Hi, I have recently been working on measuring the skeletal density of silica aerogels using helium via a pycnometer. However, the consecutive measurements gave increased results, e.g., 2.2, 2.5, 2.9 g cm-1, thus no objective data can be used (even the average number is not reliable). Does this problem come from the process of vacuuming and pressuring helium in the pores that may cause porous deformation (or sample deformation)? Is there any better way to do this? Many thanks.
Dear Vadim S. Gorshkov
, Thank you for the answer.This sample has been done with nitrogen adsorption. Despite a surface area of over 400 m2 g-1, the isotherm is an open loop where the end is open at low p/p0. The swelling effect is from a paper I read, they explained the open loop of BET isotherm was caused by the pressure-dependent swelling effect of soft materials. That's why I wonder if it may be a possible reason for both measurements.
Maybe I am wrong but I feel something is similar in both techniques.
Thank you, Vadim S. Gorshkov
I'll try to re-measure the surface area as per your advice.
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