Gas Pycnometer

Volume and density analyzes in solid samples with gas pycnometer and open-closed cell content determinations are made using appropriate software.

The test is started  by selecting the appropriate method from the software while measuring density and open-closed cell content. We have listed below a few of the parameters that can be checked for some problems that may be encountered while making measurements.

- Solid samples should be prepared by cutting them in millimeters, care should be taken to avoid any deformation due to pressure or scratching on the samples.

- A chamber suitable for the size of the sample to be measured should be selected. The chamber must be filled with sample to at least 15% by volume (Ref. ASTM 6226). However, if samples contain high open cell and macroporous content, it is recommended to fill the chamber 50-70% by volume with sample to obtain more accurate results.

- Calibration verification can be done first if there are deviations in the measurement results and these deviations are not caused by the sample. If the calibration validation results are out of the confidence interval, the instrument should be calibrated.

- Gas pressure is adjusted according to the standard used. However, the pressure value in this standard may cause doubts about the accuracy of the results by destroying the skeletal structure due to the high open cell content of the sample used. In such cases, an internal method is created by changing the pressure value for obtaining high accuracy and repeatable results.

- Gas permeability may be in question if the pressure decreases continuously and there is no leakage in the device. In cases where there is gas permeability, it is recommended to replace the gas used. But first of all, the o-ring on the device cover should be greased to ensure high insulation and if the problem is not resolved, the o-ring should be replaced with a new one.

- Continuous increase in pressure indicates that volatile substance may be trapped in the device. In such cases, it may be necessary to repeat the "purging" process several times.

Micromeritics ACCUYC II 1345 gas pycnometer and Foampyc module are used in Evoco Polymer R&D laboratory. Please contact us if you need to determine the volume, density and open-closed cell content of your samples.

Authors: Evoco Polymer R&D Team                                                                         Date: September 2022