Comparison of different waxes as processing agents for low-density polyethylene

Abstract

The influence of three different waxes on the thermal and mechanical properties of low-density polyethylene (LDPE) was investigated. The samples were prepared through melt blending in a Brabender mixer. The thermal properties of the samples were determined using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The tensile and flow properties of all the samples were determined and compared. The observations are discussed in terms of possible morphological changes when wax is mixed with LDPE. The polymer-wax miscibilities differed with the type of wax used and with the amount of wax mixed into the polymer. These miscibilities, and accompanying morphologies, had a strong influence on the flow properties, thermal stabilities and tensile properties of the corresponding blends. Based on our observations, H1 wax may be regarded as the best processing agent for LDPE. Both EnHance and H1 wax had a similar influence on the tensile properties of LDPE, but H1 wax increased the melt flow rate more than EnHance, which was specifically designed as a polyethylene processing agent. The blends seemed to be thermally more stable in the presence of EnHance than with H1 wax. Although M3 wax improved the melt flow rate in a similar way to H1 wax, it had a strong negative impact on the tensile properties of LDPE.