Poly(p-phenylene sulfide)
Polyphenylene sulfide (PPS) is an organic polymer consisting of aromatic rings linked with sulfides. Synthetic fiber and textiles derived from this polymer are known to resist chemical and thermal attack. PPS is used to make filter fabric for coal boilers, papermaking felts, electrical insulation, specialty membranes, gaskets, and packings. PPS is the precursor to a conducting polymer of the semi-flexible rod polymer family. The PPS, which is otherwise insulating, can be converted to the semiconducting form by oxidation or use of dopants.[1]
Polyphenylene sulfide is an engineering plastic, commonly used today as a high-performance thermoplastic.[2] PPS can be molded, extruded, or machined to high tolerances. In its pure solid form, it may be opaque white to light tan in color. Maximum service temperature is 218 °C (424 °F). PPS has not been found to dissolve in any solvent at temperatures below about 200 °C (392 °F).
Chevron Phillips Chemical manufactures the most common form in industry under the brand name Ryton.
An easy way to identify the plastic is by the metallic sound it makes when struck.
Fiber characteristics
PPS is one of the most important high temperature thermoplastic polymers because it exhibits a number of desirable properties. These properties include resistance to heat, acids and alkalies, and to mildew, to bleaches, aging, sunlight, and abrasion. It absorbs only small amounts of solvents and resists dyeing.
Production
The Federal Trade Commission definition for sulfur fiber is "A manufactured fiber in which the fiber-forming substance is a long chain synthetic polysulfide in which at least 85% of the sulfide (—S—) linkages are attached directly to two (2) aromatic rings."
The PPS (polyphenylene sulfide) polymer is formed by reaction of sodium sulfide with p-dichlorobenzene:
- ClC6H4Cl + Na2S → 1/n [C6H4S]n + 2 NaCl
The process for commercially producing PPS (Ryton) was initially developed by Dr. H. Wayne Hill Jr. and Mr. James T. Edmonds at Phillips Petroleum Company.[3] N-methylpyrrolidone is used as the reaction solvent since it is stable at the high temperatures required for the synthesis and it dissolves both the sulfiding agent and the oligomeric intermediates.
Linear, high molecular weight PPS that is capable of being extruded into film and melt spun into fiber was invented by Dr. Robert W. Campbell.[4]
The first U.S. Commercial Sulfur Fiber was produced in 1983 by Phillips Fibers Corporation, a subsidiary of Phillips 66 Company.[citation needed] Approximately 46M kg were produced in 1995 with a projected growth of 11% per year.[1]
PPS is marketed by different brand names and companies. Examples of these are: Ryton PPS by Chevron Phillips as cross-linked type of polymer; Fortron by Ticona, as a linear polymer.
References
- ↑ 1.0 1.1 David Parker, Jan Bussink, Hendrik T. van de Grampel, Gary W. Wheatley, Ernst-Ulrich Dorf, Edgar Ostlinning, Klaus Reinking, "Polymers, High-Temperature" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH: Weinheim. doi:10.1002/14356007.a21_449
- ↑ "Chevron Phillips Technical Library".
- ↑ H Wayne Hill Jr., James T. Edmonds, to the Phillips Petroleum Company Research Center (Bartlesville, Oklahoma, US). Patent 3,354,129, 1963. issued November 21, 1967
- ↑ Robert W. Campbell to the Phillips Petroleum Company Research Center (Bartlesville, Oklahoma, US). Patent 3,919,177, 1974 issued November 11, 1975
External links
- Polyphenylene Sulfide (PPS) Tube Coatings (NREL Geothermal).