Morphological analysis of differently sized highly porous poly(ether imide) microparticles by mercury porosimetry

Abstract

Highly porous poly(ether imide) (PEI) microparticles prepared by a spraying/coagulation process are discussed as candidate adsorber materials for apheresis applications, i.e. removal of uremic toxins from the blood of renal failure patients. PEI particles obtained by the aforementioned procedure can have a broad size distribution with particle diameters ranging from 20 to 800 µm. In order to further estimate the adsorption behavior of PEI microparticles packed in application relevant apheresis modules, a quantitative information about the relation between particle size and pore morphology is required. In this study, we explored whether the intraparticle porosity of PEI microparticles varies with altering the diameter of the particulate adsorbers. By an analytical wet sieving procedure, the obtained PEI microparticles were separated into five size fractions, which were analyzed by mercury intrusion porosimetry, nitrogen adsorption, and scanning electron microscopy. Mercury intrusion porosimetry revealed for all size fractions high porosity values in the range from 78% to 84% with pore diameters in the range from 10 to 1000 nm. A bimodal pore size distribution was found having a first peak at around 100 nm, while a second pronounced peak maximum was found at higher pore sizes that increased with raising particle diameter from 300 nm for the smallest particle size fraction (50–100 µm) to 700 nm for particles with a diameter of 200 to 250 µm. Based on these findings, it can be assumed that the main PEI particle size fraction (200–250 µm) should exhibit the highest adsorption capacity in an apheresis module. Copyright © 2016 John Wiley & Sons, Ltd.

A New Procedure for Porous Material Characterization

“…For technical application within sorption processes it is important to know the structure and the physico-chemical properties of the solid samples such as specific surface area, pore volume and PSD. Different methods to study the basic characteristics of porous solids are used; the pore volume is determined by mercury porosimetry [2,3], helium displacement measurements [4,5], t-method [6]; the specific surface area -by BET method [7]; the pore size distribution -by Barrett-Joyner-Halenda method [8], Horvath-Kawazoe method [9], and the sample's surface topography and composition by the SEM analysis [10]. A major part of the SEM analysis is the interpretation of the results.…”