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.
Nitrogen Dewpoint
Meaning
Moisture concentration threshold represents the temperature at which water vapor in a nitrogen gas supply begins to condense, establishing a critical baseline for dry gas purity in polymer analytical testing. A low nitrogen dewpoint ensures that the purge gas used during thermal characterization does not introduce water molecules into the sample chamber. By maintaining this value below negative forty degrees, analysts prevent moisture from initiating hydrolytic reactions during melt phase testing.
Thermal Analysis
Elevated temperatures in differential scanning calorimetry can cause rapid hydrolysis if moisture is present in the purge stream. When measuring the glass transition temperature of polyamides, the nitrogen dewpoint must be carefully monitored to ensure the polymer remains dry. Wet gas shifts the transition temperature downward, which yields inaccurate material data.
This discrepancy can lead to incorrect moulding parameters on the factory floor.
Moulding Protection
Blanketing systems on hopper dryers use nitrogen to prevent resin oxidation during preheating. Since engineering resins absorb water at high temperatures, the nitrogen dewpoint governs the drying efficiency of the nitrogen loop. A dry nitrogen blanket prevents the degradation of polycarbonates and polyesters.
Sensor Accuracy
Gas moisture tracking relies on high-precision aluminum oxide sensors in the gas stream. These sensors require regular calibration to measure extremely dry gas conditions reliably. Keeping the nitrogen dewpoint within specification prevents drift in the dewpoint measurement.