Muitos estudos recentes estão direcionados à área de produção de nanocompósitos poliolefínicos já que eles melhoram as propriedades dos polímeros em muitas aplicações. O desafio mais importante é a obtenção de uma boa dispersão das cargas de reforço na matriz polimérica. É consenso nos estudos realizados que a dispersão conduzida pela polimerização in situ é a mais eficiente, conferindo ao sistema, adicionalmente, as vantagens da catálise heterogênea. Esta contribuição oferece uma revisão bibliográfica das características das cargas de reforço mais empregadas, de sua utilização como suporte de catalisadores metalocênicos e da aplicação na produção in situ de nanocompósitos.
Reviews • J. Braz. Chem. Soc. 25
(12)
• Dez 2014 • https://doi.org/10.5935/0103-5053.20140247 linkcopiar
Metallocene Supported on Inorganic Solid Supports: an Unfinished History
Autoria
person Aline C. dos Ouros
schoolMicro and Mesoporous Molecular Sieves Group, Institute of Chemistry, University of Campinas, Rua Monteiro Lobato, 270, 13083-861 Campinas-SP, BrazilUniversity of CampinasBrazilCampinas, SP, BrazilMicro and Mesoporous Molecular Sieves Group, Institute of Chemistry, University of Campinas, Rua Monteiro Lobato, 270, 13083-861 Campinas-SP, Brazil
person Michèle O. de Souza
schoolLaboratory of Reactivity and Catalysis, Institute of Chemistry, University of Rio Grande do Sul, Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre-RS, BrazilUniversity of Rio Grande do SulBrazilPorto Alegre, RS, BrazilLaboratory of Reactivity and Catalysis, Institute of Chemistry, University of Rio Grande do Sul, Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre-RS, Brazil
person Heloise O. Pastore
*
schoolMicro and Mesoporous Molecular Sieves Group, Institute of Chemistry, University of Campinas, Rua Monteiro Lobato, 270, 13083-861 Campinas-SP, BrazilUniversity of CampinasBrazilCampinas, SP, BrazilMicro and Mesoporous Molecular Sieves Group, Institute of Chemistry, University of Campinas, Rua Monteiro Lobato, 270, 13083-861 Campinas-SP, Brazil
Aline Cristiane dos Ouros received her BSc degree in 2009 and her MSc degree in 2011 from the Federal University of Santa Catarina, working with proton exchange membrane fuel cell and electrical conductive polymer nanocomposite production. She is currently completing her PhD in Sciences at the University of Campinas in the Micro- and Mesoporous Molecular Sieves Group, under the supervision of Prof Pastore, working with in situ production of polymer nanocomposites. Her research interests are polymerization, polymer nanocomposites and synthesis of fillers for nanocomposites.
Michèle Oberson de Souza is Associated Professor at the Department of Physical-Chemistry of the Institute of Chemistry at the Federal University of Rio Grande do Sul (UFRGS) in Porto Alegre, where she develops her research since 1987. Her main research interests concern the conversion of light olefin oligomerization and polymerization, reactions catalyzed by heterogeneized organometallic systems to improve the production of linear and/or terminal oligomers and special polymers respectively. The grafting of active species onto inorganic nano-structured materials and the development of biphasic processes using ionic liquids are then studded. She is presently co-coordinator of the Laboratory of Reactivity and Catalysis that was, until November 2013, headed by Prof Roberto Fernando de Souza.
Heloise de Oliveira Pastore has been based in the Inorganic Chemistry Department, at the Chemistry Institute of the University of Campinas since 1994, where, at the moment, she holds a Full Professor position. Her research interests include the synthesis and modification of micro and mesoporous materials and of layered structures. The organization of molecules and entities at, and by, organoinorganic interfaces is in the core of the group’s research. In particular, the transference of properties of lamellar materials to 3D molecular sieves, and vice-versa, through inclusion of heteroatoms in the structures or by topotactic/ hydrothermal conversions has been actively studied by the group. She is presently the scientific coordinator of the Micro- and Mesoporous Molecular Sieves Group.
SCIMAGO INSTITUTIONS RANKINGS
Micro and Mesoporous Molecular Sieves Group, Institute of Chemistry, University of Campinas, Rua Monteiro Lobato, 270, 13083-861 Campinas-SP, BrazilUniversity of CampinasBrazilCampinas, SP, BrazilMicro and Mesoporous Molecular Sieves Group, Institute of Chemistry, University of Campinas, Rua Monteiro Lobato, 270, 13083-861 Campinas-SP, Brazil
Laboratory of Reactivity and Catalysis, Institute of Chemistry, University of Rio Grande do Sul, Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre-RS, BrazilUniversity of Rio Grande do SulBrazilPorto Alegre, RS, BrazilLaboratory of Reactivity and Catalysis, Institute of Chemistry, University of Rio Grande do Sul, Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre-RS, Brazil
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imageFigure 1 Unit cyclic (a), linear (b), and associate (c) structures of MAO; red balls: oxygen; gray balls: aluminum and methyl groups. Reprinted with permission from reference 35. Copyright 2014 American Chemical Society open_in_new
imageFigure 2 Structures of metallocenes used for the synthesis of PP and PE.3 open_in_new
imageFigure 3 Nanofiller families including molecules and inorganic nanoparticles. Adapted from reference 41. open_in_new
imageFigure 4 Polymer activity as a function of polymerization temperature for the nanosized and the microsized catalysts with 2 h of polymerization time; (a) [Al]/[Zr] = 570 and (b) [Al]/[Zr] = 17. Adapted from reference 53. open_in_new
imageFigure 5 Models for the interactions of metallocene Cp2ZrCl2 with species present in acidic silicate surfaces (A: acidic element). Reprinted from reference 57. Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 6 Interaction of MCM-41 with a metallocene, followed by MAO. Reprinted from reference 61. Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 7 (a) Proposed interaction between grafted metallocene species within larger and smaller diameter pores. (b) Correlation between Zr-C interatomic distance and catalyst activity. Adapted from reference 63. open_in_new
imageFigure 8 Correlation between the mean Zr-O interatomic distance in the grafted species and the Mw of the resulting PE. Reprinted with permission from reference 63. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
imageFigure 9 (A to C) SEM images of freeze-dried PE at three different magnifications. From reference 74. Reprinted with permission from AAAS. open_in_new
imageFigure 10 Conceptual scheme for the growth of crystalline fibers of PE by mesoporous silica-assisted extrusion polymerization. From reference 74. Reprinted with permission from AAAS. open_in_new
imageFigure 11 Preparation of Cp2ZrCl2-MWCNT. Reprinted with permission from reference 79. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
imageFigure 12 (A) Scheme of homogeneous surface coating of MWCNTs caused by in situ polymerization. (B) TEM micrographs of MWNTs coated by in situ grown E-N copolymers (highlighted by the arrow) (45 wt.% E-N). Adapted from references 80 and 81. open_in_new
imageFigure 13 Different routes for nanotubes’ functionalization: sidewall covalent functionalization (a); defect-group covalent functionalization (b); noncovalent polymer wrapping (c); noncovalent pi-stacking (d).82 open_in_new
imageFigure 14 Structure of 2:1 phyllosilicates and schematically illustration of clay form factors of dispersed clay and the three different types of thermodynamically achievable polymer/layered silicate nanocomposites. Reprinted with permission from reference 86. Copyright 2014 American Chemical Society. open_in_new
imageFigure 15 Scheme of the delamination of alkylammonium-exchanged layered clays (on the left) with alkoxides following a sol-gel process giving rise to intermediate organo-clay materials that after thermal treatment (> 450 °C) in the presence of oxygen leads in a second step to delaminated clay-nanoparticles (NPs) materials. Reproduced from reference 90 with permission from The Royal Society of Chemistry. open_in_new
imageFigure 16 Surface modification of clay with quaternary and tertiary ammonium salts. Adapted from reference 93. open_in_new
imageFigure 17 Proposed reactions during catalyst supporting on Cloisite 93A. Adapted from reference 93. open_in_new
imageFigure 18 Schematic illustrations of the formation process of PE/P-MMTs nanocomposites during in situ ethylene polymerization in the presence of P-MMTs with different concentration. Reprinted with permission from reference 98. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
imageFigure 19 Schematic illustration of mechanism for formation of MT-Si and the PE/clay-silica nanocomposites. Adapted from reference 99. open_in_new
imageFigure 4 Polymer activity as a function of polymerization temperature for the nanosized and the microsized catalysts with 2 h of polymerization time; (a) [Al]/[Zr] = 570 and (b) [Al]/[Zr] = 17. Adapted from reference 53. open_in_new
imageFigure 5 Models for the interactions of metallocene Cp2ZrCl2 with species present in acidic silicate surfaces (A: acidic element). Reprinted from reference 57. Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 6 Interaction of MCM-41 with a metallocene, followed by MAO. Reprinted from reference 61. Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 7 (a) Proposed interaction between grafted metallocene species within larger and smaller diameter pores. (b) Correlation between Zr-C interatomic distance and catalyst activity. Adapted from reference 63. open_in_new
imageFigure 8 Correlation between the mean Zr-O interatomic distance in the grafted species and the Mw of the resulting PE. Reprinted with permission from reference 63. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
imageFigure 9 (A to C) SEM images of freeze-dried PE at three different magnifications. From reference 74. Reprinted with permission from AAAS. open_in_new
imageFigure 10 Conceptual scheme for the growth of crystalline fibers of PE by mesoporous silica-assisted extrusion polymerization. From reference 74. Reprinted with permission from AAAS. open_in_new
imageFigure 11 Preparation of Cp2ZrCl2-MWCNT. Reprinted with permission from reference 79. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
imageFigure 12 (A) Scheme of homogeneous surface coating of MWCNTs caused by in situ polymerization. (B) TEM micrographs of MWNTs coated by in situ grown E-N copolymers (highlighted by the arrow) (45 wt.% E-N). Adapted from references 80 and 81. open_in_new
imageFigure 13 Different routes for nanotubes’ functionalization: sidewall covalent functionalization (a); defect-group covalent functionalization (b); noncovalent polymer wrapping (c); noncovalent pi-stacking (d).82 open_in_new
imageFigure 14 Structure of 2:1 phyllosilicates and schematically illustration of clay form factors of dispersed clay and the three different types of thermodynamically achievable polymer/layered silicate nanocomposites. Reprinted with permission from reference 86. Copyright 2014 American Chemical Society. open_in_new
imageFigure 15 Scheme of the delamination of alkylammonium-exchanged layered clays (on the left) with alkoxides following a sol-gel process giving rise to intermediate organo-clay materials that after thermal treatment (> 450 °C) in the presence of oxygen leads in a second step to delaminated clay-nanoparticles (NPs) materials. Reproduced from reference 90 with permission from The Royal Society of Chemistry. open_in_new
imageFigure 16 Surface modification of clay with quaternary and tertiary ammonium salts. Adapted from reference 93. open_in_new
imageFigure 15 Scheme of the delamination of alkylammonium-exchanged layered clays (on the left) with alkoxides following a sol-gel process giving rise to intermediate organo-clay materials that after thermal treatment (> 450 °C) in the presence of oxygen leads in a second step to delaminated clay-nanoparticles (NPs) materials. Reproduced from reference 90 with permission from The Royal Society of Chemistry. open_in_new
imageFigure 16 Surface modification of clay with quaternary and tertiary ammonium salts. Adapted from reference 93. open_in_new
imageFigure 17 Proposed reactions during catalyst supporting on Cloisite 93A. Adapted from reference 93. open_in_new
imageFigure 18 Schematic illustrations of the formation process of PE/P-MMTs nanocomposites during in situ ethylene polymerization in the presence of P-MMTs with different concentration. Reprinted with permission from reference 98. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
imageFigure 19 Schematic illustration of mechanism for formation of MT-Si and the PE/clay-silica nanocomposites. Adapted from reference 99. open_in_new
imageFigure 20 Schematic illustration of two different types of thermodynamically achievable polymer/layered silicate nanocomposites. Reprinted from reference 101. Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 21 Schematic representation of PLS obtained by direct polymer melt intercalation of M2(HT)2 with LLDPE. Adapted from references 112 and 113. open_in_new
imageFigure 22 Schematic representation of EVA/LLDPE/DS-LDH obtained by solution blending. Adapted from references 116 and 117. open_in_new
imageFigure 23 (a) Phase separated and (b) randomly distributed morphology of graphene/polymer nanocomposites. Reprinted from reference 104, Copyright 2014, with permission from Elsevier open_in_new
imageFigure 24 TEM images of 1 wt.% TRG with EG-8200-MA (a, b) prepared by melt compounding and (c, d) prepared by solvent blending. Adapted from reference 104. open_in_new
imageFigure 25 Schematic representation nanocomposite production of PE/OMMT with rac-ethylene bis (4,5,6,7-tetra-hydro-1-indenyl) zirconium dichloride supported obtained by in situ polymerization. Adapted from reference 120. open_in_new
imageFigure 26 Schematic representation of nanocomposite formation by ringopening reaction of cyclic oligomers in-between silicate layers. Reprinted from reference 121, Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 21 Schematic representation of PLS obtained by direct polymer melt intercalation of M2(HT)2 with LLDPE. Adapted from references 112 and 113. open_in_new
imageFigure 22 Schematic representation of EVA/LLDPE/DS-LDH obtained by solution blending. Adapted from references 116 and 117. open_in_new
imageFigure 23 (a) Phase separated and (b) randomly distributed morphology of graphene/polymer nanocomposites. Reprinted from reference 104, Copyright 2014, with permission from Elsevier open_in_new
imageFigure 24 TEM images of 1 wt.% TRG with EG-8200-MA (a, b) prepared by melt compounding and (c, d) prepared by solvent blending. Adapted from reference 104. open_in_new
imageFigure 25 Schematic representation nanocomposite production of PE/OMMT with rac-ethylene bis (4,5,6,7-tetra-hydro-1-indenyl) zirconium dichloride supported obtained by in situ polymerization. Adapted from reference 120. open_in_new
imageFigure 26 Schematic representation of nanocomposite formation by ringopening reaction of cyclic oligomers in-between silicate layers. Reprinted from reference 121, Copyright 2014, with permission from Elsevier. open_in_new
imageFigure 27 Micrographs of exfoliated nanocomposites composed by (A) PE-coated MWNTs with 12 wt.% by TEM; (B) silica (monospheres) in an isotactic PP matrix prepared with 50 wt.% by SEM; (C) silica (nanospheres) in PE with 7 wt.% by TEM and (D) MMT in a high Mw nylon-6 with 3 wt.% by TEM. Adapted from references 81, 3, 108 and 2, respectively. open_in_new
imageFigure 28 Schematic representation of silicate intercalated by an initiator or catalyst that upon introduction of a monomer an intercalated or exfoliated polymer nanocomposite is formed. Reproduced from reference 125 with permission from The Royal Society of Chemistry. open_in_new
imageFigure 29 Plot of powder X-ray diffraction intensity versus scattering angle: (a) 1-tetradecylammonium modified fluorohectorite (C14N-2); (b) C14N-2 after intercalation by the catalyst (Pd-2); (c) Pd-2 after exposure to ethylene for 135 min; (d) Pd-2 after exposure to ethylene for 24 h. Reproduced from reference 125 with permission from The Royal Society of Chemistry. open_in_new
imageFigure 30 TEM images of the 2 wt.% C15A/PP nanocomposites: without a compatibilizer (A); with 1 wt.% OTMS (B) and with 1.5 wt.% PP‑g‑MA/0.5 wt.% OTMS (C). Adapted from reference 126. open_in_new
imageFigure 31 TEM images (A) and XRD patterns (B) of PP nanocomposites with various organoclay contents (a): PPN-0.5; (b) PPN-1; (c) PPN-3; (d) PPN‑6. Adapted from reference 127. open_in_new
imageFigure 32 Electron micrographs of a highly filled rhombic PE nanocomposite crystal (54 wt.% nanoparticles) (a) with homogeneous distribution of nanoparticles (b) and of spherical nanocomposite particles for a nanoparticle loading of 7.4 wt.% at low (c) and high (d) magnification. Reprinted with permission from reference 128. Copyright 2014 American Chemical Society open_in_new
imageFigure 33 Structures of (A) DMN and (B) dimethylstearylbenzylammonium ions; (C) X-ray diffraction of high density PE nanocomposites: (a) bentonite modified with dimethylstearylbenzylammonium cations; (b) melt-compounded PE/DMSB composite; (c) in situ polymerized PE/DMSB nanocomposite; (d) high density PE. Adapted from reference 103. open_in_new
imageFigure 34 TEM-images of PE/DMSB nanocomposites of high density PE: composite prepared by melt compounding (A) and prepared by in situ polymerization (B). Reprinted with permission from reference 103. Copyright (c) 2014 [John Wiley and Sons, Inc.]. open_in_new
table_chartTable 1
Performance of different catalyst generations. Reprinted from reference 29. Copyright 2014, with permission from Elsevier
| Generation | Composition and structure | Producticity / (kg PP g-1 Cat) | II / wt.%a | Technology control | Process requirements |
|---|---|---|---|---|---|
| 1st (1957-1970) | 3TiCl3Al3/AlEt2Cl | 0.8-1.2 | 88-91 | Irregular powder | Need of purification and atactic removal |
| 2nd (1970-1978) | TiCl3/AlEt2Cl | 3-5 | 95 | Irregular powder | Need of purification and atactic removal |
| 3rd (1978-1980) | TiCl4/ester/MgCl2 + AlEt3/ester | 5-15 | 98 | Regular/irregular powder | No purification, need of atactic removal |
| 4th (1980) RGTb | TiCl4/diester/MgCl2 + AlEt3/silane three-dimensional catalyst granule architecture | 20-60 | 99 | Particles with regular shape and adjustable size and PSDe. Designed distribution of the different products inside each particle | No purification. |
| No atactic removal. | |||||
| No pelletisation | |||||
| TiCl4/diether/MgCl2 + AlEt3 three-dimensional catalyst granule archieture | 50-120 | 99 | Particles with regular shape and adjustable size and PSD. Designed distribution of the different products inside each particle | No purification. | |
| No atatic removal. | |||||
| No pelletisation | |||||
| 5th metallocenes | zirconocene + MAOc | (5-9) × 103 (on Zr) | 90-99 | To be improved | - |
| 6th multicatalyst RGT | mixed catalysis: ZNd + radical initiators, ZN + single site (catalysts) | Particles with designed distribution of both olefinic and non-olefinic materials |
-
a
II = isotacticity index;
-
b
RGT = reactor granule technology;
-
c
MAO = methylaluminoxane;
-
d
ZN = Ziegler-Natta;
-
e
PSD = particle size distribution.
table_chartTable 2
Reaction results obtained by the ethylene polymerization over the studied catalysts. Reproduced from reference 24 with permission from The Royal Society of Chemistry
-
a
Determined by ICP analysis;
-
b
kg PE molZr-1 h-1 bar-1. Polymerizarion conditions: mcat = 30 mg; Vn-heptane = 600 mL; P = 8 bar; T = 85 °C; time = 30 min; N = 900 rpm; MAO solution/Zr = 800;
-
c
determined by GPC;
-
d
measured at 70 ºC.
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