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.
Sample Vial Crimping
Meaning
Container sealing technique utilizes a mechanical tool to compress an aluminum cap with an elastomeric septum onto the rim of a chromatography vial, creating an airtight barrier. In headspace gas chromatography of polymer outgassing, sample vial crimping prevents volatile compounds from escaping before or during analysis. This hermetic seal ensures that the concentration of extracted additives or residual solvents measured in the vial reflects the true composition of the resin sample.
Volatile Containment
Heating the sample during headspace extraction generates high pressures inside the sealed vial. When testing volatile emissions from moulded plastic components, sample vial crimping prevents the septum from dislodging under elevated pressures. A loose seal allows volatile monomers and solvents to escape into the atmosphere.
This leakage leads to underestimating the emission levels, which can cause the polymer batch to fail compliance checks falsely.
Analytical Repeatability
Consistent pressure across all tested vials ensures the reproducibility of the data. Because variations in sealing force alter the volume of gas that can leak during heating, sample vial crimping requires a calibrated crimper to apply uniform force to every sample. This uniformity guarantees that different vials yield comparable chromatographic peaks.
Component Selection
Choosing the correct combination of aluminum cap and septum is critical for leak-free sealing. Tough septa require higher crimping force to compress properly against the glass rim. Executing sample vial crimping with high-quality seals reduces the risk of vial breakage during the sealing process.