Ziegler-Natta polymerization propylene

Bukatov, G.D Zakharov, V.A. Propylene Ziegler-Natta polymerization numbers and propagation rate constants for stereospecific and non-stereospecific centers. Macromol. Chem. Phys. 2001, 202, 2003-2009. 

Cyclic Polyolefins (GPO) and Gycloolefin Copolymers (GOG). Japanese and European companies are developing amorphous cycHc polyolefins as substrate materials for optical data storage (213—217). The materials are based on dicyclopentadiene and/or tetracyclododecene (10), where R = H, alkyl, or COOCH. Products are formed by Ziegler-Natta polymerization with addition of ethylene or propylene (11) or so-called metathesis polymerization and hydrogenation (12), (101,216). These products may stiU contain about 10% of the dicycHc stmcture (216). 

Ziegler-Natta Polymerization. The polymeri2ation of propylene with Ziegler-Natta catalysts, ie, complexes of TiCl3—(C2H3)3A1 on MgCl2... 

The Ziegler-Natta polymerization of ethylene and propylene is among the most significant industrial processes. Current processes use heterogeneous catalysts formed from Ti(IH)Cl3 or MgCl2-supported Ti(IV)Cl4 and some otganoaluminum compounds. The widely accepted Cossee mechanism of ethylene polymerization is illustrated in Scheme 62. 

Ziegler-Natta polymerizations have the characteristics of living polymerization with regard to catalyst active sites but not individual propagating chains. Thus the propagating chains have lifetimes of seconds or minutes at most, while active sites have lifetimes of the order of hours or days. Each active site produces many polymer molecules. The termination of a polymer chain growing at an active center may occur by various reactions, as shown below with propylene as an example. 

Problem 9.7 Under conditions of high metal alkyl concentrations the propagation rate in Ziegler-Natta polymerization of propylene is found [21] to be given by... 

Problem 9.9 The kinetic rate behavior of Ziegler-Natta polymerization of ethylene and propylene is given by the empirical equation... 

In the build-up period of the decay-type Ziegler-Natta polymerization of propylene, the rates are found to be different when propylene is introduced after TiCls and AlEts are allowed to equilibrate from the case when AlEts is added after the gas in introduced. The rates in the former case are given by the expression... 

There are systems yielding substituents on the fi and not on the a carbon, e.g. Ziegler-Natta polymerization of propylene... 

Using the above type of experimental set-up for propylene polymerization with TiCl3-AlEt3 in n-heptane, the rate of polymerization was measured P . Keii, Kinetics of Ziegler-Natta Polymerizations , Halsted Press, New York, 1973] at different... 

A major distinction between heterogeneous Ziegler—Natta polymerization and single-center polymerization is the facility with which comonomers are incorporated into the chain. Adding steric encumbrances to the catalyst has been shown to enhance this effect. With the parent biscyclopentadienylzir-conocene dichloride, ethylene polymerizes 25 times faster than propylene, with the ethylene tetrahdy-roindenyl complex ethylene is polymerized 10 times faster than propylene, and with the 2-methyl-4-aryl complexes such as 3 or 9, ethylene and propylene are polymerized with comparable rates. 

Ethylene, propylene Ziegler-Natta-catalyzed chain polymerization Automotive parts, radiator and heater hoses, seals... 

The compositions of EPDM elastomers are controlled by using the appropriate monomer feed ratio (see Eq. (2.38)) to obtain the desired composition in a continuous polymerization process. In general the excess propylene required is recycled. The molecular weights of EPDM polymers are controlled primarily by chain transfer reactions with added molecular hydrogen (Eqs. (2.86) and (2.87)), as is common with other Ziegler-Natta polymerizations (Boor, 1979). 

An elastomeric copolymer based on ethylene and propylene prepared in Ziegler-Natta polymerization. When small amount of a diene monomer is added, the resulting polymer becomes ethylene-propylene terpolymer, EPDM. 

Lee, L- M. Gauthier, W. J. Ball, J. M. Iyengar, B. Collins, S. Electronic effects in Ziegler-Natta polymerization of propylene and ethylene using soluble metallocene catalysts. Organometallics 1992, 11, 2115-2122. 

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