Kunststoffe in der Gelenkendoprothetik

Use of Plastic Materials for Joint Endoprotheses The use of plastic materials for joint endoprothetic components such as hip joint sockets, tibia plateaus and femur shafts as well as for the fixation of these components in human bones has meanwhile become common practice, and though the technological standard in this field is undoubtedly very high, it must be admitted that the extremely high biological-medical, constructional and material lrequirements still leave a lot of wishes unfulfilled. Based on the human joint and some characteristics of the human bone the current state of the use of plastic materials for joint endoprotheses is described and evaluated. Besides this, proposals are made for the further improvement of ultra high molecular eight polyethylene (UHMWPE) and bone cements based on polymethylmethacrylate (PMMA) with regard to both the materials themselves and their treatment. Current developments in fields like bioactive and porous coatings and the reinforcement of basic materials are briefly explained. In the author's opinion there are a number of measures by means of which it should be possible to gradually improve the UHMWPE. The developments that have so far been made in the field of carbon fibre reinforced plastics (CFP) and their application for endoprotheses are very encouraging and promising for the future. In spite of most intensive developmental work aimed at improving bone cements, a real break-through to new systems has not yet been made. With optimum surgical methods and technologies the reliability of the fixation is, however, nevertheless very high. This is true likewise for the cement-free fixation of endoprotheses. In this field it seems that the use of porous coatings and surgical technologies are coordinated in an optimum manner.     

Chemische und physikalische Grundlagen der Kunststoffe

Basic Chemistry and Physics of Macromolecular Materials Plastics are high polymers, and their molecular configuration differs from that of many classical materials. The molecular character governs their appearance and properties. They are produced by polymerisation, polycondensation and polyaddition processes. Plastics that are important for the construction of chemical engineering equipment are produced by polymerisation. Developments in plastics have by no means been completed. Although new classes of products can no longer be expected, the trends will be towards composites, materials systems and optimation of chemical and physical properties.     

Neue Kunststoffe für den Einsatz in der Technik

New engineering plastics. Plastics are increasingly materials for all fields of industrial, commercial and personal life. This results in numerous specific requirements with respect to their properties which cannot be fulfilled by conventional plastics. The way to improved materials is characterized by several features:

• — development of new polymers,
• — improvement of raw material production and technology,
• — copolymerization,
• — usage of all possibilities as given by multiphase systems.

     

Rheologisches Verhalten hochgefüllter Kunststoffe. Einfluss der Füllstoffe

Rheological behavior of high filled polymers. Influence of fillers The viscose properties of high filled thermoplastic composites were studied. It was shown that the rheological properties of high filled plastics depend generally on behavior of the flow of a matrix polymer, the structure of the disperse phase, the interaction between the polymer and the filler and between separate particles. In the work a theoretical relation between filled and unfilled polymer as a function of the filler content and interactions between components was presented. On the basis of the developed model a stochastic structure of filled material and non‐linear viscose properties of the polymer melt can be considered.     

Eigenschaften warmbildsamer Kunststoffe

Ohne Zusammenfassung VDI     

Gesetzmäßigkeiten im Verhalten duroplastischer Kunststoffe auf der Basis von Phenolharz

Procedure of behavior of phenolic moulded material. Investigations of composites (multiphase systems) from resin/wood flour/stone powder show that the properties of these phenolic plastics are connected with composition of material and technical climate. The knowledge of these connections allows an economic selection of parts produced by moulded material for various requirements.     

Dynamisch-mechanische Analyse naturfaserverstärkter Kunststoffe

Dynamic-mechanical analysis of natural fiber reinforced plastics Recently natural fibers are increasingly used as reinforcement in plastics. These materials are distinguished by their high tensile strength and stiffness as well as their low density at the same time. For technical applications the material behaviour in addiction of temperature is very interesting. Useing the example of flax fiber reinforced polypropylen it is shown, that the dynamic-mechanical analysis can be a meaningful test to describe the behaviour of natural fiber composites by different temperatures.     

Verpackungsplanung im Spannungsfeld zwischen ökologischen und ökonomischen Anforderungen an die Verpackung

Zusammenfassung Dieser Beitrag stellt die vielfältigen ökologischen und ökonomischen Anforderungen an eine Verpackung heraus. Er zeigt dann Möglichkeiten auf, wie im Rahmen eines interaktiven PC-gestützten Planungsprozesses, ausgehend von den an die Verpackungsgestaltung herangetragenen Anforderungen, attraktive Gestaltungsalternativen für Verpackungen generiert und hinsichtlich der Paletten- und Regalnutzung bewertet werden können.     

Versagenskriterien für Kunststoffe. Teil II: Experimentelle Ergebnisse

Failure Criteria for Polymers, Part II: Experimental Results . Using the fracture criteria, which have been analytically derived in the first part of this paper, experimental results from literature and from own experiments are compared with calculated fracture loci for thermoplastic materials, thermosets, and glassfibre-reinforced plastics. It can be shown that the change of dimension of a plastic specimen under load is simulating a higher compressive strength in comparison to the tensile strength (m > 1). Different methods are indicated for evaluating biaxial loading tests. A comparison between the results theoretically and experimentally found marks the parabolic fracture criterion to be suitable. Resins reinforced with chopped strand mats satisfy the maximum stress theory. The fracture behavior of orthotropic materials is accurately described by the fracture criterion of Tsai and Wu and Goldenblat and Kopnov. If normal stresses act parallel to the axis of orthotropy, the fracture behavior of orthogonal isotropic materials can be calculated acc. to the maximum stress theory.     

Beschichten transparenter Kunststoffe mit Kratzschutz und AR in einer kombinierten InLine‐Anlage

For the last decades, both the ophthalmic and the precision optics industries have been relying on vacuum evaporation on the production floor. This particular thin film process is not very suitable for mass production. A major problem in mass production of high quality consumer products is the lack of automatic operation in single chamber evaporation coaters. This article describes a new coating process for lenses which uses both PECVD and sputtering technologies. A new InLine machine equipped with these technologies is presented. This machine meets all requirements with respect to process stability and automation for the respective industry. With its modular design concept, this coating machine can be totally integrated into an InLine factory floor. It can also easily be scaled up or down for a wide range of applications. Given the excellent quality that has been achieved for hardcoat and antireflective coating of plastic eyeglass lenses, similar results can be expected in other thin film applications for a wide range of temperature sensitive substrates in precision optics.