Abstracts Book - IMRC 2018

• SA1-O013 Invited Talk
POROUS CARBON MATERIALS FROM POLYMERIC RESINS USING
GEL STABILIZATION METHODS
Cesar Alfredo Barbero 1 , Mariano M. Bruno 1 , Diego F. Acevedo 1 , Juan Balach 1
1 Instituto de Investigaciones en Tecnologias Energeticas y Materiales Avanzados (UNRC-
CONICET), Chemistry, Argentina.
The reaction of phenols and aldehydes under basic catalyisis produces crosslinked
polymeric resins in the form of wet porous gels. The dry gel can be
pyrolyzed to produce monolithic porous carbon. However, conventional drying
of the wet gel induces the collapse of the porous structure giving xerogels. The
process is driven by surface tension at the water/air interfaces inside each pore.
Such collapse can be avoided by drying the gel in such a way that water/air
interfaces are no present. This can be done using supercritical drying (aerogels),
lyophilization (cryogels) or evaporation of low surface tension solvents
(ambigels). Those procedures involve dangerous conditions, toxic solvents and
increase the cost of the material and the fabrication time . In the present
communication we describe different strategies, based on the stabilization of
the nanoparticulated gel matrix, to allow maintain the porous structure during
conventional drying. Intially, the use of cationic micelles si described. A model is
proposed where the cationic species adsorb on the gel nanoparticles, stabilizing
the interface and avoiding the pore collapse during conventional drying. The
method is successful with pure cationic surfactants (cetyltrimethylammonium
chloride,CTAC) and with industrial mixtures (benzalkonium chloride,BzC). Based
on the model, the method was extended to use a cationic polyelectrolyte:
polydiallyldimethylammonium chloride (PADADMAC). In both cases, a clear
effect of the ratio of the stabilization agent to the monomers is observed.
Moreover, mixtures of CTAC and PDADMAC can be also used. The synthetic
strategies are used to produce porous carbon petroleum based chemicals
(resorcinol/formaldehyde) and also biomass sourced chemicals (tannin and
furfural). The obtained carbon materials are characterized by N2 adsorption
isotherms, electrochemical measurements and Focused Ion Beam-Scanning
Electron Microscopy (FIB-SEM) nanotomography. In that way, an unordered but
fully developed pore structure is observed. The porous carbons are applied as
electrodes in electrochemical double layer capacitors and as substrates of
chemical catalysts and compared with those produced by other methods, like
those made using hard templates.