Effect of maleic anhydride grafting and the presence of oxidized wax on the thermal and mechanical behaviour of LDPE/silica nanocomposites

This paper reports on the introduction of sol–gel prepared nano-silica into low-density polyethylene (LDPE) and maleic anhydride grafted LDPE (LDPE-g-MA), as well as on the blending of these nanocomposites with different amounts of oxidized paraffin wax as a possible compatibiliser. LDPE/wax and LDPE-g-MA/oxidized wax blends were also investigated in comparison. The FTIR results indicated interactions between LDPE-g-MA, oxidized wax and nano-silica, and these interactions influenced the thermal and mechanical properties of the samples in a complex way. There are strong indications of a stronger interaction between the nano-silica and the oxidized wax, which caused the wax to preferably crystallize around the nano-silica. The melting and crystallization behaviour, thermal stabilities, tensile properties and rheological behaviour, described in this paper, could be explained in terms of these observations.