Phenylene polysulfide

In the presence of metallic lithium the reaction of 8 with 1,4-dichlorobenzene yields a linear poly(l,4-phenylene polysulfide) in which the sulfur content could be 3 sulfur atoms per phenylene unit (M as high as 12,000) [Ilia]. 

PB PBI PBMA PBO PBT(H) PBTP PC PCHMA PCTFE PDAP PDMS PE PEHD PELD PEMD PEC PEEK PEG PEI PEK PEN PEO PES PET PF PI PIB PMA PMMA PMI PMP POB POM PP PPE PPP PPPE PPQ PPS PPSU PS PSU PTFE PTMT PU PUR Poly(n.butylene) Poly(benzimidazole) Poly(n.butyl methacrylate) Poly(benzoxazole) Poly(benzthiazole) Poly(butylene glycol terephthalate) Polycarbonate Poly(cyclohexyl methacrylate) Poly(chloro-trifluoro ethylene) Poly(diallyl phthalate) Poly(dimethyl siloxane) Polyethylene High density polyethylene Low density polyethylene Medium density polyethylene Chlorinated polyethylene Poly-ether-ether ketone poly(ethylene glycol) Poly-ether-imide Poly-ether ketone Poly(ethylene-2,6-naphthalene dicarboxylate) Poly(ethylene oxide) Poly-ether sulfone Poly(ethylene terephthalate) Phenol formaldehyde resin Polyimide Polyisobutylene Poly(methyl acrylate) Poly(methyl methacrylate) Poly(methacryl imide) Poly(methylpentene) Poly(hydroxy-benzoate) Polyoxymethylene = polyacetal = polyformaldehyde Polypropylene Poly (2,6-dimethyl-l,4-phenylene ether) = Poly(phenylene oxide) Polyp araphenylene Poly(2,6-diphenyl-l,4-phenylene ether) Poly(phenyl quinoxaline) Polyphenylene sulfide, polysulfide Polyphenylene sulfone Polystyrene Polysulfone Poly(tetrafluoroethylene) Poly(tetramethylene terephthalate) Polyurethane Polyurethane rubber... 

Polysulfides can be obtained from the reaction of a dihalide and Na2S, as shown below for the formation of poly(1,4-phenylene sulfide) ... 

Poly(1,3-phenylene sulfide) also is known and has a decomposition temperature higher than poly(1,4-phenylene sulfide). The same reaction can take place with alkyl dihalides, such as 1,2-dichloroethane. However, since sodium sulfide is very frequently a mixture of sulfide and polysulfides, the polymer structure is better expressed by the formula -(R-Sx-)n- Other reactions are known to lead to polysulfides. For example, poly(phenylene sulfide) can be obtained from 4-chlorothiophenol by self condensation in the presence of a metal base. 

The Macallum polymerization (6, 7, 8) for preparing poly(arylene polysulfides) has been shown by Lenz and co-workers (9) to involve a combination of free-radical and nucleophilic substitutions. This polymerization involves the reaction of a polyhaloaromatic compound with an alkali-metal sulfide or an alkaline-earth metal sulfide catalyzed by sulfur and carried out at a high temperature without solvent. Related to the Macallum reaction are two nucleophilic processes for the preparation of poly(phenylene sulfide). One of these, reported by Lenz and co-workers (10, 11), involves heating cuprous or sodium p-bromothio-phenoxide at 250° to 305°C ... 

Aromatic polysulfides in which the sulfur atoms are attached directly to the aromatic ring, such as those studied in this work, have a substantially higher T value than the xylylene-containing polysulfides. Table II, which includes data on poly(phenylene sulfides), shows the relationships involving sulfur rank, ring substitution, and glass-transition temperature for aromatic polysulfides. 

Data have been published dealing with successful applications of HAS in stabilization of other polymers than PO elastomers, styrenic polymers, polyamides, polycarbonates, polyacetals, polyurethanes, linear polyesters, thermoplastic polyester elastomers, polyacrylates, epoxy resins, poly(phenylene oxide) or polysulfide [12]. In spite of their basicity, HAS may also be used for stabilization of PVC. This application includes less basic derivatives of piperidine and 1,4-dihydropyridine [12,13,145,146]. 

Aromatic polythioethers or polysulfides are closely related to polyethers in structure and properties. A typical aromatic polysulfide is poly(phenylene sulfide) (PPS) (20), which is used as electrical insulators and structural parts in the building of engines and vehicles. Poly(phenylene sulfide) is prepared by the condensation reaction between /7-dichlorobenzene and sodium sulfide ... 

In ordinary organic chemistry, thioether is a synonym for sulfide. A thioether or sulfide is a compound that contains the R—S—R link. This is in contrast to the nomenclature of polymer chemistry. A polysulfide is a polymer that contains the —S—S— group in the backbone. However, a poly (sulfide), with sulfide in brackets, such as poly(phenylene sulfide) or... 

The technically most important polysulfide is polythiophenylene or poly(p-phenylene sulfide), PPS. It is obtained by reacting sodium sulfide and p-dichloro-benzene in a polar solvent, for example, l-methyl-2-pyrrolidone at about 280°C under pressure. The mechanism of the reaction is very complex and cannot be described by a simple aromatic substitution. This synthesis requires special autoclaves and is therefore not suitable for a laboratory course (for an experimental procedure see Table 2.3). 

Attempts to synthesize aromatic polysulfides by electrophilic substitution methods have failed to produce linear high molecular weight polymers. During the past three decades a systematic approach has been taken for the synthesis of aromatic polysulfides. The nucleophilic reaction of sodium sulfide with p-dichlorobenzene to give poly(phenylene sulfide) has been a successful process. The polymer produced by this method is abbreviated as PPS and has been commercialized by Philips Chemical Company under the trade name Ryton (reaction 24)... 

Poly(ether sulfide)s were also prepared by a precursor route, 4,4 -Difluorodiphe-nylsulfoxide (234) was used as electrophilic monomer in combination with hydroquinone or 4,4 -dihydroxybiphenyl. The resulting poly(ether sulfoxide)s were then reduced in tetrachloroethane by means of oxalylchloride and tetrabutylammonium fluoride (235) [357]. Furthermore, the preparation of sulfonated poly(phenylene-sulfide) should be mentioned. SO3 served as sulfonating agent and the sulfonated polysulfide was treated with SOCI2, whereby a poly sulfide with SO2CI and Cl substituents was obtained [358]. 

The aliphatic thioethers (polysulfides) are unique among condensation polymers in being produced in an emulsion polymerization. The rank jr (Table 17.2, II.C) has an influence on the number of sulfur atoms in each polymer linkage. The tacky or liquid polymers are cast or applied as pastes in the case of sealants. The sulfur analog of poly(phenylene oxide) is poly(phenylene sulfide) (Table 17.2, II.C), which can be made by a condensation reaction between p-dichlorobenzene and sodium sulfide. The highly crystalline polymer is solvent resistant and has a low coefficient of friction. It can be injection molded at about 300°C and can also be used as a powder spray coating. 

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