Olefin polymers, commercially

Polyethylene. Traditional melt spun methods have not utilized polyethylene as the base polymer because the physical properties obtained have been lower compared to those obtained with polypropylene. Advances in polyethylene technology may result in the commercialization of new spunbonded stmctures having characteristics not attainable with polypropylene. Although fiber-grade polyethylene resin was announced in late 1986 (11,12), it has seen limited acceptance because of higher costs and continuing improvements in polypropylene resin technology (see Olefin POLYMERS, POLYETHYLENE). 

Attempts have been made to use cold-set adhesives in the cormgating operation, such as poly(vinyl acetate) and modified, precooked starch formulations, but these have not achieved any appreciable degree of commercial acceptance (20). The use of a polyethylene film appHed to the inside surface of the linerboard facing, which serves as a hot-melt cormgator adhesive, has achieved some commercial usage. However, its use is limited to the small, specialty product niche of fast-food hamburger cartons (see Olefin polymers, polyethylene). 

Polymerization Reactions. Polymerization addition reactions are commercially the most important class of reactions for the propylene molecule and are covered in detail elsewhere (see Olefin polymers, polypropylene). Many types of gas- or liquid-phase catalysts are used for this purpose. Most recently, metallocene catalysts have been commercially employed. These latter catalysts requite higher levels of propylene purity. 

Polymers account for about 3—4% of the total butylene consumption and about 30% of nonfuels use. Homopolymerization of butylene isomers is relatively unimportant commercially. Only stereoregular poly(l-butene) [9003-29-6] and a small volume of polyisobutylene [25038-49-7] are produced in this manner. High molecular weight polyisobutylenes have found limited use because they cannot be vulcanized. To overcome this deficiency a butyl mbber copolymer of isobutylene with isoprene has been developed. Low molecular weight viscous Hquid polymers of isobutylene are not manufactured because of the high price of purified isobutylene. Copolymerization from relatively inexpensive refinery butane—butylene fractions containing all the butylene isomers yields a range of viscous polymers that satisfy most commercial needs (see Olefin polymers Elastomers, synthetic-butylrubber). 

One of the most economical routes to most commercial grades of olefin polymers is the loop slurry process with a paraffin diluent. This process was introduced by Chevron Phillips in 1960 (7). There, a mixture of catalyst particles, growing polymer particles, comonomers, and diluent is pumped in a loop. The polymer particles are harvested by guiding a side stream of the slurry to settling chambers, where the polymer particles settle toward the bottom. 

The next polymer Standard Reference Materials, issued in 1970, were a linear and a branched polyethylene. They are representative of crystalline olefin polymers, which have assumed great commercial and scientific importance. The linear material was kindly provided by the Dupont Co. and the branched by Union Carbide Corp. 

Among the large number of olefin polymers that may be obtained by coordination polymerisation, several are produced commercially on an enormous scale high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE),... 

Table 3.9 lists the main commercially available olefin polymers synthesised by coordination polymerisation and their typical uses [556],... 

Ethylene-norbornene copolymers, which have thermoplastic properties when heated above their glass transition temperatures of ca. 200-250°C, have been commercialized by Ticona GmbH under the trade name TOPAS (Tliermoplas-tic Olefin Polymer of Amorphous Structure). Their properties - exceptional transparency, low double refraction, high stiffnes and hardness, low permeability for moisture and excellent biocompatibility - make these ethylene-norbornene copolymers particularly valuable as engineering polymers, for optical applications and as materials for food and medical packaging. 

At present, there is only one commercial source of the polyamide/polycarbonate blends (Dexcarb , Dexter Corp.). According to their patent, the blend was compatibilized by using a combination of a polyesteramide elastomer and a maleated olefinic polymer, such as male-ated polypropylene or EP rubber [Perron, 1984 1988]. However the degree or the efficiency of compatibilization achieved is unknown, since the added components are not known to be miscible or compatible with the polycarbonate. Nevertheless, the data sheet indicated good properties including a high notched Izod impact strength of > 700 J/m (Table 15.24). 

The copolymerization of ethylene and carbon monoxide to give alternating copolymers has attracted considerable interest in both academia and industry over recent decades [1, 2]. Attention was focused on aliphatic polyketones such as poly(3-oxotrimethylene) (1) because of the low cost and plentiful availability of the simple monomers. The new family of thermoplastic, perfectly alternating olefin/ carbon monoxide polymers commercialized by Shell provides a superior balance of performance properties not found in other commercial materials the an ethylene/ propene/CO terpolymer is marketed by Shell imder the tradename Carilon . About the history of polyketones see Refs. [3-11],... 

The first group consists of amorphous thermoplastic engineering polymers. These are cyclic olefin polymers (COP) or cyclic olefin copolymers (COC) with ethylene. They were commercialized, for example, as Zeonex (in 1991) and Zeonar (by Zeon), as Topas (Polyplastics), Apel (Mitsui), and Alton (JSR). Topas was originally part of Ticona, before it was sold to Daicel in 2005. A Topas plant with a capacity of 30,000 tpa started up in Oberhausen, Germany, in September 2000. Until that time, world capacity from 4 pilot-scale plants was around 10,000 tpa. 

The commercial utility of materials derived from natural sources and modified by controlled chemical reactions prompted the application of such methods to totally synthetic polymeric materials as they were discovered. The first chemical reaction on a totally synthetic pol3oner is probably the nitration of poly(styrene) in 1845. An approximate chronology of when reactions on the more common olefin polymers may have occurred may be constructed from a list of the dates these polymers were reported in the literature. An important step forward, both for pol3n[ner chemistry in general... 

There are many other commercially important olefin polymers based upon polymerization of available substituted olefins. 

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