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Dorschner, H.

Paper Title Page

THLO03

 Requirements on Electron Guns for Innovative Applications in Polymer Industry 

  • R.Bartel, U.Gohs, O.Röder
    Fraunhofer Institute of Electron Beam and Plasma Technology, Dresden, Germany
  • H.Dorschner, M.Stephan
    Leibniz Institute of Polymer Research, Dresden, Germany

Electron beam technology is well-established in many industrial branches and in manufacturing techniques. These applications use local and temporal precise input of energy into surfaces, random layers or volumes in order to exactly heat materials or to generate excited atoms or molecules and ions for subsequent molecule changes. The effect of molecule change is used for cross-linking and degradation of polymers. In comparison to alternative chemical processes the polymer structure can be change without any use of additional additives. Thus ecologically harmful agents are not required. It is well known that properties of plastics form parts can be modified by electron treatment of plastic pellets before the polymer forming process. Thus the latest electron beam technology in surface treatment of bulk goods has been tested for this application. The mobile “e-ventus” plant (Fig.1) enables a specific modification of processing qualities of plastic pellets and final properties of plastic products. The new plant generation REAMODE is designed for modification of polymers with electrons in reactive gas atmosphere. It has been tested for modification of recycled rubber meal and polypropylene. These modified raw materials were used for the production of thermoplastic elastomers. Finally, a 1.5 MeV electron accelerator was directly coupled with a typical single screw plastics processing extruder for a continuously modification of thermoplastic strands in molten/liquid state at high plastics temperatures (MOBRAD1/T, Fig.2). These tested applications of polymer modification with electrons as well as the requirements on electron beam technology will be presented in detail. Key words: electron beam technology, polymer modification, recycling Fig. 1: Mobile plant for modification of plastic pellets Fig. 2: Mobile Radiation Facility MOBRAD1/T

 

 

MOLP05

 Electron Accelerator ELV-2 In Polymer Resarch- Direct Coupling Of Polymer Extrusion For Modification In Molten State  

  • H.Dorschner, M.Stephan, U.Wagenknecht, G.Heinrich
    Leibniz- Institute of Polymer Research Dresden, Dresden, Germany

In 1972, an universal irradiation plant was built for research and service at the Leibnitz-Institute of Polymer Research Dresden. The accelerator - an industrial machine of the series ELV - of Budker Institute of Nuclear Physics, Novosibirsk, Russia (BINP), operates in the energy range from 0.6 MeV to 1.5 MeV, the beam power maximum is 20 kW, and the beam current maximum is 25 mA. The treatment by electron irradiation is a special possibility to modify polymers. Several applications in plastics industry are well known, such as radiation induced degradation, crosslinking, grafting, curing, and polymerization. Very interesting chemical reactions are to be accepted by irradiation in molten state. High temperature, intensive macromolecular mobility and the absence of any crystallinity are some reasons for achieving unexpected structures, processing behaviour and property changes in treated thermoplastics and rubbers. For examples crosslinking of polyethylene is much more effective, and long chain branching of polypropylene can be generated. These modification effects are also achievable by a direct coupling of electron beam irradiation and conventional polymer extrusion processing. For this unique processing technique a special MOBILE RADIATION FACILITY (MOBRAD1/T) was designed, constructed and manufactured in the IPF Dresden at which a lab-scale single screw extruder was adapted directly to the accelerator to realize a prompt irradiation of extruded polymer melt profiles before their solidification.