COPOLYMERIZATION OF STYRENE AND ETHYLENE WITH MONONUCLEAR AND DINUCLEAR HALF-TITANOCENES

With mononuclear half-titanocenes such as CpTiCl3, IndTiCl(3), and Me5 CpTiCl3, as well as the constrained geometry catalyst (CGC) and a new dinuclear amethyltrisiloxanediylbis(cyclopentadienyltitanium trichlori de) (TSDT), the copolymerization of styrene and ethylene was examined. The thermal properties and structure of copolymerization products wer e investigated with differential scanning calorimetry and C-13-nuclear magnetic resonance. In addition, the raw polymer was separated into h omopolymer and copolymer with an extraction method and cross fractiona tion chromatography. With the above analysis, it was concluded that th e raw polymer obtained with CpTiCl3 and IndTiCl(3) was a mixture of sy ndiotactic polystyrene and polyethylene homopolymers with 10-30 wt % c opolymer, whereas that produced by Me5CpTiCl3 and TSDT was a homopolym er mixture with a negligible amount of copolymer. Only CGC produced th e copolymer of styrene and ethylene perfectly. (C) 1998 John Wiley & S ons, Inc.