Polyphenylene sulfide applications

Newer fabrics, not in common use but in development, test, and field trials, are described for higher temperature applications by Reference [50]. Application to 400°F—2100°F are potentially available using ceramic fibers Nextel 312 , laminated membrane of expanded PTFE on a substrate, polyimid fiber P-84, Ryton polyphenylene sulfide, and woven fiberglass. The heat and acid resistance of these new materials... 

Polyphenylene sulfide Melts at 270-315°C (578-599°F) crosslinked polymer stable to 450°C (842°F) in air adhesive and laminating applications. 

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

At low temperatures, polyphenylene sulfide is used for cryogenic applications at -269°C. Generally, notched Izod impact strength does not significantly decrease between room temperature and -40°C. 

Polyphenylene sulfides are good insulators even in a hot environment, with high dielectric resistivities and low or moderate loss factors. Special grades are marketed for electrical applications. 

Mat and continuous glass fibre reinforcements theoretically all the thermoplastics are usable in these forms, but up to now developments have concentrated on polypropylenes (PP), polyamides (PA) and thermoplastic polyesters (PET) fibre-reinforced PEEK, polyetherimide (PEI) and polyphenylene sulfide (PPS) are used for high-performance applications. They are presented in a range of forms from stampable sheets to pellets, prepregs, ribbons, impregnated or coated continuous fibre rods. More rarely (as in the case of PA 12, for example), the thermoplastic is provided in liquid form. 

Dichlorobenzenes. In 1998, approximately 16 million lb of the o-dichlorobenzene was converted into 3,4-dichloroaniline, the raw material for several major herbicides. Also a small amount (3 million lb) goes to various solvent applications. The major demands for/ -dichlorobenzene come from uses in polyphenylene sulfide resins (50 million lb), room deodorants (16 million lb), and moth-control agents (11 million lb). Any future growth will have to come from the phenylene sulfide resins. 

Very few CPs are produced in bulk quantities. Polyphenylene sulfide, a member of the third generation of polymers, was produced in bulk quantities many years before CPs were established and its dopability was elucidated. Polyethylenedioxythiophene is commercially available as a water-based colloidal dispersion (Baytron P water dispersion), and presumably as dispersible powders. The powders with a conductivity of 5-10 S/cm can be dispersed in thermoplastic polymers and in organic solvents such as xylene. Polyaniline doped with dodecylbenzene sulfonic acid and complexed with zinc dodecylbenzene sulfonate is commercially available as a powder, which can be dispersed in polyolefins. The same polymer doped with p-toluenesulfonic acid is also available as a dispersible powder, Ormecon, and in a predispersed form for solution processing in polar and nonpolar media. Based on Ormecon PANi, there are many commercial products marketed for many different applications. 

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. 

Coatings. The thermal and chemical resistance of polyphenylene sulfide nas led to a wide variety of applications as a coating material. Examples are cookware with heat-resistant, easy-release coatings containing PPS, valves and fittings coated with PPS for protection against corrosive chemicals, and electrical coils coated with PPS as a temperature-resistant insulation. 

One very interesting application for polyphenylene sulfide is in coating cookware for nonstick use (10). Excellent, scratch-resistant, nonstick coatings are obtained when a formulation containing 10 to 20% polytetrafluoroethylene is used. Ryton PPS coatings are very insoluble and nontoxic, animal feeding studies indicate. 

Progress has also been made in part cooling. Portable and centralized chillers have been developed to cool the part in a minimum time. These closed loop systems use water or water-ethylene glycol combinations as the heat transfer medium. The application of heat transfer principles allows one to computer model the cooling process (35). For the new engineering resins such as polyamide-imide and polyphenylene sulfide, one must use mold heating. The use... 

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. 

Molding Resin Applications. Polyphenylene sulfide is establishing itself as a basic engineering material for bearing applications and other... 

Polyphenylene sulfide release coatings are being used in non-stick cookware. In another application, tire molds are coated to aid the release of the finished tire from the mold (15). When this release coating was used, more than 8000 tires were produced without cleaning the mold, whereas cleaning was required after producing only 500-600 tires when a conventional silicone mold release agent was used. In addition the need for a blemish paint was eliminated, tire rejects were reduced, and an improved surface finish resulted. 

PPS/PTFE (polyphenylene sulfide/polytetra-fluoroethylene) high durability and wear resistance, tensile strength, hydraulic stability, heat resistance. Applications include seals valves and bushings. 

Thermoplastic matrices, is particularly attractive for automotive applications PP, for example, is economical, it can be processed quickly and can provide much better mechanical properties such as impact resistance, (i.e., bumpers, body panels [11]). PA are successfully applied in both under hood (i.e., inlet manifolds, radiator fans) and interiors (instrument panels, doors, front-end structures). For better temperature performance and mechanical properties, in some special application areas (motor racing sector, gearbox parts), polyether ether ketone and polyphenylene sulfide ( high performance thermoplastics ) are also used as matrices. 

The major applications of LCP films in electronics are multilayer boards and multichip modules, and flexible printed circuits. Current materials used in the.se applications include polyimide film, high performance thermoplastic film such as polyphenylene sulfide and polyetherether ketone, and fiber reinforced composites such as quartz fiber-polyimide. The price of these materials for electronic packaging is in the range of. 50 to. l(K)/lb, so LCPs can compete very effectively at their current prices. Based on a two to three times increase in price... 

Polyphenylene sulfide resin is a new material with a new combination of desirable properties. Because of this, the list of applications is growing steadily and it is not possible to foresee all of them. 

---