Hello,

I want to determine the total pore volume (and size distribution) of thermoplastic composites by physiosorption (N2) using a commercial porosimeter (Gemini 2390t).

My composite materials are made from a biopolyester (PLA, PBS, PBAT) and a natural organic filler (orange peel or brewers' grains).

I want to apply the BJH (desorption) method for a relative pressure range of 0.985 to 0.42 (0.42 < p/p0 < 0.985). However, I don't know how many intermediate points I need to apply, and the distance between each point (if it's not constant)?

I think that the number of intermediate points to be applied is a compromise to be found between machine capacity and the precision of the results?

Some authors point out that the total pore volume can be determined at maximum relative pressure (i.e. 0.985 in our case). However, it seems to me that the BJH method only provides the volume and distribution of mesopores (between 1.7 nm and 50 nm), which excludes macropores and micropores. Can you confirm this? If so, do you know how I can use physiosorption (N2) to determine the pore volume of macropores and mesopores at the same time?

Sincerely,

Jules Bellon