Even though the ubbelohde viscometer principle is quite old, the technique is still widely used. The digitalized variant we use is able to measure a very wide range of different polymers. First the polymer is dissolved in a solvent which is not harmful to the polymer chains. Then a blank is measured followed by the sample in triplex with every single value within a 0.2% tolerance. When the values of the three measurements are not within 0.2% tolerance a fourth, and if needed a fifth, measurment is conducted. If the five measurements are not within a 0.2% tolerance, all the values are rejected and the measurements are repeated. Average values are reported.
Common used solvents are: m-cresol (low IV and or amorphous PET), formic acid (polyamides), dichloroacetic actid (high IV PET). Other solvents on request.