<p>This part of ISO 1628 specifies conditions for the determination of the reduced viscosity (also known as viscosity</p>
<p>number) and <i>K-</i>value of PVC resins. It is applicable to resins in powder form which consist of homopolymers of the</p>
<p>monomer vinyl chloride and copolymers, terpolymers, etc., of vinyl chloride with one or more other monomers, but</p>
<p>where vinyl chloride is the main constituent. The resins may contain small amounts of unpolymerized substances (e.g.</p>
<p>emulsifying or suspending agents, catalyst residues, etc.) and other substances added during the course of the</p>
<p>polymerization. This part of ISO 1628 is not applicable, however, to resins having a volatile-matter content in excess of</p>
<p>0,5 % ± 0,1 %, when determined in accordance with ISO 1269. In addition to this, it is not applicable to resins which are</p>
<p>not entirely soluble in cyclohexanone.</p>
<p>The reduced viscosity and <i>K-</i>value of a particular resin are related to its molecular mass, but the relationship varies</p>
<p>depending on the concentration and type(s) of other monomer(s) present. Hence homopolymers and copolymers</p>
<p>having the same reduced viscosity or <i>K-</i>value may not have the same molecular mass.</p>
<p>The values determined for reduced viscosity and <i>K-</i>value, for a particular sample of PVC resin, are influenced</p>
<p>differently by the concentration of the solution chosen for the determination. Hence the use of the procedures described</p>
<p>in this part of ISO 1628 will only give values for reduced viscosity and <i>K-</i>value that are comparable when the</p>
<p>concentrations of the solutions used are identical.</p>
<p>Limiting viscosity number is not used for PVC resins.</p>
<p>The experimental procedures described in this part of ISO 1628 can also be used to characterize the polymeric fraction</p>
<p>obtained during the chemical analysis of a PVC composition. However, the values calculated for the reduced viscosity</p>
<p>and <i>K-</i>value in these circumstances may not indicate the actual values for the resin used to produce the composition</p>
<p>because of the impure nature of the recovered polymer fraction.</p>
Registration number (WIID)
25191
Scope
<p>This part of ISO 1628 specifies conditions for the determination of the reduced viscosity (also known as viscosity</p>
<p>number) and <i>K-</i>value of PVC resins. It is applicable to resins in powder form which consist of homopolymers of the</p>
<p>monomer vinyl chloride and copolymers, terpolymers, etc., of vinyl chloride with one or more other monomers, but</p>
<p>where vinyl chloride is the main constituent. The resins may contain small amounts of unpolymerized substances (e.g.</p>
<p>emulsifying or suspending agents, catalyst residues, etc.) and other substances added during the course of the</p>
<p>polymerization. This part of ISO 1628 is not applicable, however, to resins having a volatile-matter content in excess of</p>
<p>0,5 % ± 0,1 %, when determined in accordance with ISO 1269. In addition to this, it is not applicable to resins which are</p>
<p>not entirely soluble in cyclohexanone.</p>
<p>The reduced viscosity and <i>K-</i>value of a particular resin are related to its molecular mass, but the relationship varies</p>
<p>depending on the concentration and type(s) of other monomer(s) present. Hence homopolymers and copolymers</p>
<p>having the same reduced viscosity or <i>K-</i>value may not have the same molecular mass.</p>
<p>The values determined for reduced viscosity and <i>K-</i>value, for a particular sample of PVC resin, are influenced</p>
<p>differently by the concentration of the solution chosen for the determination. Hence the use of the procedures described</p>
<p>in this part of ISO 1628 will only give values for reduced viscosity and <i>K-</i>value that are comparable when the</p>
<p>concentrations of the solutions used are identical.</p>
<p>Limiting viscosity number is not used for PVC resins.</p>
<p>The experimental procedures described in this part of ISO 1628 can also be used to characterize the polymeric fraction</p>
<p>obtained during the chemical analysis of a PVC composition. However, the values calculated for the reduced viscosity</p>
<p>and <i>K-</i>value in these circumstances may not indicate the actual values for the resin used to produce the composition</p>
<p>because of the impure nature of the recovered polymer fraction.</p>
