茂金属／Z—N复合型聚乙烯催化剂

茂金属催化剂和Z—N催化剂结合在一起制成的新型复合催化剂具有双活性中心,用于乙烯聚合可得到双峰分子量分布的聚乙烯,并且聚乙烯具有优良的综合物理性能和加工性能。新型复合催化剂以氯化镁为载体,以茂金属化合物和四氯化钛为双活性中心,解决了茂金属载体化后聚合活性大幅度下降的难题,相对地减少了助催化剂甲基铝氧烷的用量,克服了由茂金属催化剂制备的聚合物分子量分布窄、加工困难的弱点,为茂金属催化剂的开发应用开辟了新途径。     

世界聚乙烯催化剂研究新进展

综述了国内外聚乙烯齐格勒-纳塔催化剂、茂金属催化剂、非茂金属催化剂、双功能催化剂、双峰或宽峰分子量分布聚乙烯复合催化剂等的研究开发新进展。     

茂金属乙丙橡胶的制备的应用

介绍了茂金属乙丙橡胶的制备、应用以及几种催化剂对乙烯、丙烯共聚的影响，列出Ｄｕ Ｐｏｕｔ Ｄｏｗ公司生产的ＣＧＣＴ ＥＰＤＭ Ｎｏｒｄｅｌ Ｉｐ门尼粘度和ＥＢＮ含量。对国内茂金属橡胶及催化剂的开发提出一点看法。     

第二代LLDPE技术发展近况

聚烯烃“第二代技术”的目标是生产新的、性能独特的树脂 ,代替竞争中的牌号 ,或扩展常见的聚烯烃树脂的性能。在第二代技术中 ,最引人注目的是单中心催化剂体系———茂金属及非茂金属催化剂体系。第二代技术的另一个着重点就是开发易加工的线型低密度聚乙烯 (ＬＬＤＰＥ) ,采用各种分子结构 ,使产品加工性能接近于低密度聚乙烯 (ＬＤＰＥ) ,可在现有ＬＤＰＥ的加工设备 (主要是吹膜设备 )上加工 ,在终端市场上可以更多地替代常用的ＬＤＰＥ。人们主要通过 3个基本途径设计ＬＬＤＰＥ聚合物链 :创造双峰结构 (双反应器 )、宽分子量分布 (Ｍ…     

二茂二氯化钛或锆与二茂基氯化钐复合催化乙烯聚合

分别以二茂二氯化钛(Cp2TiCl2)和二茂二氯化锫(Cp2ZrCl2)与钐茂金属催化剂复合组成催化体系，并以甲基铝氧烷为助催化剂，进行宽分子量分布聚乙烯合成研究。研究发现与使用Cp2TiCl2和二(甲基茂基)氯化钐复合体系相比，使用其与二(特丁基茂基)氯化钐[(t—BuCp)2SmCl]复合体系能得到具有较高粘均分子量的聚乙烯。同样，使用Cp2ZrCl2与(t—BuCp)2SmCl复合体系也能得到具有较高粘均分子量的聚乙烯。且使用含(t-BuCp)2SmCl复合体系得到分子量分布指数达3．5以上的聚乙烯。     

宽或双峰分子量分布HDPE的研制Ⅱ.聚合工艺条件对聚合产物性能的影响

采用双金属复合催化剂制备出了宽或双峰分子量分布的高密度聚乙烯（ＨＤＰＥ）,并对所合成出的聚合物进行了结晶行为分析,分子量及分子量分布测试。结果表明：用双金属复合催化剂法制备的ＨＤＰＥ的力学性能优于传统方法。     

2000年茂金属聚乙烯消费量预测

２０００年茂金属聚乙烯消费量预测据预测，２０００年全球茂金属聚乙烯消费量可望超过２００万ｔ。茂金属聚乙烯预计将取代传统的ＰＥ和其它塑料，新的ＰＥ将加速在包装用途上取代玻璃、纸和金属。第二代聚烯烃技术包括：茂金属／单中心催化剂、双峰／三元聚合物、宽分子...     

茂金属化合物及其制法和在烯烃聚合催化剂中的应用

本发明公开了一类含有2个由亚烷基桥连的环戊二烯基环的茂金属化合物。这类茂金属化合物适合用作烯烃聚合的催化剂组分，特别是，使丙烯在基于这些茂金属化合物的催化剂存在下聚合，可以得到高收率，并具有很高的全同规整度，高的分子量和窄的分子量分布的聚合物。     

2005年世界α烯烃需求将达2Mt

据美国ＣＡＨＡ咨询公司在最近的调研报告中预测,到２００５年聚烯烃生产用的共聚单体α烯烃的世界需求量可望达到２Ｍｔ。随着茂金属类聚合物的普及,α烯烃的用量逐年增加,与１９９５年相比增长约２．４倍。考虑到如此大的市场需求,不仅各生产厂正在或计划大幅扩能,而且又涌现出一些新的厂商,今后这一被看好的市场,内部竞争将日益激烈。该报告中对具代表性的共聚单体用α烯烃１－丁烯、１－己烯、１－辛烯的未来作了详细预测。共聚单体α烯烃主要用于线性低密度聚乙烯（ＬＬＤＰＥ）,但茂金属催化剂类ＬＬＤＰＥ与以往ＬＬＤＰＥ相…     

茂金属催化剂及其应用进展

茂金属催化剂及其应用进展张志德，陈玉琴，余立新，邹志琛（山东师范大学化学系）（续上期）Ｄｏｗ化学公司还开发出用茂金属催化剂制造间规聚乙烯（ＳＰＥ），生产装置已投入运转，生产能力为６．２５万ｔ／ａ［１７］。Ｍｏｂｉｌ公司在美国首次用茂金属催化剂开发成功...     

Control of molecular weight distribution in propylene polymerization with Ziegler–Natta/metallocene catalyst mixtures

Propylene polymerization was investigated with a sequential addition of Ziegler–Natta and metallocene catalysts. From the fact that the molecular weights of polypropylene (PP) produced with Ziegler–Natta and with metallocene catalysts differ, it was possible to control the molecular weight distribution (MWD) of PP with a sequential addition of methylaluminoxane and rac-ethylenebis(indenyl)zirconium dichloride followed by triethylaluminum and magnesium dichloride-supported titanium tetrachloride catalyst. The obtained PP exhibited a wide MWD curve with shoulder peak. The position and height of each peak was controlled with the variation of polymerization time for each catalyst as well as the amount of each catalyst. The MWD of PP prepared with sequential addition of catalysts was much wider than that of PP obtained from each catalyst. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2213–2222, 1998     

Ziegler-Natta催化剂制备宽/双峰分布PE的研究进展

综述了近年来Ziegler-Natta(Z-N)催化剂制备宽/双峰分布聚乙烯(PE)的研究状况,介绍了含有无机化合物和给电子体化合物的MgCl2载体型和复合载体型两种Z-N催化剂的各种制备方法对PE相对分子质量分布的影响,同时介绍了相关Z-N催化剂的一般制法.研究发现:MgCl2载体型Z-N催化利制备的PE相对分子质量...     

The characteristics of metallocene/Ziegler-Natta hybrid catalysts supported on the recrystallized MgCl2

A metallocene catalyst or a metallocene/Ziegler-Natta hybrid catalyst supported on MgCl₂ was studied for application to the commercial slurry phase process and to the control of MWD of the polymer produced. The MgCl₂ support was prepared by the recrystallization method with different solvents: alcohols and H₂O. The recrystallized MgCl₂ support was pretreated with triisobutylaluminum (TiBAL) or trimethylaluminum (TMA), methylaluminoxane (MAO), to give different supporting environments. Metallocene/Ziegler-Natta hybrid catalysts on MgCl₂ were prepared by first supporting the metallocene catalyst, followed by the Ziegler-Natta catalyst after pretreatment with an alkylaluminum compound. The type of solvent plays a role in providing a suitable environment in the support for impregnating catalysts. The hybrid catalyst, whose support was recrystallized in n-propanol (n-PrOH) and pretreated with TiBAL, showed the highest molar ratio of Zr/Ti= 1/2.71. But the hybrid catalyst, whose support was recrystallized in H₂O and pretreated with MAO, showed the best hybrid effect showing a variety of bimodal peaks in proportion to the ratio of MAO/TEA in GPC analysis. This effect might be due to steric factor and polarity of solvent, as well as the pretreatment material. It is concluded that the MWD of polyethylene produced by metallocene/Ziegler-Natta hybrid catalyst that is supported on MgCl₂ can be controlled by regulating the amounts of MAO and TEA added as cocatalysts and by the use of different solvents and pretreatment materials.     

Characteristics of ethylene polymerization over Ziegler–Natta/metallocene catalysts Comparison between hybrid and mixed catalysts

Two types of inorganic supports, MgCl₂ and SiO₂, for the impregnation of catalysts were prepared by the recrystallization and the sol–gel method, respectively. The polyethylene produced by the Ziegler–Natta/metallocene hybrid and mixed catalysts showed two melting temperatures and a bimodal MWD corresponding to products arising from each of the individual catalysts. This suggests that these Ziegler–Natta/metallocene catalysts acted as individual active species, and as a result, produced a blend of polymers.     

茂金属催化剂及烯烃高分子材料研究新进展

介绍茂金属催化剂的一般组成、主要特性及在烯烃聚合催化技术所具有的显著优势和近年研究取得的一些新进展。详细叙述采用茂金属催化工艺技术合成的一些烯烃聚合物,如聚乙烯(PE)、聚丙烯(PP)、间规聚苯乙烯(sPS)、茂金属环烯烃、茂金属乙丙橡胶、茂金属乙烯-辛烯共聚物等。这些茂金属聚合物与传统催化剂合成的聚合物相比,具有更优良的特性和更广阔的应用范围。许多用传统催化剂难以合成的材料,在采用茂金属催化技术后变得容易进行。在烯烃聚合物合成中茂金属催化剂正在替代传统催化剂。茂金属催化剂在全球增长非常迅速,具有广阔的应用和市场前景。     

Modification of a Ziegler-Natta catalyst with a metallocene catalyst and its olefin polymerization behavior

A Ziegler-Natta catalyst was modified with a metallocene catalyst and its polymerization behavior was examined. In the modification of the TiCl₄ catalyst supported on MgCl₂ (MgCl₂-Ti) with a rac-ethylenebis(indenyl)zirconium dichloride (rac-Et(Ind)₂ZrCl₂, EIZ) catalyst, the obtained catalyst showed relatively low activity but produced high isotactic polypropylene. These results suggest that the EIZ catalyst might block a non-isospecific site and modify a Ti-active site to form highly isospecific sites. To combine two catalysts in olefin polymerization by catalyst transitioning methods, the sequential addition of catalysts and a co-catalyst was tried. It was found that an alkylaluminum like triethylaluminum (TEA) can act as a deactivation agent for a metallocene catalyst. In ethylene polymerization, catalyst transitioning was accomplished with the sequential addition of bis(cyclopentadienyl)zirconium dichloride (Cp₂ZrCl₂)/methylaluminoxane (MAO), TEA, and a titanium tetrachloride/vanadium oxytrichloride (TiCl₄/VOCl₃, Ti-V) catalyst. Using this method, it was possible to control the molecular weight distribution (MWD) of polyethylene in a bimodal pattern. In the presence of hydrogen, polyethylene with a very broad MWD was obtained due to a different hydrogen effect on the Cp₂ZrCl₂ and Ti-V catalyst. The obtained polyethylene with a broader MWD exhibited more apparent shear thinning.     

Immobilization of Titanium Tetrachloride on Mixed Support of MgCl2 · xEB/Poly(methyl acrylate-co-1-octene): Catalyst for Synthesis of Broad MWD Polyethylene

TiCl₄ immobilization on different compositions of mixed support of MgCl₂ · xEB and poly(methyl acrylate-co-1-octene) (PMO; synthesized through ARGET ATRP) resulted in the formation of solid catalysts having variation in incorporation of titanium. The effect of mixed support composition onto the titanium immobilization, catalyst morphology and performance for ethylene polymerizations has been evaluated. The polyethylenes synthesized showed broad to bimodal MWD in GPC and DSC where the broadness was found to be dependent upon the ratio of mixed support MgCl₂ · xEB/PMO. The morphological features of PE as elucidated using SEM lead to postulation of polymer formation mechanism.     

Z-N催化剂生产宽/双峰MWD聚乙烯的研究进展

介绍了Ziegler-Natta(Z-N)催化剂在单反应器中生产宽,双峰相对分子质量分布(MWD)聚乙烯(PE)的最新研究进展,概括了Z-N催化剂制备宽／双峰MWDPE的主要方法及特点,即传统的Ti系催化体系生产的双峰PE的MWD较窄,改进的Ti-V双金属催化体系活性高,可以调节MWD,但反应操作难度大。通过加入不同的配合物,调节并改进PE的MWD,取得了较好的实验结果。宽/双峰MWDPE的生产和开发是PE工业发展的一个重要方向。     

宽或双峰分子量分布HDPE的研制：Ⅰ双金属复合催化剂的制备？…

将Ｃｐ２ＺｒＣｌ２以一定方式负载于ＢＣＨ催化剂上制备了双金属复合催化剂,了ＢＣＨ／Ｃｐ２ＺｒＣｌ２对载锆量的影响以及负载温度对双金属复合催化剂催化性能的影响,并用Ｘ射线光电子能谱法证实了藏金属催化剂确已载到了ＢＣＨ催化剂上。催化乙烯聚合的动力学研究表明,双金属复合催化剂的动力学曲线与ＢＣＨ催化剂一样均属衰减型;由于双金属中心的存在,其动力学曲线出现了２个峰值。