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

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. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2216–2221, 2006