Vaporization Coulometry Moisture Analysis in Industrial Polyesters
Coulometric vaporization titration under ISO 15512 Method B2 quantifies trace moisture in industrial polyesters to prevent hydrolytic degradation during melt extrusion.
Dry Nitrogen Purge
Meaning
Inert gas displacement is a protective procedure that substitutes dry gas for atmospheric air inside polymer processing or testing equipment to eliminate oxygen and moisture. A dry nitrogen purge prevents the thermal oxidation of sensitive molten resins during capillary rheometry or high-temperature extraction. By maintaining an oxygen-free envelope around the sample, this procedure ensures that degradation does not distort the measured melt flow behavior.
Oxidation Prevention
High temperatures in analytical instruments rapidly degrade unprotected polymer samples. When testing polyamides or polyesters, a dry nitrogen purge suppresses the chain scission reactions that occur when hot polymer molecules encounter atmospheric oxygen. This protection is necessary to obtain repeatable shear viscosity curves.
Without this step, the molten material thins prematurely, which results in inaccurate process simulation.
Moisture Removal
Hygroscopic resins absorb water vapor from surrounding air in seconds. Because even trace moisture causes polymer chains to split during heating, a dry nitrogen purge removes ambient moisture from the sample chamber before the temperature rises. This drying action prevents hydrolytic degradation.
Instrument Longevity
Corrosive byproducts of polymer degradation can attack polished metal surfaces. Keeping the sample chamber inert minimizes the formation of acidic outgassing products. Regular use of a dry nitrogen purge protects delicate sensor surfaces from chemical etching.