Polyphenylene sulfide plastics

Adhesives recommended for polyphenylene sulfide include epoxies, and urethanes. Joint strengths in excess of 1000 psi have been reported for abraded and solvent-cleaned surfaces. Somewhat better adhesion has been reported for machined surfaces. The high heat and chemical resistance of polyphenylene sulfide plastics makes them inappropriate for either solvent cementing or heat welding. 

Ryton Phillips Petroleum s trade name for its family of polyphenylene sulfide plastics. 

Fig. 11. Effect of polyolefin primers on bond strength of ethyl cyanoacrylate to plastics. All assemblies tested in accordance with ASTM D 4501 (block shear method). ETFE = ethylene tetrafluoroethylene copolymer LDPE = low-density polyethylene PFA = polyper-fluoroalkoxycthylene PBT = polybutylene terephthalate, PMP = polymethylpentene PPS = polyphenylene sulfide PP = polypropylene PS = polystyrene PTFE = polytetrafluoroethylene PU = polyurethane. From ref. [73].

As regards the general behaviour of polymers, it is widely recognised that crystalline plastics offer better environmental resistance than amorphous plastics. This is as a direct result of the different structural morphology of these two classes of material (see Appendix A). Therefore engineering plastics which are also crystalline e.g. Nylon 66 are at an immediate advantage because they can offer an attractive combination of load-bearing capability and an inherent chemical resistance. In this respect the arrival of crystalline plastics such as PEEK and polyphenylene sulfide (PPS) has set new standards in environmental resistance, albeit at a price. At room temperature there is no known solvent for PPS, and PEEK is only attacked by 98% sulphuric acid. 

Graphite/ Thermo- plastic AS4/PPS Phillips Petroleum Phillips Petroleum Polyphenylene sulfide, semicrystalline thermoplastic... 

Polyphenylene sulfides are engineering plastics used only for specialized and technical applications. 

Nylon, polyacetal, polycarbonates, poly(2,6-dimethyl)phenylene oxide (PPO), polyimides, polyphenylene sulfide (PPS), polyphenylene sulfones, polyaryl sulfones, polyalkylene phthalates, and polyarylether ketones (PEEK) are stiff high-melting polymers which are classified as engineering plastics. The formulas for the repeating units of some of these engineering plastics are shown in Figure 1.15. 

Many semicompatible rubbery polymers are added to increase the impact resistance of other polymers, such as PS. Other comminuted resins, such as silicones or polyfluorocarbons, are added to increase the lubricity of other plastics. For example, a hot melt dispersion of polytetrafluoroethylene (ptfe) in polyphenylene sulfide (PPS) is used as a coating for antistick cookware. 

There is a growing list of plastic materials capable of "meeting the challenge" in many applications involving hostile environments. Polyphenylene sulfide (PPS) is one of the leaders on this list and its environmental resistance has been studied extensively. This paper summarizes the performance characteristics of PPS in harsh environments. 

Fortunately, the deficiencies of both the classic thermosets and general purpose thermoplastics have been overcome by the commercialization of a series of engineering plastics including polyacetals, polyamides, polycarbonate, polyphenylene oxide, polyaryl esters, polyaryl sulfones, polyphenylene sulfide, polyether ether ketones and polylmides. Many improvements in performance and processing of these new polymers may be anticipated through copolymerization, blending and the use of reinforcements. 

Polyphenylene sulfide will not burn when tested by any of the common standard tests used for plastics, such as ASTM D635 and UL-94. However, when exposed In a fire, It will continue to burn until the externally applied flame Is removed. It burns with a yellow-orange flame, producing gray smoke with traces of black. 

Electrical properties of polyphenylene sulfide compounds are summarized in Table III. The dielectric constant of 3.1 is low in comparison with many other plastic materials. Similarly, the dissipation factor is very low. Dielectric strength ranges from about 500-600 volts per mil for the various compounds these values are quite high. Thus, both... 

Limiting oxygen index values (LOI) of a number of plastics are shown in Table IV. The LOI is the concentration of oxygen required to maintain burning. Polyphenylene sulfide has a value of 44, and falls among the least flammable types of plastics. 

An engineering plastic core was found preferable examples included polyetherether ketone (PEEK), polyphenylene sulfide (PPS), and polyether imide (PEI). Polytetrafluoroethylene bearers were placed in the mold to keep the core material away from the walls of the mold. No special cavity modifications were required. Any hot-melt fluoroplastic could be molded surrounding the insert examples include PVDF, FEP, ETFE, PFA, ECTFE, and PCTFE. 

Ryton Polyphenylene Sulfide is a new commercial plastic which is characterized by good thermal stability, retention of mechanical properties at elevated temperatures, excellent chemical resistance, a high level of mechanical properties, and an affinity for a variety of fillers. It is produced from sodium sulfide and dichlorobenzene. Its unusual combination of properties suggests applications in a variety of molded parts such as non-lubricated bearings, seals, pistons, impellers, pump vanes, and electronic components. Tough coatings of polyphenylene sulfide can be applied to metals or ceramics by a variety of techniques and are used as protective, corrosion-resistant coatings in the chemical and petroleum industries. Incorporation of small amounts of polytetrafluoroethylene provides excellent non-stick properties in both cookware and industrial applications. 

Flammability. Polyphenylene sulfide will not support combustion under atmospheric conditions. The oxygen index, the minimum concentration of oxygen required to maintain burning, is shown for a number of polymers (12) in Table IV. The PPS sulfide value of 44 places it among the least flammable plastics. PPS has been given a UL flammability classification of VE-O. 

Polyphenylene sulfide is produced from sodium sulfide and dichlorobenzene by a novel polymerization process. This process is an excellent example of the use of chemical ingenuity in converting two low cost, abundant chemicals into a premium quality plastic which can command a much higher price than either of the starting materials. This unique polymer contains about 29% sulfur and thus is a good example of a high quality, sulfur-rich product. 

Reinforced plastics are composites in which a resin is combined with a reinforcing agent to improve one or more properties of the resin matrix. The resin may be either thermosetting or thermoplastic. Typical thermosetting resins used in RPs include unsaturated polyester, epoxy, phenolic, melamine, silicone, alkyd, and diallyl phthalate. In the field of reinforced thermoplastics (RTFs), virtually every type of thermoplastic material can be, and has been, reinforced and commercially molded. The more popular grades include nylon, polystyrene, polycarbonate, polyporpylene, polyethylene, acetal, PVC, ABS, styrene-acrylonitrile, polysulfone, polyphenylene sulfide, and thermoplastic polyesters. 

The term HT-thermoplastics is used for polymers, which in the absence of fillers, have a continuous-use temperature above approx. 200 °C. In contrast, standard plastics, such as PVC, polyethylene or polystyrene, have continuous-use temperatures of the order of 100 °C. In addition to their high temperature stability, HT-thermoplastics, in general, possess good resistance to chemicals and usually also low flammability. Among the most important HT-thermoplastics are polyphenylene sulfides (PPS), polysul-fones (PSU), polyether sulfones (PES), polyether imides (PEI), polyetherether ketones (PEEK) and polyarylates (PAR). 

---