PREPARATION OF HIGHLY BRANCHED POLYETHYLENE WITH ACENAPHTHENEDHMINE NICKEL CHLORIDE/DIETHYLALUMINUM CHLORIDE CATALYST

The homogeneous catalyst system [ArN = C(Nap) - C(Nap) = NAr]NiCl2 (Nap = 1,8-naphthdiyl, Ar = 2,6-diisopropylphenyl)/AlEt2Cl has been prepared and examined for ethylene polymerization. Polymerization conditions such as cocatalyst, Al/Ni molar ratio and polymerization temperature (Tp) have a great effect on catalytic activity and properties of polyethylenes (PE). The activity of 5.1×105g PE/mol Ni·h was obtained by the catalyst, activated with AlEt2Cl at 120 of Al/Ni ratio and 30℃. Especially, Tp had a pronounced influence on branches and molecular weight of PE. Branching degree of PE increased with increasing temperature whereas their molecular weight decreased correspondingly. At Tp lower than about 70℃, the resultant PE was an elastic material. When Tp was higher than 70℃, the product was a viscous oil. The resultant PE was confirmed by 13C-NMR to contain significant amounts of not only methyl but also ethyl, propyl, butyl, amyl, and longer branches (longer than six carbons). According to gel permeation chromatographic measurement, the weight average molecular weights of the polymers obtained ranged from 3.6×103 to 2.3×105.     

α-二亚胺镍复式催化剂/MAO制备高支化的长支链聚乙烯

研究了由两种α-二亚胺镍催化剂[Cat1:α-萘基-丁二亚胺二溴化镍,Cat2:2,6-二异丙基苯基苊二亚胺二溴化镍]组成的复式镍催化剂在MAO活化下催化单一乙烯聚合.可制备得到支化度高达上百个支链(每1000个碳),长支链的比例占到30%左右的聚乙烯.13C-NMR、GPC、DSC、WAXD、DMA结果表明此复式催化剂催化乙烯聚合可得到分子量较高、分子量分布较窄的长支链聚乙烯弹性体.在合适的条件下,此复式催化体系还具有促进提高催化活性的良好协同作用,其聚合活性比两种单一催化剂都高(4·6×105g PE/mol Ni·h).     

MORPHOLOGY AND PROPERTIES OF LINEAR LOW-DENSITY POLYETHYLENE HIGHLY LOADED WITH ALUMINUM HYDROXIDE

An experimental study was carried out to investigate the effects of isopropoxy tri(dioctyl pyrophosphoryl) titanatecoupling agent on the mechanical performance, rheological property and microstructures of polyethylene highly loaded withaluminum hydroxide (Al(OH)_3) composite. It was found that the addition of coupling agent results in reduced tensile strengthand increased percentage elongation of the filled systems. Silane crosslinkable polyethylene substituting for polyethylene asmatrix improves the tensile strength of the composite, while the percentage elongation of the composite still remains at adesired level. Melt viscosity of the composite will be improved by addition of titanate coupling agent. Microstructures of thecomposites were also studied by means of the scanning electron microscopy (SEM) technique. SEM micrographs reveal thatfiner dispersion of Al(OH)_3 will be obtained upon treatment of titanate and a transition from brittle to tough fracture takesplace before and after silane crosslinking structure is introduced into polyethylene highly filled with Al(OH)_3 composite.     

镍配合物催化乙烯低聚/聚合的研究进展

催化乙烯低聚或聚合的镍配合物催化剂研究,不仅帮助提供探索乙烯配位聚合机理的催化剂模型,更为重要的帮助探讨不同催化剂模型下的催化剂活性和选择性,为工业界寻找具有潜在应用价值的高效催化剂奠定基础.同时,利用镍配合物催化剂容易导致所得聚烯烃树脂产生支链的特点,有望制备具有优异性能的支化聚烯烃树脂.本文综述了近年来镍配合物在乙烯低聚或聚合催化剂研究方面的进展,并特别强调了催化剂结构和催化性能之间的内在规律.     

以有机镍配合物为前体制备担载镍催化剂的研究

描述了以镍单核配合物ＮｉＣｐ２和簇合物Ｎｉ３Ｃｐ３Ｎ－ｔ－Ｃ４Ｈ９为前体的ＳｉＯ２载镍催化剂的制备，通过元素分析、ＴＲＲ、ＴＰＤＥ、ＸＰＳ，ＣＯ吸附和苯加氢反应对以镍配合物和簇合物为前体制备的催化剂的性能及其制备过程了研究和表征。结果表明，镍与合物和簇合物在担载过程中同载体ＳｉＯ２表面发生了相互作用，其化学组成发生了变化，在苯加氢反应中，此催化剂的活性比以Ｎｉ（ＮＯ３）２为前体制备的催化剂高得多，     

新型镍催化体系合成Cis-1,4聚丁二烯的研究

本文研究了以加氢汽油为溶剂的Ni(Naph)_2-Al(i-Bu)_2OR-BP_3·OEt_2及Ni(NaPh)_2-Al(i-Bu)_2OAr-BF3·OEt_2两体系对丁二烯的催化聚合活性、聚合物分子量、微观结构等。各种Al(i-Bu)_2OR或Al(i-Bu)_2OAr为助催化剂组成的新型镍催化体系对丁二烯聚合都有较高的催化活性,所得聚合物Cis-1,4含量在96％以上。磁化率和紫外可见光谱研究证明,在Al(i-Bu)_2OR体系中以Ni(Ⅰ)为主及小量未还原的Ni(Ⅱ);Al(i-Bu)_2OAr中Ni(Ⅰ)及Ni(O)共存。     

SYNERGISTIC MODIFICATION OF EPDM AND CROSSLINKING AGENT IN IMMISCIBLE BLENDS OF POLYVINYL CHLORIDE WITH LOW DENSITY POLYETHYLENE

The synergism of ethylene-propylene-diene monomer copolymer （EPDM） and dicumyl peroxide （DCP, a crosslinking agent） in low density polyethylene （LDPE）/poly（vinyl chloride） （PVC） blends was investigated. When EDPM and DCP are added to the blends simultaneously, the tensile properties could be improved significantly, especially for the blends with LDPE matrix. For example, incorporation of 10/1 （mass ratio） EPDM/DCP improves the tensile strength of the LDPE/PVC （mass ratio 80/20） blend from 7.9 MPa to 8.5 MPa and the elongation at break from 25% to 503%. Results from selective extraction, phase-contrast microscopy and thermal analysis reveal that the improvement in the tensile properties of the blends with LDPE matrix is principally due to the formation of a fine crosslinking network of the LDPE and EPDM phase. The outstanding modification effect of EPDM is explained by its dual functions： molecular entanglement with LDPE and the enhanced efficiency of DCP in the blends.     

SELECTIVE PREPARATION OF α,α-DICHLOROKETONES WITH COPPER(II) CHLORIDE

ABSTRACT

Aryl and enolizable alkyl ketones react with copper(II) chloride in dimethylformamide to produce the corresponding α,α-dichloroketone in high yields. Remarkable qualities of the process are high selectivity towards these substrates, undetected polychlorinated by-products, easy work-up, commercially available reagents and HCl as the only waste stream.     

蒙脱土负载聚合催化剂用于乙烯原位共聚制备LLDPE

将蒙脱土 (MMT)负载的聚合催化剂rac Et(Ind) 2 ZrCl2 和均相低聚催化剂 { [(2 ArNC(Me) ) 2 C5H3N]FeCl2 } (Ar=2 ,4 C6 H4 (Me) 2 )组成双功能催化体系用于乙烯原位共聚制备线性低密度聚乙烯 (LLDPE) .通过调节两种催化剂之间的比例和MAO的用量制备了一系列支化度不同的LLDPE产品 .聚合反应动力学曲线表明 ,两种催化剂表现出各自的乙烯吸收特征 ,蒙脱土负载化的共聚催化剂催化乙烯聚合时反应平稳易控制 .DSC曲线表明 ,聚合物的熔点和结晶度随Fe Zr的增大而减小 .用密度梯度法测得的聚合物密度随Fe Zr的增大而降低 .从1 3C NMR谱图上可以看到 ,得到的聚合物是LLDPE ,其支化度随Fe Zr的增大而增大 ,聚合物中仍含有未共聚的α 烯烃 ,这一点从GPC上也能得到验证 .扫描电镜 (SEM)照片表明用这种双功能催化剂共聚得到的LLDPE具有良好的形态     

铁系亚胺基吡啶复配催化乙烯原位共聚产物的表征

Branched polyethylene from ethylene as single monomer was prepared by the tandem catalyst system of {2-[2-Me C6 H4 N=Me)]2 C5H3N} FeCl2 (1) and {2,6-[1-(2,6-Me2-4-Br-C6H4N=(Me)]2C5H3N} FeCl2 (2) activated with methylaluminoxane (MAO) . The products of polymerization were characterized by DSC, GPC and ^13C-NMR. The results revealed that the copolymer produced by in situ copolymerization of ethylene was a mixture of branched polyethylene and α-olefin. The content of α-olefin in the mixture was increased with increasing the molar ratio of catalysts 1/2. The MWD paramelers of polyethylene and copolymer were 28.6 and 7.9, respectively. ^13C-NMR spectra showed that there were ethyl groups, butyl groups and long chain alkyl groups in the copolymer. The average degree of branching of such branched polyethylene was less than 5C/1000C.     

SYNTHESIS AND CRYSTAL STRUCTURE OF NICKEL COMPLEX WITH TRIS(3-AMINOPROPYL)AMINE

Abstract

The crystal structure of [Ni(trpn)(NCS)₂] (trpn = tris(3-aminopropyl)amine) has been determined, in which the nickel(II) complex is octahedral. The complex forms a three-dimensional network through weak intermolecular hydrogen bonds S_NCS … H-N_amine and S … S contacts.     

Linear/branched Block Polyethylene Produced by α-Diimine Nickel(Ⅱ)Catalyst and Bis(phenoxy-imine) Zirconium Binary Catalyst System in the Presence of Diethyl Zinc

In order to promote development of linear/branched block polyethylenes based on new catalytic systems,we synthesized a novel α-diimine nickel(Ⅱ) complex with isopropyl substituents on ortho-N-aryl and hydroxymethyl phenyl substituents on para-N-aryl structures.The activity of α-diimine nickel(Ⅱ) catalyst was 3.02×106 g·molNi-1·h-1 at 70 ℃,and resultant polyethylene possessed 135/1000C branches.The linear/branched block polyethylenes were synthesized from ethylene polymerization catalyzed by the α-diimine nickel(Ⅱ) complex/bis(phenoxy-imine) zirconium in the presence of diethyl zinc.With the addition of ZnEt2 (from 0 to 400),the melting peak of resultant polyethylene changed from a single melting peak to bimodal melting peaks.The molecular weights of resultant polyethylene ranging from 26.8 kg/mol to 17.1 kg/mol and PDI values varying gradually from 24.4 to 15.2 were obtained via adjusting ZnEt2 equiv.and molar ratio of two catalysts.In addition,the branching degree of the polyethylene increased from 13/1000C to 56/1000C with the increase of the proportion of α-diimine nickel(Ⅱ) catalyst.Using this binary catalyst system,the reaction temperature of chain shuttling polymerization can be carried out at 70 ℃,which is more conducive to industrial application.     

mCMC-PEG/mCS-PEG双极膜的制备与表征

以Fe3+改性羧甲基纤维素(mCMC)和聚乙二醇(PEG)共混为阳膜;以戊二醛改性壳聚糖(mCS)和聚乙二醇共混为阴膜,制备了mCMC-PEG/mCS-PEG双极膜.以FTIR测定了膜红外光谱,以扫描电镜观察了膜表面和界面层的形态,以TG进行膜的热重分析.测定了mCMC-PEG和mCS-PEG不同比例共混膜的含水率、离子交换容量、溶胀度,及mCMC-PEG/mCS-PEG双极膜的电性能.研究结果表明,在双极膜材料中引入亲水性的聚乙二醇后,因分子间的相容性增大,故而提高了双极膜的离子交换容量,并减小了膜的溶胀性.当CMC∶PEG质量比等于10∶1和CS∶PEG质量比等于2∶1时所制得的双极膜具有良好的电化学性能,在酸碱溶液中机械强度高、溶胀小.     

镍(Ⅱ)-N-(对位取代苯基)亚氨基二乙酸配合物的生成反应动力学及机理研究

本文选择N-(对位取代苯基)亚氨基二乙酸(p-RC_6H_4N(CH_2COOH)_2,R=CH_3O,CH_3,H,Cl,简写为PRPh_1DA,以NR(OH)_2或H_2L表示)为配体,采用断流分光光度计研究了Ni(Ⅱ)与此配体生成配合物的反应动力学。结果发现,两性离子具有较高的反应活性,且反应活性随配体碱性增大而降低,其反应机理与二齿配体的反应很相似。 实验方法见[1]。其中配体N-(对位取代苯基)亚氨基二乙酸的合成见[2],用KNO_3控制离子强度0.1mol·dm~(-3),动力学研究最佳波长250nm,反应温度25.0±0.31℃。     

水溶性镍(Ⅱ)络合物催化苯乙烯环氧化

用简单的“模板”合成法合成了氯化－（１，４，８，１１－四氮杂环十四－１，３，８，１０－四烯）合镍（Ⅱ）（Ｎｉ（ｔａｃｔｄｔｅ）Ｃｌ２）和氯化－（１，４，８，１１，１５－五氮杂环十八－１，３，８，１０－四烯）合镍（ＩＩ）（Ｎｉ－（ｐａｃｏｄｔｅ）Ｃｌ２）两种新络合物，用ＮａＯＣｌ水溶液作氧化剂，水溶性镍（ＩＩ）络合物为催化剂，在无有机溶剂和相转移剂存在的条件下，环氧化苯乙烯制得苯基环氧乙烷，其中Ｎｉ     

ETHYLENE POLYMERIZATION AND COPOLYMERIZATION WITH POLAR MONOMERS BY A NEUTRAL NICKEL CATALYST COMBINED WITH CO-CATALYST OF Ni（COD）2 OR AL（i-Bu）3

A neutral nickel (Ⅱ) catalyst D, { [O-(3-cyclohexyl)(5-Cl)C6H2-ortho-C(H)=N-2,6-C6H3(i-Pr)2]Ni(Ph3P)(Ph)} has been synthesized and characterized by 1H-NMR, FTIR and elemental analysis. The results indicate that Al(i-Bu)3 is an effective cocatalyst for the neutral nickel catalyst. With bis(1,5-cyclooctadiene) nickel(0) [Ni(COD)2] or Al(i-Bu)3 as a cocatalyst, the neutral nickel catalyst D is active for ethylene polymerisation and copolymerisation with polar monomers (tertbutyl 10-undecenoate(BU), methyl 10-undecenoate (MU), allyl alcohol (AA) and 4-penten-1-ol (PO)) under mild conditions.The resulting polymers were characterized by 1H-NMR, FTIR, DSC, and GPC. From the comparative studies, Ni(COD)2 is more active than Al(i-Bu)3 for ethylene homopolymerization, while Al(i-Bu)3 is more effective than Ni(COD)2 for ethylene copolymerisation with polar monomers. The polymerization parameters which affect both the catalytic activity and properties of the resulting polyethylene were investigated in detail. Under the conditions of 20 μmol catalyst D and Ni(COD)2/D = 3(molar ratio) in 30 mL toluene solution at 45℃, 12 × 105 Pa ethylene for 20 min, the polymerization activity reaches as High as7.29×105gPE.(mol.Ni·h)-1and Mηis 7.16×104g.mol-1.For ethylene copolymerization with polar monomers,the effect of comonomer concentrations was examined. As high as 0.97 mol% of MU, 1.06 mol% of BU, 1.04 mol% of AA and 1.37 mol% of PO were incorporated into the polymer, respectively, catalyzed by D/Al(i-Bu)3 system.     

STUDIES OF MIXED LIGAND COMPLEXES FROM DIALKYLDITHIOPHOSPHATE AND THIOSEMICARBAZIDE OR THIOSEMICARBAZONES WITH NICKEL(II)

The complexes [Ni{(RO)₂PS₂}₂Tsc], [Ni{(RO)₂PS₂}₂ApTsc], and [Ni{(RO)₂PS₂}FurTsc.2H₂O] where R = methyl (Me), ethyl (Et) or propyl (Prop); Tsc = thiosemicarbazide, ApTsc = 2-acetylpyridine-thiosemicarbazone, and FurTsc = furfuraldhydethiosemicarbazone have been synthesized and characterized by elemental analysis, conductance measurements, and spectral studies (IR, UV-Vis, and mass). Thermal studies of the complexes have been carried out using TG and DTG techniques. An octahedral structure has been proposed for all types of the complexes. A representative types of the complexes are tested against various pathogenic bacteria and fungi. The [Ni{(EtO)₂PS₂}₂ApTsc] shows a high degree of activity against bacteria and fungi; this may be attributed to the pyridyl ring of the 2-acetylpyridinethiosemicarbazone ligand.     

OPTICAL PROPERTIES OF IPN-LIKE NETWORKS. II. POLYETHYLENE/POLY-(BUTYLMETHACRYLATE-CO-METHYLMETH-ACRYLATE) COPOLYMER SYSTEMS

IPN-like systems, made of Poly[butylmethacrylate(BMA)-co-methylmethacrylate (MMA)] copolymers and Low Density Polyethylene (PE) networks, were synthesized by a procedure described in previous papers.

The initial PE/copolymer molar ratio was kept constantly equal to one for all the samples. Different molar BMA/MMA copolymer ratios (50/50, 60/40, 80/20, 90/10 100/0) and a molar percentage of 1.0% of the copolymer crosslinker, 1,4-Butandioldimethacrylate (BDDM), were used.

The samples obtained were analyzed by DSC, WAXS, swelling in CCl₄, and dynamic-mechanical tests. PE crystallinity was lowered by the network formation and slightly increased, whereas, the overall network density decreased, with enhancing the BMA content.

Optical investigations were performed in a temperature range between room temperature (R.T.) and 180°C, using MMA as comonomer of BMA, instead of Styrene (S), as well as a different crosslinker (BDDM instead of DVB).

All the IPN's showed the matching-mismatching optical transition of R.I., with temperatures corresponding to a transparency condition. The larger the BMA content, in the initial reactant MMA-BMA comonomeric mixture, the higher such temperatures. An analytical expression was found relating this temperature to the copolymer composition.     

CRYSTALLIZATION AND MECHANICAL PROPERTIES OF BLENDS OF METALLOCENE SHORT CHAIN BRANCHED POLYETHYLENE WITH CONVENTIONAL POLYOLEFINS

Metallocene-catalyzed short chain branched polyethylene (SCBPE) was blended with LDPE, HDPE, PS, EPDM and iPP in the weight proportions of 80 and 20. The crystallization and mechanical properties of these blends were studied by PLM, DSC and DMA. It has been observed in PLM that SCBPE/LDPE, SCBPE/HDPE and SCBPE/EPDM can form band spherulites whose band width and size are both smaller than that of the pure SCBPE. Tiny crystallites are observed in the completely immiscible SCBPE/PS blend. The crystallites in SCBPE/iPP are very small and only irregular spherulites are seen. The crystallization kinetics and mechanical properties of SCBPE are greatly affected by the second polyolefin, but in a different way, depending on the phase behavior and the modulus of the second components. SCBPE may be phase miscible in the melt with HDPE, LDPE and EPDM and co-crystallize together with HDPE or LDPE during cooling. A big change of crystal morphology and crystallization kinetics is seen in SCBPE/iPP blend compared with pure SCBPE and the lowest tanδ is also seen for this system. DMA results show that the tensile modulus of the blends has nothing to do with phase behavior, but only depends on the modulus of the second component.     

双[N,O]配体合镍催化剂/MAO催化MMA聚合的研究

合成了双[水杨醛(对硝基苯)亚胺]合镍催化剂A和双[水杨醛(对甲氧基苯)亚胺]合镍催化剂B.该两种双[N,O]配体合镍配合物/MAO催化体系能有效地催化极性单体甲基丙烯酸甲酯(MMA)聚合,催化活性可高达105gPMMA/(molNi.h).其中配体对位含有硝基吸电子(共轭)效应的催化剂A/MAO体系有相对较高的聚合反应热稳定性,温度达50℃时仍具有高催化活性.配体对位含有甲氧基推电子(共轭)效应的催化剂B/MAO则在30℃和Al/Ni摩尔比为600时表现出最高的催化活性.催化剂B/MAO体系催化得到PMMA的链序列结构以间规为主(含高达73.2%rr三元组),具有较高的玻璃化转变温度(Tg=106.4℃).