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

Abstract

AbstractThe synthesis of a poly(amic acid) (PAA)‐supported Ziegler–Natta catalyst (PAA‐TiCl4) by the reaction of PAA and titanium tetrachloride (TiCl4) is reported. For ethylene polymerization, three catalysts were synthesized by varying the TiCl4/PAA weight ratio in a hexane medium. The resulting catalysts were characterized by Fourier‐transformed infrared (FT‐IR), ultraviolet (UV), scanning electron microscopy and energy dispersive x‐ray detector (SEM‐EDX), and x‐ray diffraction analysis (XRD). The acidity of the catalysts in an acetone/water solution was measured by a pH meter. Thermogravimetric analysis reveals that catalysts are stable up to 110–125°C. Because of their higher degree of thermal stability, these catalysts may potentially be used as a support in a conventional Ziegler–Natta catalyst for ethylene polymerization. Furthermore, because of the extensive reaction between the functional groups of PAA and TiCl4, the chain structure of the PAA was destroyed. The newly synthesized catalysts showed good storability, and the overall catalytic productivity is 4921 g PE/g Ti/h. A catalyst with titanium incorporation corresponding to 2.8 wt% showed the maximum activity. The productivity of the catalysts also depended on the titanium concentration in the polymer matrix. These catalysts are found to retain their catalytic activity for a long time (∼90 days), and a mild reaction condition is required for catalysis. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 32: E119–E130, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20276