Syndiotactic polymerization of styrene: Study of catalyst components and polymerization conditions

Abstract

Syndiotactic polystyrene (s-PS) was prepared using monotitanocene catalyst of cyclopentadienyl titanium trichloride (CpTiCl 3 ) activated by methylaluminoxane (MAO). Solution polymerization was carried out in toluene using different polymerization conditions. Syndiotacticity index (SI) between 68 and 91.6% was obtained. Increasing Al/Ti molar ratio shows an increase in both conversion percentage and SI. The conversion increased linearly with increasing Al/Ti molar ratio in the range studied. The conversion reached to an optimum value of about 65% at styrene/Al molar ratio of 2.83, while no regular behavior of SI was observed with changing the ratio. Effect of temperature of the range 50 -80°C on polymerization was studied. The most favorable temperature for the polymerization regarding activity is 70°C; however SI decreased with temperature up to 80°C. H 2 value to 140 mL/100 mL solvent increased the productivity of the catalyst, however further increase of H 2 reduced the activity of the catalyst. Polymerization time of 15 to 125 min shows a decrease in activity. The decrease was sharper for about 30 min of polymerization than longer time.

Comparative study of copolymerization and terpolymerization of ethylene/propylene/diene monomers using metallocene catalyst

“…Zirconium tetrachloride (98%) and methyllithium (5% in diethyl ether) were provided by Merck (Munich, Germany) and used as received. All solvents were provided from Luba (India), dried and deoxygenated according to the methods adopted from the literature 20–22. Triisobutyl aluminum (TIBA), methylaluminoxane (MAO) (10% in toluene) and 5‐ethyldiene‐2‐norbornene (ENB) (99%) were purchased from Aldrich (Munich, Germany).…”

Terpolymerization of Ethylene/Propylene/Diene Monomers Using (2‐PhInd)2ZrCl2 Metallocene Catalysts

“…Zirconium tetrachloride (98%) and methyl lithium (5% in diethyl ether solution) were purchased from Merck Chemical Co. (Munich, Germany). All solvents were provided from Luba (India), and dried and deoxygenated according to methods taken from the literature 25–27. Methylaluminoxane (MAO, 10% in toluene) and 5‐ethyldiene‐2‐norbornene (ENB) (99%) were purchased from Aldrich Chemical Co. (Munich, Germany).…”