SYNTHESIS OF A POLYETHYLENE-GRAFT-POLYSTYRENE COPOLYMER AND ITS COMPATIBILIZATION FOR LINEAR LOW-DENSITY POLYETHYLENE/POLY(PHENYLENE OXIDE) BLENDS

Based on unsteady diffusion kinetics, polyethylene(PE)-graft-polystyrene (PS) copolymers were designed and synthesized with a heterogeneous high yield titanium-based catalyst by copolymerization of ethylene with a PS-macromonomer using 1-hexene as a short chain agent to promote the incorporation of the PS-macromonomer. The presence of 1-hexene facilitated the diffusion of the PS-macromonomer, giving rise to the significantly increased incorporation of the PS-macromonomer. Compatibilization of blends of linear low density polyethylene (LLDPE)/poly(phenylene oxide) (PPO) with the PE-g-PS copolymer were investigated using scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA).

Polimerização de propeno com catalisadores metalocênicos via suportação in-situ utilizando SMAO como suporte

Os catalisadores metalocênicos Me2Si(Ind)2ZrCl2 e Me2Si(2-Me-Ind)2ZrCl2 foram suportados in-situ sobre SMAO e empregados na polimerização de propeno na presença de alquilalumínios tais como TEA, IPRA ou TIBA. Os resultados obtidos demonstraram que o tipo e a concentração de alquilalumínio presente no meio reacional influenciaram tanto a atividade catalítica quanto as propriedades dos polímeros gerados. Os polímeros obtidos com o catalisador suportado in-situ apresentaram propriedades distintas das obtidas no polímero gerado através da polimerização homogênea, além de morfologia controlada, confirmando que de fato a polimerização ocorreu sobre a superfície do SMAO. Através da deconvolução das curvas de GPC foi constatado o aumento do número de tipos de sítios ativos no sistema catalítico suportado in-situ, resultado que também confirmou a heterogeneização do catalisador sobre o suporte. Com o auxílio de cálculos teóricos e da deconvolução das curvas de GPC foi possível propor estruturas para os sítios ativos dos sistemas homogêneo metaloceno/MAO e heterogêneo (suportado in-situ) metaloceno/SMAO/alquilalumínio. Quando eteno foi utilizado como monômero, o comportamento do sistema catalítico metaloceno/SMAO/alquilalumínio suportado in-situ foi distinto do obtido com propeno. O catalisador Me2Si(Ind)2ZrCl2 suportado ex-situ sobre SMAO através de técnicas convencionais de suportação foi avaliado por EXAFS e foi constatado que a vizinhança eletrônica do zircônio é influenciada pela razão Zr/SMAO. Os resultados obtidos por EXAFS foram correlacionados com a variação na atividade catalítica na polimerização de eteno em função da alteração na razão Zr/SMAO.

Synthesis and properties of branched polyethylene/high-density polyethylene blends using a homogeneous binary catalyst system composed of early and late transition metal complexes

Branched polyethylene/high-density polyethylene blends (BPE/HDPE) with a wide range of molecular weights, melt flow indexes (MFI), and intrinsic viscosity were prepared using the homogeneous binary catalyst system composed by Ni(alpha-diimine)Cl-2 (1) (alpha-diimine = 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine) and {Tp(Ms*)} TiCl3 (2) (Tp(Ms*)=hydridobis(3-mesitylpyrazol-1-yl)(5-mesityl-pyrazol-1-yl)) activated with MAO and/or TIBA in hexane at two different polymerization temperatures (30 and 55 degreesC) and by varying the nickel loading molar fraction (x(Ni)). At all Temperatures, a non-linear correlation between the x(Ni) and the productivity was observed, suggesting the occurrence of a synergistic effect between the nickel and the titanium catalyst precursors, which is more pronounced at 55 degreesC. The molecular weight of the BPE/HDPE blends considerably decreases with increasing Al/M molar ratio. The melt flow indexes (MFI) and intrinsic viscosities (eta) are strongly affected by x(Ni), but the melting temperatures are nearly constant, 132 +/- 3 degreesC. Dynamic mechanical thermal analysis (DMTA) shows the formation of different polymeric materials where the stiffness vanes according, to the x(Ni) and temperature used in the polymerization reaction. The surface morphology of the BPE/HDPE blends studied by scanning electron microscopy (SEM) revealed a low miscibility between the PE phases resulting in the formation of a sandwich structure after etching with o-xylene.

Latexpartikel als Trägermaterialien in der durch Postmetallocene katalysierten Ethenpolymerisation

Die vorliegende Arbeit beschäftigte sich mit der Immobilisierung von Postmetallocenen auf einem organischen Trägermaterial für die heterogene Ethenpolymerisation. Dabei konnte gezeigt werden, dass sich mit nukleophilen Gruppen funktionalisierte Latexpartikel als Trägermaterial für empfindliche Bis(phenoxyimin)titankatalysatoren eignen. Durch geschickte Kombination aus Trägermaterial, Katalysator und Cokatalysator wurde ein Katalysatorsysteme erhalten, das ultrahochmolekulares Polyethylen mit einem Molekulargewicht Mw von bis zu 7.000.000 g/mol (GPC, PS-Standard) bei einer enger Molekulargewichtsverteilung von weniger als 3 erzeugt. Die erhaltenen Produktivitäten erreichten dabei die Anforderungen an industriellen Katalysatorsystemen. Erstaunlich war, dass nukleophile Gruppen auf den Latexpartikeln, die dafür bekannt sind, dass sie den Katalysator deaktivieren können, ein wichtige Schutzfunktion für den Titankatalysator bilden. So konnte gezeigt werden, dass Pyridingruppen auf der Oberfläche der Latexpartikel als Scavenger gegen Trimethylaluminium wirken, welches ansonsten den aktiven Titankomplex zersetzen würde. An ausgewählten Systemen auf der Basis unterschiedlicher Postmetallocene und einem Metallocen für die Ethenpolymerisation wurde durch Anwendung verschiedener Methoden das Polymerisationsverhalten der Latex-geträgerten Katalysatorsysteme untersucht. Eine Methode war die so genannte Videomikroskopie, bei der in Gasphase Ethen polymerisiert wird und so das Wachstumsverhalten der Katalysatorpartikel analysiert werden kann. In Kombination mit einer kinetischen Kontrolle des Monomerumsatzes in Suspensionspolymerisation, konnte gezeigt werden, dass die auf Latexpartikel geträgerten Katalysatorsysteme ein anderes Polymerisationsverhalten besitzen wie in der Literatur beschriebene Silica-geträgerte Katalysatoren. Dies kann auf die unterschiedliche Beschaffenheit des Trägermaterials zurückgeführt werden. Während das harte Silica-Material Monomer nur in den Poren aufnimmt und so rasch nach Beginn der Polymerisation in eine diffusionskontrollierte Polymerisation übergeht, quillt das organische Trägermaterial mit dem Monomeren an und kann den aktiven Katalysator damit bedienen bis weiteres Monomer von außen in das Katalysatorpartikel nach diffundiert ist. Durch die weiche Beschaffenheit der organischen Latexpartikel kann das entstehende Polymer das Katalysatorpartikel außerdem leicht auseinandertreiben werden. Die Polymerisation kann so im ganzen Katalysatorpartikel beginnen, während das Silica-Trägermaterial nur langsam von außen nach innen fragmentieren kann.

A new post-metallocene-ti catalyst with maltolate bidentade ligand: an investigation in heterogeneous polymerization reactions in different mesoporous supports

A new titanium catalyst easily synthesized from ethylmaltol bidentate chelator ligand was studied in homogeneous and heterogeneous ethylene polymerization. The dichlorobis(3-hydroxy-2-ethyl-4-pyrone)titanium(IV) complex was characterized by 1H and 13C NMR (nuclear magnetic resonance), UV-Vis and elemental analysis. Theoretical study by density functional theory (DFT) showed that the complex chlorines exhibit cis configuration, which is important for the activity in olefin polymerization. The complex was supported by two methods, direct impregnation or methylaluminoxane (MAO) pre-treatment, in five mesoporous supports: MCM-41 (micro and nano), SBA-15 and also the corresponding modified Al species. All the catalytic systems were active in ethylene polymerization and the catalytic activity was strongly influenced by the method of immobilization of the catalyst and the type of support.

原位聚合制备聚乙烯多相材料的微结构调控

聚合物多相材料的制备作为丰富材料品种，扩展材料用途的重要手段受到了广泛地关注和深入地研究。传统的熔融共混法制备聚合物多相材料时，一般需要加入增容剂来改善各相之间的相容性，从而使多相材料的性能达到预期的目标。但是由于增容剂本身也存在分散状态的问题，所以它的加入对多相材料的性能的影响比较复杂。因此，本论文致力于用原位共聚接枝的方法和粒子破碎的方法解决多相材料的界面结合和相分散问题。首先，采用对分散相进行共聚功能化改性的方法，使分散相与乙烯共聚，聚合过程中原位生成聚乙烯接枝物，这种聚乙烯接枝物能起到增容两相的作用，提高两相界面的粘结性，将这种方法应用到有机聚苯乙烯粒子和无机磁性钴粒子体系中，并分别进行了详细的研究；其次，通过聚苯乙烯载体的结构设计，使聚苯乙烯载体催化剂具有较高并且可控的活性，在较高的活性下，聚苯乙烯载体可以破碎，破碎后的聚苯乙烯均匀地分散到乙烯聚合产物中，并且碎片达到纳米级，用这种方法可以改善多相材料的相分散。 本论文的主要工作和研究结果总结如下： 1、采用悬浮聚合制备了交联聚苯乙烯粒子（c-PS），并且在聚苯乙烯粒子的表面引入了双键；c-PS粒子在乙烯填充聚合时，可以与乙烯共聚，从而制备了表面接枝聚乙烯的聚苯乙烯微球（PS-g-PE）；PS-g-PE微球上的聚乙烯的结晶温度与纯聚乙烯的结晶温度相比提高了6℃，说明聚乙烯与聚苯乙烯间的化学连接促进了PE的结晶；PS-g-PE与PE共混后，聚苯乙烯粒子与聚乙烯基体间的界面粘结增强。 2、采用乳液聚合制备了共聚型和不可共聚型交联聚苯乙烯乳胶粒子；将两种聚苯乙烯粒子用于乙烯填充聚合制备了聚苯乙烯/聚乙烯纳米共混材料，结果发现，共聚型聚苯乙烯/聚乙烯的断面上，两相间的界面模糊，并且拉伸断面上也没有不可共聚聚苯乙烯体系中由于拉应力作用而产生的空穴，超薄切片的透射电镜结果同样说明了可共聚型聚苯乙烯体系中界面粘结性的提高；当共聚型聚苯乙烯乳胶粒子的填充量较大（20 wt%）时，聚乙烯共混材料的凝胶含量比较高，说明有更多的共聚型聚苯乙烯在聚乙烯中充当交联点。总之，共聚型聚苯乙烯的填充量在非常少时（0.1 wt%）就能达到很好的改性效果。 3、采用阴离子共聚制备了两亲性的聚苯乙烯-b-聚-2-乙烯基吡啶嵌段共聚物（PS-b-P2VP）和聚4-（3-丁烯基）苯乙烯-聚苯乙烯-聚2乙烯基吡啶的三嵌段共聚物（PBSt-b-PS-b-P2VP）；两个嵌段共聚物在甲苯中均能自组装形成以PVP为核、PS为壳的胶束；Co2(CO)8在PS-b-PVP和PBSt-b-PS-b-P2VP甲苯胶束中热分解得到了由胶束稳定分散的Co磁流体；无水无氧的钴磁流体与乙烯填充聚合后得到了磁性聚乙烯纳米复合材料；钴纳米粒子在聚乙烯中稳定分散，不会发生聚集；PBSt-b-PS-b-P2VP与乙烯共聚后，纳米粒子与聚乙烯基体的相容性进一步提高，从而解决了金属纳米粒子在聚合物中的分散以及界面增强的问题。 4、采用悬浮聚合制备了三种溶胀能力不同的聚苯乙烯交联粒子，研究了溶胀时间对聚苯乙烯载体溶胀程度的影响，以及溶胀程度对乙烯聚合和产物聚乙烯形态的影响；实验结果发现溶胀程度较大、溶胀能力较强的聚苯乙烯载体的负载量和活性都较高；通过提高载体的溶胀程度可以增加催化剂对乙烯聚合的催化活性，最终使载体充分破碎分散到乙烯聚合产物中，原位形成纳米级聚乙烯共混物；乙烯聚合的动力学研究表明载体的破碎是一个由外向内逐步发生的过程；适当的活性可以控制载体破碎的速度，从而得到颗粒形态较好的聚乙烯产物。

新型镍系烯烃聚合催化剂的合成及催化乙烯聚合反应

合成两类含有烯烃基团的镍系烯烃聚合催化剂.一类是含有酚亚胺的中性镍系烯烃聚合催化剂,测定了其中两个催化剂的单晶结构,研究了这类化合物作为单组分催化剂催化乙烯聚合反应,系统地探讨了催化剂结构、催化剂浓度、聚合温度、乙烯压力等对乙烯聚合的影响,并对得到的聚乙烯进行了DSC和高温GPC表征.另一类是含有双亚胺的阳离子镍系烯烃聚合催化剂,测定了其中一个催化剂的单晶结构,研究了这类催化剂在MMAO的存在下催化乙烯聚合反应,以及铝镍比和温度对催化剂活性和聚乙烯的影响.用两种不同的方法对双亚胺镍系烯烃聚合催化剂进行负载.一种方法是在催化剂中引入烯烃基团,在自由基引发剂的作用下与苯乙烯共聚,生成高分子化的镍系烯烃聚合催化剂,详细研究了高分子化催化剂在不同条件下催化乙烯聚合的反应.为进一步探讨杂原子是否会破坏自固载催化剂的结构,设计合成了含有杂原子氧的非茂钛、锆催化剂,测定了其中两个化合物的单晶结构.晶体结构和乙烯聚合表明杂原子的引入没有破坏催化剂的结构,聚乙烯的形态也得到改善.在此基础上,探索合成了含有混合配体的锆化合物,测定了锆中间体23的晶体结构.

聚合物负载茂金属催化剂粒子在乙烯聚合过程中的破碎行为及其应用

本论文对聚苯乙烯颗粒用作茂金属催化剂载体方面进行了研究，重点考察了载体粒子的结构设计以及聚乙烯的粒子成核模型。此外，我们基于烯烃聚合过程中的载体破碎模型提出了制备聚合物共混物的新方法。本论文的主要工作和研究成果，急结如下：1．制备了多孔性聚苯乙烯乳胶粒，并用于负载茂金属催化剂以及乙烯聚合试验。通过与对应的实心型负载催化剂对比发现，多孔型催化剂表现出更高的活性以及聚合出形态更好的聚乙烯产物，我们用催化剂粒子的破碎模型对这种现象进行了解释。最后，通过考察载体成份在聚乙烯中的分布情况给出了多孔载体在乙烯聚合过程中破碎的证据，指出这种破碎行为是提高催化剂活性和改善聚乙烯形态的根本原因。2．制备了大孔结构以及疏松结构的聚苯乙烯树脂颗粒，并用于茂金属催化剂的负载化和乙烯聚合试验。研究了载体粒子的溶胀能力以及溶胀程度对催化剂负载量和催化剂活性的影响。结果表明，随着载体溶胀度的提高，催化剂负载量和催化剂活性都得到提高。当载体粒子充分溶胀时，大孔型和疏松型催化剂显示出很高的活性，而载体溶胀程度低时则催化剂的活性很低。实验结果证明充分溶胀的载体粒子在乙烯聚合过程中已分裂成碎片，而没有溶胀的载体粒子则不能破碎，表明载体粒子是通过溶胀过程达到破碎目的的，并因此能够提高催化剂活性和改善聚乙烯产物的形态。3．我们提出了利用多孔型聚苯乙烯微球负载茂金属催化剂催化乙烯聚合过程来原位合成聚乙烯／聚苯乙烯（PE／PS）共混材料的新方法。聚苯乙烯组分首先作为载体负载催化剂，在乙烯聚合过程中破裂成碎片而均匀的分散在聚乙烯相中。我们着重考察了载体粒子的设计以及载体的破碎效果对共混物形态结构和力学性能的影响。这种方法即使没有增容剂也可以使聚苯乙烯组分以纳米级的相尺寸分散在聚乙烯基体中，得到具有细微相形态的共混物，因而能够有效的改善材料的力学性能。

二氧化硅/粘土杂化物在乙烯聚合中的应用

一、我们通过在粘土片层之间组装二氧化硅纳米颗粒的办法合成了一种粘土／二氧化硅杂化物，并用它负载茂金属催化剂。当这种负载催化剂用于乙烯聚合时，粘土片层和二氧化硅都以纳米尺寸均匀地分散在聚乙烯基体中，成功地得到力学性能较好的聚乙烯／粘土纳米复合材料。二、通过在粘土片层间组装有机硅的办法合成了一种全新的有机一无机杂化结构的中孔粘土材料。层间有机硅的框架是由苯基三乙氧基硅烷和正硅酸乙酷在层间水和有机胺作催化剂的条件下水解缩合而成。利用有机一无机杂化中孔材料的多孔性，疏水性和粘土片层可剥离性，我们把茂错催化剂负载在中孔材料的孔中，然后引发乙烯聚合制得了力学性能较好的聚乙烯／粘土纳米复合材料。用有机一无机杂化中孔粘土作载体制备聚乙烯／粘土纳米复合材料的最大优点是在低载错量的情况下（＜0.3％wt）仍然能够得到力学性能较好的聚乙烯／粘土纳米复合材料。三、利用丙胺基三甲氧基硅烷与含水的无机中孔材料反应，成功地将功能基团-（CH2）3-NH2接枝在中孔无机材料的孔壁上。这种功能化的中孔材料用于茂锆的负载和乙烯聚合。功能化的中孔粘土作载体的最大特点是在很低Al／Zr比的清况下（A1／zr＜200），仍然能够获得非常高的催化活性（＞106gPE/mol.Zr.h），继续提高Al/Zr比反而引起活性下降。功能化的中孔粘土作载体能够控制聚乙烯的形态，所得到的聚乙烯是颗粒状，堆密度也较高（0.20g/ml）。

Synthesis, Reactivity, and Characterization of Sodium and Rare-Earth Metal Complexes Bearing a Dianionic N-Aryloxo-Functionalized -Ketoiminate Ligand

The synthesis and reactivity of a series of sodium and rare-earth metal complexes stabilized by a dianionic N-aryloxo-functionalized beta-ketoiminate ligand were presented. The reaction of acetylacetone with 1 equiv of 2-amino-4-methylphenol in absolute ethanol gave the compound 4-(2-hydroxy-5-methylphenyl)imino-2-pentanone (LH2, 1) in high yield.

Synthesis and characterisation of novel functional polyolefin containing sulfonic acid groups

The strong polar group, sulfonic acid, has successfully been introduced into ethylene/allylbenzene copolymers without degradation or crosslinking via chlorosulfonation reaction with chlorosulfonic acid as a chlorosulforiating agent in 1, 1,2,2-tetrachloroethane followed by hydrolysis. The degree of sulforiation (DS) can be easily controlled by changing the ratio of chlorosulfonic acid to the pendant phenyls of the copolymer. The microstructure of sulfonated copolymers were unambiguously revealed by H-1 NMR and H-1-H-1 COSY spectral analyses, which indicates that all the sulforiation reactions exclusively took place at the para-position of the aromatic rings.

Reactivity of Rare-Earth Metal Complexes Stabilized by an Anilido-Phosphinimine Ligand

Treatment of anilido-phosphinimine-ligated yttrium mono(alkyl) complex 1a, LY(CH2Si(CH3)(3))(THF) (L = o-(2,6-(C6H3Pr2)-Pr-i)NC6H4P(C6H4)(C6H5)N(2,4,6-C6H2Me3)), with 2 equiv of phenylsilane in DME afforded methoxy-bridged complex 2, [LY(mu-OCH3)](2), via the corresponding hydrido intermediate. When excess isoprene was added to the mixture of la and phenylsilane, a eta(3)-isopentene product, 3, LY(CH2C(CH3)=CHCH3)(THF), was isolated. A lutetium chloride, LLuCl(DME) (4), was generated through the reaction of lutetium mono(alkyl) complex 1b, LLu(CH2Si(CH3)(3))(THF), with [Ph3C]-[B(C6F5)(4)]center dot LiCl accompanied by the formation of [Li(DME)(3)](+)[B(C6F5)(4)](-). Metathesis reaction of 1b with excess AlMe3 at room temperature gave a methyl-terminated counterpart, 5, LLu(CH3)(THF)(2). In all these reactions, the Ln-C-phenyl bonds of complexes 1 remained untouched.

Synthesis of novel functional polyolefin containing carboxylic acid via Friedel-Crafts acylation reaction

The strong polar group, carboxylic acid, has triumphantly been introduced into ethylene and allylbenzene copolymers without obvious degradation or crosslinking via Friedel-Crafts (F-C) acylation reaction with glutaric anhydride (GA), succinic anhydride (SA) and phthalic anhydride (PA) in the presence of anhydrous aluminum chloride in carbon disulfide. Some important reaction parameters were examined in order to optimize the acylation process. In the optimum reaction conditions, almost all of the phenyls can be acylated with any anhydride. The microstructure of acylated copolymer was characterized by Fr-IR, H-1 NMR and H-1-H-1 COSY. All the peaks of acylated copolymers can be accurately attributed, which indicates that all the acylation reactions occur only at the para-positions of the substituent of the aromatic rings. The thermal behavior was studied by differential scanning calorimetry (DSC), showing that the melting temperatures (T(m)s) of acylated copolymers with GA firstly decrease slowly and then increase significantly with the increase of the amount of carboxyl acid groups.

The synthesis and catalytic activity of poly(bis(imino)pyridyl) iron(II) metallodendrimer

The first and second generation carbosilane dendrimers with silicon hydride terminated were synthesized, and then reacted with bis(imino)pyridyl containing allyl [4-CH2==CHCH2-2,6-(Pr2C6H3N)-Pr-i==CMe(C5H3N)MeC==N(2,6-'Pr2C6H3)], in the presence of H2PtCl6 as a hydrosilylation catalyst, to afford the first and second generation carbosilane supported ligands. Complexation reactions with FeCl(2)(.)4H(2)O give rise to iron-containing carbosilane dendrimers with FeCl2 moieties bound on the periphery. The metallodendrimers were used as catalyst precursors, activated with modified methylaluminoxane, for the polymerization of ethylene. In the case of low Al/Fe molar ratio, the metallodendrimers display much higher catalytic activity towards ethylene polymerization and produce much higher molecule weight polyethylenes than the corresponding single-nuclear complex under the same conditions.

Molecular heterogeneity and crystal morphology in metallocene short chain branch polyethylene (SCBPE)

Metallocene, a newer generation of commercial polymerization catalysts for polyolefins, is best known for its "single sitednss", and the intermolecular structural homogeneity of metallocene polyethylene copolymer is a very interesting research issue. The molecular segregation effects on the crystallization, melting and crystal morphologies of metallocene SCBPE have been investigated with DSC and TEM. The multiple endothermic peaks were observed in the DSC thermograms during heating experiments. The heterogeneity increases as branching content increases, the lamellae becomes thinner, and lamellae distribution becomes broader. Both macroscopic segregation (between two crystal aggregates) and microscopic segreation (between two lamellae) have been observed when SCBPE crystallized from phase separated melt.