In the present work, high temperature tensile properties of medium density polyethylene (MDPE) and its nanocomposites are investigated. For this purpose MDPE reinforced with different weight percentages of nano-sized calcium (2, 5, 10) are produced by compression moulding method. Tensile tests have been carried out at different temperatures, i.e. 30, 60, 90C using thermomechanical analysis (TMA) apparatus. Besides, the fracture surface of MDPE and MDPE/CaCO3 nanocomposites are also investigated using scanning electron microscopy (SEM). The TMAresults indicate that the elastic modulus and yield stress have increased by addition of nanosized calcium carbonate as reinforcement for MDPE. At elevated temperature, the tensile strength is shown to be reduced in all materials including MDPE and its nanocomposites. The obtained results confirm that the reinforcing effect of nano-sized calcium carbonate becomes significant particularly at higher temperatures.

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