bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stabilization
Authors: Al‐Malaika S. 
Published: October 2003

AbstractThis review of the fundamental aspects of polymer stabilization technology covers aspects of oxidative degradation of polymers, and the deleterious effects of oxygen and the environment: temperature, sunlight, ozone, atmospheric pollutants, water, mechanical stress, adventitious metal, and metal ion contaminants. The role of antioxidants in polymer stabilization with examples to illustrate the basic mechanisms of action and the range of chemical and physical factors that affect performance are discussed. Different classes of antioxidants that act by different and complementary mechanisms are covered. Also included are examples of recent developments and progress in areas of application where melt, heat, and light stabilizers are generally employed, as well as in more targeted areas that benefit specifically from the use of time‐control stabilizers, high molar mass antioxidants, reactive (polymerizable or graftable) antioxidants, and biological antioxidants.
Styrene–Butadiene Copolymers
Authors: Demirors Mehmet 
Published: October 2003

Abstract
Styrene–butadiene (SB) copolymers are the largest volume, and hence industrially most significant, copolymers currently in use. They are typically divided into three classes. Styrene–butadiene rubbers (SBRs) are mostly used for tire applications. SBRs are manufactured both by emulsion process and by solution process, utilizing anionic polymerization. High impact polystyrene (HIPS), the largest by volume of the three, is a thermoplastic resin and is used in food packaging, consumer electronics, and appliances. HIPS is manufactured by grafting of the polybutadiene rubber in solution during the production of polystyrene. SB block copolymers are utilized in the manufacture of transparent, impact‐resistant polystyrene as well as impact modification in other areas. SB block copolymers are exclusively manufactured by anionic polymerization of styrene and butadiene.
Vinyl Fluoride Polymers (PVF)
Authors: Ebnesajjad Sina 
Published: October 2003

AbstractHomopolymers and copolymers of vinyl fluoride are inert. They posses unique chemical and weather resistance characteristics in addition to good mechanical properties. These polymers can be rendered adherable by flame and corona discharge techniques. These attributes have spurred the application of poly(vinyl fluoride) films and coatings in indoor and outdoor functional and decorative uses. This article provides a review of methods of manufacture, properties, polymerization chemistry, fabrication techniques, applications, and economy of these polymers.
Vinylidene Fluoride Polymers
Authors: Humphrey J. S. , Amin‐Sanayei R. 
Published: October 2003

AbstractPoly(vinylidene fluoride), PVDF, [CH2CF2]n, is the addition polymer of vinylidene fluoride, VDF, CH2CF2. It has achieved a high level of usage during the past 40 years based upon the excellent resistance to chemicals, weathering elements, and oxidants, as well as for special properties such as piezoelectric characteristics and fire resistance. It is a tough, high temperature thermoplastic finding use, eg, in super heated steam environments. It may be fabricated by a variety of techniques, including solvent‐based or water‐based dispersion processes as well as typical melt extrusion and radiation cross‐linking processes. It is available from a variety of manufacturers. Copolymerization technology has produced thermoplastic resins with excellent flexibility.
Wool
Authors: Christoe John R. , Denning Ron J. , Evans David J. , Huson Mickey G. , Jones Leslie N. , Lamb Peter R. , Millington Keith R. , Phillips David G. , Pierlot Anthony P. , Rippon John A. , Russell Ian M. 
Published: October 2003

AbstractWool, the fibrous coating from sheep, is the most important animal fiber used by the textile industry. It has been used continuously for several thousand years, the earliest type of fabric made from wool probably being a felt. Although the relative importance of wool as a textile fiber has declined with the increasing use of synthetic fibers, it remains important in some sectors of the market. This article discusses raw wool specification, fiber growth, its complex morphological and chemical structure, and the physical properties that make wool unique among textile fibers. Also discussed are the processing steps used to transform raw wool into consumer products, namely, scouring, carbonizing, carding, spinning, setting, dyeing, bleaching, printing, and treatments to reduce felting shrinkage, insect damage, and flammability. A new textile fiber made from wool (Optim™, CSIRO) is also described.
Dendronized Polymers
Authors: Schlüter A. Dieter , Rabe Jürgen P. 
Published: October 2003

AbstractSynthesis, properties, and application of the novel class of comb polymers with dendritic side chains (dendronized polymers) are discussed. Different synthetic strategies are discussed and compared. The assembly and manipulation of homo‐ and amphiphilic representatives are treated with an emphasis on interfacial issues. The combination of neutron scattering data in solution, molecular dynamics simulations in vacuum, and scanning force microscopical investigations of ultrathin layers as well as individualized representatives of dendronized polymers adsorbed on highly oriented pyrolytic graphite show that dendronized polymers can be considered rigid, nano‐sized molecular objects with cylindrical shapes, depending on structure, size, and density of attachment. Although experiments were only recently started accordingly, it has already become obvious that this class of polymers, because of their size and shape and potential to be equipped with various surface functionalities and patterns, links the worlds of materials science and bioscience.
Cyclopentadiene and Dicyclopentadiene
Authors: Cheung T. T. Peter 
Published: October 2003

AbstractCyclopentadiene (CPD) and dicyclopentadiene (DCPD), which occur as by‐products in the steam cracking process in ethylene plants, are the major ingredients in the production of hydrocarbon resins, unsaturated polyester resins, elastomers, pesticides, flame retardants, and a host of specialty chemicals. The versatility of CPD as the building block in so many chemicals stems from the high reactivity of its conjugated double bonds. They react readily with dienophiles, compounds with ethylenic or acetylenic unsaturation, to give Diels–Alder adducts, with oxygen and halogen to give oxygenates and halide derivatives. Cyclopentadiene dimerizes readily, via the Diels–Alder mechanism, to DCPD at ambient conditions. The dimerization is highly exothermic. Because of its reactivity, CPD is normally available only in the stable dimer form. Pure CPD can be producedin situby the thermal cracking of the DCPD at a temperature near the normal boiling point of the DCPD.
Perfluorinated Polymers, Tetrafluoroethylene–Perfluorodioxole Copolymers
Authors: Gangal Subhash V. 
Published: October 2003

Abstract
Copolymers of tetrafluoroethylene–perfluorodioxole are perfluorinated amorphous polymers and have unusual combination of properties. These polymers, commonly known as Teflon AF, have high temperature stability, excellent chemical resistance, low surface energy, low water absorption, high limiting oxygen index, solubility at ambient temperature in fluorinated solvents, high transparency, and low refractive index. They are stiffer and have high gas permeability. The glass‐transition temperature is sensitive to polymer composition and the structure of the dioxole monomer. These polymers can be processed by various solution processing techniques such as spin coating, dip coating, spraying, or casting. Melt‐processing techniques like extrusion and injection molding are used. They are used to provide antireflective coatings, low dielectric coatings, pellicles in electronic chips, plastic optical fiber, and in gas separation membrances.
Urethane Coatings
Authors: Wicks Zeno W. 
Published: October 2003

Abstract
Various classes of urethane coatings are discussed: two package solventborne, moisture cure, blocked isocyanate, uralkyd, aqueous polyurethane dispersion, and two‐package waterborne coatings. Major end uses include architectural paints, especially varnishes; coatings for automobiles, both OEM and refinish; and maintenance coatings.
Ferroelectric Liquid Crystalline Elastomers
Authors: Zentel Rudolf 
Published: October 2003

Abstract
Ferroelectric LC‐elastomers represent an interesting class of material because they combine the ordering of liquid crystalline ferroelectric phases and the rubber elasticity of polymer networks. Switching of the electric polarization leads to deformation of the polymer network, equivalent to stretching a spring, and creates a stress in the network of polymer chains.
The interaction of mesogens and the network can be varied by using different topologies of net points: Crosslinking is carried out either within the siloxane sublayers (leading to fast switching elastomers) or between the siloxane sublayers (resulting in an elastomer that favors the ferroelectric switching state in which the cross‐linking reaction took place).
Because the orientation of the smectic phase couples to the polymer network, electromechanical measurements show a piezoelectric effect. Mechanical deformation leads to polarization or an external electric field to deformation of the sample. Applying the electric field parallel to the smectic layer structure leads to an extremly high electrostrictive strain.
Flash Devolatilization
Authors: Nauman Bruce 
Published: October 2003

Abstract
Flash devolatilization is a highly efficient method for removing volatile components from a polymer melt. A dispersed spray or an open‐celled form exposes a large surface area and enables a close approach to thermodynamic equilibrium. The process is highly scalable in the sense that the residual volatile content is insensitive to flow rate. The typical apparatus consists of a heat exchanger, flash chamber, and gear pump. Flash devolatilization also contributes to the effectiveness of devolatilizing extruders and wiped file evaporators. Foaming agents can be used to increase the surface area available for mass transfer.
Microemulsion Polymerization
Authors: Chern Chorng‐Shyan 
Published: October 2003

Abstract

Microemulsion polymerization involves free‐radical polymerization in ultrafine monomer droplets (1–10 nm in diameter) dispersed in a continuous phase. The resultant polymer colloids generally exhibit small latex particles (10 nm in diameter) and very high polymer molecular weight (10
6
– 10
7
g/mol), which cannot be achieved by conventional emulsion polymerization. This article presents a concise review of the formation and microstructure of the thermodynamically stable microemulsion. The structural characteristic of the initial microemulsion has a significant influence on the subsequent polymerization inside monomer droplets. Polymerization kinetics and nucleation and growth of latex particles are the focuses of this work. Microemulsion droplets are the primary loci of particle nucleation and particle nuclei are generated continuously throughout the polymerization. Only a few polymer chains are produced in one latex particle. In contrast, the continuous phase or bicontinuous phase of microemulsion may also serve as the locus of polymerization and this unique technique allows the preparation of various novel polymeric materials.
Microcellular Plastics
Authors: Suh Nam P. 
Published: October 2003

AbstractMicrocellular plastics (MCPs) refer to any plastic with tiny bubbles of less than about 50 μm. They are made by subjecting polymers with a large amount of dissolved gas to a thermodynamic instability so as to nucleate a large number of cells instantaneously. MCPs have been extruded and injection‐molded in order to make various industrial products. This article reviews the fundamental theory for design of MCPs and their processing methods. It also discusses the design of equipment, including the die or mold, for MCP processing. The performance of MCPs and the advantages of using MCPs are demonstrated. Some of their industrial applicatons are also highlighted.
Vinyl Acetal Polymers
Authors: Wade Bruce 
Published: October 2003

AbstractVinyl acetal polymers are terpolymers, with units of vinyl acetate, vinyl alcohol, and vinyl acetal reflecting the three reactions required for their manufacture. Manufacture involves several stages including vinyl acetate polymerization and either sequential or concurrent hydrolysis of poly(vinyl acetate) to poly(vinyl alcohol) and acetalization with an aldehyde in the presence of an acid catalyst. Only poly(vinyl butyral) and to a lesser extent poly(vinyl formal) continue to be made in sizeable commercial quantities. These polymers form hard, unpliable materials that are difficult to process without using solvents or plasticizers. Plasticized poly(vinyl butyral) interlayer for laminated safety glass is by far the largest single application for this class of polymers. Poly(vinyl butyral) provides flexible toughness over a wide range of temperatures and at a lower cost than vinyl acetal polymers derived from longer chain aldehydes. Where stiffer performance at higher temperatures is required, poly(vinyl formal) provides significant property advancement. Applications for vinyl acetal resins make use of their optical clarity, high pigment and filler binding capacity, and excellent adhesion to a variety of surfaces.
Biomolecules at Interfaces
Authors: Van Tassel Paul R. 
Published: October 2003

AbstractBiomolecules such as proteins, peptides, amino acids, polysaccharides, lipids, and nucleic acids tend to reside at interfaces. This simple fact carries immense consequences in nature and affords substantial opportunities in biotechnology. In this article, several important technological applications and intriguing intellectual challenges that motivate the study of biomolecules at interfaces are introduced. Significant discussion is directed toward applications in biomaterials and biosensors, and open questions on issues of irreversibility and history‐dependent behavior are addressed. In addition, a number of theoretical tools and experimental methods critical to advancing the study of biomolecules at interfaces are presented. Theoretical descriptions at the site, particle, colloidal, polymer, and atomistic level—as well as optical, piezoelectric, and scanning probe experimental techniques—are described and speculation is made upon their potential to broaden our application and/or deepen our understanding of biomolecules at interfaces.
Intercalation Polymerization
Authors: Duguet Etienne , Rey Stéphanie , Robles Josepha Maria Merida 
Published: October 2003

AbstractPolymer‐layered nanocomposites are made of the alternation of inorganic slabs and polymer layers. They may be obtained through (1) the synthesis of the mineral slabs from soluble precursors in a macromolecular solution, (2) mineral slab exfoliation and their subsequent restacking after adsorption of macromolecules (encapsulative precipitation), (3) the direct intercalation of macromolecules in the interslab space, (4) the intercalation of monomer molecules and theirin situsimultaneous or subsequent polymerization. In this article, the main layered inorganic lattices, which readily undergo intercalation reaction, and the corresponding intercalation driving forces are described. The synthesis of polymer‐layered nanocomposites are presented essentially from the viewpoint of the polymer chemist. The polymerization mechanisms, the molecular weight distribution, and the interslab arrangement of the intercalated macromolecules are discussed. Among the original properties of such polymer‐layered nanocomposites, a special emphasis is made on their enhanced ionic or electron conductivity and their thermal stability.
Identification of a metabolic network structure representative of arthrospira (spirulina) platensis metabolism
Authors: Cogne Guillaume , Gros J.‐B. , Dussap C.‐G. 
Published: October 2003

AbstractA comprehensive network structure for the autotrophic growth of Arthrospira platensis is proposed. The metabolic network was built up with 121 reactions and 134 metabolites including biomass synthesis, production of a growth‐associated exopolysaccharide, and energy aspects. The model supports the existence of a metabolic shunt of PEP to pyruvate through PEP carboxylase, NAD+‐dependent malate dehydrogenase and malic enzyme to convert NADH,H+ into NADPH,H+. A limit in Arthrospira growth metabolism due to NADH,H+ balancing is evidenced, explaining why the maximal light‐dependent mass yield of the growth‐associated exopolysaccharide was 0.51 kg EPS kg−1 biomass, consistent with experimental results. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 667–676, 2003.
Use of stable emulsion to improve stability, activity, and enantioselectivity of lipase immobilized in a membrane reactor
Authors: Giorno L. , Li N. , Drioli E. 
Published: October 2003

AbstractThe enantiocatalytic performance of immobilized lipase in an emulsion membrane reactor using stable emulsion prepared by membrane emulsification technology was studied. The production of optical pure (S)‐naproxen from racemic naproxen methyl ester was used as a model reaction system. The O/W emulsion, containing the substrate in the organic phase, was fed to the enzyme membrane reactor from shell‐to‐lumen. The enzyme was immobilized in the sponge layer (shell side) of capillary polyamide membrane with 50 kDa cut‐off. The aqueous phase was able to permeate through the membrane while the microemulsion was retained by the thin selective layer. Therefore, the substrate was kept in the enzyme‐loaded membrane while the water‐soluble product was continuously removed from the reaction site. The results show that lipase maintained stable activity during the entire operation time (more than 250 h), showing an enantiomeric excess (96 ± 2%) comparable to the free enzyme (98 ± 1%) and much higher compared to similar lipase‐loaded membrane reactors used in two‐separate phase systems (90%). The results demonstrate that immobilized enzymes can achieve high stability as well as high catalytic activity and enantioselectivity. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 677–685, 2003.
Crude aminoacylase from aspergillus sp. is a mixture of hydrolases
Authors: Bode Moira L. , van Rantwijk Fred , Sheldon Roger A. 
Published: October 2003

AbstractA range of cross‐linked enzyme aggregates (CLEAs) was prepared from commercially available aminoacylase I. Results from three test reactions showed that aminoacylase does not possess aminolysis or alcoholysis activity, both previously ascribed to this enzyme. This result was confirmed using aminoacylase purified by chromatographic techniques, which leads us to conclude that the previously observed acylations of esters and amines is due to other enzymes present as impurities in the crude aminoacylase I. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 710–713, 2003.
Genetically engineered binding proteins as biosensors for fermentation and cell culture
Authors: Ge Xudong , Tolosa Leah , Simpson Jen , Rao Govind 
Published: October 2003

AbstractThe signal‐transduction properties and the potential applications of two engineered binding proteins from E. coli were extensively studied. Both proteins have a single cysteine mutation in their polypeptide chains, which allow the introduction of an environmentally sensitive fluorophore: ANS for glucose‐binding protein (GBP) and acrylodan for glutamine‐binding protein (QBP). Both proteins respond to their ligands in the micromolar range. The proteins can be stored at 4°C for at least 5 months. Apparent binding constant, protein concentration, and fluorophore are three major factors that affect the biosensor's responsive ranges. The binding of the ligand is quick and reversible in solution, but the unfavorable dissociation equilibrium and mass‐transfer resistance for encapsulated proteins can delay the response to several minutes and the recovery to hours. Simulated results show that using dialysis tubing with a diameter of 1 mm or less is possible to reduce the recovery time to less than 30 minutes. The potential applications of GBP were studied in yeast fermentation and E. coli fermentations in three different scales: 150 mL, 5 mL, and 100 μL. The results were compared with an YSI 2700 Chemistry Analyzer. Although the latter could not give reliable results for the E. coli fermentations as the glucose concentration in LB medium is close to its lower detection limit, the glucose biosensor presented here was successfully applied to each situation. Glutamine‐binding protein was tested in cell cultures of two different scales (100 mL and 100 μL) and the results were also compared with those obtained with YSI. Both QBP and YSI gave good results for the 100‐mL cell culture, but the relatively large sample volume requirement of YSI (at least 5 μL) prevented it from being used in the 100‐μL cell culture. Because of their small sample volume requirements (less than 1 μL) and high sensitivity, the assays described here might find wide applications in high‐throughput bioprocessing. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 723–731, 2003.
Metabolic characteristics of an isocitrate dehydrogenase defective derivative of escherichia coli BL21(DE3)
Authors: Aoshima Miho , Ishii Masaharu , Yamagishi Akihiko , Oshima Tairo , Igarashi Yasuo 
Published: October 2003

AbstractA 7.8 kb fragment containing isocitrate dehydrogenase (ICDH) gene and its flanking regions was cloned from Escherichia coli BL21(DE3) and sequenced. Unlike the case of the K‐12 strain, the e14 element was not found. The nucleotide divergence between these two strains was about 2%. Using the cloned fragment, ICDH defective mutant strain, MA1935, was generated from BL21(DE3). Although MA1935 accumulated citrate, citrate synthase activity was not repressed but was rather high. In addition, isocitrate lyase was not highly induced at the stationary phase. MA1935 was shown to be a good host strain for ICDH gene expression. © 2003 Wiley Periodicals Inc. Biotechnol Bioeng 84: 732–737, 2003.
Prospects for diffusion enhancement of signal and resolution in magnetic resonance microscopy
Authors: Pennington Charles H. 
Published: October 2003

AbstractThe prospects for and practical requirements of the “diffusion enhancement of signal and resolution” (DESIRE) scheme proposed by Lauterbur as a method to enhance the sensitivity, spatial resolution, and contrast in magnetic resonance (MR) microscopy and localized MR spectroscopy is assessed. The method, which still has not been implemented, promises signal enhancements of 1–2 orders of magnitude in imaging or localized spectroscopy on the scale of ∼10 microns and requires magnetic field gradient strengths (∼10 T/m) that are not unreasonable. I emphasize the development of an understanding of the physical principles involved in this unfamiliar, “real‐space” imaging method. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part A 19A: 71–79, 2003.
Thermal relaxation and coherence dynamics of spin 3/2. I. Static and fluctuating quadrupolar interactions in the multipole basis
Authors: van der Maarel Johan R.C. 
Published: October 2003

AbstractThe relaxation dynamics of the spin 3/2 density operator in the presence of fluctuating and static quadrupolar interactions is reviewed. The nuclear magnetic resonance (NMR) line shapes are analyzed for any value of the static quadrupolar interaction, ranging from isotropic systems to systems exhibiting large splitting far exceeding the line widths. Pulse sequences optimized for the elimination of line broadening due to an inhomogeneous static quadrupolar interaction and for the detection of nuclei involved in slow molecular motion and/or in anisotropic, liquid crystalline environment are discussed. In Part II, the dynamics of spin 3/2 in the presence of a (pulsed) radio frequency (RF) field is reviewed. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part A 19A: 97–116, 2003.