Cross polarisation/magic-angle spinning

We used modifications of the standard solid-state CP-MAS (cross-polarisation, magic-angle spinning) experiment to allow the proton relaxation characteristics to be measured for each peak in the C spectrum. It is known that highly mobile, hydrated polymers can not be seen using either usual CP-MAS C spectrum or solution NMR (6). We found, however, that by a combination of a long-contact experiment and a delayed-contact experiment we could reconstruct a C spectrum of the cell-wall components that are normally too mobile to be visible. With these techniques we were able to determine the mobility of pectins and their approximate spatial location in comparison to cellulose. 

Key Words Polymer, Polyethylene, Nascent power, Nylon 46, Morphology, nH pulse NMR, In situ measurement, Cross-polarisation magic angle spinning. 

Solid-state and N cross-polarisation/magic-angle spinning... 

Thus the basic experimental procedure for acquiring solid state NMR spectra is cross polarisation magic angle spinning or CP-MAS. This experimental technique produces solid state carbon spectra with line-widths that are comparable to the solution state. 

GA, GB and GC resins where examined by freeze drying without curing, while the GA -I- pMDl reaction product was first hardened and then examined. Solid state CP-MAS (cross-polarisation/magic angle spinning) C-NMR spectra were recorded on a Bruker Avance 11 MSL 300 MHz spectrometer at a frequency of 75.47 MHz. Chemical shifts were calculated relative to tetramethylsilane (TMS). The rotor was spun at 12 kHz on a 4 mm Bruker probe. The spectra were acquired with 5 s recycle delays, a 90° pulse of 5 ps and a contact time of 1 ms. The number of transients was 5000. 

Comparable starch-based materials with an amylose content close to zero, even in the presence of complexing agents, do not show any peak at 947 cm. The V-type structure formation can also be detected using X-ray diffraction analysis and cross-polarisation magic angle spinning solid-state nuclear magnetic resonance [122-125]. 

Pendent vinyl groups in styrene-divinylbenzene copolymers have been analysed by IR and Raman spectroscopy [73-84] and by wet chemical methods [83, 85] after extents of reaction varying from before gelation to after nearly complete conversion of monomers. Periysamy and Ford [86] report a new analytical approach to the problem. Copolymers of styrene with methane- C-labelled p-divinylbenzene were analysed by liquid-state and solid-state cross-polarisation magic angle spinning (CP-MAS) i C-NMR methods. 

H. Saito, G. Izumi, T. Mamizuka, S. Suzuki, and T.R. Tabeta, A C cross polarisation-magic angle spinning (CP-MAS) NMR study of crystalline cyclohexa-amylose inclusion complexes. Conformation-dependent C chemical shifts are related to the dihedral angles of glycosidic linkages. J. Chem. Soc., Chem, Commun., 1386 (1982). 

Cross-polarisation magic angle spinning nuclear magnetic resonance... 

Cross-polarisation magic angle spinning Capillary column pyrolysis - gas chromatography Coefficient of variance Cyano-vinyl-acetate... 

Skibsted, J., L. Hjorth and H. J. Jakobsen. 1995a. Quantification of thaumasite in cementitious materials by Si(iH) cross-polarisation magic-angle spinning NMR spectroscopy. Adv. Cent. Res. 7, 69-83. 

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