ISO 15512 Method D

Laboratory Procedure

A weighed sample is heated to a temperature just below its melting or decomposition point inside a sealed vial or oven chamber. The dry carrier gas flows over the sample and picks up the evaporated water. This gas then bubbles through the Karl Fischer reagent where the moisture is quantified.

Technical Advantages

Isolation of the sample from the reagent prevents the polymer from clogging the titration cell or reacting with the chemicals. This approach allows for the testing of glass-filled materials and complex blends that would otherwise require difficult sample preparation. The method is highly sensitive and capable of measuring moisture levels below 0.01 percent.

Process Calibration

Temperature settings must be optimized for each resin type to ensure all water is released without causing thermal degradation. If the temperature is too low, the result will be an underestimation of the moisture content. Optimization of the oven temperature ensures that the water is fully released before the polymer begins to degrade.