MELT BLENDING OF ULTRA-HIGH-MOLECULAR-WEIGHT AND HIGH-DENSITY POLYETHYLENE - THE EFFECT OF MIXING RATE ON THERMAL, MECHANICAL, AND MORPHOLOGICAL PROPERTIES

The blends of two different ultra high molecular weight polyethylenes (UHMWPE) and high density polyethylene (HDPE) were prepared in melt at different compositions and mixing rates in Brabender Torque Rheometer. The temperature build-up due to the internal friction during melt blending was recorded and evaluated with respect to the change in the torque. The temperature at maximum torque was considered the fusion point temperature of the UHMWPE in the blend. This fusion point temperature was found to depend on the composition, mixing rate, and molecular weight. The effect of mixing rate on the mechanical properties (measured as yield and tensile strengths and elongation at break), thermal oxidative degradation and melting behavior were studied. The morphology of the blends were investigated by optical microscopy.