene]s

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