Polyisoprene, chlorinated

Parlon (Chlorinated Rubber, Tornesit, Allo-prene). A proprietary trade name (Hercules Powder Co) for a rubber chlorinated polyisoprene, CH3... 

Polyaniline (PANI) is a nonconductive polymer that could be rendered conductive by HCl doping. Several methods exist to accomplish such a doping. One of them is the incorporation of a chlorine-containing polymer into a polyaniline matrix and the irradiation of the resultant blend. Ionizing radiation (e-beam or y-irradiation) leads to the dehydrochlorination of the second polymer and the subsequent doping of the PANI (Figure 9.9). Several chlorine-containing polymers were tested in this approach, PVC, chlorinated polyisoprene, poly(vinylidene chloride-co-vinyl acetate), poly(vinylidene chloride-co-vinyl chloride). " ... 

The close structural similarities between polychloroprene and the natural rubber molecule will be noted. However, whilst the methyl group activates the double bond in the polyisoprene molecule the chlorine atom has the opposite effect in polychloroprene. Thus the polymer is less liable to oxygen and ozone attack. At the same time the a-methylene groups are also deactivated so that accelerated sulphur vulcanisation is not a feasible proposition and alternative curing systems, often involving the pendant vinyl groups arising from 1,2-polymerisation modes, are necessary. 

As with c -polyisoprene, the gutta molecule may be hydrogenated, hydro-chlorinated and vulcanised with sulphur. Ozone will cause rapid degradation. It is also seriously affected by both air (oxygen) and light and is therefore stored under water. Antioxidants such as those used in natural rubber retard oxidative deterioration. If the material is subjected to heat and mechanical working when dry, there is additional deterioration so that it is important to maintain a minimum moisture content of 1%. (It is not usual to vulcanise the polymer.)... 

The empirical shift parameters calculated from the NMR data of the 1,4-polyisoprene derivatives will provide, hereafter, a basis for assigning the carbon resonances observed in the spectrum of hydrochlorinated 1,4-polydimethyl butadiene, which like hydro-chlorinated 1,4-polyisoprene has quaternary carbons substituted by one chlorine atom. 

Polyisoprene (rubber), chlorinated polyethylene Wood, complex silicates (cement or ceramic tile), carpet (nylon, polyester, polyolefin)... 

Synthetic polyisoprenes are superior to natural rubber in terms of consistency of properties. The are also freer of contaminants, and are preferred for applications that require lighter color, for personal care items and for derivatization to chlorinated and cyclized rubber products that are used in the adhesives and coatings industries. 

Synthetic polyisoprene rubbers were found by Harries during 1910 [19], to be successfully hydrochlorinated. These synthetic polyisoprenes resemble natural rubber, which is also a polymer of isoprene which occurs naturally and therefore hydrogen chloride is rapidly added when the rubber is exposed to it thus forming a protective film of chlorinated rubber or hydrogen chloride. Polybutadiene, and butadiene acrylonitrile rubbers do not add hydrogen chloride from hydrochloric acid. 

To manufacture chlorinated rubber (CR) natural or synthetic rubber such as polyethylene, polypropylene or polyisoprene is degraded to low molecular mass compounds by mastication or addition of radical formers and dissolved in carbon tetrachloride (CTC). Chlorine contents are typically 64-68 wt%. Chlorine gas is introduced into this solution and reacts with the raw material to form CR. The solution is then introduced into boiling water. The CR is precipitated, and the solvent vaporizes. The CR is separated from water, rinsed, dried and ground to form a white powder which is the saleable product. After removal of the water, chlorine, hydrochloric acid and other impurities the solvent is reused. 

Halogenation reactions of unsaturated polymers follow two simultaneous paths, ionic and free radical. Ionic mechanisms give soluble products from chlorination reactions of polybutadiene." The free-radical mechanisms, on the other hand, cause crosslinking, isomerization, and addition products. If the free-radical reactions are suppressed, soluble materials form. Natural rubber can be chlorinated in benzene with addition of as much as 30% by weight of chlorine without cycliza-tion. " Also, chlorination of polyalkenamers, both cis and trans, yields soluble polymers. X-rays show that the products are partly crystalline. The crystalline segments obtained from 1,4-trans-polyisoprene are diisotactic poly( 0 /rw-dichlorobutamer)s while those obtained from the 1,4-cis isomer are diisotactic polyOAfieo-l,2-dichlorobutamer)s. ... 

Solution monomer dispersed in solvent with soluble catalyst free radical, ionic, Zeigler Nichols thermosets, acrylics, PVAlc, PVC, polybutadiene, polypropylene, melamine phenolic resins, polyisoprene, polycarbonate, chlorinated polyesters glass or s/s STR (2-8 kW/m mixen heat transfer area = 1-4 m /m depending on the volume of the reactor with small area associated with large volumes). 

Orientations in elongated mbbers are sometimes regular to the extent that there is local crystallization of individual chain segments (e.g., in natural rubber). X-ray diffraction patterns of such samples are very similar to those obtained from stretched fibers. The following synthetic polymers are of technical relevance as mbbers poly(acrylic ester)s, polybutadienes, polyisoprenes, polychloroprenes, butadiene/styrene copolymers, styrene/butadiene/styrene tri-block-copolymers (also hydrogenated), butadiene/acrylonitrile copolymers (also hydrogenated), ethylene/propylene co- and terpolymers (with non-conjugated dienes (e.g., ethylidene norbomene)), ethylene/vinyl acetate copolymers, ethyl-ene/methacrylic acid copolymers (ionomers), polyisobutylene (and copolymers with isoprene), chlorinated polyethylenes, chlorosulfonated polyethylenes, polyurethanes, silicones, poly(fluoro alkylene)s, poly(alkylene sulfide)s. 

Chloral adds to polyisoprene similarly. The reaction is catalyzed by Lewis acids [70]. Both AICI3 and BF3 are efficient catalysts. Less cross-Unking is encountered with aluminum chloride. Infra-red spectra of the products shows presence of hydroxyl groups, chlorine atoms, and vinyUdene unsaturation [70]. 

What term does describe the polymerization of isoprene to cis-1,4-polyisoprene Here we quote further from Eliel (1962). Stereoselective, in contrast, simply means that, of two (or more) possible stereoisomeric products in a reaction, one is produced in predominance (usually in great predominance) over all the others. An example is the 1,4 addition of chlorine to butadiene reported by Mislow and Heilman (1951). The product is only ira is-l,4-dichloro-2-butene (IX). Another example of a ster-... 

The chemical structure of CR is analogous to that of natural rubber (see Natural rubber-based adhesives) with the methyl group of cw-l,4-polyisoprene replaced by a chlorine atom, see Fig. 1. 

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