Chinese Academy of Sciences

Dongmei Cui

Chunji Wu

Bo Tong Liu

Dongtao Liu

Xinli Liu

Shihui Li

Lingfang Wang

Wei Gao

Zichuan Wang

Zhichao Zhang

Changguang Yao

A copolymer of ethylene and a conjugated diene is provided, in which ethylene content in the copolymer is greater than 20 mol %, the copolymer has a glass transition temperature between &#x2212;110&#xb0; C. and &#x2212;90&#xb0; C., and continuous methylene sequence lengths (MSL) in the copolymer are in a range of 12-162 methylene units. A method for producing the copolymer, comprising copolymerizing ethylene and a conjugated diene in the presence of a catalyst system to obtain the copolymer is also provided, in which the catalyst system comprises a heterocyclic-fused cyclopentadienyl rare-earth metal complex, an organoboron salt compound and an organoaluminum compound, wherein the heterocyclic-fused cyclopentadienyl rare-earth metal complex is represented by the structural formula: 

Copolymer of ethylene and a conjugated diene, and process for its production

Compared to the prior art, this invention provides a functionalized highly syndiotactic polystyrene, comprising a repeating unit having a structure represented by formula (I), or comprising a repeating unit having a structure represented by formula (I) and a repeating unit having a structure represented by formula (II). It is indicated by the experimental results that the syndiotacticity selectivity of the highly syndiotactic polymer provided by this invention is no less than 90%, and the proportion of the repeating unit having a structure represented by formula (I) in the polymer may be arbitrarily adjusted and may be up to 100%. Meanwhile, the oxygen- or sulfur-containing groups in the polymer may increase the polarity of the highly syndiotactic polystyrene so as to increase the blendability of the highly syndiotactic polystyrene with other polymers. 

Functionalized highly syndiotactic polystyrene and preparation method thereof

This invention provides a metallocene complex and the preparation method thereof and a catalyst composition. This catalyst composition comprises a metallocene complex represented by formula (I) and an organic boron salt. Compared to the prior art, the catalyst used in this invention, which is the metallocene complex represented by formula (I), does not contain a group bonding between the heterocyclic fused cyclopentadienyl ring and the transition metal, and the coordination space of the central metal has a large opening degree. Therefore, the catalytic activity for more sterically hindered monomers is higher, and the comonomer incorporation is also higher. Furthermore, the metallocene complex represented by formula (I) used in this invention is a heterocyclic ring fused cyclopentadienyl ligand. Heterocyclic rings have relatively strong electron-donating capacity. By fusing a cyclopentadienyl group using heterocyclic rings, it is possible to change the electronic effect of the metal center and in turn increase the activity of catalyst. Therefore, by using the metallocene complex represented by formula (I), it is possible to prepare copolymers of ethylene with other olefins at high activity and high comonomer incorporation, and it is also possible to catalyze the polymerization of styrene and substituted styrene at high syndiotacticity and high activity. 

Metallocene complex, preparation method thereof and catalyst composition

The invention provides a metal alkoxide complex of Formula (I), wherein X, M, R1, R2, R3, m, n, y and z are as defined in the Description. The invention also provides a catalyst composition comprising the metal alkoxide complex and a hydroxy-containing compound, wherein the molar ratio of the metal alkoxide complex to the hydroxy-containing compound is 1:0.1-1000. The invention also provides a production method of poly-&#x3b5;-caprolactone or polyactide, wherein an &#x3b5;-caprolactone monomer or a lactide monomer is reacted in the presence of the metal alkoxide complex or catalyst composition to obtain poly-&#x3b5;-caprolactone or polylactide. The metal alkoxide complex and the catalyst composition thereof can be used to catalyze the synthesis of poly-&#x3b5;-caprolactone or polylactide with a high efficiency. The molecular weight of polycaprolactone or polylactide can be controlled by the molar ratio of the metal alkoxide complex and the hydroxy-containing compound, and is adjustable in the range of 1000-600,000, and wherein the molecular weight distribution is from 1.03 to 1.50.[XM(OCRRR)].(organic solvent)&#x2003;&#x2003;(I)

Metal alkoxide complex, catalyst composition, and production method of polycaprolactone or polylactide

An isoprene or butadiene cis 1,4-selective polymerization catalyst system together with its polymerization method is provided. This catalyst system is composed of NCN-imine pincer type rare earth metal complex of formula [2,6-(CH&#x2550;N&#x2014;R)-4-R-1-CH]LnX(THF)and alkylating reagent. In an hydrocarbon solvent or under bulk conditions, at a polymerization temperature in a range of &#x2212;20-120&#xb0; C., the conjugated diene is polymerized by using the catalyst system, to produce polyisoprene and polybutadiene having controllable number-average molecular weight, molecular weight distribution of 3.0 or less than, and cis 1,4-content of 95% or more, even 99% or more. The crude rubber and vulcanized rubber of the polyisoprene have high strength, stretching crystallization capability and transparency.

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Changchun, China

Dongmei Cui