Hoechst Aktiengesellschaft

Manfred Fleissner

Peter Herbrechtsmeier

Joachim Berthold

Gerhard Wieners

Werner Groh

Ludwig Bohm

Rudolf Heumuller

Hartmut Luker

Rainer Lecht

Ulrich Schulte

Werner Breuers

Heiner Bromstrup

Johannes Friedrich Enderle

The invention relates to a high strength pipe of ethylene polymer having a bimodal molecular weight distribution. Such pipe has a stress cracking resistance of .gtoreq.1400 h, a fracture toughness of .gtoreq.7 mJ/mm.sup.2 and a modulus of creep in flexure, measured according to DIN 54852-Z4, of .gtoreq.1100 N/mm.sup.2. The pipe according to the invention is produced from an ethylene polymer in which the ratio of weight of the low molecular weight fraction to the weight of the higher molecular weight fraction is in the range from 0.5 to 2.0 and which has a melt flow index MFI.sub.5/190.degree. C. of .ltoreq.0.35 g/10 min. It is particularly suitable for the transportation of gases and water.

Pipe of polyethylene having improved mechanical properties

Optical waveguides of plastic usually consist of a core and a jacket, the core material having a higher refractive index than the jacket material. A suitable core material is a fluorine-free polymer and a suitable jacket material is a fluorine-containing polymer, which can also contain deuterium. The optical waveguides can be produced by passing a polymer rod through a solution of the jacket polymer and then removing the solvent. The optical waveguides are particularly suitable for the transmission of data with the aid of light waves with a wavelength of 500 to 750 nm.

Optical waveguide with an essentially fluorine-free polymer core and a

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Eschborn, Germany

Manfred Fleissner