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Über dieses Buch

The Eleventh Biennial Polymer Symposium of the Division of Polymer Chemistry, Incorporated of the American Chemical Society was held November 20-24, 1982 at -the Cerromar Beach Hotel, Dorado Beach, Puerto Rico. The theme of the meeting was "High Performance Polymers. " On this occasion Professor Herman F. Mark received the Fourth Division of Polymer Chemistry Award for his outstanding achievements and his unique missionary role in the development of Polymer Chemistry. Professor Mark was the premier organizer of many important firsts in polymer chemistry, to name just a few - the first polymer journal, the pre-eminent Journal of Polymer Science; the first U. S. academic center of Polymer Science at the Brooklyn Polytechnic Institute which led to a long procession of eminent polymer scientists; the "High Polymer" Monograph series. In the Division of Polymer Chemistry, he was the first secretary-treasurer and chairman in 1955 •• A detailed biography follows along with Professor Mark's reminiscences on the Early Days of Polymer Science, the topic of his Award lecture. It was indeed a pleasure and ultimate honor to be the Chairman and organizer of the technical program of this Symposium. The fourteen invited lectures are given herein. I have tried and believe succeeded in presenting important current research by leading workers on High Performance Polymers.

Inhaltsverzeichnis

Frontmatter

Division of Polymer Chemistry Award to Herman F. Mark

Without Abstract
Eli M. Pearce

The Early Days of Polymer Science

Synopsis
A short review is given of the events which occurred between 1926 and 1947 and led ultimately to a consolidation of Staudinger’s view concerning the existence of macromolecules as he had postu­lated them.
Three conferences may be taken as characteristic for the early development of polymer science: The meeting of the Deutsche Naturforschergesellschaft in Duesseldorf in 1926 where Staudinger successfully upheld his concept of the existence of macromolecules against powerful opposition, the Faraday Society Meeting in Cambridge in 1935 where Carothers presented his classification of addition and condensation polymers, and the First Polymer Conference of the International Union of Pure and Applied Chemistry in Liege in 1947 where polymer science established itself as an accepted and vigorous member of chemical disciplines.
Herman F. Mark

Carbohydrate Polymers:Nature’s High Performance Materials

Synopsis
The term carbohydrate polymers describes the ubiquity in nature of molecular systems containing carbohydrates. The property of conformational restriction in polysaccharides make them candidates for being the initial self-ordering molecules of prebiotic evolution. This same property in the complex carbohydrate moiety of glycoproteins is the basis of carbohydrate-mediated information transfer through cell surface oligosaccharides interacting with each other or with lectin-like proteins in cell-cell recognition processes.
Exopolysacoharides in their capacity to induce synthesis of antibodies (i.e., as immunogens) or their reactivity with antibodies (i.e., as antigens) have been on the ground floor of the development of molecular biology. The oligosaccharide repeating unit is the chemical expression of immunological character and their availability for attachment to synthetic carriers is a first step toward manmade vaccines. The exopolysaccharide gums display ordering characteristics in solution which are not matched by the plant polysaccharides or synthetic polyelectrolytes.
Finally, the term carbohydrate polymers can be stretched to include natural polyalkanoates based on hydroxyl acids of carbohydrate origin. The chemistry and properties of poly-β-hydroxybutyrate (PHB) make it a biomass transducer. A material which is intermediate microbial systems. Its potential as a natural thermoplastic, a biomedical implant and a source of chemicals from biomass is described.
R. H. Marchessault

Gene Synthesis — Toward a Future World

Synopsis
Several recent advances in molecular biology have led to dramatic progress in genetic engineering. Among these are the development of useful plasmid vectors, the characterization and usage of restriction endonucleases, and the elucidation of methods for sequencing and synthesizing DNA. A discussion of these developments and the use of these methods for synthesizing, cloning and expressing an immune interferon gene will be presented.
Marvin H. Caruthers

Polymeric Monolayers and Liposomes as Models for Biomembranes and Cells

Synopsis
Conventional model membrane systems based on natural lipids usually lack long term stability. Polymer chemistry can help to overcome this disadvantage introducing poly­merizable lipids into these systems. Polymerizable lipids used are diacetylenes, butadienes, acrylates or lipids which can undergo polycondensation.
The polymerization behaviour of these membrane systems can be characterized in monolayers and liposomes using surface pressure-area diagrams or DSC investigations respectively. Decreased membrane permeability and improved stability towards the addition of detergents of polymerized vesicles can be verified by leakage measurements of entrapped 6-carboxyfluorescein.
To introduce biological specifities into these stabilized systems polymerizable glycolipids are synthesized to provide surface recognition properties. Both monomeric and polymeric vesicles made of these lipids are agglutinated by lectins.
Further biological modifications are possible by adding natural lipids or membrane proteins (such as ATPase) to polymerizable membranes. Membrane protein activity can be retained after polymerization. The natural, non­polymerizable lipid component can be selectively degraded (for instance by phospholipase A2) to open up the previously stable compartment. The polymerization behaviour of diacetylene and butadiene lipids strongly depends on the miscibility with the natural component. Means to characterize these mixed systems are again DSC and electron microscopy, the latter evaluating patch formation using the ripple structure of phospholipids.
Besides this “synthetic” route, the combination of natural and poymerizable membrane components is principally possible via the fusion of cell membranes with polymerizable vesicles. Fusion of cells is possible using dielectrophoresis and dielectric breakdown. Since it was possible to prepare “giant” vesicles (visible under the light microscope) these techniques were also successfully applied to vesicle-vesicle fusion. Investigations on cell-vesicle fusion are currently under way.
K. Dorn, H. Ringsdorf

Polymer Carbon the Start into a New Age of Polymer Application

Synposis
Polymer carbon comprises a group of materials consisting only of elemental carbon, but differing in mechanical properties from those of graphite by high strength, resistivity against shear stress and extraordinary stiffness. These properties can be explained by the high bonding strength between sp2-hybridized carbon atoms and the special microstructure with parallel arrangement of polyaromatic sheets, however, without any crystallographic order in direction perpendicular to the sheets. The relation to the MARCK-BERNAL structure of graphite (1924) and that of amorphous carbon, as described by DEBYE - SCHERRER in 1917 and as defined today is discussed.
E. Fitzer

Recent Developments in the Science and Technology of Ultra-High Modulus Polyolefines

Abstract
A comprehensive survey is presented of the development of tensile drawing, hydrostatic extrusion and die drawing processes for the manufacture of ultra high modulus polyethylene and polypropylene in the form of fibres, films and extruded shapes. The properties of the highly drawn products are described, including mechanical stiffness, creep, strength, melting behaviour, shrinkage, thermal expansion, thermal conductivity, barrier properties and chemical resistance. Finally, there is an account of recent research into possible applications of these materials with particular attention to the reinforcement of brittle matrices, including polymer resins, cement and concrete.
Ian M. Ward

Liquid Crystal Polymers: VI. Liquid Crystalline Polyesters of Substituted Hydroquinones

Synopsis
The use of monosubstituted hydroquinones enables the preparation of liquid crystalline polyesters with lower melting points than can be obtained with hydroquinone. When the substituent is chloro, methyl, tert-butyl, or 1,1-dimethylhexyl, the polyterephthalate homopolyesters still melt at too high a temperature to be injection-molded or melt spun without thermal degradation, but additional modification with a flexible aliphatic component, a kinked rigid group, or 2,6-naphthalenedicarboxylic acid reduces the melting point further and enables the preparation of melt processable liquid crystalline polyesters. The stability of substituted hydroquinone polyesters in air at 150ºC decreases with various substituents in the order of phenyl, tert-butyl, chloro, methyl. At 300ºC in air, the hydroquinone polyesters containing phenyl or tert-butyl substituents are the most stable. The effects of composition on liquid crystallinity and on the properties of injection-molded plastics and melt spun fibers also are discussed.
W. Jerome Jackson

New Developments in High Temperature and High Strength Polyquinolines

Synopsis
The relationships between the structures and the morphology, solution properties and mechanical properties of polyquinolines depend upon the manner in which the quinoline units are linked together.A wide variety of structures account for polyquinolines that either are amorphous, soluble in common organic solvents and have moderately high glass transition temperatures (~250°C) or are crystalline, are soluble only in acidic solvents, forming anisotropic solutions, and have high crystalline transition temperatures (>500°C). The conducting properties of certain doped polyquinolines containing either total conjugation or sulfur linkages between quinoline units are described. Polyquinolines containing biphenylene units either in the main chain or at the chain ends undergo crosslinking and chain extension reactions. The use of biphenylene end-capped oligomeric polyquinolines as matrix resins in graphite composites is discussed.
J. K. Stille

Advances in Inorganic Fiber Developments

Synopsis
Inorganic fiber based materials offer potential for the develpoment of next generation advanced materials beyond fiber reinforced plastics. Inorganic fiber needs and technology are briefly reviewed. The difference in structure and properties of alumina and alumina/silica fibers are discussed. The addition of silica to alumina increases the tensile strength but significantly lowers the modulus of the 100% alumina fibers. Next generation advanced aluminum alloys based on reactive Al-Li compositions are shown to be compatible with dense microstructure and relatively stable 100% alumina fibers to yield wellbonded alumina fiber reinforced aluminum matrix composites having predicted mechanical properties. Examples of potential applications for inorganic fibers materials in aerospace and automotive are shown. An important milestone in inorganic fibers technology was recently reached with the introduction of the world’s first inorganic fiber reinforcedmetal matrix composite as a piston insert for an automotive diesel engine.
Ashok K. Dhingra

Synthesis and Properties of Polyetherimide Polymers

Synopsis
Polyetherimides are a new class of high performance polymers whose chemical compositions can be tailored to provide materials having glass transition temperatures ranging from ~150°C to ~300°C. Their outstanding thermo-oxidative stability and flame and solvent resistance are characteristic of aromatic polyimides but, unlike many other polyimides, they can also be processed by conventional techniques (e.g., injection molding). The key reactions in their various syntheses were nucleophilic aromatic nitrodisplacements by aryloxide ions. This and other chemical steps are discussed in detail along with a description of some of the physical properties of the polymers.
H. M. Relles

Reflections on the Design, the Structure and the Properties of Highly Conducting Polymers as Related to other Organic Metals

Synopsis
Structural requirements for the design and synthesis of an organic metal are discussed using the cation-radical salts of arenas, naphthalene being an example. These cation radical salts serve as models for conducting polymers. The chemistry of the “doping” of polymers to the conductive state is discussed in terms of redox reactions and redox equilibria. The structure of oxidized poly(acetylene) is discussed based on available X-ray data and in analogy to the cation radical salts of arenas. A chain-chain-interaction is postulated to play an important role in the conductivity mechanisms.-The oxidation (“doping”) is linked to a phase transition by which regions of high conductivity in a less conductive matrix are formed. Model compounds for poly(acetylene) and oxidized poly (acetylene) are discussed with regard to the explanation of the spectral features observed in the conducting polymer.
G. Wegner

Polymers as Electronic Materials — Today’s Possibilities and Tomorrow’s Dreams

Synopsis
Semiconducting and metallic organic polymers can be obtained by the addition of either electron donors or electron acceptors to insulating organic polymers. A status report is made for such presently available highly­conducting polymers, emphasizing both properties aspects which might find applications and problem areas. From this starting point, predictions are made of properties which might ultimately be obtainable - in part, by eliminating the gross structural and chemical irregularities of today’s materials. The properties include conductivities comparable with copper, ultimate strengths and modulii higher than for strong steels, and the possibility of superconductivity. Finally, the applications horizon is critically examined, both by comparison with competing materials for today’s technologies and by examining the materials needed for future technologies.
R. H. Baughman

High Temperature Polymers For Electronic Devices

Synopsis
In this paper, the potential advantages of polymers as dielectric insulating layers in advanced microelectronic devices are described along with the requirements for their use in chips. Some of the key results obtained from a detailed study of polyimides carried out within IBM are summarized along with efforts aimed at optimizing the polyamic acid precursor to achieve improved processibility. Finally, some preliminary results of work on a new type of high temperature polymer are described that appears to satisfy many of the shortcomings of existing systems.
J. Economy

Aromatic Ionomer Membranes: Synthesis, Structure and Properties

Synopsis
The syntheses of three new aromatic ionomers with equivalent weights of ca. 800, 600 and 400 have been carried out. Thus, 3,3’-(oxydi-p-phenylene)bis[2,4,5-triphenylcyclopentadienone] and 3,31-(oxydi-p-phenylene)bis[2,5-diethoxycarbonyl-4-phenylcyclopentadienone] were copolymerized with 4,4’-diethynyldiphenyl ether in molar ratios of 70:30:100, 60:40:100 and 40:60:100 to afford the corresponding alkoxycarbonyl-substituted polyphenylene oxides, which were converted to the ionomers by treatment with potassium hydroxide.
The materials were studied in the form of thin films. Physical and mechanical properties were determined by DSC, torsion pendulum, stress strain, stress relaxation and water contact angle measurements. Transport properties were determined in alkaline solution. Evidence of the films’ microporosity is seen from ion and water sorption, sodium ion self-diffusion and electrolytic conductance measurements. The latter results for lower equivalent weight samples in concentrated NaOH solutions demonstrate that these materials are promising candidates as separators in advanced alkaline water electrolysis cells.
A. Eisenberg, E. Besso, F. W. Harris, R. K. Gupta, H. L. Yeager, A. Steck

Some Recent Aspects of Polymer Flammability

Synopsis
There are various stages in the pyrolytic degradation and combustion of volatile products leading to the flammability behavior of polymers. Mechanisms to decrease flammability involve modifying condensed phase or volatile phase reactions. The reported studies relate our recent progress in the understanding and controll of these mechanisms.
Some general known relationship between flammability and polymer structure are reviewed. Our studies on relating polymer end groups and molecular weights to flammability indicated that the known thermal degradation mechanisms for nylon 6 and polyethylene terephthalate (PET) are, in part, related to their flammability behavior.
The question of the flammability behavior of similar flame retarding structures when used as additives or as comonomers in PET is discussed. For the case of structures related to tetrabromo-bisphenol-A, there was little difference, but for those containing triphenylphosphine oxide related structures a switch from volatile phase to condensed phase mechanisms was possible.
Efforts in regard to understanding char formation mechanisms and improvements in the amount of char have been studied for systems such as polystyrene, cardopolymers, phenol-formaldehyde resins, aromatic polyamides and styrylpyridine based polymers. Increased char formation occurred when thermally stable thermally induced crosslinking structures occurred and/or thermally stable aromatic rings wre produced.
Crosslinking could be induced in polystyrene structures containing vinylbenzyl chloride as a comonomer which enhanced char formation. For the cardopolumers, the phenolphthalein based polymers were shown to have increased char formation because of the rearrangement of the lactide group to a thermally stable ester crosslink. Although other cardopolymers showed improvements in flammability, the mechanisms were not explored. Vapor phase and condensed phase mechanisms were applicable for subtituted phenolic resins but mechanisms for the latter were not elucidated.
Specific halogen substituted aromatic polyamides have given substantial increases in char formation due to the formation, in part, of thermally stable benzoxazole units. Another system in which ring formation accounts for increased char formation were those which contained styrylpyridine units. In this case a Diels Alder addition reaction could account for these results.
Eli M. Pearce

Backmatter

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