The influence of drying and calcination on surface chemistry, pore structure and mechanical properties of hierarchically organized porous silica monoliths

Florian Putz, Anna Waag, Christian Balzer, Stephan Braxmeier, Michael S. Elsaesser, Lukas Ludescher, Oskar Paris, W. J. Malfait, Gudrun Reichenauer, Nicola Hüsing

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

11 Zitate (Scopus)

Abstract

Hierarchically organized, porous materials exhibit unique combinations of physical and chemical properties depending on their pore sizes, pore structure and surface chemistry. Extraction and drying methods as well as post synthetic thermal treatments influence the characteristics of the resulting porous network and thus the achievable properties. Here we present a comprehensive investigation of the effects of drying conditions and post synthesis treatments on surface chemistry, pore structure and resulting mechanical properties of hierarchically structured silica monoliths comprising pores on three hierarchy levels (micro-, meso- and macropores). Samples were either dried supercritically (SCD) with carbon dioxide or at ambient pressure (APD) after surface silylation. In addition, the impact of a post synthetic heat treatment at two different temperatures (300 °C and 500 °C) is investigated. The focus of the study is on chemical and structural changes in/at the (meso-)pore walls, including the presence of micropores and the influence of organic components on the macroscopic properties. We discuss the implications of these modifications on mechanical properties, such as their deformation behavior during fluid adsorption related to their respective bulk and skeletal Young's moduli. Scanning electron microscopy, nitrogen adsorption/desorption measurements, simultaneous thermal analysis, solid-state NMR spectroscopy, small-angle X-ray scattering, sound velocity measurements and nitrogen adsorption/desorption with in-situ dilatometry were performed on each sample. This set of data illustrates the significant impact of different fabrication steps such as drying or calcination on material properties.
OriginalspracheEnglisch
Aufsatznummer109578
Seitenumfang10
FachzeitschriftMicroporous and Mesoporous Materials
Jahrgang288.2019
Ausgabenummer1 November
Frühes Online-Datum27 Juni 2019
DOIs
PublikationsstatusVeröffentlicht - 1 Nov. 2019

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