Synthesis mechanisms of poly[styrene‐co‐(acrylic acid)]‐supported TiCl₄ catalysts modified by magnesium compounds

Abstract

Soluble poly[styrene‐co‐(acrylic acid)] (PSA) modified by magnesium compounds was used to support TiCl4. For ethylene polymerization, four catalysts were synthesized, namely PSA/TiCl4, PSA/MgCl2/TiCl4, PSA/(n‐Bu)MgCl/TiCl4, and PSA/(n‐Bu)2Mg/TiCl4. The catalysts were characterized by a set of complementary techniques including X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, and element analysis. Synthesis mechanisms of polymer‐supported TiCl4 catalysts were proposed according to their chemical environments and physical structures. The binding energy of Ti 2p in PSA/TiCl4 was extremely low as TiCl4 attracted excessive electrons from COOH groups. Furthermore, the chain structure of PSA was destroyed because of intensive reactions taking place in PSA/TiCl4. With addition of (n‐Bu)MgCl or (n‐Bu)2Mg, COOH became COOMg‐ which then reacted with TiCl4 in synthesis of PSA/(n‐Bu)MgCl/TiCl4 and PSA/(n‐Bu)2Mg/TiCl4. Although MgCl2 coordinated with COOH first, TiCl4 would substitute MgCl2 to coordinate with COOH in PSA/MgCl2/TiCl4. Due to the different synthesis mechanisms, the four polymer‐supported catalysts correspondingly showed various particle morphologies. Furthermore, the polymer‐supported catalyst activity was enhanced by magnesium compounds in the following order: MgCl2 > (n‐Bu)MgCl > (n‐Bu)2Mg > no modifier. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Poly(amic acid)‐Supported Heterogeneous Titanium‐Based Ziegler‐Natta Catalyst for Ethylene Polymerization in a Slurry Process

“…TiCl 4 forms complexes with PAA and disrupts the packing of the polymer chain. This phenomenon confirms the presence of TiCl 4 in the polymer matrix 28…”

“…In 2011, Lei et al produced PE with a nanofiber structure (20–80 nm) from a porous poly (styrene‐ co ‐divenylbenzene‐acrylnitrile)‐supported Ziegler–Natta catalyst with productivity of 100–200 g PE/mmol Ti h atm 22. In addition, poly (styrene‐ co ‐4‐vinylpyridine),23 polyethylene‐ g ‐2‐tert‐ butyl amino ethyl methacrylate,24 ethene‐propene‐diene monomer,25 poly(ethylene‐ co ‐acrylic acid),26 chlorinated organic polymers,19 polyethersulfone,27 and poly[styrene‐ co ‐(acrylic acid)],28 etc., have been employed as supports for the titanium‐based Ziegler–Natta catalyst. The foremost objective of this research was to develop a catalyst with tremendous properties having high activity and high storability.…”