Ethylene propylene copolymer and

Ethylene and Propylene Copolymers Contaning Different S tems of Two Conjugated Double Bonds... 

At the first time ethylene and propylene copolymers were put into industrial production in 1959 in Italy due to Ziegler-Natta catalytic systems discovery [176,177]. At present various SKEP(T) types are produced in all leading in industry countries particularly in USA, Italy, Germany, Holland, Great Britain, Canada, Japan, France, etc. Nevertheless, there is a lack of ethylene-propylene rubbers at world markets at present and this fact determines advisability of their production expansion. 

It is obvious from obtained results (Table 5.1) that brominated butyl rubber can be synthesized by proposed method. Moreover in turbulent regime halogenation of other elastomers in particular ethylene and propylene copolymers was carried out. 

S.2.2 Ethylene and propylene copolymers and polymer blends. As outlined above under EVA, the study of copolymers by SEC is complicated, since molecular species can be separated by both composition and by molecular mass. Ethylene/propylene copolymers have a heterogeneous composition [45], due to the considerable difference in the reactivities of the two monomers to the active polymerizing entity. The RI chromatograms reflect differences between solution and solvent, and if composition is not constant throughout, the difference will not be proportional to weight of sample eluted at each... 

Figure 6.9 PMR spectra of (a) ethylene and propylene copolymers and (b) mixture of polyethylene and polypropylene copolymers. Source Author s oum files)...

The copolymers of ethylene and propylene (OCVP) are obtained by coordination catalysis using a derivative of vanadium and a derivative of an aluminum alkyl. Molar compositions of ethylene and propylene are usually on the order 45 and 55%. 

Some data on copolymers of ethylene and propylene (not shown) is also consistent inasmuch as the values of f decrease as the ethylene (unsubstituted) content increases. 

Similarly, the random introduction by copolymerization of stericaHy incompatible repeating unit B into chains of crystalline A reduces the crystalline melting point and degree of crystallinity. If is reduced to T, crystals cannot form. Isotactic polypropylene and linear polyethylene homopolymers are each highly crystalline plastics. However, a random 65% ethylene—35% propylene copolymer of the two, poly(ethylene- (9-prop5lene) is a completely amorphous ethylene—propylene mbber (EPR). On the other hand, block copolymers of the two, poly(ethylene- -prop5iene) of the same overall composition, are highly crystalline. X-ray studies of these materials reveal both the polyethylene lattice and the isotactic polypropylene lattice, as the different blocks crystallize in thek own lattices. 

The economic importance of copolymers can be cleady illustrated by a comparison of U.S. production of various homopolymer and copolymer elastomers and resins (102). Figure 5 shows the relative contribution of elastomeric copolymers (SBR, ethylene—propylene, nitrile mbber) and elastomeric homopolymers (polybutadiene, polyisoprene) to the total production of synthetic elastomers. Clearly, SBR, a random copolymer, constitutes the bulk of the entire U.S. production. Copolymers of ethylene and propylene, and nitrile mbber (a random copolymer of butadiene and acrylonitrile) are manufactured in smaller quantities. Nevertheless, the latter copolymers approach the volume of elastomeric butadiene homopolymers. 

Copolymers of ethylene and propylene (EPM) and terpolymers of ethylene, propylene, and a diene (EPDM) as manufactured today are mbbers based on the early work of G. Natta and co-workers (1). A genetic formula for EPM and EPDM may be given as follows, where ra = (- GO mol%),... 

A copolymer, on the other hand, results from two different monomers hy addition polymerization. For example, a thermoplastic polymer with better properties than an ethylene homopolymer comes from copolymerizing ethylene and propylene ... 

Random copolymers made by copolymerizing equal amounts of ethylene and propylene are highly amorphous, and they have rubbery properties. 

Ciebien J.F., Cohen R.E., and Duran A., Catal3ftic properties of palladium nanoclusters synthesized within diblock copolymer films Hydrogenation of ethylene and propylene, Supramol. Sci., 5, 31, 1998. 

E-plastomers, based on ethylene and its copolymers with alpha olefins such as propylene or octene, combine the desirable attributes of processibUity, economy, and resistance to environmental degradation [20]. These properties, in conjunction with excellent elastomeric attributes such as... 

Permeation tubes are very popular devices for generating stemdard vapor concentrations. The permeation tube contains a volatile liquid sealed in an inert permeable membrane, usually Teflon or a fluorinated copolymer of ethylene and propylene, through which it diffuses at a fixed and controlled rate. The driving force for the process is the dif ce in partial... 

The preferred systematic abbreviation for ethylene-propylene terpolymer, also designated EPT. The use of the term EPR for a copolymer of ethylene and propylene, and the use of EPT for a terpolymer of these monomers with a small amount of a diene to provide double bonds is common but is not recommended. Epichlorohydrin... 

Olefins or alkenes are defined as unsaturated aliphatic hydrocarbons. Ethylene and propylene are the main monomers for polyolefin foams, but dienes such as polyisoprene should also be included. The copolymers of ethylene and propylene (PP) will be included, but not polyvinyl chloride (PVC), which is usually treated as a separate polymer class. The majority of these foams have densities <100 kg m, and their microstructure consists of closed, polygonal cells with thin faces (Figure la). The review will not consider structural foam injection mouldings of PP, which have solid skins and cores of density in the range 400 to 700 kg m, and have distinct production methods and properties (456). The microstructure of these foams consists of isolated gas bubbles, often elongated by the flow of thermoplastic. However, elastomeric and microcellular foams of relative density in the range 0.3 to 0.5, which also have isolated spherical bubbles (Figure lb), will be included. The relative density of a foam is defined as the foam density divided by the polymer density. It is the inverse of the expansion ratio . 

Another approach is to use copolymers where the structures of the copolymer are similar to that of the other phase. This is what occurs for PE and copolymers of ethylene and propylene. 

Industrial companies have long-term strategies. For example, Exxon (now ExxonMobil) is the third largest chemical company in the United States. Some time ago, they made the decision to emphasize the ethylene and propylene monomers that are obtained from the petrochemical interests of ExxonMobil. Thus, ExxonMobil has a research emphasis on the commercialization of products from these monomers. The major materials made from ethylene and propylene are polymeric, either homopolymers or copolymers. Efforts include developing catalysts that allow the formation of polymeric materials from the ethylene and propylene monomers and the use of these catalysts to synthesize polymeric materials that have varying properties allowing their application in different marketplaces in society. 

How might you prepare a block copolymer of styrene and an alternation copolymer of ethylene and propylene ... 

---