TiCl_4/MgCl_2系负载高效催化剂中各组分对丙烯聚合的影响

本文叙述了采用共研磨法制备丙烯聚合用TiCl_4/MgCl_2系高效催化剂的实验结果。所研制的催化剂在常压条件下催化丙烯聚合的效率高达11600克聚丙烯/克钛(反应1.5小时),等规度95.4%。2立升釜本体聚合催化效率达12.8万克聚丙烯/克钛。4米~3釜生产试验反应1小时,催化效率达10万克聚丙烯/克钛,等规度均高于90%。文中着重介绍了常压聚合条件下载钛量、C_6H_5COOC_2H_5(以下简写为E.B)、硅化合物及助剂三异丁基铝对催化剂性能及聚合动力学行为的影响。     

丙烯聚合的新型复合高效催化剂的研究

采用研磨-反应法研制成一种丙烯聚合新型复合高效催化剂-CP型催化剂。含有TiCl_4、TiCl_3、MgCl_2、有机硅化合物、复合第三组份等组成的母体催化剂,和烷基铝等构成高效催化剂体系。在常压下丙烯聚合催化效率为2500-4000克PP/克Ti,产品等规度为94-97％,具有较平稳的催化聚合反应速率和长寿命的催化活性。在4米~3聚合釜生产试验催化剂效率达13万-18万克PP/克Ti,产品全等规度大于90％,含钛和氯离子低,可免除后处理。催化剂制备方法简便,无“三废”。文中还讨论了CP型催化剂组成和性能,聚合条件的影响,以及4米~3釜生产试验结果。     

SC型高效催化剂丙烯液相本体聚合

SC型高效催化剂是用无水MgCl_2、醇、蘸、TiCl_4以及添加剂制备的,SC型催化剂和A1Et_3助催化剂、Ph_2Si(OMe)_2外给电子体,用于丙烯液相本体聚合,丙烯在70℃聚合2h具有高效率(大于3万gPP/gCat),得到的聚丙烯等规度(大于98％)和堆密度(大于0.45g/cm~3)高,颗粒形态好,粒度分布窄,聚丙烯的MFR容易用氢调节。     

规化丁二烯的聚合催化系统

1,4-顺式聚丁二烯因为具有与天然橡胶相似的结构,因之是一种极有发展前途的合成橡胶。目前国际化学界对于这种合成橡胶的制备方法研究得十分广泛。一般比较成功的聚合方法,大多采用以下几种催化系统(1)四碘化钛-烷基铝;(2)四氯化钛-碘-烷基铝;(3)烃氧基钛-二烷基铝卤化物。意大利的一些化学家最近经过一系列的对比试验,认为丁二烯规化聚合的催化剂,一般是三元系统比二元系统的为好。他们曾经以Al(C_2H_5)_3·Al(C_2H_5)_2I·TiCl_4为催化剂进行丁二烯的规化聚合,克分于比为Al(C_2H_5)_3:Al(C_2H_5)_2I:Ii=4:4:1,从甲苯为溶剂,在-5℃下     

共振磨载体催化剂中含钛量对丙烯聚合的影响

本文报导了用共振磨法制得不同含钛量MgCl_2—TiCl_4—C_6H_5COOC_2H_5(以下简称为EB)催化体系,以Ali-Bu_3为活化剂。考察了催化剂含钛量对恒定单体浓度下的丙烯聚合动力学行为的影响。发现含钛量1—7％范围内,随着含钛量的提高,值化剂活性增加,但衰减加快.结果表明,游离钛随含钛量增高而增高,是影响催化剂活性衰减的主要因素.同时聚丙烯产物的熔融温度也随游离钛增加而降低。     

TiCl4/SiO2负载型催化剂用于丁二烯聚合Ⅰ .催化剂制备条件对聚合的影响

用球磨法制备的SiO_2负载TiCl_4催化剂进行丁二烯溶液聚合,考察了催化剂制备条件对催化效率的影响,分析了聚合物的结构。结果表明：球磨48 h,负载钛质量分数4％的催化剂具有较好的催化效率;SiO_2在负载TiCl_4前用适量Al(i－Bu)_3处理,或将球磨法制备的TiCl_4/SiO_2催化剂与适量Al(i－Bu)_2Cl 在100 ℃下反应1 h,均能大幅度提高催化剂的活性;在40～50 ℃下,聚合按溶液淤浆聚合形式进行,产物为低顺式聚丁二烯。     

空气湿度对合成四异丙基钛酸酯的影响

四异丙基钛酸酯是以相应的醇与四氯化钛直接反应而成,其反应式为: 4C_3H_7OH+TiCl_4→Ti(OC_3H_(74))+4HCl↑在反应进行的同时,还伴随着一系列副反应: TiCl_4+nROH→TiCl_(4-n)(OR)_n+nHCl↑ROH+HCl→RCl+H_2O水的出现导致四异丙基钛酸酯的缩聚: Ti(OR)_4+nH_2O→     

TiCl_4—MgCl_2—DBP负载型丙烯聚合高效催化剂的研究

一、前言丙烯聚合负载型高效催化剂中,七十年代广泛使用苯甲酸乙酯[1]作为提高聚合产物等规度的给电子体。八十年代已改为用邻苯二甲酸二酯[2]作给电子体。由于使用了邻苯二甲酸二酯,使得丙烯聚合催化效率、产品等规度大大提高。达到了催化效率高、等规度高两者兼得的理想状态。使用这一催化剂聚合过程动力学曲线较平稳、活性中心寿命长,共聚性能好,催化剂更具优越性能。     

用BF_3·O(C_4H_9)_2代替BF_3·O(C_2H_5)_2作催化剂组份合成顺丁橡胶——Ⅰ.催化剂配比、用量的研究

关于用BF_3·O(C_4H_9)_2代替BF_3·O(C_2H_9)_2作催化剂组份[Al(i-Bu)_3和Ni(naph)_2不变]合成顺丁橡胶的优越性已有报导。为了提供适宜的催化剂配方和控制手段,我们在40立升三釜连续聚合装置上进行了实验。结果表明,采用BF_3·O(C_4H_9)_2后,催化剂配比和工艺条件对     

丙烯聚合化学改性的负载型高效催化剂的研究 (Ⅱ)催化剂的性能和聚合产物的性质与表征

研究了化学改性的负载型高效催化剂的性能。该催化剂含钛化合物、MgCl_2、硅化合物、酯、烷基铝等组分,在常压下反应1.5h,催化效率为4～8kgPP/g Ti,产品等规度可在90％～97％范围内调节。详细考察了聚合反应条件对催化效率、产品等规度的影响,用偏光显微镜、广角X-射线衍射、红外光谱以及热谱分析对聚合产物结构性质进行表征,表明是一种良好的等规PP。还讨论了催化剂的生产应用前景。     

复合载体法制备聚丙烯-蒙脱土复合材料

将传统Z-N催化剂TiCl4负载于蒙脱土．乙醇镁复合载体上,进行丙烯常压原位聚合,制备聚丙烯-蒙脱土纳米复合材料,克服了单-蒙脱土作载体时聚合活性低、产物分子量小的缺点。对比不同制备过程的催化剂,发现TiCl4的后处理可以大幅提高催化活性。引入苯乙烯可有效降低Mg—MMT／Mg(OEt)2/TiCl4/EB体系制备的Cat5催化聚合时所需的Al／Cat比。由Mg—MMT／Mg(OEt)2/Ti(OBu)4/TiCl4/EB体系制备的Cat6具有活性高,所需Al／Cat低的优点,为合适的制备聚丙烯-蒙脱土纳米复合材料的催化剂。WAXS和TEM表明复合材料中蒙脱土主要呈剥离杰分散干聚丙烯基体中。产物的熔点和商用聚丙烯的熔点接近。     

Basic characterization of polypropene‐block‐poly(methylene‐1,3‐cyclopentane‐co‐propene) synthesized from propene and 1,5‐hexadiene with modified stopped‐flow method

Block copolymerization of propene and 1,5‐hexadiene was carried out by a modified stopped‐flow polymerization method with an MgCl₂‐supported Ziegler catalyst. The resulting polymer, polypropene‐block‐poly(methylene‐1,3‐cyclopentane‐co‐propene) (PP‐b‐(PMCP‐co‐PP)), in which the crystallizable PP part was linked with the non‐crystallizable PMCP‐co‐PP part, was characterized by optical microscopy, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and tensile testing. The block copolymer having a chemical linkage between PP and PMCP‐co‐PP showed properties different from those of homopolymer, random copolymer and blend polymer. © 2001 Society of Chemical Industry     

Influence of tacticity on solubility of propene monomer in isotactic and syndiotactic polypropylene

Solubility of propene monomer in isotactic polypropylene (i-PP) and syndiotactic polypropylene (s-PP) is investigated using Gibbs ensemble MC simulation. Tacticity was found to influence the solubility with propene having higher solubility in i-PP. The higher solubility is explained by the more favorable interaction of the propene molecules with i-PP. By analyzing the pair correlation functions of propene with PP it was found that propene favors being in the neighborhood of the PP side methyl groups. In addition, it was found that the propene two end segments orient themselves so that they can be in the proximity of the side methyls. This study provides insight into the effect of tacticity and molecular architecture on solubility in polymers.     

Long Chain Branched Polypropene Prepared by Means of Propene Copolymerization with 1,7‐Octadiene Using MAO‐Activated rac‐Me2Si(2‐Me‐4‐Phenyl‐Ind)2ZrCl2

Small amounts of 1,7‐octadiene (OD) comonomer, ranging from 0.5–5.0 mol‐%, were added during propene polymerization, catalyzed with methylalumoxane (MAO) activated rac‐Me₂Si(2‐Me‐4‐phenyl‐Ind)₂ZrCl₂ (MPI), in order to incorporate long chain branches and small amounts of high molecular mass polypropene (PP), thus improving melt processability of isotactic metallocene‐polypropene. As a function of the OD content the PP melting temperatures varied from 120 to 160°C. The presence of long chain branches was reflected by increased zero shear viscosities combined with pronounced shear thinning behavior in the case of propene/OD copolymers with molecular mass distribution of M̄_w/M̄_n < 4. Rheological measurements clearly revealed crosslinking occurring at high OD content. OD addition impaired catalyst activities. However, in the presence of trace amounts of ethene, catalyst activities increased significantly even in the presence of high OD content.     

一种复合内给电子体聚丙烯催化剂的研究

以MgCl2为载体,以TiCl4为主催化剂,采用复合双酯类物质为内给电子体制备了一种高效丙烯聚合催化剂。采用了这一关键的创新技术,使该催化剂产品具有效率高,活性持久,等规度可调优点。     

贫燃条件下丙烯选择还原NO铜基SO_4~(2-)改性钛交联蒙脱催化剂的制备与性能

采用水热法制备钛交联蒙脱土,SO2-4改性后作为载体,担载上铜,制成铜基SO2-4改性钛交联蒙脱土(Cu Ti PILM/SO2-4)催化剂,用C3H6作还原剂,考察了贫燃条件下不同空速、不同氧浓度以及H2O对催化剂活性的影响。结果表明,SO2-4用量w(SO2-4)为30%、Cu2+担载量w(Cu2+)为5%、500℃焙烧制得的Cu Ti PILM/SO2-4催化活性高,反应温度为250℃时,能使NO转化率高达70 6%,在水蒸气存在下,NO最大转化率仅下降7 0%。     

Plausible guard effect on the active sites of heterogeneous Ziegler–Natta catalyst by coordinating monomers and growing polymer chains in the initial stage of propene polymerization

Investigation of propene polymerization by a modified stopped‐flow technique using TiCl₄/ethylbenzoate(EB)/MgCl₂ Ziegler–Natta catalyst with or without pretreating the catalyst with triethylaluminium (TEA) within an ultra‐short period (ca 1 s) was conducted to gain new understanding of the nature of active sites related to TEA in the early stage of polymerization. When the catalyst was pretreated by a cocatalyst, deactivation behaviour was clearly observed, even within an extremely short pretreatment period. In contrast, without pretreatment, the deactivation of active sites can be neglected within the polymerization period indicating that the activated Ti species might be protected from deactivation by TEA when monomer is present in the system. A plausible guard effect on the active sites by coordinating monomer and growing polymer chains in the initial stage of polymerization is proposed to account for this phenomenon. Copyright © 2004 Society of Chemical Industry     

环保型无卤阻燃聚丙烯的研制

采用几种不同类型的无卤阻燃剂研制环保型阻燃聚丙烯(PP),讨论各阻燃剂的阻燃机理,对研制的阻燃PP进行了阻燃性能测试和燃烧热的测试。结果表明,Mg(OH)2复合阻燃体系和氮磷复合阻燃体系对PP均有良好的阻燃效果;研制的Mg(OH)2复合阻燃PP具有良好的阻燃性能和力学性能,并具有实际应用价值。     

Polyolefins containing 1,3‐disubstituted cyclopentane units as nucleating agents for isotactic polypropylene

Polyolefins containing 1,3‐disubstituted cyclopentane units in the main chain have been synthesized by 1,3‐polymerization of cyclopentene (PCP), cyclization polymerization of 1,5‐hexadiene (PHD), and ring‐opening metathesis polymerization of norbornene following hydrogenation of the unsaturated main chain (H‐PNB) with various transition metal catalysts. These polyolefins were applied to nucleating agents for isotactic polypropylene, and relationship between the structure of the polyolefins and nucleating effect was studied by DSC, polarized optical microscope, and WAXD. All the polyolefins had an effect of nucleation for isotactic polypropylene (PP). Of the polymeric nucleating agents, H‐PNB showed the most effective nucleation. Addition of PCP, which was obtained with a nickel catalyst with diimine ligand, to PP induced β‐modification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2953–2958, 2006     

Kinetics study of Ziegler-Natta catalyst based on TiCl3 modified by Lewis bases

Summary The kinetic in propylene polymerization of catalysts containing di-n-butyl ether (DBE) - Cat.A or di-n-butyl ether and ethyl benzoate (EB) - Cat. B used as internal electron-donor compounds was investigated. Comparing catalyst compositions with performances, one could conclude that the different kinetics observed were due to the different Lewis bases employed during catalyst synthesis. It seems that the electron-donors have modified the catalyst sites. It has found that added ethyl benzoate modified the structure of the active sites and increased the polymerization rate constant.