Molecular structure of metallocene catalyst Cp^tt₂ZrCl₂ and structural analysis of PE catalyzed by Cp^tt₂ZrCl₂

Abstract

Abstract Cp tt 2 ZrCl 2 (Cp tt = η 5 − t Bu 2 C 5 H 3 ) was synthesized by the reaction of LiCp tt with ZrCl 4 and characterized by X‐ray crystallographic studies. It was used as catalyst for ethylene polymerization. Structural analysis was carried out on the polyethylene (PE) catalyzed by Cp tt 2 ZrCl 2 via wide‐angle X‐ray diffraction (WAXD) and small‐angle X‐ray scattering (SAXS). The degree of crystallinity ( W c,x ) was calculated by WAXD. The semiaxises of the particles ( a , a , b ) of PE were determined by SAXS and it could be found that the crystalline particles of PE are mainly rod shaped determined by the characteristic function v 0 ( r ). The radius of gyration R g , crystalline thickness L c , the thickness of noncrystalline region L a , long period L , electron‐density difference between the crystalline and noncrystalline regions η c − η a , and the invariant Q are determined by SAXS. The results also indicate that a transition zone exists between the traditional “two phases” with a clear dimension of 1.3 nm. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 169–175, 2005