A review of clay-supported Ziegler–Natta catalysts for production of polyolefin/clay nanocomposites through in situ polymerization

Abedi, Sadegh; Abdouss, Majid

doi:10.1016/j.apcata.2014.01.028

Cited by 86 publications

(33 citation statements)

References 107 publications

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“…Such materials are desired for a combination of high energy densities, high permittivity, mechanical flexibility, and processability (131). Active catalyst formulations are indeed available using clay minerals, such as montmorillonite and kaolin, along with MAO and metallocene (132), preferably by adding MAO-metallocene premix to clay (133). Incorporation of a polyhedral oligomeric silsesquioxane (POSS) on a side chain via incorporation of a norbornyl-substituted POSS reportedly imbues polypropylene with enhanced thermooxidative stability (134).…”

Section: Silicamentioning

confidence: 98%

Metallocenes

Kuhlman¹

2016

Encyclopedia of Polymer Science and Technology

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Once narrowly defined as metal complexes of precise chemical formula (η 5 ‐C 5 H 5 ) 2 M, the word “metallocene” has evolved to represent a versatile class of polymerization technology that is slowly but significantly reshaping the polyolefin industry. Metallocene catalysts enable production of polyethylenes with narrow molecular weight and composition distributions, efficient incorporation of standard and nonstandard comonomers, an excellent spectrum of tacticity control in poly‐α‐olefins, and remarkable adaptability enabled by accumulated scientific endeavors relating ligand designs to polymer microstructures. Olefin polymerization is reviewed in some detail with emphasis on commercially relevant technologies, and a brief commercial overview is included. Nonpolymerization catalysis and (co)polymerization of functional monomers are also briefly summarized.

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Section: Silicamentioning

confidence: 98%

Metallocenes

Kuhlman¹

2016

Encyclopedia of Polymer Science and Technology

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“…This avoids the steric hindrance caused by the surface of the support that tends to hinder the access of monomer to the active sites, and also removes impurities. The fixation of MAO in the hydroxyl groups of clays can lead to the formation, after the addition of the metallocene complex, of stabilized catalytic sites which are similar to those of the homogeneous precursor catalysts …”

Section: Introductionmentioning

confidence: 99%

“…The fixation of MAO in the hydroxyl groups of clays can lead to the formation, after the addition of the metallocene complex, of stabilized catalytic sites which are similar to those of the homogeneous precursor catalysts. [13,14] Some researchers have also utilized triisobutylaluminum (TIBA) for chemical pretreatment of the support. The TIBA fixing mechanism in the support (clay) consists basically of two steps as follows: First of all, TIBA is added to a suspension of clay where the Si-OH acidic groups from clay surface react with the aluminum alkyl to produce a heterogeneous cocatalyst, aluminoxane, which prevents the deactivation of the metallocene complex that will be added in the next step.…”

Section: Introductionmentioning

confidence: 99%

Polypropylene Nanocomposite Employing Sodium Clay as Support for an Isospecific Metallocene Complex

Fátima

Rocha

Santos

2019

Macromolecular Symposia

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Propylene polymerization was performed using homogeneous and supported rac‐SiMe2(2‐Me‐Ind)2ZrCl2 catalysts. The supports used were commercial sodic bentonites from different sources. The influence of polymerization time and nature of catalyst support on the nanocomposites syntheses and the consequent properties of obtained composites, were evaluated at two different reaction temperatures and with two cocatalyst systems (MAO and a mixture of MAO/TIBA). The highest catalytic activities were obtained at 60 °C with the cocatalyst mixture MAO/TIBA in the reaction medium. Polymerization rate profiles were obtained as well as melting and crystallization temperatures, crystallinity degree, isotactic index, and number‐average molecular weight. The polypropylene produced with the supported catalyst pretreated with TIBA instead of MAO showed higher crystallinity degree, melting and crystallization temperatures, however, it presented lower catalyst activity. Clay exfoliation was verified by the absence of diffraction peak in the range of 2θ from 2.5° to 7° of X‐ray diffractometry analyses and by transmission electron microscopy. The thermogravimetric analyses showed an increase of PP degradation temperature of above 70 °C when synthesized with clay supported catalysts in relation to the PP obtained by means of homogeneous system.

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“…Mixing these two categories of materials, that is, polymers and nanoparticles has been led to produce polymeric nanocomposites as an attractive field with applicable yields. There are four methods in preparation of the polymer nanocomposites including melt intercalation, template synthesis, exfoliation adsorption, and in situ polymerization intercalation . But, using these methods met limitations due to the presence of the some disadvantages such as grain growth, aggregation, and low distribution in polymer matrix .…”

Section: Introductionmentioning

confidence: 99%

Improvement in mechanical properties of polyurethane‐urea nanocomposites by using modified SiO₂ nanoparticles

Yarmohammadi

Adeli

Pedram

et al. 2018

J of Applied Polymer Sci

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Poly(propylene glycol) (PPG)‐based nanocomposites have been prepared one shot using various contents of functionalized SiO2 nanoparticle as filler‐crosslinker agent. Triethoxy silyl propane‐1‐amine has been used as coupling agent for functionalization of SiO2 nanoparticle to improve its reactivity. The results revealed that the mechanical properties of the samples have been improved due to the functionalized SiO2‐nanoparticle effect on chemical and three‐dimensional physical crosslinking of the polyurethane–urea nanocomposites. Addition of the functionalized nanoparticle increased strength from 0.75 to 1.58 MPa in comparison to polyurethane sample. Moreover, storage moduli of PPG‐based polyurethane sample reduced in higher than room temperatures. While, using functionalized nanoparticle improves elasticity from 0.88 MPa in polyurethane sample to 2.84 MPa in polyurethane–urea nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46707.

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A review of clay-supported Ziegler–Natta catalysts for production of polyolefin/clay nanocomposites through in situ polymerization

Cited by 86 publications

References 107 publications

Metallocenes

Metallocenes

Polypropylene Nanocomposite Employing Sodium Clay as Support for an Isospecific Metallocene Complex

Improvement in mechanical properties of polyurethane‐urea nanocomposites by using modified SiO₂ nanoparticles

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A review of clay-supported Ziegler–Natta catalysts for production of polyolefin/clay nanocomposites through in situ polymerization

Cited by 86 publications

References 107 publications

Metallocenes

Metallocenes

Polypropylene Nanocomposite Employing Sodium Clay as Support for an Isospecific Metallocene Complex

Improvement in mechanical properties of polyurethane‐urea nanocomposites by using modified SiO2 nanoparticles

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Product

Resources

About

Improvement in mechanical properties of polyurethane‐urea nanocomposites by using modified SiO₂ nanoparticles