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Hydrophobization of resorcinol-formaldehyde gels

Henn, Fabian Alexander and Tannert, René (2020) Hydrophobization of resorcinol-formaldehyde gels. Online International Seminar on AEROGELS-2020, 16.-18. Sep. 2020, online.

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Abstract

The chemical modification of aerogels and xerogels at their surface can drastically change their properties. The wetting behavior of silica aerogels, for example, is reverted upon trimethylsilylation. While silylation using trimethylsilyl chloride is routinely applied to silica gels on an industrial scale, only few examples of the silylation of organic gels such as resorcinol-formaldehyde (RF) xerogels are known, and these are basically restricted to trimethylsilyl and related unhindered moieties.[1-3] The trimethylsilylation of RF gels has been shown to provide hydrophobicity for a limited time before the silyl ethers hydrolyze in aqueous environment.[3] In solution phase organic chemistry, phenols are often modified (“protected”) as silyl ethers owing to the high chemoselectivity of silyl reagents and the mildness and orthogonality of their removal. However, in case of sterically and/or electronically more demanding alcohol substrates, more activated silyl reagents and corresponding bases have to be used in order to achieve acceptable yields.[4] We have investigated the silylation of resorcinol-formaldehyde gels in solution using a number of sterically demanding silyl reagents and amine bases. This poster describes the functionalization of resorcinol-formaldehyde gels and their resulting long-term hydrophobic properties as determined by contact angle measurements over the course of several months.

Item URL in elib:https://elib.dlr.de/136202/
Document Type:Conference or Workshop Item (Poster)
Title:Hydrophobization of resorcinol-formaldehyde gels
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Henn, Fabian AlexanderFabian.Henn (at) dlr.deUNSPECIFIED
Tannert, RenéRene.Tannert (at) dlr.dehttps://orcid.org/0000-0001-9484-8886
Date:16 September 2020
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Editors:
EditorsEmailEditor's ORCID iD
Smirnova, Irinairina.smirnova@tuhh.dehttps://orcid.org/0000-0003-4503-4039
Status:Published
Keywords:resorcinol-formaldehyde gels, aerogels, xerogels, silylation, hydrophobicity, contact angle
Event Title:Online International Seminar on AEROGELS-2020
Event Location:online
Event Type:international Conference
Event Dates:16.-18. Sep. 2020
Organizer:International Society for the Advancement od Supercritical Fluids
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Transport
HGF - Program Themes:Road Transport
DLR - Research area:Transport
DLR - Program:V ST Straßenverkehr
DLR - Research theme (Project):V - NGC Fahrzeugstruktur II
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Aerogels and Aerogel Composites
Deposited By: Tannert, Dr. René
Deposited On:19 Oct 2020 10:01
Last Modified:16 Sep 2021 03:00

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