bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic Polymerization
Authors: Kobayashi Shiro , Uyama Hiroshi 
Published: October 2003

AbstractThis article deals with recent advances in enzymatic polymerizations, defined as chemical polymer synthesisin vitro(in test tubes) via nonbiosynthetic pathways catalyzed by an isolated enzyme. The principal target macromolecules via the enzymatic polymerization are polysaccharides, poly(amino acid)s, polyesters, polycarbonates, polyaromatics, and vinyl polymers.For synthesis of polysaccharides, poly(amino acid)s, polyesters, and polycarbonates, hydrolases are used as catalyst; hydrolases, enzymes catalyzing a bond‐cleavage reaction by water, induce the reverse reaction of hydrolysis, leading to polymer production by a bond‐forming reaction. Specific enzyme catalysis provides a novel synthetic route for not only natural biopolymers such as cellulose, xylan, and chitin, but also unnatural polysaccharides, polyesters, poly(amino acid)s, and polycarbonates, many of which are difficult to be synthesized by conventional methodologies.Oxidoreductases act as catalyst for oxidative polymerization of phenol, aniline, and their derivatives, for polymer modification via oxidative coupling, and for production of vinyl polymers. A new class of phenolic polymers are synthesized without use of toxic formaldehyde under mild reaction conditions. Enzyme‐model complexes also catalyze the synthesis of new phenolic polymer materials.
Ethylene–Norbornene Copolymers
Authors: McNally Donal 
Published: October 2003

AbstractA new family of addition copolymers based on ethylene and norbornene became commercially available in 2001. These totally amorphous copolymers are strong, stiff, highly transparent, and colorless and have very high moisture barrier as well as interesting electrical properties. This article describes the raw materials, manufacturing, properties, and applications of these new materials.
Ethylene–Propylene Elastomers
Authors: Noordermeer Jacobus W. M. 
Published: October 2003

AbstractEthylene–propylene–diene rubbers, commonly called EPDM or EPM, continue to be one of the most widely used and fastest growing synthetic rubbers. They are particularly known for their excellent ozone and aging resistance in comparison with natural rubber and polydiene synthetic rubbers. The technology of producing EP(D)M rubber is still very much in development. Later years have seen major breakthroughs in production technologies relative to the solution and slurry processes based on Ziegler–Natta catalysis, ie, gas‐phase technology and technology based on metallocene catalysis.EPDM rubber can be extended with fillers and oil plasticizers to a very high level, leading to an attractive price/performance ratio in comparison with other rubbers. EPM can be vulcanized radically by means of peroxides; a small amount of built‐in nonconjugated diene monomer in EPDM permits conventional vulcanization with rubber. Particular emphasis is put on the different processing steps involved in the production of vulcanized EPDM articles. Typical applications of EP(D)M are in automotive weatherstrip profiles, solid and sponge, and radiator hoses; in building and construction as sealing profiles and roofing foils; in cable and wire as insulating and jacketing material; in blends with general‐purpose rubbers to improve ozone resistance; as impact modifier for thermoplastics; and as additive to lubricating oils.
Fractography
Authors: Ehrenstein G. W. , Raue F. 
Published: October 2003

Abstract
This article gives a brief overview about the science of fractography, which comprises the visualization, description, and interpretation of a fracture or a fracture surface, often in order to establish structure–property relationships.
First, the basic observation methods are outlined. Optical microscopy is a simple and inexpensive method to obtain an overall view. However, the depth of field is insufficient at large magnifications. Therefore, when evaluating the topology of a surface, scanning electron microscopy is widely used.
The fracture modes are classified and illustrated with examples of fracture surfaces of polymeric materials. Here, the modes are divided into load fractures, fatigue fractures, influence of chemicals, and special crack causes. The appearance of the surface gives clues to the origin of the fracture and the load which lead to the failure.
Finally, the quantitative evaluation of fracture surfaces is discussed. Quantitative fractography describes the surface in terms of parameters such as roughness, fiber orientation, phase content, and particle size distribution.
Graft Copolymers
Authors: Hadjichristidis N. , Pispas S. , Pitsikalis M. , Iatrou H. , Lohse D. J. 
Published: October 2003

AbstractGraft copolymers are composed of a main polymer chain (the backbone) to which one or more side chains (the branches) are chemically connected through covalent bonds. They are widely used today in many applications. This is mainly because of the great versatility in making such polymers and the utility they have. Herein we describe the great variety of methods that have been developed to make them and some of the uses to which they have been put.
Inorganic Polymers
Authors: Bourke Sara C. , Manners Ian 
Published: October 2003

AbstractThis article is an overview of inorganic polymer science. In the area of main group polymers, a synopsis of polyphosphazenes and polysilanes is offered followed by more comprehensive reviews of polygermanes, polystannanes, boron‐containing polymers, polycarbophosphazenes, sulfur–nitrogen–phosphorus polymers, and polyoxothiazenes. Polymers based on transition elements are also covered and the survey includes ferrocene‐based polymers, face‐to‐face metallocenes, coordination polymers, and rigid‐rod organometallic polymers.
Light‐Emitting Diodes
Authors: Greiner Andreas , Weder Christoph 
Published: October 2003

Abstract
During the 1990s, light‐emitting diodes (LEDs) have been developed, in which the semiconducting, electroluminescent (EL) material is a polymer. These devices, usually referred to as polymer LEDs, or PLEDs, have attracted significant attention in academic and industrial environment, as reflected by the already more than 5000 scientific publications and numerous patents that address this subject. This article presents an overview of fundamental concepts, with focus on the application of PLEDs. Device physics and general device design, as well as materials concepts, have been addressed. Furthermore, the development of EL polymer systems is discussed based on important key design considerations. Finally, the perspectives for the technological exploitation of PLEDs are elucidated.
Liquid Crystalline Polymers, Main‐Chain
Authors: Chung Tai‐Shung , Cheng Si‐Xue , Jaffe Michael 
Published: October 2003

AbstractThis review covers the most recent study on the nature of thermotropic liquid crystalline polymers (LCPs) and their progress. We summarize and review the newly developed thin‐film polymerization technique for the investigation of liquid crystalline formation as a function of monomer moieties, and for the study of reaction kinetics, the evolution of liquid crystal texture, and surface energy during polycondensation reactions. We also highlight various modification approaches to yield main‐chain LCPs suitable for conventional processing equipment, without compromising the unique liquid crystalline characteristics and the superior mechanical properties. The thermal stability, degradation behavior, and crystallization kinetics of commercial available main‐chain LCPs are recapitulated. Attention is also given to the rheology, polymer blends, micro‐ and nanostructures, and processing of LCPs and their applications.
Lithographic Resists
Authors: Hinsberg W. D. , Wallraff G. M. , Allen R. D. 
Published: October 2003

Abstract
An introduction to lithographic resists is presented. The principles of lithography are described and the essential attributes resist materials must possess are enumerated. The chemical and physical properties of resists of current technological importance are discussed within this framework, with an emphasis on how functional performance is related to these properties. Finally, examples are provided of how resist materials are being tailored for future lithographic imaging technologies.
Molecular Modeling
Authors: Eichinger B. E. , Khare Rajesh 
Published: October 2003

AbstractThe application of the methods of computational chemistry and physics to polymeric systems within the last two decades has generated an arsenal of techniques that are designed to analyze and predict the properties of this important class of materials. Much effort has been devoted to solving the length and timescale problems that polymers present. Concurrently, accurate force field descriptions of condensed phases, including efforts to treat reacting systems, is enabling significant predictions of properties to be made reliably. Many of these techniques are discussed, as is an array of results that have been obtained by a variety of methods.
Nanocomposites, Polymer–Clay
Authors: Lefebvre Jean‐Marc 
Published: October 2003

AbstractPolymer–clay nanocomposites are a new class of filled polymers in which disc‐shaped, 1‐nm‐thick, clay platelets are dispersed in a polymer matrix. The unique combination of large interfacial area and small interparticle distances, obtained at low filler loadings, is responsible for a material response unexpected from what is observed in conventional microcomposites. This shows in a panel of property enhancement which includes strength, stiffness, heat and dimensional stability, as well as barrier and fire‐retardant behavior. The significant challenge is to gain a basic understanding of elaboration–structure–property relationships for these highly promising materials.
Optical Properties
Authors: Galiatsatos Vassilios 
Published: October 2003

AbstractIn studying the interaction of light with polymers one discovers a multitude of exciting phenomena. Thorough knowledge of these phenomena yields thories and instrumentation that can be applied to a wide spectrum of academic and industrial subjects. Most markets served by polymers benefit from understanding of optical properties of polymers. This article provides an overview of some of the theory and properties central to the subject. It covers most properties that are of fundamental importance and macroscopic properties directly important to industrial applications. Examples of computational methods are given. Definitions, testing methods, references, and examples accompany each property to further help understanding.
Packaging, Flexible
Authors: Wooster Jeffrey J. 
Published: October 2003

AbstractFlexible packaging can come in many forms, from the simple to the extremely complex. Whatever its form its purpose is to protect a product from the time of its manufacture until it is used by the ultimate consumer. The performance requirements that must be met in order to protect a given product ultimately determine the type of packaging that is used. These requirements are used in the selection of polymers, film structures, and packaging methods. The listed applications and packaging types in this article show the range of uses of flexible packaging. As the development of new materials and packaging machinery continues, the number of uses for flexible packaging is sure to grow as well.
Plasticizers
Authors: Wadey Brian L. 
Published: October 2003

AbstractPlasticizers are added to materials to make the material softer, more flexible, and easier to process. There are four theories of plasticization along with various interaction parameters. The largest family of plasticizers are phthalate esters. These are used mainly to plasticize poly (vinyl chloride) (PVC). Phthalate esters are made by the reaction of phthalic anhydride with various chain length alcohols. These alcohols can be branched or linear in nature. Other families of plasticizers such as trimellitates and adipates can be manufactured by changing the acid component of the reaction. Polymeric plasticizers are made through polycondensation reaction of an acid, glycol, and either an alcohol or an acid. The choice of plasticizer affects the end property performance of flexible PVC. Polymers other than PVC can also be plasticized to improve flexibility. Worldwide plasticizer production and consumption is illustrated as are the health, safety, and environmental aspects of plasticizers.
Polyamides, Plastics
Authors: Palmer Robert J. 
Published: October 2003

Abstract
Polyamides (nylons) are important engineering plastics as well as being well known for fiber applications. This article covers the properties, manufacture, processing, and use of polyamide plastics together with information on specifications, sales, pricing, and suppliers. Materials discussed include nylon‐6,6, nylon‐6, nylon‐6,9, nylon‐6,12, nylon‐11, nylon‐12, nylon‐4,6, amorphous nylon, and other semiaromatic nylons. Physical properties described are crystallinity, thermal properties, moisture absorption, electrical properties, and flammability. Chemical properties are hydrolysis/polycondensation, thermal degradation, oxidation, uv aging, and effect of chemicals and solvents. Manufacture is described including solid‐state polymerization, compounding, and pultrusion. Compounding also includes a review of additives and modifications covering lubricants, nucleants, stabilizers, impact modifiers, flame retardants, plasticizers, reinforcements, nanocomposites, and polymer blends. The following processing routes are detailed: injection molding, extrusion, film, tubing and pipe, monofilament, rods and profiles, wire and cable coating, blow molding, rotomolding, reaction injection molding, powder coating, and also assembly techniques. Uses and automotive, electrical/electronic, consumer, and industrial applications are described. A discussion of recycling is followed by a summary of economic aspects including suppliers, sales, and pricing. Specifications, standards, and quality control are also reviewed with an indication of appropriate test methods.
Polycyanoacrylates
Authors: Woods John 
Published: October 2003

Abstract
Cyanoacrylates are important materials in the production of rapidly curing structural adhesives. The monomers are generally low viscosity liquids, which are prepared in a two‐step process by a base‐catalyzed condensation of paraformaldehyde and cyanoacetate, followed by thermally induced depolymerization of the resultant oligomer under acidic conditions. The monomers are highly reactive toward basic materials and undergo extremely rapid anionic polymerization on contact with catalytic amounts of even weakly nucleophilic compounds or species. The polymers are amorphous materials that are readily depolymerized at elevated temperatures. They are generally soluble in polar aprotic solvents, although polymer solutions are unstable in the presence of basic materials. Adhesives are by far the most important end use for cyanoacrylates and they are widely used for component assembly and repair. The adhesive products are characterized by high rates of curing, high adhesive strength, and good adhesion to a wide range of different materials. They are becoming increasingly important materials as tissue adhesives and sealants for various surgical procedures.
Polyphosphazenes
Authors: Wycisk Ryszard , Pintauro Peter P. 
Published: October 2003

AbstractAn overview of polyphosphazene science is given. A brief history of over 100 years of synthetic developments is presented, from the work of Stokes to the latest cationic condensation polymerization, followed by discussions of blending, cross‐linking, and functionalization. Applications of polyphosphazenes as elastomers, solid polymer electrolytes, membranes, and flame retardants are reviewed. Biomedical research is referenced and hybrid polyphosphazenes and polymers containing cyclophosphazenes are also covered briefly.Although the limitless derivatization possibilities along with the attractiveness of the inorganic P–N backbone has generated enormous scientific interest in polyphosphazenes, current synthetic routes are characterized by high costs of the substrates, high instability of the intermediate polydichlorophosphazene, and sensitivity of the resultant polyphosphazene to the synthesis conditions. The need for costly process equipment must also be taken into account when assessing the cost of synthesizing polyphosphazenes on a commercial scale. Initial manufacturing efforts by Firestone, Ethyl Corporation, and Elf Atochem were terminated, but various polyphosphazene derivatives are available from custom synthesis companies. Therefore, polyphosphazenes should be considered still under the development stage.
Poly(trimethylene terephthalate)
Authors: Chuah Hoe H. 
Published: October 2003

Abstract

Poly(trimethylene terephthalate) (PTT) is a newly commercialized odd‐numbered aromatic polyester made by the melt polycondensation of 1,3‐propanediol and terephthalic acid. It has a melting point of 228°C and a glass‐transition temperature of 45°C. PTT crystallizes into triclinic unit cell with two chemical repeating units in the
c
‐axis. The three methylene units are arranged in
gauche–gauche
conformation. Crystal and amorphous densities are 1432 and 1295 kg/m
3
, respectively. PTT crystallization rate is in between those of poly(ethylene terephthalate) and poly(butylene terephthalate), with a crystallization half‐time of 2.4 min at 180°C. A rapidly quenched PTT shows cold crystallization at about 65°C, which could affect its drawing behavior if crystallization were to occur during hot drawing. Heat of fusion of 100% crystalline PTT is 30 ± 2 kJ/mol. Isotropic PTT has a flexural modulus of 2.76 GPa and a tensile strength of 67.6 MPa. The notched Izod impact is 48 J/m. Current commercial applications are in textile and carpet fibers. Applications in monofilament, nonwoven, film, and engineering thermoplastics are under development. PTT is processed at 250–270°C. Melt viscosity of a 0.92 dl/g intrinsic viscosity fiber grade PTT is about 240 Pa·s at 265°C. PTT fibers are soft and have very good hand. It also has excellent elastic recovery similar to nylon fiber and is stain‐resistant. The fibers are disperse‐dyed at atmospheric boil without using a carrier.
Polyurethanes
Authors: Ulrich Henri 
Published: October 2003

AbstractThe properties of thermoplastic and thermoset polyurethanes are discussed. The subjects include flexible and rigid polyurethane foams, poly(urethane isocyanurate) foams, thermoplastic polyurethane elastomers, thermoset cast and reaction injection molding elastomers, engineering thermoplastics, liquid crystalline polyurethanes, and polyurethane containing interpenetrating polymer networks. Principal raw materials, such as isocyanates, polyether polyols, and polyester polyols, as well as catalysts, fire retardants, and surfactants are described. The manufacture of flexible foam, rigid foam, coatings, adhesives, sealants, and elastomers are included, as is the use of polyurethane ionomers in aqueous dispersions and blocked isocyanates in one‐component and powder coating applications. The global trend in polyurethanes is a shift from toluene diisocyanate‐based formulations to polymeric isocyanate and 4,4′‐methylenebis(phenyl isocyanate) whenever possible, and substitution of chlorinated fluorocarbon blowing agents by hydrochlorofluorocarbons, hydrofluorocarbons, or hydrocarbons. Recycling of polyurethanes, health and safety factors, including toxicity and safe handling of isocyanates and tertiary amine catalysts, as well as principal uses of polyurethanes and market information are all discussed.
Release Agents
Authors: Owen Michael J. 
Published: October 2003

Abstract
Release agents are used in a wide variety of industries to control or eliminate the adhesion between surfaces. Key product requirements and trends are reviewed and a classification based on chemical type is presented. The mechanisms of release are reviewed, emphasizing the importance of minimizing both the strength of the interaction across the interface and the degree of contact. The dominant role of materials such as those based on aliphatic hydrocarbon and fluorocarbon entities or particulate solids is thus explained. Simple thermodynamic arguments are presented, stressing the need for release surfaces to have lower surface energies than the substrates they are designed to function with. Industrial applications are succinctly summarized, focusing on the specific needs of each particular application and the types of release agents currently used therein. The categories considered are metal, glass, rubber, plastics, textiles, adhesive transfer processes, furniture, and food. Economic aspects and health and safety factors are also briefly considered.
Rotational Molding
Authors: Dodge Phillip T. , Andrzejewski Steve , Mahan Duane 
Published: October 2003

Abstract
Rotational molding, also referred to as rotomolding, is one of the oldest plastics processing techniques. This article introduces the reader to the manufacturing process, including equipment, molds, and secondary operations required to produce parts. In‐depth resin requirements and comparison are also discussed.
Semicrystalline Polymers
Authors: Li Christopher Y. , Cheng Stephen Z. D. 
Published: October 2003

AbstractThe crystalline state in polymers is distinguished from that in other materials by the fact that polymer crystals are not in a single phase having 100% crystallinity, but are only partially crystallized; therefore, they are called semicrystalline polymers. In a bulk semicrystalline polymer, one can find both crystalline and amorphous regions, and the crystalline region may form different aggregates in shapes in different length scales. These length scales are identified as follows: crystal unit cells in a length scale of a few tenth to one nanometer; single lamellar crystals having at least one dimension size less than a few tens of nanometers; lamellar aggregates in a length scale of a few hundreds of nanometers. Crystallinity is a concept in the macroscopic scale. Each structural or morphological level influences the ability of a polymer to respond to its environment. As a result, macroscopic properties are critically associated with different structural and morphological levels, which complicates structure–property relationships. This article, focuses on the formation mechanisms of the crystalline structures and morphologies in these length scales and tries to explore their interrelationships and interdependencies in semicrystalline polymers.
Smart Materials
Authors: Benee L. S. , Snowden M. J. , Chowdhry B. Z. 
Published: October 2003

AbstractThe nature and properties of “smart” colloidal microgels are reviewed. Detailed descriptions including mechanistic information are reported with respect to the preparation of a number of physically different microgel structures including homopolymers, copolymers, polyelectrolyte, and core–shell type materials. The principal techniques used for the characterization of microgels are described, including dynamic light scattering and differential scanning calorimetery. Microgel properties are reviewed with respect to temperature sensitivity, pH sensitivity, colloid stability, rheological behavior, osmotic deswelling, and the influence of copolymers on microgels. Applications of these types of materials are also discussed and, include drug delivery devices, binding/adsorption agents, and catalytic compounds.