Polyphenylene sulfide thermal

Table 15.10 Thermal and Physical Properties of Polyphenylene Sulfides...

RYTON Polyphenylene sulfide Physical, Chemical, Thermal, and Electrical Properties, TSM-266, Phillips Chemical Co., Bartlesville, Okla., Apr. 1981, p. 2. 

This crystalline aromatic nylon, combines the high strength and stiffness of nylon with the thermal stability of polyphenylene sulfide. Molding characteristics are similar to nylon 6/6, with similar or better chemical resistance, but its 24 h water absorption is only 0.2 versus 0.7% for nylon 6/6. A key behavior is high heat resistance. 

Several other types of encapsulants have been evaluated for use by the semiconductor industry. Polyphenylene sulfide, a thermoplastic, has the advantage of good thermal characteristics and a low viscosity for device encapsulation. In addition, since it is a thermoplastic, the molded runners can be reused. This improves the material utilization and reduces cost. Unfortunately, this material also contains a significant amount of impurities that caused device reliability problems and efforts to remove them have met with mixed success. 

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. 

When polyphenylene sulfide Is heated In air at approximately 815°C, the major components of thermal degradation are hydrogen, methane, carbon monoxide, carbon dioxide and carbonyl sulfide. 

In the Phillips process, polyphenylene sulfide (PPS) is obtained from the polymerization mixture in the form of a fine white powder, which, after purification, is designated Ryton V PPS. Characterization of this polymer is complicated by its extreme insolubility in most solvents. At elevated temperatures, however, Ryton V PPS is soluble to a limited extent in some aromatic and chlorinated aromatic solvents and in certain heterocyclic compounds. The inherent viscosity, measured at 206°C in 1-chloronaphthalene, is generally 0.16, indicating only moderate molecular weight. The polymer is highly crystalline, as shown by x-ray diffraction studies (9). The crystalline melting point determined by differential thermal analysis is about 285°C. 

Figure 1. Differential thermal analysis of polyphenylene sulfide in nitrogen...

Table VII. Thermal Stability of Polyphenylene Sulfide Coatingsft...

PTFE can be compounded with polymeric fdlers with adequate thermal stability. Examples of such polymers include polyarylates such as polyether-ketone, polyphenylene sulfone, and polyphenylene sulfide. Surface characteristics such as wear rate, coefficient of friction, and surface tension can be modified with these additives. 

Polyphenylene Sulfide Sulfone - Thermoplastic with good thermal stability, chemical resistance, and dielectric properties, and low flammability and creep. Processed by injection molding. Used in electrical components. Also called polyphenylene sulfide sulfone. 

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. 

Figure 1. Differential thermal analysis of polyphenylene sulfide in nitrogen. Sample A melted under nitrogen and quenched before DTA. Sample B heated at 370°C in air 4 hrs and quenched before DTA. Heating ratet 10° C /minute.

Polyphenylene-sulfide, PPS thermal and environmental stability, fire extinguishing machinery and electronics, high temperature coatings... 

Perng [5] also used stepwise Py-GC-MS and TGA-MS techniques in a study of the mechanisms and kinetics of the thermal decomposition characteristics of polyphenylene sulfide at various temperatures between ambient and 900 "C. The major decomposition products were benzene thiol, hydrogen sulfide, benzene and carbon disulfide always being the dominating component. 

Polyphenylene sulfides (PPS), partially crystalline polymers, are produced by the reaction of p-dichlorobenzene and sodium sulfide. This polymer has metallic-like properties and responds well to reinforcement. PPS possesses good creep and good moisture resistance and a low coefficient of thermal expansion. 

Structural adhesives must have a glass transition temperature higher than the operating temperature to avoid a cohesively weak bond and possible creep problems. Modem engineering plastics, such as polyimide or polyphenylene sulfides, have very high glass transition temperatures. Most common adhesives have a relatively low glass transition temperature so that the weakest thermal link in the joint may often be the adhesive. 

Polyimide and polyphenylene sulfide (PPS) resins present a problem in that their high-temperature resistance generally requires that the adhesive have similar thermal proper-... 

Polyimide and polyphenylene sulfide resins present a problem in that their high temperature resistance generally requires that the adhesive have similar thermal properties. Thus, hi -temperature epoxies adhesive are most often used with polyimide and PPS parts. Joint strength is superior (greater than 1000 Ib/in ) but thermal resistance is not better than the best epo3 systems (300 to 400°F continuous). 

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