In chemical industry, material science and industrial manufacturing, density measurement is one of the important methods to evaluate the properties and characteristics of materials. In this paper, the determination methods of apparent density and true density and their application in the measurement of granular solids and powder coatings will be described in detail.

Determination of apparent density

The apparent density describes the ratio between the space occupied by a loose solid and its mass as it accumulates. It takes into account the volume of the solid itself and the voids within it. This density is related to the packaging and storage of substances, and is suitable for the inspection of powder coatings, particles and fine powder resins, curing agents, pigments, etc. The determination method can be compared with the previous method.

densitometry

This measurement method is used to measure the ratio of the mass of the measured object to its actual occupied volume, that is, the true density. Suitable for the measurement of powder coatings, fillers, crosslinkers and resin powders. The occupied volume of the sample is measured by liquid method and gas method.

Study on density measurement method and application

Liquid assay

The liquid method is simple and economical, using kerosene or n-hexane as the medium. The true density is calculated by measuring the mass and volume of the sample with a specific gravity bottle. It is necessary to carry out three parallel measurements of the sample and calculate the average value.

Gas determination

The gas method requires equipment such as cylinders, pistons, valves and differential pressure gauges, using air as a medium. By moving two pistons and measuring the value of the differential pressure meter, the volume of the sample under test is calculated, and the true density is calculated. It is also necessary to carry out three parallel measurements of the sample and calculate the average value.

Study on density measurement method and application

Result representation and reference standard

After completing the three measurements, the arithmetic average is taken as the measurement result of the true density and reported to one decimal place. Standards such as ISO81302, ISO81303, ISO 787-10, GB/T 5211.4 provide relevant guidance and specifications for density determination.

Density measurement is of great significance in industrial production, especially for the preparation and application of materials such as powder coatings and pigments. By accurately measuring density, the performance and economy of materials can be evaluated, providing strong support for product design and manufacturing.