| In this research, the effects of electron beam radiation cross-linking on the mechanical properties of a foamed extrudate were investigated. This research is part of an on-going project at the University of Massachusetts Lowell where the goal is to develop a high strength foamed jacketing material for an underwater communications cable application. Metallocene linear low-density polyethylene is being studied for its use as a base material for a syntactic foam cable jacketing material. Expandable syntactic microballoons, Expancel RTM, were employed as the foaming agent where 8 and 10% concentrations by mass were investigated. Samples were irradiated at doses of zero (0) to 200 kGy. Mechanical properties, including tensile, compression set under constant deflection, hardness, as well as overall foam cell quality and surface quality, were evaluated.; The overall project goal for density was 0.35 g/cc. This was achieved while maintaining excellent closed cell foam quality and excellent skin quality. Hardness was not significantly affected by the radiation doses, however, Expancel RTM concentration did have a slight effect whereas a lower hardness was observed for the higher concentration at 10%. The modulus appeared to be unaffected by the treatment, while there was a significant reduction in percent strain at break and only a slight increase in stress at break indicating that cross-linking had taken place to some degree. Results for percent strain at yield and stress at yield both showed increasing trends. Compression set properties appeared to be only slightly affected by the irradiation treatment for both formulations. |
