The different
topics currently considered in the research activity are mainly
related to the study sorption, diffusion and permeation of gases
and vapors in different materials and to the other phenomena, such
as swelling or modification of physicochemical properties, that are
to these processes.
The different
research topics can be summarized as follows:
-
Study of
diffusion sorption and of organic vapors in glassy polymers with
particular attention to those endowed with very high free volume
such as poly(1-trimethylsilyl-1-propyne)
-
Permeability measurements on different nanocomposite and
barrier materials to water vapor nitrogen and oxygen to test their
potential use in the food packaging industry
-
Fabrication and testing of Pd-Ag based membrane for
hydrogen purification
-
Study of
water and methanol diffusion in perfluorosulfonated materials as
proton exchange membrantop be used in fuel cell
systems
A brief overview of the different research activities of Dr.
Giacinti Baschetti is reported below. For a more complete
description the reader can refer to the bibliography section.
Characterization and modelling of Perfluorosulphonate
ionomeric materials for fuel cells applications.
The study of perfluorosulphonated ionomeric (PFSI)
materials to be used inside Proton exchange membranes Fuel cells
(PEM-FCs), is a research field which started within a collaboration
with Ausimont S.p.A in years 2000 and it is still one of the most
active research field for the diffusion in polymer group of the
University of Bologna.
Dr. Giacinti Baschetti's interest in particular is focused on
the study of the mass transport properties of Aquivion® (formerly
known as Hyflon Ion®) a new short side chain PFSI material,
produced by Solvay-Solexis, that could be used as PEM inside a fuel
cells having good proton conductivity and higher mechanical
resistance with respect to Nafion®, the benchmark material for
these kind of applications. During the experimental work which
covered more than five years of activity, the water and methanol
sorption and permeation in extruded as well as cast films of
Aquivion® were measured with different experimental techniques and
in different experimental conditions allowing to confirm the
similarities with Nafion for extruded membranes and the need for a
better production protocols for cast films which showed lower water
absorption with respect to extruded ones. The experimental work was
accompanied also by a modelling activity which allowed to describe
in a quantitative manner the process of water sorption in Aquivion®
through a diffusion reaction model, which then proved to be
suitable also for Nafion® membranes.
Membranes and membrane separation processes for
hydrogen purification
Another very active research field for Dr. Giacinti
Baschetti was, in the last years, the one related to the study of
palladium membranes for purification of hydrogen produced through
methane reforming, which was conducted in the framework of an
Italian project started in 2005 and then continued as an activity
sponsored by the Interdepartmental Centres for Industrial Research
(CIRI) of the University of Bologna. To carry out the different
activities Dr. Giacinti Baschetti and his colleagues set up a new
experimental apparatus for the measurements of permeability of
different gases in Pd-based membranes in different experimental
conditions and characterized different Pd and Pd-Ag membranes both
produced inside the research group or supplied by other partners.
The activity was focused not only on membranes characterization but
also on the modelling of the permeation process, with particular
attention to the influence of gas phase resistance and palladium
poisoning on the membrane module efficiency. In particular the
modelling work allowed to develop mathematical tools able to
account for both these effects starting from a sound theoretical
approach and without the use of simplified or empirical
correlations which are sometimes used for this purpose. Moreover a
numerical model based on a computational fluid-dynamics approach
was also developed which could be of great help in the design and
scale up of Pd based membrane separation modules for these kind of
applications.
Even if it has not produced any publication yet, it is
worthwhile also to mention that in the very last years a research
has started also in the field polymeric membranes for purification
of hydrogen produced through bio-chemical reactions inside an
Italian project in which Dr. Giacinti Baschetti is coordinating the
activity of the membrane separation working group.
Analysis of diffusion in nanocomposites and
barrier materials for packaging applications
The attention to barrier materials for packaging
applications has been one of the interest of Dr. Giacinti Baschetti
since his participation to a national research project related to
clay based nanocomposites materials in 2004, and to the Sustainpack
project founded in the EU FP6. The work was once again focused both
on experimental and modelling activity. In particular the
experiments were focused on the characterization of permeability of
innovative films based on microfibrillated cellulose (MFC) which
showed extremely interesting barrier properties, comparable with
those of oil based non biodegradable materials such as PET. The
water solubility as well a water and oxygen permeability of these
films were measured confirming the interesting properties of MFC
but also their sensitivity to water which caused a permeability
increase of more than two order of magnitude in pure MFC
membranes.
The modelling was instead related to the analysis of transport
properties of clay based nanocomposite. Diffusion in these
materials was indeed modelled by considering a numerical approach
which allows to describe the behaviour of gas diffusing in
heterogeneous systems where impermeable flakes are dispersed in a
permeable matrix. This approach gave consistent results for ordered
systems, for which an analytical solution exists, and also allowed
to obtain guidelines for the prediction of permeability in
disordered systems, where the clay platelets are randomly
distributed in the polymeric matrix.
In the last years the involvement in two COST Actions and in a
Marie Curie Training network, where Dr. Giacinti acts as training
coordinator, gave new force to this research field which among the
other results allowed to develop a new method for depositing MFC
coatings on hydrophobic biopolymers such as Polylactid Acid which
is now being patented by the University of Bologna.
Analysis of sorption and diffusion in Glassy polymers and
other complex systems
The interest on mass transport properties of complex
materials, such as non equilibrium glassy polymers, nanocomposites
or phase segregated block-copolymers, has accompanied Dr. Giacinti
Baschetti from the beginning of his research activity. Apart from
the already considered research on PSFI and nanocomposites, indeed
he also worked on a number of other systems and research activities
which are briefly described below:
- Polytrimethylsilylpropyne (PTMSP), alone or combined
Polytrimethylsilylhexine to form block-copolymers was studied in
order to describe and understand the peculiar transport properties
of this materials. In particular the determination of solubility,
diffusivity of different vapors in both materials was considered
focusing the attention on the analysis of the effect of ageing,
which resulted more pronounced for PTMSP homo-polymer with respect
to block-copolymers, that were endowed with lower free volume and
permeability but were characterized by higher long term stability.
On PTMSP also a modelling analysis was considered to find an
explanation of the deviation from solution diffusion permeation
mechanism sometimes observed for this material. In particular Dr.
Giacinti Baschetti developed a numerical approach for the
description of the diffusion of this nanoporous material which was
considered as a web of semi interconnected voids channel
constituting a preferential pathway for diffusion of penetrant
molecules.
- Apart from high free volume systems, the interest on glassy
polymers has always been present in the research activities of Dr.
Giacinti Baschetti in view of the modelling of solubility in these
materials through the use of a non-equilibrium approach developed
inside the Diffusion in polymers research group. The Non
Equilibrium Thermodynamics for Glassy polymers (NET-GP) approach
indeed that was initially elaborated by Profssor Sarti and Doghieri
and then extended, applied and adapted, also with contribution of
Dr. Giacinti Baschetti, to different systems, such as biopolymers,
polymer blends and penetrants inducing not negligible polymer
swelling.
- Related to the previous activity also the analysis and the
measurement of polymer dilation upon sorption has been an active
field of investigation; NET-GP approach indeed needs polymer
density to be known during sorption for a complete prediction of
the system behaviour. As a consequence the experimental
measurements of sorption induced polymer swelling was one of the
other interests of Dr. Giacinti Baschetti who, during its career at
University of Bologna, contributed to the set up of al least three
different apparatuses which could give contemporary information on
sorption and swelling processes in the polymer-penetrant system.
One of this experimental systems in particular exploited the
technique of Attenuated total reflectance Fourier transport
infrared spectroscopy (FTIR-ATR) with which he learned during his
stay at Johns Hopkins University in Baltimore.
- Dr. Giacinti Baschetti also worked with block copolymer which
included the analysis rheological and transport properties of phase
segregated diene-styrene based block copolymers, made in
collaboration with Polimerieuropa a National company leader in the
production of elastomeric materials, as well as the analysis of
sorption and diffusion behaviour of homogeneous but semicrystalline
poly(ethylene-co-octene)s which was carried out while tutoring a
PhD student in secondment from the Royal Institute of Technology
(KTH) in Stockholm, Sweden, and, more recently, the analysis of
transport behaviour of semi-crystalline
polystyrene-block-poly(ethylene oxide) copolymers to be used as
solid electrolytes in lithium batteries and potentially interesting
also for CO2 recovery from gaseous streams.
