Bis(cyclopentadienyl) zirconium dichloride (Cp2ZrCl 2) as a homogeneous metal- locene catalyst was manufactured in laboratory scale under highly controlled con- ditions. Ethylene polymerization was carried out using this catalyst while, methyla- luminoxane (MAO) was used as a cocatalyst. Activity of 5759 gPE/mmol Zr.h at [Al]/[Zr] molar ratio of 770/1 was obtained. Polymer yield was increased with increasing in [Al]/[Zr] ratio to a limiting value. Addition of hydrogen as a chain transfer agent up to 120 cm3/L solvent, increased the activity of the catalyst. Polymerization was carried out at monomer pressure of 1 to 5 atm, and temperature of 40o C to 80o C. Polymerization activity was increased with increasing temperature to 60o C and slightly decreased with more increase in temperature. Upon the addition of catalyst a sudden increase of 10o C in temperature was observed, particularly when polymerization temperature was higher than 50o C. This increase could be due to high rate of polymerization which at high temperature could affect catalyst activity. Monomer pressure up to 2 atm increased productivity of catalyst. Increase in [Al]/[Zr] ratio, polymerization temperature and H2 concentration decreased Mv of polymer obtained. Melting point of polymer also decreased with increasing [Al]/[Zr] ratio. Density of obtained polyethylene was 0.940-0.950 g/cm3. Tg of one of the polymer samples was determined which was 99.9o C.
کلید واژگان :metallocene; methylaluminoxane; homogeneous catalyst; ethylene polymerization
ارزش ریالی : 600000 ریال
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