Can a rotational viscometer be used to measure the viscosity of polyacrylamide instead of an Ubbelohde viscometer, and to calculate the molecular weight?
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Gentlemen, I have polyacrylamide anionic flocculants for water treatment, and I would like to determine their molecular weight by measuring viscosity, as the molecular weight generally reflects the flocculation efficiency of such agents. Standard GB17514-2008 uses an Ubbelohde viscometer to measure viscosity, from which the molecular weight is then calculated. I currently only have an NDJ-1 type rotational viscometer for measuring viscosity. I would appreciate it if everyone could help me out. Can the viscosity value obtained using a rotational viscometer be used to calculate the molecular weight? Is the viscosity (dynamic viscosity) measured by a rotational viscometer the same as that measured by an Ubbelohde viscometer? If they are different, can the two be converted? Also, what is the relationship between limiting viscosity and dynamic viscosity?
This post was last edited by qugd on 2017-9-28 09:30. Some solutions of polymers do not exhibit Newtonian fluid behavior; there is no simple conversion relationship between their dynamic viscosity and kinematic viscosity. The use of a rotational viscometer instead of an Ubbelohde viscometer to determine viscosity may not be suitable for calculating the average molecular weight. Under high shear forces, the viscosity properties of non-Newtonian fluids differ from those of conventional fluids. In this case, the original poster needs to conduct some comparative experiments on their own.