Structural Characterization of Silicon Carbonitride Ceramics from Polymeric Precursors using Nuclear Magnetic Resonance

1992 ◽  
Vol 287 ◽  
Author(s):  
Corine M. Gerardin ◽  
F. Taulelle ◽  
J. Livage
Keyword(s):  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Free Carbon ◽  
Silicon Carbonitride ◽  
Magic Angle ◽  
Chemical Analyses ◽  
Carbon Phase ◽  
Different Temperatures ◽  
Angle Spinning

ABSTRACTThe pyrolytic conversion of a polyvinylsilazane precursor to Si-C-N ceramics is studied using solid-state NMR. 13C and 29Si magic angle spinning and 1H static NMR experiments allow us to investigate the structure of the disordered multiphased intermediates formed during the pyrolysis. The Si environments are quantitatively analyzed by 29Si MAS NMR spectra simulations. The relative abundance of SiHCN2, SiC2N2, SiN3C and SiN4 sites at different temperatures are used to calculate elemental compositions that characterize the Si-containing phase. The comparison of these compositions with those obtained from chemical analyses shows evidence of the presence of a free carbon phase.We have also determined the H and C contents in the free carbon phase.

Characterization of Polymer Compatibility by1H Dipolar Filter Solid-State NMR under Fast Magic Angle Spinning

2007 ◽  
Vol 40 (25) ◽  
pp. 9018-9025 ◽  
Author(s):  
Xiaoliang Wang ◽  
Qiang Gu ◽  
Qing Sun ◽  
Dongshan Zhou ◽  
Pingchuan Sun ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Polymer Compatibility ◽  
Angle Spinning ◽  
Fast Magic Angle Spinning

Solid State NMR Characterization of Crosslinked Brominated Poly(Isobutylene-co-4-Methylstyrene)

1993 ◽  
Vol 66 (1) ◽  
pp. 109-120 ◽  
Author(s):  
R. R. Eckman ◽  
I. J. Gardner ◽  
H-C. Wang
Keyword(s):  
Solid State ◽  
Functional Groups ◽  
Solid State Nmr ◽  
Phenyl Ring ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Crosslinked Polymers ◽  
Nmr Characterization ◽  
Angle Spinning

Abstract The curing of brominated poly(isobutylene-co-4-methylstyrene) was studied using solid-state magic-angle-spinning NMR, a technique which is uniquely suited to investigate cured or crosslinked polymers. This brominated copolymer contains 4-bromomethylstyryl and 4-methylstyryl functional groups and was compression cured with pure ZnO. It was proposed that a precomplex is formed between zinc and the 4-bromomethylstyryl group, which generates a benzylic carbocationic intermediate. Crosslinking predominantly occurs by alkylation of the phenyl ring of another 4-bromomethylstyryl group by the benzylic intermediate. The ZnO brings the two bromides of these groups into proximity. The dependence of the cure chemistry on the concentration of 4-bromomethylstyryl functional groups was studied. Conversion of some 4-bromomethylstyryl groups to oxygenated species upon curing was also observed.

scholarly journals Combination of solid state NMR and DFT calculation to elucidate the state of sodium in hard carbon electrodes

2016 ◽  
Vol 4 (34) ◽  
pp. 13183-13193 ◽  
Author(s):  
Ryohei Morita ◽  
Kazuma Gotoh ◽  
Mika Fukunishi ◽  
Kei Kubota ◽  
Shinichi Komaba ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Dft Calculation ◽  
Magic Angle Spinning ◽  
The State ◽  
Mas Nmr ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Hard Carbon ◽  
Angle Spinning

We examined the state of sodium electrochemically inserted in HC prepared at 700–2000 °C using solid state Na magic angle spinning (MAS) NMR and multiple quantum (MQ) MAS NMR.

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