Meaning
Quantitative analytical technique used to determine the total inorganic content of a polymer sample by burning off the organic resin. During gravimetric ash testing, a precise mass of material undergoes combustion in a crucible at a controlled temperature. The final weight of the remaining material indicates the percentage of mineral fillers or glass reinforcements present in the resin.
Furnace Configuration
Muffle furnaces provide the uniform heat environment needed to oxidize the polymer matrix without causing excessive turbulence that might scatter the ash. Precise temperature settings are chosen to ensure complete resin removal while preserving the chemical state of the fillers. The choice between a ventilated furnace and a closed chamber depends on the volatility of the specific additives being measured.
Filler Verification
Identifying the ratio of mineral to polymer allows manufacturers to predict the mechanical strength and shrinkage of the final moulded part. If the results of gravimetric ash testing show a lower loading than the specification, the parts may lack the necessary stiffness. Excessive filler levels can lead to brittleness and increased tool wear during high volume production runs.
Result Interpretation
Analysts must compare the final mass to the initial sample weight to calculate the residue percentage. Variations in the cooling process or the type of crucible used can introduce small errors in the final calculation. Using desiccators during the weighing phase prevents the hot ash from gaining mass through moisture absorption.
