Binary Blends of Polypropylene : A Study on its Rheological and Thermal Properties
Rahul Gupta, Deepak Srivastava
RMIT University
Australia

Keywords: PP, HDPE, CaCo3 filler

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Blend samples of PP/HDPE/ CaCO3 have been prepared by changing the HDPE content, 0-100 wt%, and filler, 10-30 wt%, in PP by using HAAKE rheocordmeter (HBI System-90) for 10 min. at 160°C, with 100 rpm rotor speed and 120 cm3 charge volume. The torque and material temperature were recorded as a function of time. The torque at 190°C (M190) and the activation energy of flow (Eh) were determined from the curves. It has been concluded that the melt viscosity of PP first increased upto 40 wt% HDPE addition with 20% CaCO3 filler and then decreased whereas for 10 and 30% filler addition, the value of the melt viscosity decreased slowly upto 90 wt% HDPE addition in the blends. The tensile strength increased upto 20 wt% HDPE addition and then decreased whereas the filler concentration decreased the value of maximum tensile strength as obtained by the addition of HDPE. The elongation-at-break was found to be maximum with 20 wt% HDPE and 10% filler addition in the blends. The melting peak temperature was found to have maximum value without filler addition whereas it was minimum for 30 % filler addition with 20 wt% HDPE content in the blend. The heat of fusion of PP in the blends decreased with the addition of filler as well as HDPE concentration.