Karl Fischer Determination of Trace Water in Polyethylene Terephthalate
Polyethylene terephthalate trace moisture determination relies on Karl Fischer coulometric oven extraction at 170 to 180 degrees Celsius to prevent chain scission.
Microgram Water Determination
Meaning
Quantitative analysis of trace water at the parts per million level provides the precision needed for engineering resins. The process of microgram water determination uses coulometric Karl Fischer titration to measure very small amounts of water in polymers that are sensitive to even slight moisture levels. Resins like polycarbonate require this level of detail to avoid cosmetic defects such as splay or structural failures like embrittlement.
The technique detects water masses as low as ten micrograms with high repeatability.
Detection Precision
Limits for modern analytical equipment allow for the identification of minute water quantities in a sample. Precise microgram water determination ensures that the resin has reached the drying target specified on the material datasheet. Without this level of detail, a moulder might process material that appears dry but still contains enough moisture to cause hydrolytic degradation.
Reliable precision supports the production of high strength components for medical or automotive applications.
Structural Integrity
Performance of a moulded part is directly linked to the moisture content of the melt. Effective microgram water determination identifies batches that would result in weak molecular bonds if processed. Excess water at the microgram scale can lead to a measurable drop in impact strength and tensile properties.
Quality departments use these measurements to set the boundary between acceptable material and scrap.
Electronic Sensitivity
Control of the titration current allows for the measurement of the tiny amounts of charge needed to neutralize water. Constant monitoring of the background drift ensures that the microgram water determination is not affected by ambient humidity. High sensitivity requires a well sealed titration cell and fresh reagents to maintain accuracy.