Viscometry Ostwald

For Molecular weight determination by viscometry we do not need absolute h value, viscosity measurements may be carried out in simple Ostwald Viscometer. Because of (the non-Newtonian behaviour of most macromolecular solutions at high velocity gradients in the capillary, the viscometer dimensions are chosen in such a manner that the viscosity gradient is the smallest possible. 

The analytical approach to the rotational viscometry of non-Newtonian flow as presented by Oka [4] is derived from the de Waele-Ostwald power law ... 

Molecular weight determination of the oligomer prepared by telomerization was carried out by viscometry. For such low molecular weights extremely clean equipment was essential. Intrinsic viscosity in benzene solution was determined using an Ostwald viscometer at 30 0.05°C the relationship [n] = 1 04 x 10 v was used to calculate the viscosity average molecular weights. ... 

Viscosity measurements began to be used by colloid chemists when Thomas Graham investigated the peptisation of silicic acid in the 1860 s. Soon, with the introduction of the Ostwald U-tube viscometer, viscometry became one of the most widely used methods of investigating colloidal solutions—and to a large extent it still is used for this purpose. 

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