Melting points measuring

The end point may be ehecked by noting the extent of flow of a heated pellet down a given slope or by melting point measurements. Other control tests include alcohol solubility, free phenol eontent and gelation time with 10% hexa. 

Table XXXIV.—Heats of Fusion and Energy of Interaction Constants as Obtained from Melting Point Measurements on Mixtures of Cellulose Tributyrate with Diluents s...

Melting points, measured in open capillary tubes using a Thomas-Hoover melting point apparatus, are uncorrected. Elemental analyses were performed by Galbraith Laboratories, Knoxville, Tennesee. % and 19C-NMR spectra were generally obtained with an IBM AF-100, if necessary the higher field Bruker WP-200 or AM-400 NMR spectrometer were employed. Chemical shifts are given in parts per million (ppm) on a a scale downfield from tetramethylsilane (TMS). Infrared spectra were recorded with a Perkln-Elmer 283 spectrophotometer. 

Depending on the size and shape of the polymer particles, solid-state polycondensation (SSP) is performed at temperatures between 220 and 235 °C, which lie above the glass transition temperature ( 70-85 °C) and below the melting point (measured by DSC 245-255 °C) of PET. The temperature range for operation of SSP is rather small because on the one hand, the temperature should be as... 

In the case of Fe and Si, although melting point measured by several authors are not very different, a high difference in [Pg.149]

Capillary tubes for melting point measurement are available commercially and are supplied open at both ends or closed at one end or closed at both... 

Your thermometer may be a major source of error in melting point measurement. Occasionally thermometers for routine laboratory use may not be accurate and may read up to 10 °C high or low. To avoid this problem you should always calibrate your thermometer to determine any error and be... 

Recrystallization is designed to remove all these types of impurity and provide a pure produet suitable for melting point measurement. Purification by recrystallization is based on the theory of saturated solutions (p. 50) and a suitable recrystallization solvent is one in which the chemical to be purified is insoluble in the cold solvent and soluble in the hot solvent. 

Boehler R. (1993) Temperatures in the Earth s core from melting-point measurements of iron at high static pressures. Nature 363, 534-536. 

MHz high resolution solid-state NMR spectroscopy [53, 54]. All the samples used for this NMR study are random copolymers and not mixtures of random copolymers as confirmed by the solution NMR sequence analysis and by DSC melting-point measurements [43, 54]. Before taking NMR measurements, possible effects of the thermal history and recrystallization are avoided as mentioned above. 

Figure 6. TFE content and melting point measured by DSC for perfluorosulfonic...

If you are carrying out several melting point measurements, it is common sense to measure the melting point of the lowest melting compound first -less time for the apparatus to cool to room temperature. 

In addition to melting point measurements, there are other methods to evaluate or prove the achieved progress in purification. These are gas chromatography, density measurements, or the different types of color tests. 

Thermodynamic Parameters Derived from Melting Point Measurements... 

Goe] Simple fliermal analysis, melting points measurements 700-1400°C, <12 mass% P, < 12 mass% C... 

LDPE-g-GMA (glyddyl methacrylate) as compatibilizer temperature using, and melting point measurements using DSC temperature and a reduction in melting point of nylon phase were observed with additirai of the compatibilizeas etal. 1995... 

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