The Bruker Avance MSL200 spectrometer operates at 200 MHz or 4.7 Tesla. It comprises a magnet, a console and the computer. It is used for high-resolution solid-state 50 MHz 13C NMR analyses and high-temperature 1H NMR analyses. The solid-state 13C NMR analyses are carried out using two probes, namely a 4 mm Bruker probe and a 7 mm Bruker probe, both operating with magic angle spinning (MAS). Cross polarisation (CP) and single pulse excitation (SPE) pulse sequences are used in conjunction with MAS. The samples are packed tight into a cylindrical (7 mm o.d.) zirconia rotor with a cap made of a homopolymer of chlorotrifluoroethene (Kel-F) and spun at the magic angle (5444’) with a spinning rate of approximately 5 kHz. Tetrakis(trimethylsilyl)silane (TKS) can be added to the samples as an internal standard. The amount of sample required for the test must be higher than 0.3 g (4 mm probe). A Doty Scientific 200 MHz 1H NMR probe is used to determine fluidity development in solid samples as a function of temperature. This probe can operate at temperatures up to 500°C and the amount of sample required must be higher than 0.1 g. A flow of 35 L/min dry nitrogen is used to transfer heat to the sample and to remove the volatiles that escape from the ceramic sample container. The sample temperature is monitored using a thermocouple in direct contact with the sample container. The solid echo pulse sequence (90o - - 90o) is used to acquire the data. The spectra obtained are deconvoluted into Gaussian and Lorentzian distribution functions, which enables the calculation of the fraction of total hydrogen that is mobile and its mobility (T2L). The higher the concentration and mobility of the fluid phase the higher the fluidity.
Model: Avance 200