ISO 1628-2-2020 pdf free.Plastics — Determination of the viscosity of polymers in dilute solutionusing capillary viscometers — Poly(vinyl chloride) resins.
1.1.This document specifies conditions for the determination of the reduced viscosity (also knownas viscosity number) and K-value of PVC resins. It is applicable to resins in powder form which consistof homopolymers of the monomer vinyl chloride and copolymers, terpolymers, etc. of vinyl chloridewith one or more other monomers, but where vinyl chloride is the main constituent.The resins maycontain small amounts of unpolymerized substances (e.g. emulsifying or suspending agents, catalystresidues, etc.) and other substances added during the course of the polymerization. This documentis not applicable, however, to resins having a volatile matter content in excess of 0,5 %0,1 %, whendetermined in accordance with ISO 1269.in addition to this, it is not applicable to resins which are notentirely soluble in cyclohexanone.
1.2.The reduced viscosity and K-value of a particular resin are related to its molecular mass, but therelationship 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 samemolecular mass.
1.3.The values determined for reduced viscosity and K-value, for a particular sample of PVC resin, areinfluenced differently by the concentration of the solution chosen for the determination.Hence the useof the procedures described in this document only gives values for reduced viscosity and K-value that arecomparable 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 thepolymeric fraction obtained during the chemical analysis of a PVC composition.However, the valuescalculated for the reduced viscosity and K-value in these circumstances might not indicate the actualvalues for the resin used to produce the composition because of the impure nature of the recoveredpolymer fraction.
2.Normative references:The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document.For dated references,only the edition cited applies. Forundated references, the latest edition of the referenced document (including any amendments) applies.ISO 1628 pdf download.