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Books > Science & Mathematics > Chemistry > Organic chemistry > Polymer chemistry
Viscoelasticandtransportpropertiesofpolymersintheliquid(solution,melt)or
liquid-like (rubber) state determine their processing and
application to a large extent and are of basic physical interest
[1-3]. An understanding of these dynamic properties at a molecular
level, therefore, is of great importance.
However,thisunderstandingiscomplicatedbythefactsthatdi?erentmotional
processes may occur on di?erent length scales and that the dynamics
are governed by universal chain properties as well as by the
special chemical structure of the monomer units [4,5]. The earliest
and simplest approach in this direction starts from Langevin
equations with solutions comprising a spectrum of relaxation modes
[1-4]. Special features are the incorporation of entropic forces
(Rouse model, [6]) which relax uctuations of reduced entropy, and
of hydrodynamic interactions (Zimm model, [7]) which couple
segmental motions via long-range back ow elds in polymer solutions,
and the inclusion of topological constraints or entanglements
(reptation or tube model, [8-10]) which are mutually imposed within
a dense ensemble of chains. Another approach, neglecting the
details of the chemical structure and
concentratingontheuniversalelementsofchainrelaxation,isbasedondynamic
scalingconsiderations[4,11].Inparticularinpolymersolutions,thisapproach
o?ers an elegant tool to specify the general trends of polymer
dynamics, although it su?ers from the lack of a molecular
interpretation. A real test of these theoretical approaches
requires microscopic methods, which simultaneously give direct
access to the space and time evolution of the segmental di?usion.
Here, quasi-elastic scattering methods play a crucial role
sincetheyallowthemeasurementofthecorrespondingcorrelationfunctions.In
particular,thehigh-resolutionneutronspinecho(NSE)spectroscopy[12-15]is
very suitable for such investigations since this method covers an
appropriate range in time (0.005)t/ns)40) and space (r/nm [15).
Furthermore, the
possibilityoflabellingbyhydrogen-deuteriumexchangeallowstheobservation
of single-chain behavior even in the melt.
Leading Nordic-Baltic scientists and their colleagues from other
countries present recent research on a broad range of topics in
surface and colloid science: adhesion, adsorption processes,
characterization of solid/liquid and solid/polymer interfaces,
chemical and particle depositions, colloid stability,
emulsification and encapsulation, interfacial reactions, new
surfactants, polymer-surfactant interactions, self-assembly
processes, and functionalized surfaces for bio- and chemosensors.
The papers were presented at the 1st Nordic-Baltic Meeting on
Surface and Colloid Science, which was held in Vilnius, Lithuania
on August 21-25, 1999, as a continuation of the traditional
Scandinavian Symposium on Surface Chemistry.
The Fifth Chinese Peptide Symposium, hosted by Lanzhou University,
was held at Lanzhou, China July 14-17, 1998, with 156 participants,
including 30 scientists from abroad, representing nine countries.
The four-day conference was both intense and spiritually rewarding.
Our goal for CPS-98 was to provide a forum for the exchange of
knowledge, cooperation and friendship between the international and
Chinese scientific communities, and we believe this goal was met.
The symposium consisted of 8 sessions with 42 oral and 90 poster
presentations, including synthetic methods, molecular diversity and
peptide libraries, structure and conformation of peptides and
proteins, bioactive peptides, peptide immunology, De Novo design
and synthesis of proteins and peptides, ligand-receptor
interactions, the chemistry-biology-interface and challenging
problems in peptides. The enthusiastic cooperation and excellent
contributions were gratifying and the active response of the
invited speakers contributed to the success of the symposium. The
presentations were of excellent caliber and represented the most
current and significant aspects of peptide science. Dr. Kit Lam of
the University of Arizona and Dr. Yun-Hua Ye of Peking University
were the recipients of "The Cathay Award" sponsored by the H. H.
Liu Education Foundation, offered for their seminal contribution in
peptide science and the Chinese Peptide Symposium. Four outstanding
young scientists were selected by the organizing committee to
receive awards sponsored by Haikou Nanhai Pharmaceutical Industry
Co. Ltd. (Zhong He Group).
Shunsuke Hirotsu "Coexistence of Phases and the Nature of
First-Order Transition in Poly-N-isopropylacrylamide Gels,"
Masayuki Tokita "Friction between Polymer Networks of Gels and
Solvent," Masahiro Irie "Stimuli-Responsive Poly(N-isopropyl-
acrylamide), Photo- and Chemicals-Induced Phases Transitions Edward
Cussler, Karen Wang, John Burban"Hydrogels as Separation Agents,"
Stevin Gehrke "Synthesis, Equilibrium Swelling, Kinetics
Permeability and Applications of Environmentally Responsive Gels,"
Pedro Verdugo "Polymer Gel Phase Transition in Condensation-
Decondensation of Secretory Products," Etsuo Kokufuta "Novel
Applications for Stimulus-Sensitive Polymer Gels in the Preparation
of Functional Immobilized Biocatalysts," Teruo Okano "Molecular
Design of Temperature-Responsive Polymers as Intelligent
Materials," Atsushi Suzuki "Phase Transition in Gels of
Sub-Millimeter Size Induced by Interaction with Stimuli," Makoto
Suzuki, O. Hirasa "An Approach to Artificial Muscle by Polymer Gels
due to Micro-Phase Separation."
This volume of the series gives an overview on Rigid Polymer
Networks written by two reputed experts in the field. A broad range
of densely-branched, highly-crosslinked aromatic networks and gels
of increasing rigidity are discussed, with special emphasis on
aromatic rigid liquid-crystal polymer networks. The synthetic
procedures to create the networks are briefly described and
extensively referenced. Features of one-step and two-step rigid
networks in their pre-gel and post-gel states are discussed. Some
first steps are then taken in the theoretical treatment of LCP
networks with long aromatic segments of decreasing stiffness. The
current state of theory dealing with the broader class of
highly-crosslinked rigid aromatic networks and gels is finally
mentioned.
This book summarizes the properties and applications of
conventional and commercially available fiber-forming,
bioresorbable polymers, as well as those currently under study, for
use as biotextiles. Factors affecting the performance of these
biomaterials are presented, and precautionary measures to reduce
premature, hydrolytic degradation during manufacturing and
processing are discussed. Because of the structural requirements of
medical devices and the technological advancements in synthetic
fibers and textile technology, the new field of "Biotextiles" has
evolved to exploit the potential of various woven, knitted, braided
and non-woven textile structures for biomedical applications.
Textile substrates provide certain unique mechanical properties to
the medical device and because of an inherently high level of
porosity, they can encourage cell growth and promote migration and
proliferation. Bioresorbable devices that assist in the repair and
regeneration of damaged tissues have in recent years replaced many
of the permanent prosthetic devices. Thus, the topic of
"Bioresorbable Biomaterials" generates much interest and research
activity in the field of biomaterials science today. For this
reason, the use of bioresorbable polymers as fibers is currently
dominating the field of resorbable biomaterials for applications
from sutures to tissue engineering scaffolds.
Drawing a picture of the current situation of this new field, this
volume both summarizes the past achievements and analyzes the
present unsolved problems.
This is the second edition of Melt Rheology and its Role in
Plastics Processing, although the title has changed to reflect its
broadened scope. Advances in the recent years in rheometer
technology and polymer science have greatly enhanced the usefulness
of rheology in the plastics industry. It is now possible to design
polymers having specific molecular structures and to predict the
flow properties of melts having those structures. In addition,
rheological properties now provide more precise information about
molecular structure. This book provides all the information that is
needed for the intelligent application of rheology in the
development of new polymers, the determination of molecular
structure and the correlation of processability with laboratory
test data. Theory and equations are limited to what is essential
for the use of rheology in the characterization of polymers, the
development of new plastics materials and the prediction of
plastics processing behavior. The emphasis is on information that
will be of direct use to practitioners. Extensive references are
provided for those wishing to pursue certain issues in greater
depth. While the primary audience is applied polymer scientists and
plastics engineers, the book will also be of use to postgraduate
students in polymer science and engineering and as a text for a
graduate course.
This book contains the proceedings of the Symposium on FT-IR
Characterization of Polymers, which was held under the auspices of
the Division of Polymer Chemistry, American Chemical Society (ACS)
during the annual ACS meeting in Philadelphia, August, 1984. The
content of each paper has been substantially extended from the
papers presented during the conference. Due to the accidental,
irrecoverable loss of the entire contents of the book by the
computer system used for editorial purposes, the publication of
this book has been delayed more than one year over the initial
scheduled date. It has been a continuous, frustrating experience
for the editor as well as for the authors. An extended Murphy's
law, -anything can go wrong goes multiply wrong- has been
demonstrated in editor's office. It necessitated, otherwise
unnecessary, repeated proof reading during which time the editor
had valuable experience ~n familiarizing himself with each paper
much more than usual. The papers in this book are state-of-the-art
even after such a delay. It is the authors pride and integrity
toward the quality of each paper that makes the value of this book
long lasting, while responsibility of the loss of any timeliness
rests at the editor's hand. For the purpose of official records,
submission and acceptance dates must be stated. All papers had been
submitted by September, 1984, and had been accepted for publication
by November, 1984, after the critical review processes.
This book is concerned with the configuration of polymers at the
interfacial zone between two other phases or immiscible components.
In recent years, developments in technology combined with increased
attention from specialists in a wide range of fields have resulted
in a considerable increase in our understanding of the behavior of
polymers at interfaces. Inevitably these advances have generated a
wealth of literature and although there have been numerous reviews,
a critical treatment with adequate descriptions of both theory and
experiment, including detailed analysis of the two, has been
missing. This text hopes to fill this gap, providing a timely and
comprehensive account of the field as it stands today. This long
needed work will be invaluable to experts as well as newcomers in
the broad field of polymers, interfaces and colloids, both in
industry and academia. Whilst industrial laboratories involved in
this field will find it indispensable, it will be equally important
to anyone with an interest in interfacial polymer or colloidal
research.
In recent years, a growing number of engineering applications of
light weight and energy efficient plastics can be found in high
quality parts vital to the func tioning of entire equipments and
structures. Improved mechanical properties, especially balance of
stiffness and toughness, are among the most frequently desired
features of the new materials. In addition, reduced flammability is
con sidered the single most important requirement for further
expansion of plastics into large volume and demanding markets such
as construction and mass trans port. Production of power cables
also requires flame retardant cable jacketing plastics to replace
or at least to reduce consumption of environmentally unsound PVC.
The two principal ways to achieve the goals mentioned above include
the development of completely new thermoplastic polymers and
various modifica tions of the existing ones. Development and
commercialization of a new ther moplastic require mobilization of
large human and financial resources, the lat ter being within the
range from $100 million to $10 billion, in comparison to $100
thousand to $10 million needed to develop and commercialize
polymeric mate rial with prescribed end use properties using
physical or chemical modification of an existing plastic. In
addition, the various markets utilizing thermoplastics demand large
flexibility in material properties with only moderate volumes, at
the best.
This book is derived from a Symposium held at the 190th National
American Chemical Society Meeting, which was held in the Fall of
1985, in Chicago, and was sponsored by the Division of Polymeric
Materials: Science & Engineering. This Symposium was, in turn,
a follow-up on an earlier one held in Houston, TX, in the Spring of
1980, which was pub lished as the book *Biomedical and Dental
Applications of Polymers* [Plenum Press, New York, 1981]. In that
earlier book, our opening Preface passage quoted King David, *1
will praise Thee; for I am fearfully and made . ** * (Psalm
139:14). As we noted five years ago, sickness wonderfully of many
types does occur in our wonderfully made bodies, but much human
suffering can be aided by biomedical polymers. That earlier book
con sidered much of the fantastic progress that had been made in
biomedical polymers during the previous quarter century and brought
many of these topics up to date. That Symposium, and book, noted
that much help was available for the varied afflictions and
problems that sometimes beset, and upset, our God-given bodies, and
the promise of new and important advances was held out as a shining
ray of hope amidst the gloom of sickness and affliction. The
present volume is an update on the advances that have occurred
since the 1981 book and sets the stage for even greater advances in
the future.
Technology and Development of Self-Reinforced Polymer Composites,
by Ben Alcock und Ton Peijs; Recent Advances in High-Temperature
Fractionation of Polyolefins, by Harald Pasch, Muhammad Imran Malik
und Tibor Macko ; Antibacterial Peptidomimetics: Polymeric
Synthetic Mimics of Antimicrobial Peptides, by Karen Lienkamp,
Ahmad E. Madkour und Gregory N. Tew; Collagen in Human Tissues:
Structure, Function, and Biomedical Implications from a Tissue
Engineering Perspective, by Molamma P. Prabhakaran;
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