Polyethylenes produced with zirconocene immobilized on MAO-modified silicas

Bianchini, Daniela; Bichinho, Kátia M.; Santos, João Henrique Zimnoch dos

doi:10.1016/s0032-3861(02)00129-5

Cited by 42 publications

(21 citation statements)

References 23 publications

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“…It can be observed that, on the one hand, the polydispersity indices are approximately constant, as expected for these single-site-catalyzed copolymers [26] and, on the other hand, within each series, the copolymers have a similar molecular weight. Therefore, it will be considered in the following that these variables are not relevant for discussion of the changes in the different properties of the samples for a particular copolymer series, and the comonomer content is the most relevant parameter.…”

Section: Resultssupporting

confidence: 67%

Metallocenic Isotactic Poly(propylene) and its Copolymers with 1‐Hexene and Ethylene

Arranz-Andrés

Suárez

Peña

et al. 2007

Macro Chemistry & Physics

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A comprehensive study of the structure and properties has been performed for copolymers of propylene‐1‐hexene, CiPH, and propylene‐ethylene, CiPE, synthesized by an isotactic metallocene catalyst system. The comonomer content constitutes the most important factor affecting the structure and properties of these CiPH and CiPE copolymers, although the length of the comonomer is also very important. Thus, a considerable decrease in crystallinity is observed in the two kinds of copolymers as the comonomer content increases. The structure in the CiPH copolymers evolves, however, from the typical, monoclinic crystal lattice to mesomorphic‐like, ordered entities for the highest 1‐hexene molar fraction, whereas in the CiPE copolymers the structural evolution with molar fraction goes from a monoclinic lattice to an almost amorphous material. All of these variations in crystal structure significantly influence the viscoelastic and mechanical behavior of these CiPH and CiPE copolymers. Consequently, the location and intensity of the different relaxation mechanisms, as well as the rigidity parameters (storage and Young's moduli and microhardness) and deformation mechanism are strongly dependent upon composition.magnified image

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Section: Resultssupporting

confidence: 67%

Metallocenic Isotactic Poly(propylene) and its Copolymers with 1‐Hexene and Ethylene

Arranz-Andrés

Suárez

Peña

et al. 2007

Macro Chemistry & Physics

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“…It is worth mentioning that according to previous study, higher catalyst activity was found in the case of grafting (nBuCp) 2 ZrCl 2 on MAO-modified silica bearing 2-4 wt % Al/SiO 2 . 41 Similar results were observed in the case of grafting{Tp Ms* }TiCl 3 on MAO-modified silica, bearing 4 wt % Al/SiO 2 .…”

Section: Resultssupporting

confidence: 74%

Supported hybrid catalysts based on zirconocene and tris(pyrazolyl)borate titanium derivatives

Pires

Gil

Rohrman

et al. 2005

J of Applied Polymer Sci

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A series of hybrid supported catalysts were prepared by combining (iBuCp) 2 ZrCl 2 and {Tp Ms* }TiCl 3 complex (Tp Ms* ϭ HB(3-mesityl-pyrazolyl) 2 (5-mesityl-pyrazolyl) Ϫ ) sequentially grafted onto MAO (methylaluminoxane)-modified silica according to a Plackett Burmann 2 3 design. Supported catalysts were prepared taking into account the immobilization order, silica pretreatment temperature, and grafting temperature. Grafted metal content was comparatively determined by Rutherford backscattering spectrometry (RBS), X-ray photoelectronic spectroscopy (XPS), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). The resulting catalysts were evaluated in terms of catalyst activity and polymer properties. According to RBS measurements, grafted metal content remained comprised between 0.1 and 0.5 wt % Zr/SiO 2 and 0.1 and 0.3 wt % Ti/SiO 2 depending on the immobilization order and on silica pretreatment temperature. All the systems were shown to be active in ethylene polymerization having external MAO as cocatalyst. Catalyst activity seemed to be governed by the zirconocene species, influenced slightly by Ti ones. Resulting polymers were characterized by DSC and GPC. The polyethylenes mostly presented higher molecular weight than those produced by homogeneous catalysts or by zirconocene grafted on bare or on MAO-modified silica.

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“…This technique has been applied very successfully to industries, to the routine determination in polyethylene and polypropylene samples of the following elements: aluminum, bromine, calcium, chlorine, magnesium, potassium, sodium, titanium and vanadium [43]. The WD-XRF method was also used for the determination of elements in the commercial polymers produced by zirconocene (Al), Ziegler-Natta (Ti and V), Philips (Cr) and metallocene (Zr) technology [44,45]. Another application of this technique is the determination of metals (Co, Cu, Fe, Ni and Zn) in polybutadiene, polyisoprene and polyester resins [46].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of a new copper(II) ion-imprinted polymer

Kuras

Więckowska

2015

Polym. Bull.

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In this study, a new copper(II) ion-imprinted polymer (Cu(II)-IIP) was synthesized by the precipitation method. Itaconic acid, ethylene glycol dimethacrylate and 2,2 0 -azobisisobutyronitrile were used as functional, cross-linking monomer and a free-radical initiator, respectively. This polymer has been characterized on the basis of Fourier transform infrared spectroscopy and surface area measurements. The imprinted Cu(II) ions were completely removed from the polymer by leaching with the mixture of 0.1 M EDTA and 1 M HCl. The optimum pH for the adsorption of Cu(II) on to the polymer was 6. The selective performance of the polymer was compared to non-imprinted polymer (NIP) for the binary mixture Cu 2? /Ni 2? and Cu 2? /Zn 2? . The relative selectivity of Cu(II)-IIP was 12.8 and 32.4 times greater than that of NIP as compared with the Zn 2? and Ni 2? ions, respectively. At optimal pH value, the maximum static adsorption capacity of Cu(II)-IIP and NIP was found to be 14.8 and 4.08 mg/g, respectively.

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Polyethylenes produced with zirconocene immobilized on MAO-modified silicas

Cited by 42 publications

References 23 publications

Metallocenic Isotactic Poly(propylene) and its Copolymers with 1‐Hexene and Ethylene

Metallocenic Isotactic Poly(propylene) and its Copolymers with 1‐Hexene and Ethylene

Supported hybrid catalysts based on zirconocene and tris(pyrazolyl)borate titanium derivatives

Synthesis and characterization of a new copper(II) ion-imprinted polymer

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