Plastics — Determination of the viscosity of polymers in dilute solution using capillary viscometers — Part 2: Poly(vinyl chloride) resins
1.2 The reduced viscosity and K-value of a particular resin are related to its molecular mass, but the relationship varies depending on the concentration and type(s) of other monomer(s) present. Hence, homopolymers and copolymers having the same reduced viscosity or K-value might not have the same molecular mass.
1.3 The values determined for reduced viscosity and K-value, for a particular sample of PVC resin, are influenced differently by the concentration of the solution chosen for the determination. Hence the use of the procedures described in this document only gives values for reduced viscosity and K-value that are comparable when the concentrations of the solutions used are identical.
1.4 Limiting viscosity number is not used for PVC resins.
1.5 The experimental procedures described in this document can also be used to characterize the polymeric fraction obtained during the chemical analysis of a PVC composition. However, the values calculated for the reduced viscosity and K-value in these circumstances might not indicate the actual values for the resin used to produce the composition because of the impure nature of the recovered polymer fraction.