Half-sandwich titanocene catalysts such as cyclopentadienyltitanium trichloride (CpTiC1₃), indenyltitanium trichloride (IndTiC1₃), fluorenyltitanium trichloride (FluTiC1₃), trimethylsilylindenyltitanium trichloride ((Me₃Si)IndTiCl₃) and pentamethylcyclopentadienyltitanium trichloride (Cp^*TiCl₃) have been examined with modified methylaluminoxane(MMAO) for styrene polymerization. IndTiC1₃ showed higher activity than CpTiC1₃. Polystyrene (PS) of the highest syndiotactic index and molecular weight was obtained by using Cp^*TiCl₃. By supporting IndTiC1₃ or Cp^*TiCl₃ on silica or cyclodextrin, the catalyst had a reasonable activity even with a smaller amount of MMAO compared to the unsupported catalysts. For microtacticity observed with ³C-NMR, PS of higher syndio triads [rr] was obtained by using IndTiCl₃ or Cp^*TiCl₃ instead of CpTiCl₃. Crystalline structure of sPS was found to be mainly δ form with X-ray Diffractometer.

Half-sandwich형 titanocene 촉매인 cyclopentadienyltitanium trichloride (CpTiCl₃), indenyltitanium trichloride (IndTiC1₃), fluorenyltitanium trichloride (FluTiCl₃), trimethylsily-lindenyltitanium trichloride ((Me₃Si)IndTiC1₃) 및 Pentamethylcyclopentadienyltitanium trichloride (Cp^*TiC1₃) 등과 공촉매로 modified methylaluminoxane (MMAO)을 사용하여 스티렌중합을 행하고 그들의 중합거동을 조사하였다. IndTiC1₃가 CpTiCl₃ 보다 높은 촉매활성을 보였고, 폴리스티렌의 분자량 및 신디오탁틱 지수는 Cp^*TiCl₃ 촉매를 사용한 경우에 가장 높게 나타났다. 또한 IndTiC1₃ 및 Cp^*TiCl₃를 실리카 또는 시클로덱스트린에 담지시켜 제조한 촉매는 적은 양의 MMAO를 사용하고도 높은 촉매활성을 나타내었다. 중합체의 미세구조를 ¹³C-NMR로 조사한 결과, CpTiCl₃로 얻은 sPS에 비해 IndTiC1₃ 및 Cp^*TiC1₃로 얻은 것의 입체규칙성이 더 높았다. X-ray Diffractometer로 분석한 sPS의 결정구조는 대부분 δ형이었다.

Keywords: syndiotactic polystyrene; half-sandwich titanocene; activity; syndiotactic index