Olefin polymerisation with hafnocenes: A bridged alicyclic alcohol as a ligand and as the hafnocene modifier

Grafov, Andriy; Firme, Caio Lima; Grafova, Iryna; Benetollo, Franco; Dias, Marcos L.; Abadie, M. J. M.

doi:10.1016/j.polymer.2005.07.076

Cited by 8 publications

(9 citation statements)

References 28 publications

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“…Comparison of our results with those previously published indicates the presence of nonfunctionalized aliphatic chains absorbed on the clay particle surface is necessary, but evidently not sufficient for efficient compatibilization with the PP matrix. A certain degree of the surfactant molecule functionalization is crucial for better compatibilizing performance.…”

Section: Resultssupporting

confidence: 61%

“…They find a variety of applications as catalysts, ion‐exchangers, drugs, agricultural, cosmetic, and nutritional ingredients . Nowadays, Mg‐Al LDH may be considered as “green” filler to improve mechanical properties, enhance fire retardancy, and reduce photodegradation of PP . Preparation and characterization of different polyolefin‐LDH composites reported in the literature involve the inorganic phases modified by long‐chain aliphatic fatty acid anions like stearate or lauryl sulphate in combination with PP ‐g‐ MA compatibilizer.…”

Section: Introductionmentioning

confidence: 99%

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Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Araújo

Grafova

Marques

et al. 2013

J of Applied Polymer Sci

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Polypropylene (PP) is the second most widespread commodity polyolefin. Even a small quantity of inorganic component is sufficient to achieve significant improvement of stiffness, strength, thermal stability, biodegradability, etc. The major drawback of inorgano-organic composite materials is insufficient compatibility of the PP matrix with inorganic filler. A suitable choice of the layered double hydroxide-modifying anion opens a possibility to obtain PP-inorganic nanocomposites without a need to use compatibilizers like maleic anhydride grafted PP. The nanocomposites were prepared by melt blending in a twin-screw mini-extruder and characterized by dynamic mechanical thermal analysis, and electron microscopy. Nonpolar PP matrix mix uniformly with clay organophilized with functionalized surfactant acids, giving rise to composites with improved thermo-mechanical properties. Influences of the anionic modifier and the filler content (2 or 5% w=w) on mechanical properties and nanoscale structure of the composites are discussed.As far as inorganic layered components are concerned, extensive deal of research was dedicated to natural clay minerals and their organophilic derivatives. 1,4,7,8 The main reasons of such interest were a low cost, relatively low layer charge density and hence, easy exfoliation of phillosilicate-based materials. 9 However, their

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Section: Resultssupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Araújo

Grafova

Marques

et al. 2013

J of Applied Polymer Sci

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“…Chlorine and methyl r-bonded groups do not affect the stereo-and regioregularity of the produced polymers via bent metallocene catalysts. However, voluminous r-bonded alcoholato ligands can affect either the molecular weight or the regioregularity of the produced polypropylenes [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Topological study of bis(cyclopentadienyl) titanium and bent titanocenes

Firme

Pontes

Antunes³

2010

Chemical Physics Letters

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The electronic nature of ferrocene, titanocene and some bent titanocenes was analyzed by QTAIM. PBE1PBE-optimised geometrical data agreed well with X-ray diffraction data, this method being chosen to extract and analyze the wave functions of all studied metallocenes within the QTAIM framework. Within the studied metallocenes, the number of bond paths can be used as an indicative of their stability. The Ind 2 Ti(CH 3 ) 2 has less Ti-C bond paths than the Cp 2 Ti(CH 3 ) 2 as well as the Cp 2 Ti has less C-Mt bond paths than Cp 2 Fe. These results concords with the smaller stabilities of Ind 2 Ti(CH 3 ) 2 and Cp 2 Ti relative to their counterparts.

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“…60 The tert-butoxy ligand bonding is also similar to that in 2.2.5. CpTiBr 2 (O t Bu) (5). Similar to 4, there are two crystallographically independent but closely similar molecules in the unit cell of 5; only molecule "A" will be discussed here.…”

Section: Resultsmentioning

confidence: 99%

Multicomponent Mechanochemical Synthesis of Cyclopentadienyl Titanium tert-Butoxy Halides, Cp_xTiX_y(O^tBu)_4–(x+y) (x, y = 1, 2; X = Cl, Br)

2018

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Titanium tert -butoxy halides of the formula Cp x TiX y (O t Bu) 4–( x + y ) ( x , y = 1, 2; X = Cl, Br) have been prepared thorough milling the reagents without solvent. In the case of the chloride derivatives, Cp 2 TiCl 2 is used as a starting material; in the case of the bromides, a mixture of LiCp, TiBr 4 , and Li[O t Bu] is used. The stoichiometric ratios of the starting materials are reflected in the major products of the reactions. Single-crystal X-ray structures are reported for Cp 2 TiCl(O t Bu), Cp 2 TiBr(O t Bu), and CpTiBr 2 (O t Bu), as well as for Cp 2 TiCl(O i Pr) and a redetermination of Cp 2 TiCl(OMe). The tert -butoxy derivatives are notable for their nearly linear Ti–O–C angles (>170°) that reflect Ti–O π-bonding, an interpretation supported with density functional theory calculations.

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Olefin polymerisation with hafnocenes: A bridged alicyclic alcohol as a ligand and as the hafnocene modifier

Cited by 8 publications

References 28 publications

Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Topological study of bis(cyclopentadienyl) titanium and bent titanocenes

Multicomponent Mechanochemical Synthesis of Cyclopentadienyl Titanium tert-Butoxy Halides, Cp_xTiX_y(O^tBu)_4–(x+y) (x, y = 1, 2; X = Cl, Br)

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Olefin polymerisation with hafnocenes: A bridged alicyclic alcohol as a ligand and as the hafnocene modifier

Cited by 8 publications

References 28 publications

Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Properties and nanoscale structure of polypropylene‐layered double hydroxide composites prepared by compatibilizer‐free way

Topological study of bis(cyclopentadienyl) titanium and bent titanocenes

Multicomponent Mechanochemical Synthesis of Cyclopentadienyl Titanium tert-Butoxy Halides, CpxTiXy(OtBu)4–(x+y) (x, y = 1, 2; X = Cl, Br)

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Multicomponent Mechanochemical Synthesis of Cyclopentadienyl Titanium tert-Butoxy Halides, Cp_xTiX_y(O^tBu)_4–(x+y) (x, y = 1, 2; X = Cl, Br)