Preparation of Ultra-High Molecular Weight Polypropylene Using Ziegler-Natta Catalyst via Combining Internal Electron Donor and Cocatalyst Loading

Due to the development of the new energy industry,polypropylene with ultra-high molecular weight plays a crucial role for battery isolation membrane.This work investigated the effect of internal electron donor of Ziegler-Natta catalyst system on the molecular weight of the obtained polypropylene.The scanning electron microscope(SEM)and Canon camera were used to characterize the surface morphologies of catalyst particles and polymer particles,respectively.Compared with the polypropylene particles featuring a spherical shape,these study results confirmed that the morphology duplication theory from the catalyst particle to the morphology of polymer particle was exhibited.The gel permeation chromatography(GPC)results revealed that the obtained polypropylene has a much higher average molecular weight than those prepared by conventional method.The Fourier transform infrared spectrometry(FT-IR)and X-ray photoelectron spectroscopy(XPS)revealed that the carbonyl oxygen atom on ester group was preferentially bound to Mg and Ti,as compared to the ether oxygen atom.The XPS results showed that the ratio of Ti^(3+)/Ti^(4+)could be changed by internal electron donors.When Ti3+content was nearly 99%in the Ziegler-Natta catalyst system,isotactic polypropylene with an ultra-high molecular weight of up to 1.42×10^(6)g/mol was obtained by Cat.3.This result implied that internal electron donor ID3 could reduce theβ-hydride elimination reaction to further increase the molecular weight of the obtained polymer.

Study on Property of Polypropylene Catalyst with New Internal Donor

A P-substituted sulfonyl-containing compound was synthesized in the lab. The structure of the compound was demonstrated by 1H and 31P NMR. The propylene polymerization catalysts were prepared by incorporating an internal donor, and the content of Ti, H and C in the catalysts was also checked by elemental analysis. The effect of dosage of the donor, the Al/Ti ratio and the polymerization temperature on the catalyst activity were studied, the results suggested that the dosage of donor, the Al/Ti ratio and the polymerization temperature could affect not only the activity of catalyst but also the isotacticity index of the polymer. A catalyst with high activity was selected, and the polypropylene formed in the presence of this catalyst had high isotacticity index.

SUPPORTED CATALYST WITHOUT EXTERNAL ELECTRON DONOR FOR PROPYLENE POLYMERIZATION Ⅱ. TACTICITY DISTRIBUTION AND MICROSTRUCTURE OF POLYPROPYLENE

Propylene was polymerized with a novel supported Ziegler-Natta catalystcontaining 2,2-di-iso-butyl-1,3-dimethoxy-propane (DIBDMP) as internal donor and in theabsence of external donor. The tacticity distribution of polypropylene was obtained by usingtemperature rising elution fractionation (TREF) technique and microstructure of fractionswas studied with ^(13)C-NMR. Compared with the catalyst without electron donor, this cat-alyst gives a considerably narrower tacticity distribution. Fractionation data demonstratethat DIBDMP shows better performance than aromatic diester DNBP (di-n-butyl phtha-late). Chemically inverted propylene units and less stereoblockiness are found in the firstfraction. Possible reasons for these were presented.

The Synthesis of Isotactic Polypropylene with Spherical Morphology via Supported Metallocene Catalyst

Polymerization of propylene was carried out under bulk process at 70 degrees C using the supported metallocene catalyst with four kinds of SiO2 as carrier with triethylaluminum used as cocatalyst. The morphology of the products was studied by SEM. It was found the property of the carriers gave great effect on the fine structure of the products as well as the apperance.

两种丙烯聚合用球形Ziegler-Natta催化剂的性能研究

采用扫描电子显微镜、激光粒度仪、密度仪和熔体流动速率仪(MFR)等研究了2种丙烯聚合用球形齐格勒-纳塔(Ziegler-Natta)催化剂(记为1#和2#)的性能。结果表明:与2#相比,1#的平均粒径更小,粒径分布更宽,活性更高,对氢气更敏感,且所得聚丙烯(PP)堆积密度更高,但PP颗粒粒径较小。不同外给电子体对丙烯聚合的影响不同。采用二环戊基二甲氧基硅烷为外给电子体时,2种催化剂活性均最高,所得PP的MFR均最小。

球形Ziegler-Natta催化剂在中石化环管聚丙烯工艺装置的应用

在中国石化茂名分公司国产第二代环管聚丙烯工艺装置上,采用国产球形Ziegler-Natta催化剂(催化剂1)生产了PPH-T03、N-Z30S和PPR-M55-S三种牌号聚丙烯。研究了球形催化剂在生产三种牌号聚丙烯时的催化剂效率和氢调性,同时分析了各牌号聚丙烯的粉料粒径及产品质量,并将其与另一个国产球形催化剂(催化剂2)进行了对比分析。实验结果表明,与催化剂2相比,两种催化剂生产的聚丙烯在产品质量上相当,但催化剂1的氢调性更加优异,更有利于装置生产高熔融指数产品。

Bis(trifluoromethylsulfonyl)phenylamines as Internal Donors for Ziegler-Natta Polymerization Catalysts

Several bis（trifluoromethylsulfonyl）phenylamines have been synthesized and used as internal donors for the preparation of heterogeneous Ziegler-Natta catalysts for propylene polymerization. These new cata- lysts are highly active and stereospecific in combination with an external donor for the polymerization of propylene. The activity of these catalysts is dramatically influenced by the electronic capability of the phenyl substituents on the sulfonyl phenylamines. Therefore, the performances of the catalysts can be modified by adjusting the electronic property of the phenyl substituents of the sulfonyl phenylamines.

COPOLYMERIZATION OF PROPYLENE WITH HINDERED PIPERIDINE MONOMER OVER A HIGH ACTIVITY SUPPORTED ZIEGLER-NATTA CATALYST

Copolymerization of propylene and hindered piperidine monomers was carried out over a high activity supported Ziegler-Natta catalyst, using Al(C2H5)(3) as cocatalyst. Factors which affect the copolymerization were studied, The copolymers exhibited high light stability without adding extra light stabilizers. A self-stabilized polypropylene was prepared.

STUDY ON 1-HEXENE POLYMERIZATION BASED ON ZIEGLER-NATTA CATALYSTS WITH DOPED SUPPORT

A series of Ti/Mg supported catalysts are prepared by using ball-milled mixtures of MgCl2-ethanol adducts and NaCl as supports, and 1-hexene polymerizations catalyzed by the novel catalysts are studied. It is found that the molecular weight distribution of poly(1-hexene) becomes apparently narrower when catalysts with doped supports are used, indicating that changing the structure of the support is an effective way to regulate the active center distribution of heterogeneous Ziegler-Natta catalyst.

Study of a Novel Fourth-generation Supported Ziegler-Natta Catalyst for Propylene Polymerization: Relationship between Catalyst Structure and Polymerization Properties

This article presents a detailed structural study of a new spherical Mg Cl2-supported Ti Cl4 Ziegler-Natta catalyst for isotactic propylene polymerization, and researches on the relationship between catalyst structure and polymer properties. The spherical support with the chemical composition of CH3CH2 OMg OCH(CH2Cl)2 has been synthesized from a new dispersion system and is used as the supporting material to prepare Ziegler-Natta catalyst. The XRD analysis indicates that the catalyst is fully activated with δ-Mg Cl2 in the active catalyst. The far-IR spectrometric results confirm again the presence of δ-Mg Cl2 in the active catalyst. Textural property of the active catalyst exhibits high surface area coupled with high porosity. The high activity in propylene polymerization is mainly ascribed to the full activation and the porous structure of the catalyst. Scanning electron microscopy/energy dispersive spectrometer mapping results indicate a uniform titanium distribution throughout the catalyst particles. Particle size analysis shows that the catalyst has a narrow particle size distribution. The perfect spherical shape, uniform titanium distribution and narrow particle size distribution of the catalyst confirm the advantage of polymer particles production with less fines. The solid state 13 C NMR and mid-IR spectroscopic analyses indicate that there exists strong complexation between diisobutyl phthalate and Mg Cl2, which leads to the high isotacticity of polypropylene.

EFFECTS OF EXTERNAL DONOR ON ACTIVE CENTER DISTRIBUTION OF SUPPORTED ZIEGLER-NATTA CATALYST

The composition distribution (CD) and microisotacticity distribution (ID) of propene/1-hexene copolymer synthesized by MgCl2/DIBP/TiCl4 (DIBP: diisobutyl phthalate) were determined by fractionating the copolymers according to crystallinity and characterizing the fractions by (CNMR)-C-13. The effects of two alkoxysilane donors, triethoxyphenylsilane (PTES) and dimethoxydi-tert-butylsilane (TBMS), on CD and ID of the copolymers were compared. Three main parts in the CD diagram of each copolymer were distinguished, which were correlated to active center distribution (ACD) based on three groups of different active centers. By studying the changes in l-hexene content, microisotacticity and reactivity ratio product of three typical fractions, the effects of external donor on ACD were better elucidated. It was found that TBMS shows much stronger effects on ACD than PTES. In the former system, most fractions were produced on active centers with relatively lower r(1)r(2), higher reactivity to I-hexene, and higher stereospecificity as compared to the system without external donor. It is concluded that the observed very extensive changes in ACD are mainly resulted by the formation of new types of active centers, possibly by coordination of external donor to certain positions on the catalyst.

Study on the distribution of active centers in novel low Ti-loading MgCl2-supported Ziegler-Natta catalyst

Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by these novel catalysts were analyzed using the method of fitting the molecular weight distribution (MWD) curves with a multiple Flory-Schulz function. It was found that multiple active centers exist in these novel catalysts. Detailed study of the effects of the Ti-loadings in the catalysts on the distribution of the active centers showed that the Ti-loadings in the novel MgCl2-supported Z-N catalysts might affect the proportion of each type of active centers; and might be the main factor responsible for the effect of the Ti-loadings on the microstructure, the molecular weight and molecular weight distribution width of the resultant polymer, the catalytic activity and polymerization kinetics.

丙烯聚合用Ziegler-Natta催化剂预聚合的研究进展

综述了丙烯聚合用Ziegler-Natta催化剂预聚合的研究进展,包括预聚合对催化剂的影响、预聚合方法及其应用。预聚合可以提高催化剂活性、改善聚合物的颗粒形态、影响聚合动力学行为。现有研究已经开发了不同的预聚合方法,进一步改善了催化剂和聚合物的颗粒形态,提高了聚合物的性能。经过预聚合制备的预聚合催化剂,适用于无预聚合操作单元的气相丙烯聚合工艺,不仅能有效解决聚合物中细粉含量高、聚合物结块等问题,还能获得具有高性能、高附加值的聚丙烯产品。

A New Method for Dissolving MgCl_2 for Preparation of Ziegler-Natta Propylene Polymerization Catalysts

A new method for the activation of crystalline magnesium chloride by polyethylene glycol was described. Polyethylene glycol could solubilize crystalline magnesium chloride. The resulting solution was used for the preparation of Ziegler-Natta propylene polymerization catalysts. These catalysts are highly active and stereospecific. The relationship between the catalytic activity and the Al/Ti ratio was studied in detail.

DEPENDENCE OF THE DISTRIBUTION OF ACTIVE CENTERS ON MONOMER IN SUPPORTED ZIEGLER-NATTA CATALYSTS

Distribution of active centers(ACD)of ethylene or 1-hexene homopolymerization and ethylene-1-hexene copolymerization with a MgCl_2/TiCl_4 type Z-N catalyst were studied by deconvolution of the polymer molecular weight distribution into multiple Flory components.Each Flory component is thought to be formed by a certain type of active center. ACD of ethylene-1-hexene copolymer with very low 1-hexene incorporation was compared with that of ethylene homopolymer to see the effect of introducingα-olefin on ethyle...

POISONING OF ACTIVE SITES ON ZIEGLER-NATTA CATALYST FOR PROPYLENE POLYMERIZATION

The effects of poisoning materials on catalytic activity and isospecificity of the supported Ziegler-Natta catalyst were investigated.A minor amount of simple structure of Lewis base,i.e.,methanol,acetone,ethyl acetate,was introduced into the catalyst slurry for partial poisoning catalytic active centers.It was found that the variations in deactivation power were in the order of methanol>acetone>ethyl acetate.The kinetic investigation via stopped-flow polymerization showed that poisoning compounds cau...

EFFECTS OF REACTION AND PROCESSING PARAMETERS ON ETHYLENE POLYMERIZATION USING DIFFERENT ZIEGLER-NATTA CATALYSTS:EMPLOYMENT OF TAGUCHI EXPERIMENTAL DESIGN AND RESPONSE SURFACE METHOD

Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and temperature, a Taguchi experimental design was worked out. An L27 orthogonal array was chosen to take the above-mentioned parameters and relevant interactions into account. Response surface method was the tool used to analyze the experimental design results. Al/Ti, ethylene pressure and temperature were selected as experimental design factors, and catalyst activity and polymerization yield were the response parameters. Increasing pressure, due to an increment in monomer accessibility, and rising Al/Ti, because of higher reduction in the catalysts, cause an increase in both polymerization yield and catalyst activity. Nonetheless, a higher temperature, thanks to reducing ethylene solubility in the slurry medium and partially catalyst destruction, lead to a reduction in both response parameters. A synergistic effect was also observed between temperature and pressure. All catalyst activities will reduce in the presence of hydrogen. Molecular weight also shows a decline in the presence of hydrogen as a transfer agent. However, the polydispersity index remains approximately intact. Using SEM, various morphologies, owing to different catalyst morphologies, were seen for the polyethylene.

Catalytic Degradation of Mixed Polypropylene, Low and High Density Polyethylene into Environmental Friendly and Useful Products

Using novel catalyst the pyrolysis of mixed plastics has been considered as an effective way to convert waste plastics into environmental friendly and industrially useful hydrocarbon gas and liquid products. Catalytic cracking is a promising alternative for plastic wastes recycling. More than 99% of a polymer mixed converted into combustible hydrocarbon in a catalytic converting reaction. The products are mainly middle distillates. In this work equally weighted mixed HDPE （high density polyethylene）, LDPE （low density polyethylene） and Polypropylene were degraded. The reaction occurred in a semi batch reactor at several temperatures and catalyst/polymer ratios in search for an optimum operating condition. The products are liquid and gaseous hydrocarbons with minor of residue. The liquid and gas products were in the range of middle distillate cuts of gasoline, kerosene and gas oil. Finally, with a metallic base, yielded 99.5% of given mixed to valuable middle distillate products that include 86% liquid hydrocarbon and 13.5% gas, ranging between C1 and C5 with less percent of residue. The optimum condition for this yield reports at a temperature of 450 ℃ and 10% of catalyst w/w at atmosphere pressure.

Synthesis of PE with Broad MWD Catalyzed by Supported Ziegler-Natta Catalyst Consisting of Cycloalkoxy Silane as IED

Two kinds of cycloalkoxy silane compounds were synthesized and used as the internal electron donors （IEDs） of supported Ziegler-Natta catalyst for ethylene polymerization to produce polyethylene with broader molecular weight distribution （MWD）, The effect of the structure and the amount of these IEDs on the polymerization performance was in- vestigated. The results implied that the molecular weight distribution of the obtained polyethylene could be adjusted by the incorporation of IEDs. SEM result showed that the morphology of catalyst particle was spherical and uniform in size distribution. The titanium content of these catalysts was higher, the active TiCl4 species were easily anchored on the support than that without adding IED, which was determined by ICE The GPC result confirmed that the polyethylene with broader molecular weight distribution in the range of from 23.4 to 25.6 was obtained using triethoxy-（-cyclopentyloxy）-silane （ED1） and triethoxy-（-cyclohexyloxyl）- silane （ED2） as the internal electron donors.

Ziegler-Natta催化体系中影响聚丙烯等规度的因素

Ziegler-Natta(Z-N)催化剂是生产等规聚丙烯的最主要的催化剂,其不同组分对Ti活性中心立构选择性都有不同的影响,本文详细论述了MgCl_(2)载体、给电子体和烷基铝助催化剂以及它们之间的相互作用对Z-N催化剂立构选择性的影响。