Advanced Materials

Cover image for Advanced Materials

March 1992

Volume 4, Issue 3

Pages fmi–fmi, 133–246

  1. Masthead

    1. Top of page
    2. Masthead
    3. Articles
    4. Research News
    5. Articles
    6. Book Reviews
    1. Masthead (page fmi)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040301

  2. Articles

    1. Top of page
    2. Masthead
    3. Articles
    4. Research News
    5. Articles
    6. Book Reviews
    1. Materials research strategy at hoechst (pages 133–135)

      Dr. Utz-Hellmuth Felcht

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040302

      A refocusing of materials research strategy has been necessary for many chemical companies engaged in the materials sector due to increased competition and the ever more international nature of the market. It is aimed at bringing the products of research nearer to the market, and in producing research efforts which are more dynamic, international and interdisciplinary. The historical development of the chemical industry's involvement in materials and anew tri-regional concept with which Hoechst will approach future challegnes is presented.

    2. Materials Research Concepts in the Chemical Industry (pages 138–142)

      Dr. Fritz Aldinger, Prof. Harald Cherdron, Prof. Klaus Kühlein and Dr. John Riggs

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040303

      Structural and functional polymers and ceramics are the main activities of the chemical industry in the materials area. The general concepts and considerations in the development of new materials are discussed from the point of view of research directors from the Hoechst group. In descrribing the various approaches to materials the opportunity is taken to intrroduce the following articles which deal with the individual topics in more detail.

    3. High-Performance Polymers (pages 143–152)

      Dr. Friedrich Herold and Dr. Arnold Schneller

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040304

      The various applications of high-performance polymers, for example in hollow-fiber membranes (see figure) or as gears in chemical pumps, require materials with widely differing properties. An overview of the different classes of high-performance polymers available, including polyetherketones, polysulfones, and polyamides, is provided and the various combinations of mechanical strength, thermal stability, chemical resistance, and electrical properties are discussed.

    4. Polymers for Nonlinear Optics (pages 153–158)

      Dr. Alan Buckley

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040305

      Active otpicla devices for application in communications data storage, and computing are based on nonlinear opticla materials. While a need for such devices has been identified, the properties of the materials available have greatly limited their use. Specially designed polymers would seem to offer the solution to this problem. A general introduction of the basic design conceppts and of the nonlinear phenomena themseelves is presented.

    5. The stability of Poled Nonlinear Optical Polymers (pages 159–168)

      Dr. Hong-Tai Man and Dr. Hyun N. Yoon

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040306

      The long-term thermal stability of poled polymers is of cruciial importance because the poled structure is inherently in a non-equiilibrium state and relaxation in the poled polymers results from thermal reorientation effects. A quantitative understanding of the relaxation behavior is therefore of great use in optimizing the design of new polymer systems. The major factors involved are explained, and various theoretical models are applied to some nonlinear optical polymers developed at Hoechst.

    6. Covalent High-Performance Ceramics (pages 169–178)

      Dr. Wolfgang D. G. Böcker, Dr. Rainer Hamminger, Dr. Jürgen Heinrich, Dr. Jürgen Huber and Dr. Andreas Roosen

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040307

      Non-oxide ceramics, for example aluminum nitride, silicon carbide, and silicon nitride, are ideal materials for applications under high thermal and mechanical stress. The synthetic methods including liquid-phase sintering processes, the microstructures of the resulting materials (figure shows Si3N4 from powder produced using the diimide route), and some aspects of the characteization and application of the materials are discussed.

    7. Heat-Reflecting Systems for automotive glazing (pages 179–188)

      Dr. Gerhard Grolig and Dr. Karl-Heinz Kochem

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040308

      Special layer systems which reflect infrared radiation but have high transmission in the visible part of the spectrum are being incorporated into automobile windows in order to improve passenger comfort through reducing the amount of solar radiation reaching (and heating) the interior of the vehicle. The materials used, the structure of the multilayer systems, and the techniques used to produce them are discussed and a look is taken at the possibillity for future markets and developments.

    8. Ferroelectric liquid crystals in high information content displays (pages 189–197)

      Dr. Claus Escher and Dr. Rainer Wingen

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040309

      Rugged, light, high-resolution flat panel displays are now being developed using liquid-crystal (LC) technology with the aim of replacing cathode ray tubes in for example computer monitors and televisions. The basic concepts of the displays are described, the advantages and drawbacks of the most important technologies are compared, and some recent work on ferroelectric LC displays which promise high contrast and brightness (see figure) is reviewed.

    9. Miscible Polymer Blends: Local interaction energy theories and simulations (pages 198–205)

      Dr. Solomon H. Jacobson, Dr. Douglas J. Gordon, Dr. Gregory V. Nelson and Prof. Anna Balazs

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040310

      The design of miscible polymer blends can be simplified by the use of models and calculations which predict the interaction energies for a range of possible components, including three-component blends. The theories and calculational methods are introduced and some recent work aimed at the optimization of the design of polyimides, benzimidazoles, and related high-performance polymers is described.

    10. Synthesis, processing sand properties of thermotropic liquid-crystal polymers (pages 206–214)

      Dr. Hyun N. Yoon, Dr. Larry F. Charbonneau and Dr. Gordon W. Calundann

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040311

      Polymer chains with stiff, extended conformations organize into nematic melts and are readily oriented by processing flow fields (see figure). The materials which result have a property profile uniquee to the liquid-crystal polymers and have a wide range of applications as cost-effective high-performance engineering resins and high-modulus fibers.

    11. Molecular relaxations in highly oriented polymer structures (pages 215–220)

      Dr. Dieter Eichenauer and Dr. Holger Jung

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040312

      The properties of high-modulus fibers based on aromatic monomer units linked by ester or amide groups depends on the relative monomer concentrations. The morphologies of various copolymers are examined and the relationship between the thermo-mechanical properties of the polymers and the dynamics of the individual polymer chains, as studied using dielectric spectroscopy, discussed.

  3. Research News

    1. Top of page
    2. Masthead
    3. Articles
    4. Research News
    5. Articles
    6. Book Reviews
    1. Particle size control during production of ceramic nitride powders (pages 221–224)

      Dr. Friedrich W. Dorn, Dr. Werner Krquse and Dr. Frank Schröder

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040313

      Modern high-performance ceramics, such as silicon nitride, silicon carbide, and aluminum nitride are manufactured from ceramic powders (see figure) which have to meet sstringent requirements regarding purity and grain size. Control of the grain size during the first steps of the chemical synthesis of the powders is importnat and has been achieved in the manufacture of silicon nitride via silicon diimide, and aluminum nitride via the carbothermal nitridation of aluminum hydroxide.

    2. Polymer-derived silicon nitride and silicon carbonitride fibers (pages 224–226)

      Dr. Tilo Vaahs, Martin Brück and Dr. Wolfgang D. G. Böcker

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040314

      The pyrolysis of organoelemental polymerss provides a powerful route to high-ppurity, high-performance ceramics. The various factors influencing the production of low-oxygen-content ceramic fibers from polymeric silazanes are examined and the possibility of controlling the composition of the fibers by varying the pyrolysis atmosphere resulting in stable, amorphous phases is described. The fibers have great potential in the reinforcement of metal and ceramic matrix composites.

    3. Cross-linking in water-absorbent polymers (pages 227–230)

      Dr. Fritz Engelhardt, Dr. Gerlinde Ebert and Dr. Rüdiger Funk

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040315

      Super-absorbant polymerss based on poly(acrylic acid) networks are formed by radical copolymerization of the monomer with small amounts of certain cross-linking agents. The structure of the polymer network has a major bearing on the performance of the product. It can be influenced during the polymerization by severla parametes, among which the functiionality and the reactivity of cross-linking agents are the most important. The various factorss involved are discussed.

    4. Microparticles from biodegradable polymers (pages 230–234)

      Dr. Michael Ahlers, Dr. Volker Krone and Dr. Axel Walch

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040316

      Intelligent routes of delivery for pharmaceutical productss are provided by the application of biodegradable polymers. Microparticles formed from the polymers can be used to protect sensitive or unstable protein or peptide-based drugs enabiling them to be delivered to the desired site in the body before being released. The microparticles can take on a number of shapes, an example of which is shown in the figure.

    5. High-density polyethylene pipe resins (pages 234–238)

      Dr. Ludwig L. Bohm, Dr. Hans F. Enderle and Dr. Manfred Fleifßner

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040317

      Efficient catalyst systems and an appropriate polymerization technology are required for the production of pipe resins which must exhibit both high stiffness and excellent service lifetimes (i.e. resistance to environmental stress cracking). The problem is that these requirements are contradictory but recently a polymer alloy has been developed with an elastic modulus over 1000 MPa and a failure time two orders of magnitude higher than that of standard materials.

    6. Hexafluoroacetone in resist chemistry (pages 239–242)

      Dr. Klaus J. Przybilla, Dr. Horst Röschert and Dr. Georg Pawlowski

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040318

      Photo-and radiation-sensitive materials are used are resists in the fabrication of memory and logic devices. The 64 MB DRAMs, scchedules for 1995, will requre feature sizes below 0.5 μm (see figure). Deep-UV lithography is a promising method of achieving these targets meaning that new resists with faovrable transmission and bleaching characteristics in this spectral region are required.

    7. Electrical contactswith low resistance for melt-processed high-Tc Superconductors (pages 242–244)

      Dr. Steffen Elschner and Dr. Joachim Bock

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040319

      Low electrical resistance and high thermal and mechanical stability are required of the materials used to connect ssuperconducting materials with normal conducting leads. The sputter deposition of silver or gold layers into melt-processed BSCCO superconducting material results in contacts in the mω range which is too high for high-current applications. An alternative method is presented which takes advantage of the BSCCO production method and requires no additional processing steps.

  4. Articles

    1. Top of page
    2. Masthead
    3. Articles
    4. Research News
    5. Articles
    6. Book Reviews
    1. Materials Forum (pages 244–245)

      Version of Record online: 15 SEP 2004 | DOI: 10.1002/adma.19920040320

  5. Book Reviews

    1. Top of page
    2. Masthead
    3. Articles
    4. Research News
    5. Articles
    6. Book Reviews