Polymerization of Acrylamide with a Redox System in Aqueous Solution

Polymerization of Acrylamide with a Redox System in Aqueous Solution 

Safetyprecautions Befote this experiment is carried out,Sect.2.2.5 must be read as 

Safety precautions Before this experiment is carried out, Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for all chemicals and products used. 

A solution of 250 mg of poly(acrylamide) from Example 3-9 in 25 ml of distilled water is introduced at the top of the column. At the same time the collection of the eluate is commenced, taking 10 ml portions (measuring cylinder) for each fraction.Theflow time under these conditions is about 10 ml/h. When the meniscus of the poly(acrylamide) solution reaches the gel layer, distilled water is added to the column as eluting agent. 

The fractions coilected are each run dropwise into 100 ml of stirred methanol to which two drops of concentrated hydrochloric acid have been added.Turbidity or precipitation will be observed from about the 6th fraction to about the 20th fraction.The precipitated fractions are filtered off, washed with methanol and dried to constant weight in vacuum at 20 °C. For each fraction the viscosity is measured in water at 25 °C using a capillary viscometer (capillary diameter 0.35 mm) and at as high a concentration as possible (10 g/l) in order to minimize errors.The limiting viscosity number, and hence the molecular weight, is estimated (see Sect. 2.3.3.3.1). Adjacent fractions for which there may be insufficient material for a viscosity measurement,can be combined where necessary. 

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