Although Ziegler–Natta (ZN) catalysts play a major role in the polyolefin market, true understanding of their properties at molecular level is still missing. In particular, there lack knowledge on electronic Ti sites. Theoretical calculations predict that electron density sites precatalysts correlates with activation energy for olefin insertion Ti-alkyl bond generated these after by Al-alkyls. ...

several types of hybrid catalysts are made through mixing of 4th generation ziegler-natta (zn) and (2-phind)2zrcl2metallocene catalysts using triethylaluminum (tea) as coupling agent. response surface methodology (rsm)is used to evaluate the interactive effects of different parameters including amounts of metallocene and tea andtemperature on metallocene loading. analyzing the amounts of al and...

in the current work, ethylene polymerization was investigated from a mathematical modeling point of view. the initiation (activation), propagation, termination, and deactivation reactions were taken into account and the relevant equations used in the modeling were obtained from the elementary reactions. some assumptions including neglecting the transfer and deactivation reactions were considere...

supported catalysts synthesized via the interaction of mg(oet)2 with ticl4 in the presence or absence of an internal stereoregulating donor (di-n-butyl phthalate), with different solvents (chlorobenzene, n-undecane, n-heptane) at different titanation temperatures have been studied by a set of physicochemical methods. data on the chemical composition, x-ray structure and pore structure of these ...

This paper reports the principal discoveries which have played a major role in the polyolefin field and have positioned polyolefins as the most produced plastics. The early development of polyolefins covering the production of LDPE (Low density polyethylene) at ICI (Imperial Chemical Industries) and the discovery of Phillips or Ziegler-Natta catalysts are highlighted in the first section. In th...

In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl3/MgCl2 model catalysts with minimum Ti heterogeneity was analyzed by combined solvent fractionation and the two...