Mechanical Properties of Polymers Based on Nanostructure and Morphology edited by G. H. Michler F. J. Balta Calleja

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Mechanical Properties of Polymers Based on Nanostructure and Morphology edited by G. H. Michler F. J. Balta Calleja

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Preface

The mechanical behavior of polymers has been the subject of considerable
research in the past. Mechanical properties are, indeed,
of relevance for all applications of polymers in industry, medicine,
household, and others. The improvement of properties in general
and the better fitting of specific properties to defined applications
is a continuous goal of polymer research. Of particular interest is
not only the improvement of the special properties themselves,
such as stiffness, strength or toughness, but also the combined
improvement of usually contradictory mechanical properties (like
strength and toughness) in combination with other physical properties
(e.g., transparency, flame resistance, conductivity, etc.). The
outstanding role of the mechanical properties applies, as well, to
many of the applications of polymers in which other properties are
those playing the primary role, such as in medicine, optics, electronics,
micro-system techniques and others. The defined improvement
of the mechanical properties demands a better understanding
of the multiple dependence between molecular structure, morphology,
polymerization and processing methods on the one hand, and
ultimate mechanical properties, on the other; i.e., structure-property
correlations. The bridge between the structure, the morphol-
© 2005 by Taylor & Francis Grwoupw. w.Techbooksyard.com
ogy and the mechanical properties is the micromechanical processes
or mechanisms occurring at microscopic level: the so-called
field of micromechanics.
Polymeric systems become increasingly complicated and multifunctional
if they entail a larger level of structural complexity. In
the last two decades the level of interest has gradually shifted from
the μm-scale to the nm-scale region. Systems with at least one
structural size below 100 nm are considered nowadays as new
classes of materials: the so-called
nanostructured polymers, nanopolymers
or nanocomposites
. However, nanomaterials in the form of
rubber carbon black composites have existed already for nearly one
century, and biomedical materials such as bone, teeth, and skin also
have been known for millions of years. Thus, although, the class of
nanomaterials is not totally new, rapid development of research
activity aiming for a better understanding of the basic mechanisms
contributing to the properties of this class of remarkable systems
has been recently observed. Natural materials, like human bone or
seashell (abalone), reveal more and more very complex hierarchical
structures with highly specific functions that have been optimized
during bio-evolution over very long periods of time. Far-off these
biomaterials, in most synthetic polymer blends and composites the
hierarchical structure is most often created accidentally during synthesis
or processing. Therefore, the mechanical properties of these
man-made polymers must be better understood by examining the
length scale, architecture and interactions occurring in these synthetic
materials.
This volume focuses on selected results concerning the mechanical
properties of polymers as derived from the improved knowledge
of their structures at the μm- and nm-scale as well as from the
interactions (micro- and nanomechanisms) between the complex
hierarchical structures and functional requirements. The interest
in the topic for this volume arose at the 1998 Europhysics Conference
on Macromolecular Physics “Morphology and Micromechanics
of Polymers” that was held in Merseburg (Germany) (see special
volume of the
Journal of Macromolecular Science-Physics,
Vol. B38,
1999). Several authors of this book contributed as main lecturers
to the success of the conference.
The structure of the book is organized as follows:
In the first part, “Structural and Morphological Characterization,”
the main aspects of the morphology of semicrystalline polymers,
as revealed by electron microscopy
are highlighted. Emphasis on the
© 2005 by Taylor & Francis Grwoupw. w.Techbooksyard.com
nanostructure of amorphous block copolymers and blends (
methods of polymer modifications are based on micro- and nanolayered
In addition to the wide spectrum of properties present in the
above polymers, toughness enhancement is a particular aim of many
of the discussed modifications. In the different chapters the usual
routes of rubber-toughening of amorphous and semicrystalline polymers
are completed by effects of toughness enhancement due to
nanoparticle and nanofiber modification, micro- and nanolayer production
and hot compaction of oriented polymers.
© 2005 by Taylor & Francis Grwoupw. w.Techbooksyard.com
The book is directed particularly at polymer scientists in
research institutes and in industry, and should serve as a link
between more practical aspects of polymers and the knowledge
about the influence of the different levels of structure and morphology
on properties. It additionally aims to provide a better understanding
on new effects and new possibilities to improve mechanical
properties of polymer systems. Therefore, the book will be also
helpful for students of polymer physics, chemistry and engineering,
as well as those researchers interested in materials science.