Terpolymerization of Ethylene/Propylene/Diene Monomers Using (2-PhInd)2ZrCl2 Metallocene Catalysts

2010 ◽  
Vol 4 (11-12) ◽  
pp. 707-714 ◽  
Author(s):  
Saeid Ahmadjo ◽  
Hassan Arabi ◽  
Mehdi Nekoomanesh ◽  
Gholam Hossein Zohuri ◽  
Mohammad Mehdi Mortazavi ◽  
...  
2014 ◽  
Vol 8 (12) ◽  
pp. 796-804
Author(s):  
Kenda Tourkmani ◽  
Emilio Casas ◽  
Beatriz Paredes ◽  
Jovita Moreno ◽  
Ponciano Perez ◽  
...  

2006 ◽  
Vol 245-246 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Griselda Barrera Galland ◽  
João Henrique Zimnoch dos Santos ◽  
Maiara Dall'Agnol ◽  
Rubens Bisatto

2011 ◽  
Vol 38 (4) ◽  
pp. 23-28
Author(s):  
I.A. Arutiunov ◽  
O.L. Ivanis'ko ◽  
P.V. Kostoglodov ◽  
D.A. Maksimov ◽  
A.I. Kochnev ◽  
...  

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1093 ◽  
Author(s):  
Jun Won Baek ◽  
Su Jin Kwon ◽  
Hyun Ju Lee ◽  
Tae Jin Kim ◽  
Ji Yeon Ryu ◽  
...  

Hafnium complexes have drawn attention for their application as post-metallocene catalysts with unique performance in olefin polymerization. In this work, a series of half-metallocene HfMe2 complexes, bearing a tetrahydroquinoline framework, as well as a series of [Namido,N,Caryl]HfMe2-type post-metallocene complexes, bearing a tetrahydrophenanthroline framework, were prepared; the structures of the prepared Hf complexes were unambiguously confirmed by X-ray crystallography. When the prepared complexes were reacted with anhydrous [(C18H37)2N(H)Me]+[B(C6F5)4]−, desired ion-pair complexes, in which (C18H37)2NMe coordinated to the Hf center, were cleanly afforded. The activated complexes generated from the half-metallocene complexes were inactive for the copolymerization of ethylene/propylene, while those generated from post-metallocene complexes were active. Complex bearing bulky isopropyl substituents (12) exhibited the highest activity. However, the activity was approximately half that of the prototype pyridylamido-Hf Dow catalyst. The comonomer incorporation capability was also inferior to that of the pyridylamido-Hf Dow catalyst. However, 12 performed well in the coordinative chain transfer polymerization performed in the presence of (octyl)2Zn, converting all the fed (octyl)2Zn to (polyolefinyl)2Zn with controlled lengths of the polyolefinyl chain.


1999 ◽  
Vol 72 (2) ◽  
pp. 283-298 ◽  
Author(s):  
T. C. Chung ◽  
H. L. Lu ◽  
S. Hong

Abstract This paper summarizes the experimental results of three new polyolefin elastomers, i.e., poly(1-octene-co- p-methylstyrene (O-p-MS), poly(ethylene-ter-propylene-ter-p-methylstyrene) (EP-p-MS) and poly(ethylene-ter-1-octene-ter-p-methylstyrene) (EO-p-MS), containing “reactive” p-MS units. Both Ziegler-Natta and metallocene catalysts were used in studying co- and ter-polymerization reactions. In the copolymerization of 1-octene and p-MS, Ziegler-Natta catalyst TiCl3/AlEt3 exhibits higher catalyst reactivity to produce high molecular weight O-p-MS copolymers, containing up to 20 mol % p-MS. However, the copolymers show very broad composition and molecular weight distributions. On the other hand, two EP-p-MS and EO-p-MS terpolymers with narrow molecular weight and composition distributions were prepared by [C5Me4(SiMe2NtBu)]TiCl2 metallocene catalyst with constrained ligand geometry. The sharp glass transition temperature (Tg) with flat baseline in each differential scanning calorimetry (DSC) curve indicates homogeneous terpolymer microstructures. The Tg of EP-p-MS is very sensitive to the terpolymer composition (ethylene/propylene ratio and p-MS content). In the compositions with ideal ethylene/propylene ratio ∼ 55/45, the Tα is almost proportional to the content of p-MS. Only with the concentration of p-MS < 2 mol %, does the EP-p-MS show alow Tg<−45°C. On the other hand, the EO-p-MS system exhibits a low Tg<−50°C in a wide range of copolymer compositions, even ones with relatively high p-MS contents (< 7 mol %).


Author(s):  
Gudrun A. Hutchins

In order to optimize the toughening effect of elastomers in engineering polymers, it is necessary to characterize the size, morphology and dispersion of the specific elastomer within the polymer matrix. For unsaturated elastomers such as butadiene or isoprene, staining with osmium tetroxide is a well established procedure. The residual carbon-carbon double bond in these materials is the reactive site and forms a 1,2-dilato complex with the OsO4. Incorporation of osmium tetroxide into the elastomer not only produces sufficient contrast for TEM, but also crosslinks the elastomer sufficiently so that ultramicrotomy can be accomplished at room temperature with minimal distortion.Blends containing saturated elastomers such as butyl acrylate (BA) and ethylene propylene diene monomer (EPDM) cannot be stained directly with OsO4 because effective reaction sites such as C=C or -NH2 are not available in sufficient number. If additional reaction sites can be introduced selectively into the elastomer by a chemical reaction or the absorption of a solvent, a modified, two-step osmium staining procedure is possible.


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