Study of nano-creep of unfilled and filled cross-linking polypropylene

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 nano-indentation creep of unfilled and glass fiber filled Polypropylene (25%). Nano-indentation creep were measured by the DSI (Depth Sensing Indentation) method on samples which were non-irradiated and irradiated by different doses of the β – radiation (0, 30, 45 and 60 kGy). The purpose of the article is to consider to what extent the irradiation process influences the resulting nano-indentation creep measured by the DSI method. The unfilled and filled Polypropylene tested showed significant changes of indentation creep. The measured results indicate, that electron beam irradiation is very effective tool for improvement of creep properties of unfilled and filled Polypropylene. The nano-indentation creep after irradiated unfilled Polypropylene was decreased up to 16 % (filled Polypropylene was decreased up to 9%) compared to non-irradiated surface. These changes were examined and confirmed by Gel content. © 2018 Trans Tech Publications, Switzerland