Abstract
The titanium catalyst (C5(CH3)4Si(CH3)2NR)TiCl2 has been tethered to the interior pore surfaces of p-aminophenylsilyl-functionalized mesoporous silica materials in a single-step process to form supported constrained-geometry catalysts (CGCs), and the polymerization of ethylene and copolymerization of ethylene and 1-octene by the resulting heterogenized CGCs have been studied. Confirmation that the intended supported CGC is correctly assembled and is the only catalytically active species is provided by spectroscopic characterization (29Si CP MAS NMR) and by ethylene/1-octene copolymerization. The use of tailored mesoporous silica supports with different uniform pore sizes (25−70 Å) permits investigation of the influence of the structure of the support matrix (i.e., the “second sphere of influence”, where the ligand environment provides the primary influence) on catalyst activity and on product properties. Homopolymerization of ethylene by the supported CGCs shows a clear trend in the crystallinity of the high-density polyethylene (HDPE) produced, with a higher degree of crystallinity observed for HDPE formed by the heterogenized CGC within the smaller-pore substrates. The observation that a “second sphere of influence” is indeed significant introduces an additional tunable parameter for the tailored synthesis of polyolefins using supported catalysts.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
