Effects of cocatalysts on styrene polymerization

Abstract

Syndiotactic polystyrene is a semi-crystalline engineering thermoplastic with heat and chemical resistant properties. Therefore, it has a potential for various applications for example, electronics, automotive and packaging industries. From this research, the combined catalyst system Cp*TiCl[subscript 3])-TIBA)/[Ph[subscript 3]C][superscript +][B(C[subscript 6]F[subscript 5])[subscript 4][superscript -] or/[PhNMe[subscript 2]H][superscript +][B(C[subscript 6]F[subscript 5])[subscript 4]][superscript -] has proved to be able to induce syndiospecific styrene polymerization. The polymerizations were carried out by varying reaction parameters. Teh results indicated that the best condition for Cp*TiCl[subscript 3]-TIBA/[Ph[subscript 3]C][superscript +][B(C[subscript 6]F[subscript 5])[subscript 4]][superscript -] system is: 0.087 mole of styrene, Al/Ti = 200, 0.005 mmol of catalyst at polymerization temperature of 70 degree celsius and polymerization time for 60 minutes. The appropriate condition for Cp*TiCl[subscript 3]-TIBA/[PhNMe[subscript 2]H][superscript +][B(C[subscript 6]F[subscript 5])[subscript 4]][superscript -] system is; 0.087 mole of styrene, Al/Ti = 200, 0.001 mmol of catalyst at polymerization temperature of 70 degree celsius and polymerization time for 60 minutes. The preactivation step is necessary to increase the activity by increasing the active species. Moreover, the addition of phenylsilane in the system increases the activity. All polymers obtained with these catalyst systems have melting temperature in the range of 268-269 degree celsius and narrow molecular weight distribution (1.54-1.78).