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. ...

a two-dimensional (2d) single particle model for the copolymerization of propylene-ethylene with heterogeneous ziegler-natta catalyst is developed. the model accounts for the effects of the initial shape of the catalyst and carck/ pore patterns on the copolymer composition, polymerization rate and the average molecular weight properties. the spherical and oblate ellipsoidal shapes of catalyst p...

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...