给电子体在丙烯聚合MgCl2载体催化剂体系中的作用

制备了3种含有不同内给电子体(邻苯二甲酸二异丁酯,9,9-二甲氧基甲基-芴和1,1-双甲氧基甲基-环丁烷)的MgCl2负载型丙烯聚合齐格勒-纳塔(Z-N)催化剂,研究了给电子体结构与聚合性能之间的关系,用红外光谱剖析了催化剂及其相关化合物的结构,结果发现催化剂中的内给电子体直接与MgCl2配位,而没有与TiCl4结合.内给电子体的加入,降低了Z-N催化剂中钛的含量,提高催化丙烯聚合的活性,使聚合物的分子量分布变窄.聚合物立构规整度的变化强烈依赖于内给电子体的结构.     

用无外给电子体Ziegler-Natta催化剂催化丙烯聚合的研究

采用 9,9 双 (甲氧基甲基 )芴 (BMMF)为内给电子体合成MgCl2 /TiCl4 /BMMF催化剂 ,以三乙基铝为助催化剂在无需外给电子体的情况下得到高等规度的聚丙烯 .该催化剂具有高活性和高立体定向性 ,并与以邻苯二甲酸二丁酯 (Phthalate)为内给电子体 ,二苯基二甲氧基硅 (DDS)为外给电子体合成的MgCl2 /TiCl4 /Phthalate AlEt3 /DDS催化剂的性能进行比较 ,结果表明无外给电子体催化剂具有较高的活性 ,且聚丙烯的等规度大于 95 % .研究了聚合温度 ,铝钛比等聚合条件对催化剂的活性 ,聚合物的分子量、等规度和熔点的影响 ,并用13 C NMR对聚合物的序列结构进行了分析     

氨基硅烷外给电子体用于1-丁烯聚合的研究

合成了4种氨基硅烷类外给电子体,并用于MgCl2载体型Ziegler-Natta催化剂催化1-丁烯聚合,研究了不同外给电子体结构对催化效率和聚合物等规度、熔点、分子量及其分布的影响.结果表明,含二甲氧基的氨基硅烷类外给电子体更有助于聚(1-丁烯)等规度的提高,含二乙氧基的氨基硅烷类外给电子体可以使聚(1-丁烯)分子量分...     

用于丙烯聚合的MgCl2负载Ziegler-Natta催化剂研究进展

综述了用于丙烯聚合的MgCl2负载Ziegler-Natta催化剂研究进展,包括内给电子体的发展及其作用研究,催化剂活性中心的模型,用MgCl2负载的Z-N催化剂制备抗冲聚丙烯合金.     

硅烷类外给电子体的取代基变化对丙烯聚合影响的研究

合成了2种新型硅烷化合物双环己基二甲氧基硅烷(Donor-H)、双哌啶二甲氧基硅烷(Donor-Py),将其与工业化的环己基甲基二甲氧基硅烷(Donor-C)分别作为外给电子体,用于MgCl2负载的Ziegler-Natta催化剂催化丙烯聚合,通过DSC、GPC、SSA和13C-NMR等分析手段研究了3种外给电子体取代基的变化对催化剂的催化活性、氢调敏感性、聚丙烯的等规度、分子量分布、结晶能力、等规序列分布的影响.结果表明,随着外给电子体取代基体积的增大,外给电子体的给电子能力逐渐增强.与Donor-C相比,随着外给电子体取代基体积的增大,合成的具有较大取代基的Donor-H和Donor-Py用于丙烯聚合时都表现优异的催化性能,特别是新型含有N杂原子的氨基硅烷类Donor-Py为外给电子体的催化剂的催化活性和制备的聚丙烯的等规度最高,聚丙烯的熔融指数可调范围最宽,结晶能力更强.氨基硅烷类Donor-Py制备的聚丙烯SSA热分级后的高等规组分含量最多,可高达64.5%,聚丙烯等规序列长度最长,聚丙烯的等规序列分布最窄,而且13C-NMR结果也表明聚丙烯等规序列长度MSL最长,聚丙烯的分子链最规整.     

极少量1,4-戊二烯对典型Ziegler-Natta催化剂催化的丙烯聚合反应及聚丙烯性质的影响

以9,9-二(甲氧基甲基)芴(BMMF)为内给电子体的MgCl2/TiCl4催化剂与三乙基铝(TEA)组成典型Ziegler-Natta催化剂体系,催化丙烯本体聚合,考察极少量1,4-戊二烯作为共聚单体对聚合反应行为的影响.结果发现,在[1,4-戊二烯]/[丙烯]共单体摩尔比非常低(0.1%)的范围内,随着1,4-戊二烯浓度增大,催化剂活性迅速降低,[1,4-戊二烯]/[丙烯]比为0.08%时仅为约初始的1/4.但由特性黏数得到的聚合物分子量对1,4-戊二烯浓度呈现不规则变化,1,4-戊二烯并未使聚合物分子量单调降低,而在极低浓度时反而使其有所提高.凝胶渗透色谱(GPC)表征结果不但进一步确认了聚合物分子量的变化规律,还表明1,4-戊二烯并未使聚合物链发生支化.动态剪切流变测试结果显示极少量的1,4-戊二烯使聚合物的剪切黏度上升,模量提高,松弛时间延长;聚合物的拉伸黏度在拉伸流变测试中呈现相同的规律.通过1,4-戊二烯/氢气在聚合反应中协同作用的探讨,提出了对MgCl2/TiCl4/BMMF-TEA催化的丙烯/1,4-戊二烯反常共聚合行为的解释.     

MgCl_2负载TiCl_4催化剂中内给电子体对活性组分钛的影响

应用XPSI、R等表征手段研究了以MgCl2为载体,苯甲酸酯、邻苯二甲酸酯以及1,3-二醚为内给电子体的Ziegler_Natta(Z-N)催化剂中内给电子体对活性组分Ti的作用.实验结果表明,不同内给电子体Z-N催化剂中Ti的氧化状态是不同的,给电子体不与Ti直接发生作用,而是通过MgCl2为媒介向Ti发生电荷转移,造成Ti周围电子云密度增大,Ti的氧化状态降低,表现为Ti的结合能下降.     

DNBP给电子体构象分析及在Ziegler-Natta丙烯聚合中作用机理研究

首次采用TINKER构象搜索和DFT结构优化相结合方法,基于对Ziegler-Natta丙烯聚合催化体系邻苯二甲酸正丁酯(DNBP)给电子体快速搜索出的1 023种构象,筛选出其优势构象,减少了给电子体初始稳定结构搭建模型的盲目性和随机性.采用DFT方法,对DNBP两种构象与MgCl2载体相互作用及丙烯插入立体选择性机理进行了研究.结果表明,DNBP构象影响其在MgCl2表面的吸附,s-顺、反式构象可以单齿、桥连和螯合方式吸附在MgCl2(110)表面;s-顺、顺式仅存在桥连吸附.双氯原子缺陷载体模型上TiCl4吸附的稳定性高于DNBP,成为可能的活性中心;给电子体对活性位的作用与其吸附方式有关,DNBP以桥连方式吸附在Ti的邻位,可将无规活性中心有效转化为等规活性中心,而螯合方式不能改善催化剂的立体结构和区域选择性.     

一种复合载体丙烯聚合催化剂的研究

采用SiO2-MgCl2复合载体制备了一种丙烯聚合催化剂,考察了SiO2活化条件、SiO2和MgCl2质量比和催化剂的不同制备工艺对催化剂性能的影响,通过对催化剂的氢调和聚合时间的试验,发现该催化剂用于催化丙烯聚合时,无需加入外给电子化合物就可以使树脂达到较高的等规指数。     

异双桥联茂金属催化剂催化丙烯聚合制备高分子量无规聚丙烯

采用2种分别具有Cs对称性和C1对称性的异双桥联茂金属催化剂(Me_2C)(Me_2Si)Cp_2TiCl_2、[(CH_2)_5C](Me_2Si)Cp_2TiCl_2,在助催化剂甲基铝氧烷(MAO)的作用下用于丙烯聚合.通过对聚合温度、助催化剂用量和聚合时间的研究,详细考察了这些因素对聚合活性和聚合物结构的影响.由核磁共振碳谱(13CNMR)、示差扫描量热分析(DSC)和凝胶渗透色谱法(GPC)表征了所得聚合物的结构和分子量及分子量分布.这2种催化剂催化丙烯常压聚合活性最高可达10~6g PP/mol·h,重均分子量可达7×10~5,分子量分布在2.0左右,所得聚丙烯为高分子量的无规聚丙烯.这两种异双桥联茂金属催化体系在低温下表现出良好的聚合活性;但聚合温度升高,聚合活性和聚丙烯的分子量呈现明显的下降趋势.随铝钛比的增加,聚合活性和聚合物分子量均呈现先上升后降低的趋势.聚合时间增加活性下降,聚合物分子量有所增加.研究表明,这2种催化剂具有的大二面角(71.0°,70.3°)结构对催化性能和聚合物的结构有较大影响.     

Effect of Hydrogen,Electron Donor,and Polymerization Temperature on Poly(propylene) Microstructure

Summary: Polypropylene made with an industrial heterogeneous Ziegler-Natta catalyst was characterized using high temperature GPC, ¹³C NMR, and Crystallization Elution Fractionation (CEF). The effect of hydrogen and electron donor during polymerization on poly(propylene) microstructure was investigated at two temperatures. In addition to the expected electron donor effect on polypropylene tacticity, hydrogen was also found to increase polypropylene tacticity. The effect of changing these polymerization conditions on molecular weight and polydispersity was also investigated. Finally, CEF profiles show how the crystallizability of polypropylene increases by adding hydrogen and electron donor to the reactor.     

由Mg(nBu)2制备的MgCl2载体催化剂的烯烃聚合动力学

讨论了催化剂ＣＤ，ＣＭ和ＣＤ－Ａ的乙烯和丙烯聚合动力学曲线，只有催化剂ＣＤ在丙烯聚合时加入外给电子体其动力学曲线为上升－衰减型，其它均为衰减型，催化剂ＣＤ丙烯聚合活性高于催化剂ＣＭ。丙烯聚合时加入外给电子体使总活性中心浓度降低，但等规中心浓度反应增加。同种载体制备的催化剂ＣＤ和ＣＤ－Ａ载钛过程中加入内给电子体，可使其聚合活性增加，在一定范围内，随Ａｌ／Ｔｉ增加，在一定范围内，随Ａｌ／Ｔｉ增加，催化     

Broad Molecular Weight Polypropylene Synthesis using Mixed Internal Donor Incorporated Magnesium Dichloride Supported Titanium Catalyst

Magnesium dichloride supported titanium tetrachloride catalyst with mixed internal donor, comprised of ethylbenzoate and sulfolane, were synthesized. The composition characteristics of catalysts indicate incorporation of sulfolane to max 8.2 wt%, in addition to ethylbenzoate. The amount of incorporated donors in solid catalyst is dependent on the sulfolane concentration and reaction temperature of the process. A physical characteristics study of catalyst indicated that morphology, crystallite size, surface area, pore volume and titanium distribution have not been influenced much by incorporation of the second internal donor (sulfolane). The catalysts, in combination with triethyl aluminum as cocatalyst and p-ethoxyethylbenzoate as external donor, show good activity for propylene polymerization. The polypropylene synthesized with an optimized catalyst system shows broad molecular weight distribution as compared to ethylbenzoate based catalyst.     

A convenient,highly-efficient method for preparation of hydroxyl-terminated isotactic poly(propylene) and functional di-block copolymer

Both terminated functional isotactic polypropylene （iPP） and block copolymers containing iPP segment are desirable for commercial applications. This paper provides a convenient, highly-efficient method to prepare hydroxyl-terminated isotactic polypropylene （iPP-t-OH） and functional di-block copolymer containing the iPP segment through a combination of coordination polymerization and coupling reaction. The coordination polymerization was catalyzed by TiCI4/MgCI2/AIEt3 catalyst system using ZnEt2 as chain transfer agent. Further, the Zn-terminated iPP was oxidized and subsequently hydrolyzed to provide iPP-t-OH. Soxhlet extraction and 13C NMR were used to calculate the isotacticity of iPP-t-OH. The degree of polymerization and the number of hydroxyl groups at the chain end of iPP-t-OH were measured by GPC and 1H NMR. Despite the high molecular weight and heterogeneous reaction, iPP-t-OH is effectively linked with PEG-t-NCO to produce di-block copolymers. DSC analysis of the di-block copolymer shows an obvious decrease in Tm and To, which indicated that PEG was successfully linked to the terminal end of iPP.     

Effects of external donors and hydrogen concentration on oligomer formation and chain end distribution in propylene polymerization with Ziegler‐Natta catalysts

The effect of type and concentration of external donor and hydrogen concentration on oligomer formation and chain end distribution were studied. Bulk polymerization of propylene was carried out with two different Ziegler‐Natta catalysts at 70 °C, one a novel self‐supported catalyst (A) and the other a conventional MgCl₂‐supported catalyst (B) with triethyl aluminum as cocatalyst. The external donors used were dicyclopentyl dimethoxy silane (DCP) and cyclohexylmethyl dimethoxy silane (CHM). The oligomer amount was shown to be strongly dependent on the molecular weight of the polymer. Catalyst A gave approximately 50 % lower oligomer content than catalyst B due to narrower molecular weight distribution in case of catalyst A. More n‐Bu‐terminated chain ends were found for catalyst A indicating more frequent 2,1 insertions. Catalyst A also gave more vinylidene‐terminated oligomers, suggesting that chain transfer to monomer, responsible for the vinylidene chain ends, was a more important chain termination mechanism for this catalyst, especially at low hydrogen concentration. Low site selectivity, due to low external donor concentration or use of a weak external donor (CHM), was also found to increase formation of vinylidene‐terminated oligomers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 351–358, 2010     

合成高分子量无规聚丙烯—在烷烃溶剂中聚合及性能初步表征

丙烯聚合;茂金属催化剂;立体结构;合成高分子量无规聚丙烯—在烷烃溶剂中聚合及性能初步表征     

Increased rubber content in high impact polypropylene via a sirius ziegler‐natta catalyst containing nanoparticles

High impact polypropylene was produced in a two‐reactor polymerization process operating in series using two different Ziegler‐Natta catalysts (referred to as catalysts A and B) that had been prepared by Sirius emulsion technology in the absence and presence of SiO₂ nanoparticles, respectively. The homo polypropylene matrix was produced in liquid bulk and the ethylene/propylene rubber in gas phase under industrial conditions. Catalyst B was prepared with the same emulsion technology as catalyst A, except that SiO₂ nanoparticles (average particles size 80 nm) were added during catalyst preparation. Scanning electron microscopy studies showed that the nanoparticles were fairly evenly distributed within catalyst B particles, although there was some agglomeration. It was shown that the nanoparticles in catalyst B increased the internal porosity in the homo polypropylene matrix particles and this enabled a significant increase in the rubber content. Maximum rubber content, before running into stickiness problems, was approximately 25 wt % for catalyst A without nanoparticles, whereas the maximum rubber content for catalyst B was almost doubled to 45 wt % due to the beneficial transformation of the internal catalyst morphology by the nanoparticles. In addition, it was also found that the reaction was not mass transfer limited during the ethylene/propylene rubber polymerization stage, even at very high rubber contents where all pores and cavities were filled with rubber. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

STUDIES ON TiCI4/Mg (OEt)_2/EB SUPPORTED CATALYSTS FOR PROPYLENE POLYMERIZATION

The supported catalysts for propylene polymerization were prepared by milling Mg (OEt)_2 with EB (ethylbenzoate) and treating with TiCl_4 solution. When TiCl_4/(Mg(OEt)_2/EB) (mol.) ratio was increased, decrease in contents of-OEt and Ti of the catalysts was observed, while the content of EB increased. It is proved by analyses of IR, X-ray and XPS that during co-milling Mg(OEt)_2 with EB no reactions have taken place. But after treatment with TiCl_4 solution, Mg(OEt)_2 converts into MgCl_2 and EB coordinates on the resulting MgCl_2 carrier, a surface complex forms.The activity of catalysts,isotacticity and vicosimetric molecular weight of polypropylene increase with the decrease of the content of ethoxyl group. The kinetic curves of propene polymerization obtained with present catalysts system display decay curves. It is found from the triad tacticity calculated from the expanded spectra of methyl carbon region that, ethoxyl group in catalyst has an effect on the configuration of polymer chain.