Molecular weight determination dilute solution light scattering

Methods of determining molecular weight include osmotic pressure, light scattering, gel permeation chromatography, dilute solution viscosity, vapor pressure, freezing temperatures, and others. Odian GC (2004) Principles of polymerization. John Wiley and Sons Inc., New York. Ehas HG (2003) An introduction to plastics. John Wiley and Sons, New York. Slade PE (2001) Polymer molecular weights, vol 4. Marcel Dekker, New York. 

In the case of polyelectrolytes another parameter has to be considered the degree of dissociation. Molecular weight determination in pure water can not be performed. The reason for this is that the viscosity is also very high in the dilute state and therefore the purification procedure (filtration, centrifugation) is difficult to perform. In addition, the difference between the scattering intensity of the light in the solvent and in the polymer solution is very small at this low concentration, which makes such measurements impossible. Therefore, all measurements have to be performed in a low... 

Molecular weight determinations were done using a Brice-Phoenix Model BP-3000 Universal Light Scattering Photometer. Molecular weight determinations were carried out in the usual manner using 1 polymer solutions with serial dilutions. Refractive Index Increments were determined using a Baush and Lombe Abbe Refractometer Model 3-L. 

The amount of excess light scattered by dilute polymer solutions compared with that scattered by the pure solvent is used routinely to determine the weight average molecular weight of polymers, A/, ... 

Until the mid-1960s, molecular-weight averages were determined only by techniques such as dilute solution viscosity, osmometry, and light scattering. Most of these techniques work best for polymers with a narrow... 

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