 Prof.
RNDr. Josef Jančář, CSc.
Fakulta chemická Vysokého učení technického v
Brně
Název přednášky:
The role of chain-nanoparticle interactions in
synthetic and bio-based nanocomposites
Abstrakt přednášky:
The control of the performance of polymer composites can
be excercised at various length scales. Properties of the constituents,
their content and spatial arrangement and the 3D-interphase phenomena
are the main variables at the micro-scale. It seems possible to
consider an additional length scale in the design of future polymer
composites to achieve composite structures capable of signaling their
integrity status and capable of self repair locally by taking advantage
of the nano-scale materials design. This approach simulates, to some
extent, multiscale structure of biocomposites such as wood, bones and
shells. The hierarchical structure and multifunctional performance of
biocomposites is controlled at the various length-scale interfaces
between the individual structural levels. Unlike at the micro-scale,
where the 3D-interphases existing between the individual components is
considered continuous, at the nano-scale, the interphase phenomena must
be considered at the length scales corresponding to the dimensions of
individual molecules.
Effect of the type and strength of chain-particle interactions on the
manifestation of interphase phenomena will be reviewed and some aspects
of the principal differences between the role of interface/interphase
phenomena as affected by the dimension scale from 10-6 m to 10-9 m. In
order to provide experimental background for understanding micro-scale
interphase, thickness dependence of elastic moduli of thin organic
layers deposited on solid glass surfaces will be discussed. Effects of
molecular structure and type of surface interactions on the elastic
moduli of these layers will be described. An attempt will be made to
correlate the obtained data with the results of the single embedded
fiber fragmentation tests.
Further, temperature and composition dependeces of
elastic moduli of model nanocomposites containing particles of varying
shape with smilar specific surface area of approximately 150 m2/g will
be interpreted using chain reptation dynamics approach to describe the
molecular reinforcing mechanism at the nano-scale and the controlling
role of the area of contact between the matrix and the reinforcement. A
"hybrid" approach to bridge the micro-scale continuum mechanics models
with the nano-scale discrete chain dynamics models will be demonstrated
to provide means for transforming mechanical response of a polymer
composite accross the individual length scales from nano- to
macro-scale. Potential applicability of the models derived for
synthetic hierarchical composites in mechanics of hard tissues will be
discussed.
Curriculum vitae
Professor of Macromolecular Chemistry
Adjunct Professor, Polymer Program, University of Connecticut, USA
Director, Institute of Materials Chemistry, Brno University of
Technology, CZ
RNDr. (1983) Masaryk University Brno, CZ
(solid state physics)
CSc (1988) Czech Academy of Sciences, Prague,
CZ (macromolecular chemistry)
Associate Professor, University of
Connecticut, USA (1992) (polymer science)
Associate Professor, Brno University of
Technology, CZ (1994) (macromolecular chemistry)
University Professor, Brno University of
Technology, CZ (1997) (macromolecular
chemistry)
Adjunct Professor, Polymer Program,UCONN, USA
(1999-) (polymer science)
Awards: Czech Society for Sciences 2000 Senior
Award
Publications: 162 papers in impacted
journals, 8 books, 12 chapters in books, 7 patents
Research interests: Heterogeneous polymer
systems, deformation behavior and fracture phenomena,
interphase/interface phenomena, nanocomposites, biomaterials
Recent papers relevant to the proposed project:
- Jancar, J (2006), Hydrolytic stability of PC/GF
composites with engineered interphase of varying elastic modulus.
Composites Science and Technology 66: 3144 - 3152
- Jancar, J (2006), Effect of interfacial shear
strength on the mechanical response of polycarbonate and PP reinforced
with basalt fibers. Composite Interfaces 13: 853 - 864
- Zidek J., Jancar J (2006), Simulation of Inelastic
Stress Strain Response of nanocomposites by a Network Model. Key
Engineering Materials 334-335: 857 - 860
- J. Kalfus and J. Jancar (2007). Elastic response of
nanocomposite poly(vinylacetate)-hydroxyapatite with varying particle
shape. Polym. Compos. 28: 365-371
- Kalfus J, Jancar J (2007), Viscoelastic response of
nanocomposite poly(vynil acetate) hydroxyapatite with varying particle
shape- Dynamic strain softening and modulus recovery, Polym. Compos.
28: 743-747
- J. Kalfus and J. Jancar (2007), Relaxation processes
in PVAc-HA nanocomposites. Polym. Sci.: Part B: Polym. Phys. 45, 1380
(2007)
- Kalfus J, Jancar J (2007), Immobilization of
polyvinylacetate macromolecules on hydroxyapatite nanoparticles,
Polymer 48: 3935-3938
- Kalfus J, Jancar J, Kucera J (2008), Effect of weakly
interacting nanofiller on the morphology and viscoelastic response of
polyolefins, Polym. Eng. Sci. 38: 000-000, accepted
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