ELECTRON RADIATION EFFECT ON INDENTATION CREEP OF CONSTRUCTION POLYMERS

Abstract

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. Creep value is an important parameter that describes the behaviour of a material for the duration of its exposure to long term stress. Most of the technical parts used in industry are subjected to the long term stress for their whole life cycle. This can lead to material creep, which directly results in the transformation of dimensions. To eliminate this problem, a number of construction materials was chosen and subsequently irradiated by a source of electrons. This created a 3D network within the polymer structure, which led to an increase of the micro-mechanical and micro-creep properties. Evaluation of these modifications was done by state of the art device Micro-combi tester manufactured by Anton Paar. This device lowers the time required to measure the creep by standard technology and it fluently records the changes of indentation depth in relation to applied force. This dependence is then used to calculate the creep values. Due to the electron irradiation, a 40 % increase was reached in creep resistance; therefore the useful properties of selected construction materials were improved.