Polyethylene sulfide

In a 3-1. round-bottomed flask fitted with a mechanical stirrer and a reflux condenser is placed 2.0 1. of anhydrous ethanol. To this is added 11.5 g. (0.5 g.-atom) of sodium cut into small pieces. When the sodium is completely dissolved, 23.6 g. (21.0 ml., 0.25 mole) of 1,2-ethanedithiol2 is added, followed by 47.0 g. (21.7 ml., 0.25 mole) of ethylene dibromide. The mixture is stirred and refluxed for 4 hours, cooled, and filtered to remove some sodium bromide mixed with polyethylene sulfide. The solid is washed with 100 ml. of ethanol, and the combined filtrates are distilled with stirring. When bumping becomes troublesome, as it generally does when 1.3-1.5 1. of distillate has been collected, the hot reaction mixture is filtered to remove sodium bromide, and the sodium bromide is washed with 100 ml. of hot ethanol. 

The conformational energy E(op) associated with gauche states about CH2-CH2 bonds in polyethylene sulfide) (PSE) is estimated from the RIS analysis of experimental dipole moments and their temperature coefficients corresponding to the alternating copolymer of pentamethylene sulfide and ethylene sulfide (PXS) as well as to 1,2-bis(butylthio)ethane. 

In a similar environment, the opisulfide reaction (Kq, 3 ) is not readily terminated by solvent, but instead, a polyethylene sulfide (LXII) is formed. This is understandable when one notes that although the mercaptide ion is a weaker base than the alkoxide ion, it Is a ttim-h stronger nucleophile. Thus the alkoxide ions are depleted in the forma tion of mercaptide ions, and the newly generated mercaptide ions react... 

Referring to the cationic polymerization of spiro tetrathioorthocarbonates, a five-membered spiro compound, l,4,6,9-tetrathiaspiro[4.4)nonane (129) quantitatively gave polyethylene sulfide) with the complete extrusion of ethylene tri-thiocarbonate as found in the corresponding oxygen counterpart. [103] A six-membered spiro compound, l,5,7,ll-tetrathiaspiro[5.5]undeeane (130), did not... 

Sulfur analogs of spiroorthocarbonates, namely spirotetrathiocarbo-nates, also undergo cationic polymerization [212]. A 5-membered monomer gives the mixture of polyethylene sulfide) and ethylene trithiocar-bonate ... 

Although it is relatively easy to prepare high-molecular-weight polysulfides, these products have not yet found applications. This is mostly due to a lack of industrially applicable monomer preparation methods. Neither ethylene sulfide nor propylene sulfide can be prepared by direct reaction of the corresponding olefins with elemental sulfur. Moreover, it is difficult to obtain polyethylene sulfide) sufficiently stable at higher temperatures and its odour may become offensive. 

These composites may be flexibllzed by the addition of polyethylene sulfide (Thiokol) or a carboxyl terminated butadiene polymer. Coal tar may also be added as an extender, polyvinyl-p-vlnylphenol may be used as the curing component and hard aggregates may be added to improve wear resistance.12. 

This elastomer which was introduced commercially in 1929, had limited use until liquid polymers with reactive thiol end groups were obtained by the reduction of this elastomer. The liquid polyethylene sulfides are readily oxidized and cured by the addition of oxidants, such as lead peroxide.22... 

A good example of large-size fiber-reinforced components in aerospace application is the radome covering the underbelly radar on the Hercules transport aircraft. It is made from very thin polyethylene sulfide (PES) film interleaved with PES-impregnated glass fiber cloth, which is subsequently hot molded in a closed die. The composite radome, nearly 1 m in diameter and 6 mm thick, weighs only 10 kg. 

Episulfide, thiophene, thiol-suhstituted thiophene and alkyl- and vinyl-substituted thiophenes were formed as the major products, which indicate that formation of cyclics is favonred during thermal degradation of polyethylene sulfide. The formation of thiophenes and alkyl-substituted thiophenes are due to the elimination of hydrogen sulfide cyclisation followed by a dehydrogenation reaction. The loss of hydrogen from 2,5-dihydrothiophene to form thiophene has been reported in the literature. Some of the product formations are illustrated in Equation 6.6. 

Polyethylene disulfide Polyethylene oxide Propyl ester phosphazine Polyethylene sulfide Polyethylene terephthalate Polyethylene phosphorodichloridate Polyethylene tetrasulfide Phenol Polyimide(s)... 

Ultra high molecular weight-PE HOPE 30% Gfr Polymide Polymide 30% Gfr Polyethylene sulfide Polypropylene (PP) PP 10-40% talc PP 10-30 Gfr High impact polystyrene Styrene acrylonitrile (SAN)... 

Polyethylene sulfide 20% polytetrafluoroethylene lubricated Antifriction gears... 

The mechanical destruction of chemical bonds that occurs on grinding polymers like polyethylene sulfide [86] is a curious way to generate sulfur-based radicals. However, thiyl radicals have never been found in these systems. In the two known examples the products identified by ESR were not RS but RSS species. It is quite possible that thiyl radicals did appear as primary intermediates but reacted to form more stable species. 

Elastomeric vulcanized natural rubber and hard rubber and oil-resistant polyethylene sulfide (Thiokol) and polychloroprene (Duprene, Neoprene) were all available commercially in the 1930s. 

Polybutylcyanoacrylates [63], polyacrylics [64], polybutadiene [65], flame retardant PE [66], PS [67-70], PS - divinyl benzene copolymer [71], PS - acrylonitrile copolymer [72], acrylonitrile-butadiene-styrene terpolymer [73, 74], styrene-maleic anhydride copolymer [75], polyvinyl-cyclohexane [76], polyphenylene triazine [77], poly-4-vinyl pyridine [78], polyethylene sulfide [79], PSF [80], brominated PES [81], tetrafluoroborate doped polythiophene [82], polysiloxane [56, 83], vinyl pyrrolidone-methacryloxy silicone copolymer [50], polyvinyl indene [84], poly-E-lactide [3, 85, 86], epoxy resins [87, 88], polyaryl ether ketone [89, 90], ethylene... 

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