Meaning
Evaluation method used to calculate the volume of solid samples by measuring the displacement of a fluid or gas within a sealed chamber. Laboratory staff use density pycnometry to detect subtle variations in polymer crystallinity and void content. It provides a more precise measurement than simple displacement when dealing with irregular shapes.
Measurement Precision
Operation of the gas displacement mechanism accounts for tiny surface pores that liquid methods might skip. While density pycnometry remains common in research, simple immersion methods often suffice for routine floor checks. This procedure removes the air factor from the volume calculation to arrive at the true density of the moulded component.
Inorganic Content
Verification of filler loading levels becomes possible through the careful monitoring of specific gravity. Because density pycnometry reveals exactly how much space the polymer occupies, it exposes instances where regrind levels exceed the specification. The technique identifies density changes triggered by the introduction of pigments or glass fibres.
Resin Purity
Detection of contaminants is a primary use case for this high-precision instrument in secondary sorting operations. In cases where batches look identical, density pycnometry distinguishes between high-density and low-density polyethylene with high repeatability. It proves useful for establishing the exact mass-to-volume ratio of feedstock before expensive masterbatch additives are mixed in.
