|
|
Books > Science & Mathematics > Chemistry > Organic chemistry > Polymer chemistry
Polymers and polymer composites have been increasinqly used in
place of metals for various industries; namely, aerospace,
automotive, bio-medical, computer, electrophotography, fiber, and
rubber tire. Thus, an understanding of the interactions between
polymers and between a polymer and a rigid counterface can enhance
the applications of polymers under various environments. In meet
ing this need, polymer tribology has evolved to deal with friction,
lubrication and wear of polymeric materials and to answer some of
the problems related to polymer-polymer interactions or oolymer
rigid body interactions. The purpose of this first International
Symposium was to introduce advances in studies of polymer friction
and wear, especially in Britain and the U.S.S.R. Most earlier
studies of the Fifties were stimulated by the growth of rubber tire
industries. Continuous research through the Sixties has broadened
the base to include other polymers such as nylon, polyolefins, and
poly tetra fluoroethylene, or PTFE. However, much of this work was
published in engineering or physics journals and rarely in
chemistry journals; presumably, the latter have always considered
the work to be too applied or too irrelevant. Not until recent
years have chemists started to discover words such as
tribo-chemistry or mechano chemistry and gradually become aware of
an indispensable role in this field of polymer tribology. Thus, we
were hoping to bring the technology up to date during this
SympOSium, especially to the majority of participants, polymer
chemists by training."
This book is a collection of selected papers presented at the
symposium titled "In situ Spectroscopy in Monomer and Polymer
Synthesis," held at the April, 2001 ACS National Meeting in San
Diego, California, USA. The co-organizers of this symposium were
Timothy Long, Judit E. Puskas, Robson F. Storey, and J. Andrews. In
situ spectroscopic monitoring is gaining popularity both in
academia and industry. FfIR monitoring is used most frequently, but
UV-visible, raman, and NMR spectroscopy are also important. This
book concentrates mostly on FfIR monitoring, both in the near and
mid-infrared ranges. The first chapter is a short general overview
of FfIR spectroscopy, followed by the symposium contribu tions. We
thought that this would be especially useful for student readers.
We hope that the book will present a state-of-the-art overview of
research related to in situ spectroscopic monitoring. -Judit E.
Puskas ix Acknowledgments This book would not have been possible
without the dedicated effort of the chapter contributors and the
symposium committee: Professor Judit E. Puskas Professor Timothy
Long Professor Robson F. Storey Professor J. Andrews The symposium
was financially supported by: ACS-Petroleum Research Fund REMSPEC
Co. Wyatt Technology Co.
The present book is devoted to a rapidly developing field of
science which studies the behavior of viscoelastic materials under
the influence of deformation~the rheology of polymers. Rheology has
long been treated as the theoretical foundation of polymer
processing, and from this standpoint it is difficult to overesti
mate its importance in practice. Rheology plays an important role
in developing our ideas on the nature of viscoelastic behavior in
connection with the structural features of polymers and composites
based on them. This expands the possibilities of employing
rheological methods to characterize a variety of materials and
greatly magnifies the interest in this field of research. The
rheological properties of polymer systems are studied experimen
tally, chiefly under conditions of shear and tensile strains. One
explana tion is that many aspects of polymer material processing
are associated with the stretching of melts or a combination of
shear and tensile strains. In scientific investigations, either
periodic or continuous conditions of shear deformation are
employed. Each mode provides widespread infor mation. In periodic
deformation, most attention is generally given to conditions with
low deformation amplitudes that do not alter the structure of the
polymer system during an experiment (the region of linear
deformation conditions). Here the viscoelastic parameters are
generally determined with respect to the frequency. Continuous
deforma tion involves considerable strains, and may be attended by
significant reversible and irreversible changes in the structure of
a polymer.
Determining the composition and properties of complex hydrocarbon
mixtures in petroleum, synthetic fuels, and petrochemical products
usually requires a battery of analytical techniques that detect and
measure specific features of the molecules, such as boiling point,
mass, nuclear magnetic resonance frequencies, etc. there have
always been a need for new and improved analytical technology to
better understand hydrocarbon chemistry and processes. This book
provides an overview of recent advances and future challenges in
modern analytical techniques that are commonly used in hydrocarbon
applications. Experts in each of the areas covered have reviewed
the state of the art, thus creating a book that will be useful to
readers at all levels in academic, industry, and research
institutions.
"Functionalized Conjugated Polyelectrolytes "presents a
comprehensive review of these polyelectrolytes and their biomedical
applications. Basic aspects like molecular design and
optoelectronic properties are covered in the first chapter.
Emphasis is placed on the various applications including sensing
(chemical and biological), disease diagnosis, cell imaging,
drug/gene delivery and disease treatment. This book explores a
multi-disciplinary topic of interest to researchers working in the
fields of chemistry, materials, biology and medicine. It also
offers an integrated perspective on both basic research and
application issues. Functionalized conjugated polyelectrolyte
materials, which have already drawn considerable interest, will
become a major new direction for biomedicine development.
This is truly an exciting time to be in the ?eld of polymer
science. Advances in polymerization methods are providing polymer
scientists with the ability to specify and control polymer
composition, structure, architecture, and molecular weight to a
degree that was not possible just a decade ago. This, in turn, is
resulting in many novel application possibilities of polymers
ranging from drug delivery systems and nanolithographyto
stimuli-responsivematerials and many others. In addition,many of
the application areas of polymers - such as coatings, adhesives,
thermoplastics, composites, and personal care - are also taking
advantage of the ability to design polymersduringtheir
developmentefforts. Not to forget,manyof these applications of
polymers involve mixing polymers with solvents, catalysts,
colorants, and many other ingredients to prepare a formulated
product. However, the tuning of polymer composition and structure
as well as polymer formulations to optimize the ?nal performance
properties can be challenging, - pecially since in many cases
several interacting variables need to be optimized simultaneously.
This is where the methodologies and techniques of combinatorial and
high-throughput experimentation to synthesize and characterize
polymer - braries can be an invaluable approach. Simply put, a
polymer library is a collection of multiple polymer samples having
a systematic variation in one or more variables related to
composition, structure, or process. Various methods and strategies
have been explored to ef?ciently prepare a large number of polymer
samples and also to screen these samples for key properties of
interest.
With the aim of providing a deeper insight into possible mechanisms
of biological self-organization, this thesis presents new
approaches to describe the process of self-assembly and the impact
of spatial organization on the function of membrane proteins, from
a statistical physics point of view. It focuses on three important
scenarios: the assembly of membrane proteins, the collective
response of mechanosensitive channels and the function of the twin
arginine translocation (Tat) system. Using methods from equilibrium
and non-equilibrium statistical mechanics, general conclusions were
drawn that demonstrate the importance of the protein-protein
interactions. Namely, in the first part a general aggregation
dynamics model is formulated, and used to show that fragmentation
crucially affects the efficiency of the self-assembly process of
proteins. In the second part, by mapping the membrane-mediated
forces into a simplified many-body system, the dynamic and
equilibrium behaviour of interacting mechanosensitive channels is
derived, showing that protein agglomeration strongly impacts its
desired function. The final part develops a model that incorporates
both the agglomeration and transport function of the Tat system,
thereby providing a comprehensive description of this
self-organizing process.
Flammability has been recognized as an increasingly important
social and scientific problem. Fire statistics in the United States
(Report of the National Commission on Fire Prevention and Control.
"America Burning: ' 1973) emphasized the vast devastation to life
and property--12.000 lives lost annually due to fire. and these
deaths are usually caused by inhaling smoke or toxic gases: 300.000
fire injuries: 11.4 billion dollars in fire cost at which 2.7
billion dollars is related to property loss: a billion dollars to
burn injury treatment: and 3.3 billion dollars in productivity
loss. It is obvious that much human and economic misery can be
attributed to fire situations. In relation to this. polymer
flammability has been recognized as an in creasingly important
social and scientific problem. The development of flame-retardant
polymeric materials is a current example where the initia tive for
major scientific and technological developments is motivated by
sociological pressure and legislation. This is part of the
important trend toward a safer environment and sets a pattern for
future example. Flame retardancy deals with our basic everyday life
situations-housing. work areas. transportation. clothing and so
forth-the "macroenvironment" capsule within which "homosapiens"
live. As a result. flame-retardant polymers are now emerging as a
specific class of materials leading to new and diversified
scientific and technological ventures."
The development and application of bioactive nano-structured
constructs for tissue regeneration is the focus of the research
summarised in this thesis. Moreover, a particular focus is the
rational use of supercritical carbon dioxide foaming and
electrospinning technologies which can lead to innovative polymeric
bioresorbable scaffolds made of hydrolysable (both commercial and
'ad-hoc' synthesized) polyesters. Mainly, the author discusses the
manipulation of polymer chemical structure and composition to tune
scaffold physical properties, and optimization of scaffold 3D
architecture by a smart use of both fabrication techniques. The
multidisciplinary nature of this research is imperative in pursuing
the challenge of tissue regeneration successfully. One of the
strengths of this thesis is the integration of knowledge from
chemistry, physics, engineering, materials science and biomedical
science which has contributed to setting up new national and
international collaborations, while strengthening existing ones.
This volume is devoted to solidification of polymers in general;
crystalline, liquid crystalline, and amorphous polymers, including
oriented polymers and the effects of pressure and processing are
discussed. A distinguished international group of authors has
contributed to the volume.
H. Yoshida, T. Ichikawa Electron Spin Echo Studies of Free Radicals
in Irridated Polymers M. Ogasawara Application of Pulse Radiolysis
to the Study of Polymers and Polymerizations I. Kaetsu Radiation
Synthesis of Polymeric Materials for Biomedical and Biochemical
Applications S. Tagawa Radiation Effects of Ion Beams on Polymers
H.Yamaoka Polymer Materials for Fusion Reactors
With contributions by: R.H. Boyd; B.G. Sumpter, D.W. Noid, G.L.
Liang, B. Wunderlich; M.D. Ediger, D.B. Adolf; R.-J. Roe; I. Bahar,
B. Erman, L. Monnerie; A.A. Gusev, F. Muller-Plathe, W.F. van
Gunsteren, U.W. Suter; L.R. Dodd, D.N. Theodorou; E. Leontidis,
J.J. de Pablo, M. Laso, U.W. Suter; K.S. Schweizer."
"Imagination and shrewd guesswork are powerful instruments for
acquiring scientific knowledge . . . " 1. H. van't Hoff The last
decades have witnessed a rapid growth of quantum chemistry and a
tremendous increase in the number of very accurate ab initio
calculations of the electronic structure of molecules yielding
results of admirable accuracy. This dramatic progress has opened a
new stage in the quantum mechanical description of matter at the
molecular level. In the first place, highly accurate results
provide severe tests of the quantum mecha nics. Secondly, modern
quantitative computational ab initio methods can be synergetically
combined with various experimen tal techniques thus enabling
precise numerical characterization of molecular properties better
than ever anticipated earlier. However, the role of theory is not
exhausted in disclosing the fundamental laws of Nature and
production of ever increasing sets of data of high accuracy. It has
to provide additionally a means of systematization, recognition of
regularities, and ratio nalization of the myriads of established
facts avoiding in this way complete chaos. Additional problems are
represented by molecular wavefunctions provided by the modern
high-level computational quantum chemistry methods. They involve,
in principle, all the information on molecular system, but they are
so immensely complex that can not be immediately understood in
simple and physically meaningful terms. Both of these aspects,
categorization and interpretation, call for conceptual models which
should be preferably pictorial, transparent, intuitively appealing
and well-founded, being sometimes useful for semi quantitative
purposes."
This volume contains the proceedings of the "International Workshop
on Optical Methods and the Physics of Colloidal Dispersions," held
in memory of Prof. Dr. Klaus Schatzel at the end of September,
1996, in Mainz, Germany. The meeting focused on two special aspects
of colloidal science, namely novel optical methods and the physics
of colloidal dispersions. In particular, the contributed papers
show that the increase in the quality and number of suitable model
systems has significantly enhanced our knowledge of colloidal
properties, structures and dynamics."
The action of enzymes fascinated mankind long before they were rec
ognized for the complex chemicals that they are. The first
application of these remarkable compounds to produce ethanol by
fermentation is lost to antiquity. Payer and Persoz (Ann. Chim.
Phys., 53, 73 (1833ii)) appear to have provided the first step
toward understanding this com plex area when they reported the
isolation of diastase in 1833. These workers showed that diastase
could catalyze the hydrolysis of starches to sugars. Somewhat
earlier Kirchhoff (Schwigger's Journal, 4, 108 (1812)) had shown
that a small amount of dilute acid could hydrolyze a seemingly
endless amount of starch to sugars. The genius of Berzelius
recognized the commonality of these two observations in connection
with a few other isolated observations and in 1834 coined the term
catalysis to describe such actions. Professor Leibig was one of the
giants of the chemical world in 1840. In addition to his own work,
Liebig was training the world's next generation of chemists in his
laboratory in Giessen. This cadre of chemists were very impressed
by the master teacher so that is it only natural that Liebig's
views should dominate with this next generation of chemists. Leibig
was, in the 1830s and 1840s, developing his mastery of agricultural
chemistry. The mechanism of putrefication was of great concern to
Leibig, and he turned to the newly defined area of catalysis for an
explanation."
A reasonable case could be made that the scientific interest in
catalytic oxidation was the basis for the recognition of the
phenomenon of catalysis. Davy, in his attempt in 1817 to understand
the science associated with the safety lamp he had invented a few
years earlier, undertook a series of studies that led him to make
the observation that a jet of gas, primarily methane, would cause a
platinum wire to continue to glow even though the flame was
extinguished and there was no visible flame. Dobereiner reported in
1823 the results of a similar investigation and observed that
spongy platina would cause the ignition of a stream of hydrogen in
air. Based on this observation Dobereiner invented the first
lighter. His lighter employed hydrogen (generated from zinc and
sulfuric acid) which passed over finely divided platinum and which
ignited the gas. Thousands of these lighters were used over a
number of years. Dobereiner refused to file a patent for his
lighter, commenting that "I love science more than money." Davy
thought the action of platinum was the result of heat while
Dobereiner believed the ~ffect ~as a manifestation of electricity.
Faraday became interested in the subject and published a paper on
it in 1834; he concluded that the cause for this reaction was
similar to other reactions.
The subject of this volume is limited in that it addresses
amphiphiles at liquid/air, liquid/liquid, and liquid/solid
interfaces, with litte attention paid to vapor/solid interfaces.
This volume will serve to summarize our current understanding of
interfacial structure at the molecular level in these systems, and
the relation of this structure to chemical and physicochemical
phenomena.
In this book, academic researchers and technologists will find
important information on the interaction of polymeric and
non-polymeric inhibitors with a variety of scale forming crystals
such as calcium phosphates, calcium carbonate, calcium oxalates,
barium sulfate, calcium pyrophosphates, and calcium phosphonates.
Moreover, the book delivers information to plant managers and
formulators who would like to broaden and deepen their knowledge
about processes involved in precipitation of sparingly soluble
salts and learn more about the inhibitory aspects of various
commercially available materials. Furthermore, experienced
researchers will obtain fruitful and inspiring ideas from the
easily accessible information about overlapping research areas,
which will promote discoveries of new inhibitors (synthetic and/or
natural) for the currently unmet challenges.
Asphaltenes have traditionally been viewed as being extremely
complex, thus very hard to characterize. In addition, certain
fundamental properties of asphaltenes have pre viously been
inaccessible to study by traditional macroscopic methods, further
limiting understanding of asphaltenes. These limitations inhibited
development of descriptions regarding the microscopic structure and
solution dynamics of asphaltenes. However, a variety ofmore recent
studies have implied that asphaltenes share many chemical
properties with the smaller, more tractable components of crude
oils. Recent measurements have indicated that asphaltene molecular
weights are not as arge as previously thought, perhaps in the range
of 600 to I 000 amu. In addition, new experimental methods applied
to asphaltene chemical structures have been quite revealing,
yielding a broad understanding. Conse quently, the ability to
relate chemical structure with physical and chemical properties can
be developed and extended to the understanding of important
commercial properties of asphal tenes. This book treats significant
new developments in the fundamentals and applications of
asphaltenes. In the first section ofthe book, new experimental
methods are described that characterize asphaltene structures from
the molecular to colloidallength scale. The colloidal properties
are understandable in terms of asphaltene chemical structures,
especially with regard to the heteroatom impact on bonding.
However, quantitative measurements of the of asphaltene
self-association still need to be determined. In the second section
of enthalpy this book, the fundamental understanding of asphaltenes
is related riirectly to asphaltene utilization."
|
|