Modification of geometrical macrostructure of polyethylene pipes and tubes
Tomasz Klepka
Department of Polymer Processing, Technical University of Lublin
Poland

Keywords: extrusion, pipes and tubes, polyethylene

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Receiving required, strictly defined properties of constructional elements produced in extrusion process is possible by appropriate selection of polymer plastics, course of physical and chemical row effects as well as external inputs and conditions connected with course of process.
By conscious modification of outer-surface layer of extrusion product as pipes or tubes, characteristic appropriate geometrical macrostructure of the layer were received. Macrostructure in form of repeated macroheights and macrohollows, directly determined the range and possibilities of further use of these products in many technical systems, like especially as the installation pipes or tubes for optotelecommunication cables, wires, ect.
Elements of geometrical macrostructure - macrodeviations were made on the inner surface of the product in technological process on extrusion line, using several appropriate forming cores. This cores had dimension and shapes elaborated considering of the rheological properties of processed polymer to receive finally defined macroheights.
As a result of the experimental research conclusion which enable evaluation of possibilities and restriction of modification of geometrical macrostructure were presented . Possibilities of receiving more advantageous tribological properties (mainly sliding coefficient of friction) or mechanical strength of pipes and tubes were elaborated.