Nano, micro, and bulk structures in atactic polystyrene - syndiotactic polystyrene blends obtained in situ in presence of the CpTiCl3/SiO2/MAO catalysts (Cp - cyclopentadienyl, MAO - methylaluminoxane)

Authors:

• W. Skupiński,
• A. Plewka,
• Z. Wieczorek,
• Leszek Wachowski,
• Magdalena Hofman-Bieniek,
• B. Czajka

Abstract

CpTiCl₃/SiO₂/MAO (Cp=cyclopentadienyl, MAO - methylaluminoxane) catalysts, where the Al:Ti varies from 20:1 to 500:1, were used in styrene polymerization. Atactic - syndiotactic polystyrene blends (aPS-sPS) were obtained in situ, the morphology of which was investigated by means of scanning electron microscopy. The blends morphology changed according to the kind of catalytic centers: cationic and syndiotactic on the catalyst surface, which create individually atactic or syndiotactic polystyrenes forming specific blends containing nano or micro-forms: when the Al:Ti ranges from 50:1 and to 100:1 in the blends, there occur nano-sPS particles 40-120nm in size, if the Al:Ti≥300:1, the filament of δ-sPS polymorph, is produced where the filament size ranged from 30 to 10nm. A decay of this form leads to the formation of spherical sPS forms several hundreds of nm in size. When the Al:Ti ranges 20:1-50:1, blend rods of several dozen micrometers were obtained. © 2013 Elsevier Inc.