Polyethylene composites filled with n‐alkyl‐functionalized siloxane‐silsesquioxane resins and sol‐gel silicas

Abstract High‐density polyethylene (HDPE) composites filled with silicon‐based fillers were prepared by melt blending. The use of non‐functionalized and n‐octyl‐functionalized siloxane‐silsesquioxane resins and the sol‐gel silicas as fillers allowed us to evaluate the influence of functionalization of the fillers on the properties of the composites. The melting and crystallization temperatures of the composites were found to be only slightly affected by the addition of the silicon‐based fillers. In turn, the crystallization degree values were increased, in particular for the materials containing non‐functionalized fillers. The free‐volume properties of the composites did not change significantly in comparison with the neat polyethylene. The composites filled with the n‐octyl‐functionalized fillers were characterized by high thermal stability (in air) due to improved polymer/filler compatibility and consequently due to more uniform dispersion of the silicon‐based compounds in the polymer matrix. Better mechanical properties were obtained for the composites with functionalized fillers as compared to the materials with non‐functionalized ones.