Propylene copolymerization of ethylene and

Although hdpe and it-PP are crystalline, the commercial random copolymer of ethylene and propylene (EP) is an amorphous elastomer. The most widely used EP copolymer (EPDM) is produced by the copolymerization of ethylene and propylene with a small amount of an alkyldiene this permits cross-linking or vulcanization. 

With larger amount of propylene a random copolymer known as ethylene-propylene-monomer (EPM) copolymer is formed, which is a useful elastomer with easy processability and improved optical properties.208,449 Copolymerization of ethylene and propylene with a nonconjugated diene [EPDM or ethylene-propylene-diene-monomer copolymer] introduces unsaturation into the polymer structure, allowing the further improvement of physical properties by crosslinking (sulfur vulcanization) 443,450 Only three dienes are employed commercially in EPDM manufacture dicyclopentadiene, 1,4-hexadiene, and the most extensively used 5-ethylidene-2-norbomene. 

The effect of nucleophilic dienes on the copolymerization of ethylene and propylene has been reported by Gladding, Fisher and Collette (88). Table 8 shows that 1.4-hexadiene decreased the tendency for propylene to enter into the ethylene-propylene terpolymer, produced by a triisobutyl aluminum-vanadium oxychloride catalyst. 

Johnson LK, Mecking S, Brookhart M, Copolymerization of Ethylene and Propylene with Functionalized Vinyl Monomers by Palladium(II) Catalysts, J Am Chem Soc, 118, 267-268 (1996)... 

The same model has been used lt6) to explain the copolymerization of ethylene and propylene with TiCl+/EB/MgCl2—AlEt3, with various amounts of EB added to the cocatalyst. The triad sequence distribution calculated for the copolymer obtained without EB was in disagreement with reactivity ratios, while the values obtained with high concentrations of EB did agree. Thus, the two active species mentioned, having two and one vacancies respectively, would be characterized by... 

The copolymerization of ethylene and propylene is found to be essentially random r ri = 1) with (C2H5)2AICI/VO(OC2H5)3 catalyst in chlorobenzene at 30°C. (Such polymerizations are discussed in Chapter 9.) The control of such systems is frequently on monomer concentration in the gas phase over the reaction mixture. This is because gas phase concentrations vary less with temperature, pressure, and solvent. What monomer composition in the gas phase is needed to produce a copolymer containing 30 mol% propylene. The reactivity ratio of ethylene (rj) has been found to be 5, based on gas phase concentrations. 

The composition of ethylene-propylene copolymers allows the relative reactivities of olefins to be estimated. In the copolymerization of ethylene and propylene on titanium trichloride the reactivity ratio is 16 (at 75 °C) should be hi er in the homopolymerization of each component. This corresponds to the ratio ( 100 for... 

Note Ethylene may be copolymerized with varying percentages of other materials, e.g., 2-butene or acrylic acid a crystalline product results from copolymerization of ethylene and propylene. When butadiene is added to the copolymer blend, a vulcan-izable elastomer is obtained. 

Waymouth has recently reported the alternated copolymerization of ethylene and propylene using 39. Preliminary analysis of the polymers using C NMR spectroscopy revealed that the alternated polymers are isotactic. ... 

Typical soluble catalysts for copolymerization of ethylene and propylene are formed from mixtures of vanadium salts with alkylaluminum chlorides, e.g., VCI4 with either AIR2CI or AIRCI2 where R = alkyl group (Ver Strate, 1986). A possible hexacoordinated metal structure for the resulting active catalyst is shown below. 

TABLE 2.16 Monomer Reactivity Ratios for Copolymerization of Ethylene ) and Propylene ( 2) with Ziegler-Natta Catalysts... 

Copolymerization of ethylene and propylene produces an elastomeric polymer that is virtually inert because of the absence of carbon-carbon double bonds (EPM). Such polymers thus tend to be crossUnked with peroxides or by radiation. To improve the reactivity of ethylene-propylene copolymers, 1-10% of a third monomer can be added to give a terpolymer or ethylene-propylene-diene monomer (EPDM). The primary diene monomers used in EPDM are 1,4-hexadiene, dicyclopentadiene, and ethyUdene norbomene. Introduction of an unsaturated monomer such as ethylidene norbomene will enable use of sulfur-based crosslinking systems. 

On the base of results received in this work the scheme of continuous solution copolymerization of ethylene and propylene (Fig. 6.2) was developed and introduced into production (OAO "Nizhnekamskneftekhim"), tubular turbulent apparatus are used in it at the following stages ... 

Valuable thetic rubbers are produced by the copolymerization of ethylene and propylene. The structure may be represented as... 

Figure 2.34 simulates the copolymerization of ethylene and propylene in the presence of hydrogen. Ethylene, being the faster comonomer, has a much steeper radial concentration profile than propylene. In the same way, hydrogen reacts much more slowly and also diffuses rather fast and therefore has a flat radial concentration profile. The effect of these profiles on the CLD and CCD is clear polymer made near the surface of the particle will have higher molecular weight and ethylene fraction than the polymer made near the center of the particle. This modeling approach was first proposed by Soares and Hamielec for a version of the PFM [70]. 

Derlin and Kaminsky [101] reported copolymerizations of ethylene and propylene with a sterically hindered monomer, 3-methyl-1-butene, using titanium and zirconium metallocenes with methyl... 

F.PM/EPDM (Ethylene Propylene Rubbers) A group of elastomers (rabber-like material) obtained by copolymerization of ethylene and propylene for EPM and a third monomer (diene) for EPDM. Their properties are similar to those of robber. 

Ethylene, polymerization n. A chemical reaction in which two or more molecules combine to form larger molecules that contain repeating structural units. Ethylene-propylene rubber (E/P, EPDM, SPM, and EPR) n. Any of a group of elastomers obtained by the stereospecific copolymerization of ethylene and propylene (EOM, or of these two monomers and a third monomer such as an unconjugated diene (EPDM). Their properties are similar to those of natural rubber in many respects, and they have been proposed as... 

Many types of rubber which resist ozone were obtained by copolymerization of ethylene and propylene with asymmetric dienes such as 1,4-hexadiene, dicyclopen-tadiene, or ethylidenenorbornene. The addition to the reaction mixture of a certain amount of diene allows preparation of a very stable polymer, because the formation of a linear polymer requires breaking of one double bond while the other bond is utilized to net the copolymer which takes place during the polymerization process. Vanadium... 

Copolymers of ethylene and propylene show, in some cases, elastic properties (324,325). Further incorporation of dienes, such as ethylidenenorbomene or 1,4-hexadiene, produces ethylene-propylene-diene monomer (EPDM) elastomers. Kaminsky (326) and Waymouth (327) have reported the predominantly alternating copolymerization of ethylene and propylene, using Ci and Cg symmetric (cyclopentadienyD(fluorenyl) aasa-zirconocene-based catalysts (eq. 3), demonstrating yet another example of preparation of new materials through rational exploitation of SSC systems. 

Johnson, L. K. Mecking, S. Brookhart, M. Copolymerization of ethylene and propylene with functionalized vinyl monomers by palladium(II) catalysts. J. Am. Chem. Soc. 1996,118, 267-268. 

---