The present disclosure relates to a Ziegler-Natta catalyst system comprising a pro-catalyst, a co-catalyst and a selectivity control agent. The pro-catalyst comprises a magnesium compound, a titanium compound and a multi-dentate internal donor, wherein the internal donor is tetraethyl 3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobiindane-5,5′,6,6′-tetracarbonate. The present disclosure further relates to a process for polymerization of an olefin using the Ziegler-Natta catalyst system. The Ziegler-Natta catalyst system of the present disclosure shows very high hydrogen response and thus can be used to produce low to high molecular weight polyolefin.

A propylene copolymer, a preparation method therefor, and an application thereof are provided. The copolymer forms a cross-linked network by means of a reaction between a furan-containing propylene copolymer and a small molecule of a coupling agent, thereby achieving a chemical bond connection between a polypropylene resin phase and an ethylene-propylene copolymer elastomer phase, fundamentally strengthening the force between the two phases, and improving the mechanical properties of a material. Meanwhile, the copolymer can achieve the decrosslinking of a material during melt processing such that the material has thermoplasticity, and after cooling, it can be crosslinked again to produce network structure.

The present disclosure relates to olefin polymerization catalysts, and discloses a catalyst component for olefin polymerization or copolymerization and a preparation method therefor, and a catalyst and an application thereof. The catalyst component for olefin polymerization or copolymerization in the present disclosure comprises titanium element, magnesium element, an electron donor, an organic silicon polymer, and an inorganic oxide support, wherein the molecular composition of the organic silicon polymer is [R.sub.xSiO.sub.(4-x)/2].sub.m, wherein R is selected from alkyl, aryl, vinyl or oxygen, x is 0 or more and 2 or less, and the value of m makes the number-average molecular weight of the organic silicon polymer be 1×10.sup.3-1×10.sup.6 g/mol. The catalyst has the characteristics of high activity, good hydrogen-regulating copolymerization performance, high bulk density of resulting polymer powder, and a low content of fine powder in the polymer powder when applied to olefin polymerization, particularly to ethylene and α-olefin polymerization.

Provided is an olefin polymerization catalyst carrier with a general structure formula of Mg(OR.sup.I).sub.n(OR.sup.II).sub.2-n, wherein: 0≦n≦2, and R.sup.I and R.sup.II can be the same or different and are each independently selected from a C.sub.1-C.sub.20 hydrocarbon group. In the X-ray diffraction pattern of the catalyst carrier, there are a set of diffraction peaks in the range of a 2θ diffraction angle of 5°-15°, and the set of diffraction peaks contain 1-4 main diffraction peaks. Also disclosed is an olefin polymerization solid catalyst component which is prepared from the carrier Mg(OR.sup.I).sub.n(OR.sup.II).sub.2-n, a titanium compound, and at least one electron donor compound. In addition, also disclosed is an olefin polymerization catalyst containing the solid catalyst component, at least one organic aluminum compound, and optionally, an external electron donor compound.

Disclosed are catalyst compositions having an internal electron donor which includes a 3,6-di-substituted-1,2-phenylene aromatic diester. Ziegler-Natta catalyst compositions containing the present catalyst compositions exhibit very high hydrogen response, high activity, high selectivity and produce propylene-based olefins with high melt flow rate.

The invention relates to the technical field of heterogeneous catalytic olefin polymerization, and discloses a polyolefin catalyst, its preparation and its us. A method for preparing the polyolefin catalyst comprises: (i) providing a thermally activated mesoporous material, with the thermal activation treatment being performed at a temperature of 300 to 900° C. for a period of time of 3 to 48 hours; (ii) under an inert atmosphere, (iia) conducting impregnation treatment of the thermally activated mesoporous material with a solution containing a magnesium component and then with a solution containing a titanium component, (iib) conducting impregnation treatment of the thermally activated mesoporous material with a solution containing a titanium component and then with a solution containing a magnesium component, or (iic) conducting co-impregnation treatment of the thermally activated mesoporous material with a solution containing both a titanium component and a magnesium component, to obtain a slurry to be sprayed; and (iii) spray drying the slurry to be sprayed from step (ii), to obtain a solid polyolefin catalyst component. When used in olefin polymerization, the polyolefin catalysts prepared by using the method provided by the invention have high catalytic activities, and polyolefin products having a narrow molecular weight distribution and an excellent melt index can be obtained.

The present disclosure relates to a process for synthesizing a multi- or dual-headed composition by using an alpha,omega-diene and an organometallic compound in the presence of a catalyst precursor. The present disclosure further relates to use of the compositions, as well as the process to make the same, in olefin polymerization.

The present disclosure relates to a capped, multi- or dual-headed chain composition comprising derivatives of a strained olefin. The present disclosure further relates to a process for synthesizing the capped, multi- or dual-headed composition by using an organometallic compound and a co-catalyst in the presence of a catalyst precursor and a strained olefin. The present disclosure further relates to use of the compositions, as well as the process to make the same, in olefin polymerization.

Disclosed are catalyst compositions having an internal electron donor which includes a 3,6-di-substituted-1,2-phenylene aromatic diester. Ziegler-Natta catalyst compositions containing the present catalyst compositions exhibit very high hydrogen response, high activity, high selectivity and produce propylene-based olefins with high melt flow rate.

Disclosed is a catalyst component for olefin polymerization. The catalyst component comprises magnesium, titanium, halogen and an internal electron donor. The internal electron donor includes an imine compound with a ketone group as shown in Formula I. Disclosed further is a method of preparing the catalyst component, and a catalyst for olefin polymerization containing the catalyst component. When the catalyst is used in olefin polymerization reaction especially propene polymerization reaction, the catalyst has a high activity and a long term activity and good hydrogen response, and the obtained polymer has characteristics of an adjustable isotactic index and a relatively wide molecular weight distribution. ##STR00001##