Superconductivity magnetic field

A Bruker WM-500 NMR spectrometer was used to study the carbon-13 resonances for the various epoxy components dissolved in deuterated chloroform (CDClj). Pure components of TGDDM, DDS, and DGOP were dissolved in solvent-containing 10 mm NMR tube. Room temperature carbon-13 NMR spectra were measured at 125 MHz using a superconducting magnetic field of 11.7 Tesla. 

Nuclear Magnetic Resonance Spectroscopy. Like IR spectroscopy, NMR spectroscopy requires little sample preparation, and provides extremely detailed information on the composition of many resins. The only limitation is that the sample must be soluble in a deuterated solvent (e.g., deuterated chloroform, tetrahydro-furan, dimethylformamide). Commercial pulse Fourier transform NMR spectrometers with superconducting magnets (field strength 4-14 Tesla) allow routine measurement of high-resolution H- and C-NMR spectra. Two-dimensional NMR techniques and other multipulse techniques (e.g., distortionless enhancement of polarization transfer, DEPT) can also be used [10.16]. These methods are employed to analyze complicated structures. C-NMR spectroscopy is particularly suitable for the qualitative analysis of individual resins in binders, quantiative evaluations are more readily obtained by H-NMR spectroscopy. Comprehensive information on NMR measurements and the assignment of the resonance lines are given in the literature, e.g., for branched polyesters [10.17], alkyd resins [10.18], polyacrylates [10.19], polyurethane elastomers [10.20], fatty acids [10.21], cycloaliphatic diisocyanates [10.22], and epoxy resins [10.23]. 

Figure 3. Schematic illustration of superconducting magnetic field heat treatment system.

Figure Bl.l 1.2. Simplified representation of an NMR spectrometer with pulsed RF and superconducting magnet. The main magnetic field Bq is vertical and centred on the sample.

Three important characteristics of the superconducting state are the critical temperature, the critical magnetic field, and the critical current. These parameters can be varied by using different materials or giving them special metallurgical treatments. 

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