Ash Content
Ash Content analysis of plastics ASTM D2584, ASTM D5630, ISO 3451
Scope
An ash test is used to determine the total filler content in a material, but cannot identify individual percentages of different fillers in multi-filled materials without additional test procedures. The ash test is not suitable for determining the percent of carbon fiber or carbon black in a material as carbon burns off during the test.
Procedure
Aan ash test involves:
Taking a known amount of sample
Weighing the sample and placing it into a dried/pre-weighed porcelain crucible
Burning away the polymer in an air atmosphere at temperatures above 500°C
Weighing the crucible after it has cooled to room temperature in a desiccator
The ash residue remaining in the crucible is considered filler, unless the residue is less than 1%, which is typically the result of additives that did not burn off
Results
The ash test result is expressed as a percentage of the original sample weight. The result is calculated by dividing the weight of the ash residue by the weight of the original sample, and then multiplying by 100%. This gives the percentage of the original sample that was filler or non-polymer material. A magnified optical examination of the ash residue is performed to determine if the ash is glass, mineral, or a combination of both.
Sample
Typically, six grams of sample is used for an ash test, which is divided into three crucibles, each containing two grams of sample.