Towards Porous Silicon Oxycarbide Materials: Effects of Solvents on Microstructural Features of Poly(methylhydrosiloxane)/Divynilbenzene Aerogels.

Susana Aguirre-Medel,Prasanta Jana,Gian Sorarù,Peter Kroll

doi:10.3390/ma11122589

Susana Aguirre-Medel, Prasanta Jana + Show 2 more

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https://doi.org/10.3390/ma11122589

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Abstract

We investigate the impact of solvents on the microstructure of poly(methylhydrosiloxane)/divinylbenzene (PMHS/DVB) aerogels. The gels are obtained in highly diluted conditions via hydrosilylation reaction of PMHS bearing Si-H groups and cross-linking it with C=C groups of DVB. Polymer aerogels are obtained after solvent exchange with liquid CO2 and subsequent supercritical drying. Samples are characterized using microscopy and porosimetry. Common pore-formation concepts do not provide a solid rationale for the observed data. We postulate that solubility and swelling of the cross-linked polymer in various solvents are major factors governing pore formation of these PMHS/DVB polymer aerogels.

Highlights

Aerogels are a class of porous solids first synthesized in 1931 by Kistler [1]
Relative shrinkage and density data aligns with other quantitative data shown in Table 1 and displays two groups of polymer aerogels: samples synthesized in cyclohexane and THF exhibit linear shrinkage of over 30%, while samples synthesized in acetone and n-hexane contract only about 25%
The foregoing discussion indicates that pore formation and control of pore morphology in processing of PMHS/DVB polymer aerogels is strongly related to solubility and swelling of the processing of PMHS/DVB polymer aerogels is strongly related to solubility and swelling of the polymer during synthesis

Summary

Introduction

Aerogels are a class of porous solids first synthesized in 1931 by Kistler [1]. The Polymer Derived Ceramic (PDC) route has been extensively used for synthesizing. Si-based ceramics it was not until recently that SiC, SiCN and SiOC aerogels were synthesized using the PDC route [3,4]. In this process, first a polymer aerogel is synthesized and converted, through a pyrolysis process in inert atmosphere, into the corresponding PDC aerogel. The polymer aerogel is synthesized via hydrosilylation of a silicon-based polymer bearing Si-H bonds with molecules bearing

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