Determination of number-average

The determination of the molecular weight of nanoparticles is performed by gel permeation chromatography (GPC). The experimental setup consists of a high performance liquid chromatography system with a size exclusion column and a refractive index detector. The nanoparticles are usually freeze-dried and dissolved in tetrahydrofuran for analysis on the system. Poly(styrene) or poly(methylmethacrylate) standards are used to calibrate the column, to enable the determination of number average molecular weight (Mn), as in... 

TABLE 2 DETERMINATION OF NUMBER AVERAGE BY BENZYL PICOLYL MAGNESIUM IN MOLECULAR WEIGHTS OF BENZENE. POLY(2-VINYL PYRIDINE) INITIATED... 

Determination of Number-Average Molecular Weights by Ebulliometry... 

FIGURE 7.8 Determination of number average molecular weight by osmometry. [Graph reconstructed from data by Roughton and Kendrew, Haemoglobin, Butterworth, London, 1949, p. 197.]... 

An unconventional technique was developed by Schulz and his co-workers261. It calls for determination of number average degree of polymerization, DP , at various degrees... 

Over the last ten years evidence has accumulated that pectin can undergo self disaggregation (1-4). More recently, by size exclusion chromatography (SEC) and determination of number-average degrees of... 

This technique has also been applied to the fractionation and determination of number-average MWD of anionic and cationic water-soluble polymers such as PS sulfonate (molecular weight 6500-690,000) and polyvinyl pyridine (molecular weight 28,000-240,000) [239]. Schuch and co-workers [240] carried out a field flow fractionation of polyvinyl formamide. 

The determination of number average sequence lengths for the vinyl chloride and vinylidene chloride is challenging because six of eight trimers are not resolved by Py-GC. As mentioned previously, there is no way to know how much chlorobenzene peak intensity is contributed from triad CCD and DCC or from CDC. The same situation exists for the dichlorobenzene peak from the triad of DDC, CDD and DCD. They utilise the equations listed below but it is necessary to make a third assumption to obtain all six terms of triad intensities. 

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