Polyphenylene sulfide coatings

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. 

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. 

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. 

In other high-temperature tests, Ryton polyphenylene sulfide coatings on aluminum will pass an 80 inch-pound reverse impact test after exposure in air at 600°F for eight days, or at 700°F for two days (Table VIII). 

Ryton polyphenylene sulfide coatings are finding excellent acceptance as corrosion-resistant, protective coatings for oil-field pipe, valves,... 

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. 

Table VI. Properties of Polyphenylene Sulfide Coatings on Steel...

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. 

Polyphenylene sulfide (PPS) is obtained from the polymerization mixture as a fine off-iiAite powder which after purificatloi can be used directly in some coating appUcations. It is not soluble in any known solvent below about 200°C, but above that tmq>erature it is soluble to a limited extent in s< ie aromatics, chloroaromatics and heterocyclic confounds. The inherent viscosity, measured at 206°C in l-chlcronaphthalene is typically 0.16, indicating only moderate molecular weight. The annealed polymer is highly crystalline as shown by X-ray diffraction, (Ij) and the... 

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

J. N. Short and H. W. Hill, Jr., Polyphenylene sulfide coating and molding resins, Chem. Technol. 2, 481 (1972). 

Thermoplastic polymer polyphenylene sulfide (PPS)/BST composites were obtained with various BST contents. Particles were uniformly dispersed in PPS matrix using a twin-screw extruder, and composites with 70 wt% BST had a dielectric constant and dielectric loss of 13.5 and 0.0025, respectively, at 1 GHz [139]. Li et al. [140] embedded Bao.6Sro.4Ti03/silver core-shell nanoparticles into PVDF matrix. The silver-coated Bao.6Sro.4Ti03/PVDF nanocomposites showed 73% higher dielectric constant than composites of bare BST meanwhile, the dielectric loss was still low (less than 0.2) at 55 vol% filler content. 

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