What is ISO 1628-5 - Viscosity of polymers using capillary viscometers about?  
Both synthetic and natural polymers have essential uses in everyday life because of their broad spectrum of properties. 
ISO 1628-5 specifies a method for the determination of the viscosity number of dilute solutions of TPs in certain specified solvents. The method applies to poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly-(cyclohexylenedimethylene terephthalate) (PCT), and poly(ethylene naphthalate) (PEN), as well as to copolyesters and other polyesters, defined in ISO 77921, that are soluble in one of the specified solvents under the specified conditions. 
Who is ISO 1628-5 - Viscosity of polymers using capillary viscometers for?  
ISO 1628-5 on the viscosity of polymers using capillary viscometers is useful for manufacturing companies associated with:  
- Fibres and textiles  
- Floor coverings  
- Garbage disposal bags  
- Packaging  
- Plastic parts for machinery and equipment  
- Insulation  
- Wood substitutes  
- Adhesives  
- Mould 
Why should you use ISO 1628-5 - Viscosity of polymers using capillary viscometers?  
Polymers with larger molecular sizes have a higher molecular weight which provides higher viscosity. The viscosity number of a polymer is determined by the general procedure specified in ISO 16281, observing the particular conditions specified in ISO 1628-5. The determination of the viscosity number of a thermoplastic polyester provides a measure of the relative molecular mass of the polymer. 
ISO 1628-5 provides the test method of determining the viscosity of polymers. This includes: 
- Storage of the solvents
- Selection of the solvent
- Determination of inorganic materials or other additives in the sample
- Determination of the content of inorganic materials
- Determination of the content of other additives
- Preparation of solution
- Measurement of flow time
The guidelines in ISO 1628-5 help you determine the viscosity of polymers for choosing the right material for industrial purposes, so that end customers can use superior quality products. 
