The data on the effect of ethylene concentration on polymerization rate for several modifications of modern highly active titanium–magnesium catalysts TiCl4/MgCl2 are presented. These catalysts differ in titanium content and conditions of support preparation, activities, and the shape of kinetic curves. It is found that the observed order of polymerization rate with respect to ethylene in the r...

This contribution presents an updated overview of the different copolymers containing stereoregular polystyrene blocks. Special emphasis is placed on syndiospecific and isospecific copolymerization of styrene with co-monomers (ethylene and α-olefins, conjugated and non-conjugated dienes, styrene derivatives, etc.). The catalytic systems involved are described and the polymerization mechanisms a...

This research aimed to investigate the copolymerization of ethylene and various 1-olefins. The comonomer lengths were varied from 1-hexene (1-C₆) up to 1-octadecene (1-C₁₈) in order to study the effect of comonomer chain length on the activity and properties of the polymer in the metallocene/MAO catalyst system. The results indicated that two distinct cases can be described for the effect of 1-...

the data on the effect of ethylene concentration on polymerization rate for several modifications of modern highly active titanium–magnesium catalysts ticl4/mgcl2 are presented. these catalysts differ in titanium content and conditions of support preparation, activities, and the shape of kinetic curves. it is found that the observed order of polymerization rate with respect to ethylene in the r...

MgCl(2)-SiO(2)/TiCl(4) Ziegler-Natta catalysts for ethylene polymerization were prepared by impregnation of MgCl(2) on SiO(2) in heptane and further treatment with TiCl(4). MgCl(2)·nEtOH adduct solutions were prepared with various EtOH/MgCl(2) molar ratios for preparation of the MgCl(2)-supported and MgCl(2)-SiO(2)-supported catalysts in order to investigate the effect on polymerization perform...

We already reported that an intramolecular benzylation of the imino moiety of bidentate iminopyrrolyl ligands afforded an amido-pyrrolyl complexes 1 and they exhibited better catalytic activity for ethylene polymerization compared to the corresponding bis(iminopyrrolyl) dichloro complexes of zirconium. In this contribution, we prepared amido-pyrrolyl complexes of zirconium (3a-d) and hafnium (4...

Novel Zr(iv) and Hf(iv) complexes bearing two constrained bulky β-enaminoketonato ligands {[ArN[double bond, length as m-dash]CH-C8H3(CH2)n(R)O]2MBn2, M = Zr or Hf; n = 1, 2 or 3; R = H or C6H5; Ar = C6H5 or C6F5} were synthesized and clearly characterized. X-ray crystal structure analysis reveals that these complexes adopt a distorted octahedral geometry. Compared with non-constrained analogue...

Particles of linear polyethylene (M(n) = (2-3) x 10(3) g x mol(-)(1); M(w)/M(n) = 2-4) obtained by catalytic emulsion polymerization of ethylene possess a nonspherical, lentil-like shape with an average aspect ratio of ca. 10 and diameters from 30 to >300 nm, as determined by TEM and AFM. The particle structure results from a stacking of the lamellae along the one shorter axis of the lentils (i...