Polymers based on ethylene

There are two general types of polymers based on ethylene and propylene ethylene-propylene rubber (EPM) and ethylene-propylene terpolymer (EPDM). EPM accounts for approximately 20 percent of the polyolefin rubber produced. Comprising a totally saturated polymer, these materials require free-radical sources to cross-link. EPDM was developed to overcome this cure... 

Whinfield and Dickson quickly realized that the polymer based on ethylene glycol and terephthalic acid was the best suited for fibers (Figure 11). They did, however, make and describe several other polyesters including poly(butanediol terephthalate) (PBT). Many years later a number of polyester fiber producers became interested in PBT. One producer explained that he was interested in PBT because it made a fiber that resembled nylon. Because nylon was becoming popular as a carpet yarn, and because he was not in the nylon business, he considered PBT a means of competing in carpet yarns. 

Polymers based on ethylene sulfide (thiirane, ethylene episulfide) have not been developed into commercial products yet. 

Polyethylene (PE) is a family of addition polymers based on ethylene. Polyethylene can be linear or branched, homopolymer, or copolymer. In the case of a copolymer, the other comonomer can be an alkene such as propene, butene, hexene, or octene or a compound having a polar functional group such as vinyl acetate (VA), acrylic acid (AA), ethyl acrylate (EA), or methyl acrylate (MA). If the molar percent of the comonomer is less than 10%, the polymer can be classified as either a copolymer or homopolymer. Figure 4.1 presents a diagram of the family of polymers based on ethylene monomer. 

The plastics shown here were manufactured with a polymer based on ethylene. 

Polymers based on ethylene or copolymers of ethylene, where ethylene has the greatest share. 

A number of other comb-shaped polyethers containing coordinatively active oxyethylene side chains attached to a supporting, seemingly nonactive, polymer backbone have been prepared with low TgS [9, 15]. They include comb-shaped polymers based on ethylene oxide monomers having... 

Cowie, J. M. G., Martin, A. C. S., and Firth, A. M., Ionic conductivity in mixtures of salts with comb-shaped polymers based on ethylene oxide macromer. Bn Polym. J., 20, 247-252 (1988). 

The Development and Properties of Polymers Types of Polymers Polymers Based on Ethylene... 

One further group of polymers based on ethylene is possible and these have all four hydrogen atoms of the ethylene molecule replaced. When the substituent is fluorine the resultant polymer is polytet-rafluoroethylene alternatively, the hydrogen atoms may be replaced by three fluorine atoms and one chlorine atom in which case the resultant polymer is polychlorotrifluoroethylene... 

There are two general types of polymers based on ethylene and propylene ethylene/propyl-... 

Within the scope of the original definition, a very wide variety of ionomers can be obtained by the introduction of acidic groups at molar concentrations below 10% into the important addition polymer families, followed by partial neutralization with metal cations or amines. Extensive studies have been reported, and useful reviews of the polymers have appeared (3—8). Despite the broad scope of the field and the unusual property combinations obtainable, commercial exploitation has been confined mainly to the original family based on ethylene copolymers. The reasons for this situation have been discussed (9). Within certain industries, such as flexible packaging, the word ionomer is understood to mean a copolymer of ethylene with methacrylic or acryhc acid, partly neutralized with sodium or zinc. 

Catalytic oxidation of ethylene produces ethylene oxide, which is hydrolyzed to ethylene glycol. Ethylene glycol is a monomer for the production of synthetic fibers. Chapter 7 discusses chemicals based on ethylene, and Chapter 12 covers polymers and copolymers of ethylene. 

Ethylene reacts by addition to many inexpensive reagents such as water, chlorine, hydrogen chloride, and oxygen to produce valuable chemicals. It can be initiated by free radicals or by coordination catalysts to produce polyethylene, the largest-volume thermoplastic polymer. It can also be copolymerized with other olefins producing polymers with improved properties. Eor example, when ethylene is polymerized with propylene, a thermoplastic elastomer is obtained. Eigure 7-1 illustrates the most important chemicals based on ethylene. 

About 100 billion pounds of chemicals and polymers are made from ethylene each year. In fact, over 40% of all organic chemicals produced are based on ethylene. These ethylene-based materials are found in almost every conceivable application encountered in daily life, for example, containers, flooring, adhesives, pharmaceuticals, oil and gasoline additives, paints, surfactants, etc. 

PET is a polycondensation polymer based on the reaction of terephthalic acid (TA) and mono-ethylene glycol (MEG) or alternatively with di-methyl terephtha-late (DMT) plus MEG (Figure 10). 

Ionomer. Ionomer is the generic name for polymers based on sodium or zinc salts of ethylene-methacrylic acid copolymers in which interchain ionic bonding, occurring randomly between the long-chain polymer molecules, produces solid-state properties. 

Other uses of blends include controlled rate of fertilizer release(77) based on ethylene/vinyl acetate/carbon monoxide polymers which is U.V. sensitive, polyolefin blends with any biodegradable polymers,(78) and polyolefins blended with metals and autoxidizable substrates. (79) Doane and co-workers(80) at the U.S.D.A. have used grafted starches in many applications, including soil stabilization. 

In 1969, 90% of vinyl acetate was manufactured by this process. By 1975 only 10% was made from acetylene, and in 1980 it was obsolete. Instead, a newer method based on ethylene replaced this old acetylene chemistry. A Wacker catalyst is used in this process similar to that for acetic acid. Since the acetic acid can also be made from ethylene, the basic raw material is solely ethylene, in recent years very economically advantageous as compared to acetylene chemistry. An older liquid-phase process has been replaced by a vapor-phase reaction run at 70-140 psi and 175-200°C. Catalysts may be (1) C—PdCb—CuCb, (2) PdClj—AI2O3, or (3) Pd—C, KOAc. The product is distilled water, acetaldehyde, and some polymer are... 

The vast majority of commercial polymers based on the vinyl group (H2C=CHX) or the vinylidene group (H2C=CX2) as the repeat unit are known by their source-based names. Thus, polyethylene is the name of the polymer synthesized from the monomer ethylene poly(vinyl chloride) from the monomer vinyl chloride, and poly(methyl methacrylate) from methyl methacrylate. 

The thermal stability of polyimides prepared from l,l-dichloro-bis(3-amino-4-chlorophenyl)-ethylene is lower than that of polyimides prepared with other 3,3 -diamino-4,4 -dichloroarylenes, in particular 3,3 -diamino-4,4 -dichlorobenzophenone. This suggests a negative effect of 1,1-dichloroethylene groups on thermal stability in these polymers. Based on softening temperatures, the heat resistance of polyimides with different dianhydride residues decreases in the series ... 

However, a method to improve the flow properties of such fuel oils of animal or vegetable origin, has been developed (26). This consists in adding a EVA copolymer or a comb polymer based on methyl acrylate and a-olefins. In addition, terpolymers of ethylene, vinyl acetate and isobutylene have been found to be useful as cold flow improvers (29). 

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