Small-Angle X-ray scattering studies of Nafion®/[silicon oxide] and Nafion®/ORMOSIL nanocomposites

Deng, Qingchun; Cable, Kevin M.; Moore, Robert B.; Mauritz, Kenneth A.

doi:10.1002/(sici)1099-0488(199608)34:11<1917::aid-polb9>3.0.co;2-o

Cited by 51 publications

(17 citation statements)

References 1 publication

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“…After specified times, the membranes were removed, washed in MeOH for 1-2 s, blotted and dried at 100°C under vacuum for 24 h to remove trapped volatiles and promote further condensation of SiOH groups within the in situ silicon oxide phase. At this point, for these particular dried weight uptakes, isolated silicon oxide `cores' exist within the ionomer template, as discussed earlier 3,5 . The Nafion®-SiO2 sample used for TGA-FTi.r.…”

Section: Nafion®-sio2 Hybridsmentioning

confidence: 74%

“…Silicon oxide invasion of Nafion® to this degree (13.4 wt.%) is thought to disrupt neither cluster structure nor TFE crystallinity significantly; the Bragg spacing corresponding to the SAXS `ionomer' peak for Nafion® is essentially unchanged upon silicon oxide incorporation via the in situ sol-gel process [5] . Side-chains are envisioned as being immobilized within silicon oxide cages that retard reactions involving -SO3 groups.…”

Section: Nafion®-sio2mentioning

confidence: 99%

“…1. SAXS studies 4,5 established that the morphology of unfilled Nafion® persists after its invasion by the sol-gel-derived phase. Molecular structure was characterized within these siliconcontaining nanophases using FTi.r.…”

Section: Introductionmentioning

confidence: 99%

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TGA–FTi.r. investigation of the thermal degradation of Nafion® and Nafion®/[silicon oxide]-based nanocomposites

Deng

Wilkie

Moore

et al. 1998

Polymer

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151

101

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The integrated TGA-FTi.r. technique probed the thermal degradation of: (1) a Nafion®-H + membrane; (2) this membrane as modified by incorporation of a SiO2[1-x/4] (OH)x phase via in situ sol-gel reactions for tetraethoxysilane; and (3) this modified membrane as further modified, organically, via post-reaction with diethoxydimethylsilane. Gravimetric loss is multistep for (1) and (2), but occurs in a single step for (3) which has the greatest thermal degradative stability. The considerable inhibition of SO2 evolution for (2) and (3) is rationalized in terms of side-chains that are immobilized within silicon oxide cages that block reactions involving SO3 groups. Degradation of SiO2[1-x/4] (OH)x `cores' by generated HF is retarded by their organic `shells' in (3). Substituted carbonyl fluorides and CF2-containing fragments appear. Si-CH3 and CH3 groups and/or-CH and CH2 vinyl compounds are degradation products for (3). It is unlikely that intact R-SO2-OH groups, or perfluoroalkylether groups issuing from the side-chains of Nafion®, exist as gas phase products. The origins of some peaks are in question owing to spectral complexity. Altogether, the hybrid (3) is superior with respect to degradation onset temperature, subsequent mass loss over a range of about 100°C, and low quantity of evolved products.

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Section: Nafion®-sio2 Hybridsmentioning

confidence: 74%

Section: Nafion®-sio2mentioning

confidence: 99%

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TGA–FTi.r. investigation of the thermal degradation of Nafion® and Nafion®/[silicon oxide]-based nanocomposites

Deng

Wilkie

Moore

et al. 1998

Polymer

Self Cite

151

101

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“…In this way, it is possible to produce structures with closed pores which have the right density, pore size, pore distribution, mechanical and thermal properties proper for insulating panels or microcellular foams (Kiatkamjornwong et al, 2001;Xanthos et al, 2004;Chem &Curliss, 2003;Carotenuto et al, 2000). The "repaired" POST-PET can be modified in order to make of cheap composites for expanded panels (Deng at al., 1996).…”

Section: Sheets and Foamed Panelsmentioning

confidence: 99%

Overview on Mechanical Recycling by Chain Extension of POSTC-PET Bottles

Dimonie¹,

Socoteanu²,

Pop³

et al. 2012

Material Recycling - Trends and Perspectives

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“…The enhanced water retention capability and the sustained proton conductivity of composite membranes have not been fully understood on the molecular level, despite characterizations by X-ray diffraction and scattering [85][86][87][88] , electron microscopy 88,89 , and NMR 57,73 . Yang et al claimed that the inorganic particle may act as rigid scaffolds that provide the membrane with dimension stability against swelling 90 , while Ye et al 57 suggested that high density of hydroxyl groups on the particle surface are essential to facilitate proton transport.…”

Section: Improved Pem With Inorganic Nanoparticlesmentioning

confidence: 99%

Characterization of proton exchange materials for fuel cells by solid state nuclear magnetic resonance

Kong¹

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The water-polymer interfacial area, which is reflected in the Porod region of small-angle scattering data, is an important parameter of different models of the Nafion fuel cell membrane. Therefore, we have compared published experimental data of Nafion with various structural models, in particular the parallel water-channel model. The surface-tovolume ratio extracted at intermediate hydration levels typical of fuel-cell conditions matches that of the parallel water-channel model with molecular corrugation. In addition, it is shown that for less than 3.5 water molecules per Nafion sidegroup, the interfacial area must increase strongly with hydration, contrary to the predictions of the polymer bundle model.

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Small-Angle X-ray scattering studies of Nafion®/[silicon oxide] and Nafion®/ORMOSIL nanocomposites

Cited by 51 publications

References 1 publication

TGA–FTi.r. investigation of the thermal degradation of Nafion® and Nafion®/[silicon oxide]-based nanocomposites

TGA–FTi.r. investigation of the thermal degradation of Nafion® and Nafion®/[silicon oxide]-based nanocomposites

Overview on Mechanical Recycling by Chain Extension of POSTC-PET Bottles

Characterization of proton exchange materials for fuel cells by solid state nuclear magnetic resonance

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