The present book discloses a most recent trial to overcome this complexity by
visualizing the three-dimensional (3D) image of nanofillers in rubber matrix, which
has been enabled by applying a state-of-the-art technique using 3D transmission
electron microscopy (3D-TEM), or alternatively called ‘electron tomography,’ to
rubber/nanofiller composites. Through the analysis of 3D images displaying
nanofiller dispersion, we have successfully visualized the aggregation state of
nanofillers in rubber matrix, from which we suggest the formation of a unique
semiflexible nanofiller network. This result is reasonably assumed to be the most
important factor for rubber reinforcement by filler loading. In the case of crosslinked natural rubber, self-reinforcement effect (without any filler loading) upon
stretching is effectively functioning, and a new polymer crystallization mechanism,
template crystallization, is suggested for the strain-induced crystallization responsible for the unique self-reinforcement.
From the meaning of the word ‘reinforcement’ itself, engineering investigation
based on fracture mechanics should be one of the approaches to the elucidation of
rubber reinforcement. However, fracture mechanical studies on rubber materials
have not been much successful so far, compared with those on metallic and inorganic materials. We hope that our results presented in this book may accelerate
studies for establishing the fracture mechanical behaviors of rubber. In addition,
reinforcement of rubber justifiably involves not only mechanical strength but also
various functional properties: For example, the required functions of the tread
rubber of pneumatic tires in driving include lots of dynamic properties such as
traction, grip, rolling resistance, skid resistance, wear of rubber, and so on. Hence,
only mechanically supporting the weight is absolutely insufficient for automobile
and aircraft tires.
All these functional requirements make rubber reinforcement too complex to be
fully elucidated by conventional techniques. The authors were fortunate to have an
opportunity of applying a most recent nanometer visualizing technique, 3D-TEM,
to nanofiller/rubber composites. Combined with the resultant 3D images of nanofiller in rubber matrix with both retrospective and prospective insights into rubber
reinforcing mechanism, nanofiller structuring process to form the filler networks is
elucidated by our studies. At the same time, well-known bound rubber, which is
due to the rubber-to-filler interaction, is found to be involved in nanofiller networking and to play an important role of affording semiflexibility to the nanofiller
network. This book is summarizing these studies, and the essential results disclosed
here are expected to provide rubber engineers with a novel fundamental base for the
scientific design of rubber reinforcement. The design would possibly contribute to
the development of higher-performance rubber products in this century, which, we
sincerely hope, might promote the sustainable development of transportation
society further toward the next century.
vi
Preface
visualizing the three-dimensional (3D) image of nanofillers in rubber matrix, which
has been enabled by applying a state-of-the-art technique using 3D transmission
electron microscopy (3D-TEM), or alternatively called ‘electron tomography,’ to
rubber/nanofiller composites. Through the analysis of 3D images displaying
nanofiller dispersion, we have successfully visualized the aggregation state of
nanofillers in rubber matrix, from which we suggest the formation of a unique
semiflexible nanofiller network. This result is reasonably assumed to be the most
important factor for rubber reinforcement by filler loading. In the case of crosslinked natural rubber, self-reinforcement effect (without any filler loading) upon
stretching is effectively functioning, and a new polymer crystallization mechanism,
template crystallization, is suggested for the strain-induced crystallization responsible for the unique self-reinforcement.
From the meaning of the word ‘reinforcement’ itself, engineering investigation
based on fracture mechanics should be one of the approaches to the elucidation of
rubber reinforcement. However, fracture mechanical studies on rubber materials
have not been much successful so far, compared with those on metallic and inorganic materials. We hope that our results presented in this book may accelerate
studies for establishing the fracture mechanical behaviors of rubber. In addition,
reinforcement of rubber justifiably involves not only mechanical strength but also
various functional properties: For example, the required functions of the tread
rubber of pneumatic tires in driving include lots of dynamic properties such as
traction, grip, rolling resistance, skid resistance, wear of rubber, and so on. Hence,
only mechanically supporting the weight is absolutely insufficient for automobile
and aircraft tires.
All these functional requirements make rubber reinforcement too complex to be
fully elucidated by conventional techniques. The authors were fortunate to have an
opportunity of applying a most recent nanometer visualizing technique, 3D-TEM,
to nanofiller/rubber composites. Combined with the resultant 3D images of nanofiller in rubber matrix with both retrospective and prospective insights into rubber
reinforcing mechanism, nanofiller structuring process to form the filler networks is
elucidated by our studies. At the same time, well-known bound rubber, which is
due to the rubber-to-filler interaction, is found to be involved in nanofiller networking and to play an important role of affording semiflexibility to the nanofiller
network. This book is summarizing these studies, and the essential results disclosed
here are expected to provide rubber engineers with a novel fundamental base for the
scientific design of rubber reinforcement. The design would possibly contribute to
the development of higher-performance rubber products in this century, which, we
sincerely hope, might promote the sustainable development of transportation
society further toward the next century.
vi
Preface