Molar mass measure

Viscosity and molar mass measurements for 70 and 71 supplemented with broad H-NMR signals which depended on concentration, temperature, and solvent but independent of NMR frequency, strongly suggested self-association of these macromolecules (in a CHC13 solution). 

A viscosity online detector in a size exclusion chromatography (SEC) instrument allows for a universal calibration for polymers with known K- and a-values. For polymers that are only soluble at high temperature, e.g., polyolefines, high-temperature detectors are available, which can be operated up to 200°C. In addition to molar mass measurements, viscosity detectors have also been employed successfully to obtain structural information of branched polymers [28]. 

Billingham, N. C. Molar mass measurements in polymer science. London Kogan Page 1977, Chapt. 5... 

N.C. Billingham, Molar Mass Measurements in Polymer Science, Wiley, Halstedt, NY, 1977. 

Billingham, N.C., "Molar Mass Measurements in Polymer Science", John Wiley, New York, 1977. 

Hydrolysis must appear in principle as a pseudo-zero-order process, except if the end-life conversion nf/E0 exceeds largely 10%, which seems unlikely. In linear polymers, the number of chain scissions n can be determined from molar mass measurements. In thermosets, it is considerably more difficult to determine. Some possible ways are discussed in the following section. 

The molar mass of SrO has an established relative standard uncertainty of 1.1 xlO-4 which is almost entirely due to the variability in the isotopic composition of terrestrial strontium. This uncertainty is small and could be reduced further by one order of magnitude by a direct molar-mass measurement of the specific stron-... 

These numbers approximate the numbers of atoms in the molecule with small deviations from values resulting from the approximate nature of the molar mass measurement. The molecular formula, C4H6O2, is obtained without going through the intermediate evaluation of an empirical formula. 

Bark LS and Allen NS (Eds) "Analysis of Polymer Systems", Applied Science Publishers, London, 1982. Billingham NC "Molar Mass Measurements in Polymer Science", Halsted Press (Div. of Wiley), New York 1977. Chu B "Laser Light Scattering", Academic Press, Orlando, FL, 1974. 

Higher molar mass averages sometimes are quoted. For example, certain methods of molar mass measurement (e.g., sedimentation equilibrium) yield the z-average molar mass (Afx) which is defined as follows... 

It is clear that FFF comprises a family of flexible analytical techniques which can supply a tremendous amount of physicochemical information when complimentary FFF methods are used. Also, the application range (1 nm-100 pm for colloids or 1000 g/mol up to more than 1018g/mol for polymers) is larger than with any other analytical technique for particle size or molar mass measurement coupled with usually short measurement times. 

SEC with light-scattering detection direct copolymer molar mass measurement for chemically homogeneous and segmented copolymers independent of their structure. 

Billingham, N. C., Molar Mass Measurements in Polymer Science, John Wiley Sons, New York, 1977. Zimm, B. H., J. Chem. Phys. 16 1093 (1948) 16 1099 (1948). 

The measurement of particle size and molar mass distributions are typically carried out off-line with relatively expensive instruments. Techniques used for particle size include transmission electron microscopy, photon correlation spectroscopy, or capillary hydrodynamic fractionation and molar mass measurement with GPC. 

Billingham, N.C., Molar Mass Measurements in Polymer Science, Kogan Page, 1977. Billmeyer, F.W., Textbook of Polymer Science, 3rd ed., John Wiley and Sons, 1979. Bohdanecky, M. and Kovar, J., Viscosity of Polymer Solutions, Elsevier, 1982. 

Mass Spectrometric Methods of Molar-Mass Measure... 

Characterization techniques being used in the 1950s and 1960s, such as NMR, infrared spectroscopy. X-ray diffraction, microscopy etc., could only measure the average values this was also the case for the molar mass measurement. In some cases, there was a need to separate the amorphous and crystalline fractions by solvent extraction methods because no other means to measure the distributions were available. 

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