AUTHORS: Michal Stanek, Martin Ovsik, David Manas, Martin Reznicek
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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 behavior. This paper describes the effect of electron beam irradiation on the surface properties (nano-indentation test) of glass fiber filled polypropylene (30%). These nano-mechanical properties were measured by the DSI (Depth Sensing Indentation) method on samples which were non-irradiated and irradiated by low (33, 66 and 99 kGy) and high (132 and 165 kGy) doses of the β – radiation. Nano-indentation test was performed at (400mN) indentation loads. The purpose of the article is to consider to what extent the irradiation process influences the resulting nano-mechanical properties measured by the DSI method. The polypropylene tested showed significant changes of indentation hardness and modulus. The best results were achieved by irradiation at doses of 99 and 132 kGy (increase about 68%) by which the highest nano-mechanical properties of filled polypropylene were achieved. These changes were examined and confirmed by X-ray diffraction and Gel content.
KEYWORDS: polypropylene, glass fiber, morphology, irradiation, nano-hardness, nano-indentation
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