Polyphenylene sulfide

from Wikipedia, the free encyclopedia
Structural formula
Structure of polyphenylene sulfide
General
Surname Polyphenylene sulfide
other names
  • Poly (thio- p -phenylene)
  • PPS
CAS number 26125-40-6 or 25212-74-2
Monomer 1,4-dichlorobenzene and Na 2 S
Molecular formula of the repeating unit C 6 H 4 S
Molar mass of the repeating unit 108.16 g mol −1
Type of polymer

Thermoplastic

properties
Physical state

firmly

density

unreinforced 1.35 g / cm 3

Melting point

about 285 ° C

Glass temperature

90 ° C

hardness

90 Shore hardness at 70-150 ° C

modulus of elasticity

4000 MPa

Water absorption

0.05%

Thermal expansion coefficient

26 (dry) to 42 (humid) 10 −6 K −1

safety instructions
GHS labeling of hazardous substances
no classification available
H and P phrases H: see above
P: see above
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Polyphenylene sulfide ( abbreviated PPS , also poly (thio- p called phenylene)) is a high temperature resistant thermoplastic resin having the general formula (SC 6 H 4 ) n . Technically, it is mostly produced by the polycondensation of 1,4-dichlorobenzene with sodium sulfide in aprotic solvents such as N -methylpyrrolidone .

history

As early as 1888, Charles Friedel and James Mason Crafts discovered PPS, which was quite an early stage for a polymer. Attempts to make the material on a large scale were made in late 1940, but it was not until 1967 that Edmonds and Hill of the Phillips Petroleum Company developed a method to synthesize PPS from 1,4-dichlorobenzene and sodium sulfide. This development marks the actual commercialization of PPS. In 1973, Chevron Phillips in Texas put the first commercial plant into operation. Since then, the name Ryton has stood for injection-mouldable PPS.

After the basic patents expired in 1984, new production facilities were built by competitors around the world. These were then not only able to produce cross-linked material, as was previously known on the market, but also the first products with a linear chain structure came onto the market.

properties

PPS is a semi-crystalline high-performance plastic . The connection of aromatic monomer units via sulfur atoms results in particularly resistant polymers whose good mechanical properties are retained even at temperatures well above 200 ° C, so that continuous use up to 240 ° C is possible depending on the load. For a short time, loads of up to 270 ° C are withstood. The chemical resistance of the PPS to almost all solvents, many acids and alkalis and, to a limited extent, to atmospheric oxygen, even at high temperatures, is also outstanding.

In addition to low water absorption , PPS also has good dimensional stability and inherent flame retardancy . It has excellent electrical properties ( insulator ) is highly impermeable to most liquids and gases ( impermeable ), has only a low tendency to creep even at high temperatures and is due to its good flowability for long, narrow moldings and complex tool geometries.

There are basically two different types of PPS: linear and networked. While the branched polymer chains in crosslinked PPS are reversibly connected to one another via physical crosslinking points, the chains of the slightly branched linear PPS accumulate to form highly ordered superstructures. This morphological structure is mainly reflected in the mechanical properties. Above all, linear PPS has higher toughness and elongation at break than crosslinked PPS.

The thermoplastic, which is normally an electrical non-conductor , can be converted into an organic semiconductor by doping .

use

Polyphenylene sulfides are used in particular for mechanically, electrically, thermally and chemically highly stressed molded parts in the electronics and vehicle sectors.

Linear PPS can be molded into components using a wide range of processing methods (blow molding, extrusion, injection molding), but around 80% are manufactured using injection molding. In contrast, with networked PPS there are changes in properties that lead to restrictions in processability. It can mostly only be injection molded and extruded only to a very limited extent.

A melt spinning process can produce monofilament yarns , multifilament yarns , but also staple fibers that can be carded , needled or spun into staple fiber yarns . The first PPS fiber was manufactured by Philips Fibers in 1973. PPS can also be processed into melt-blown nonwovens. The PPS fibers have excellent thermal stability and can be used permanently at up to 190 ° C (up to 230 ° C for a short time) without serious damage. The fiber is flame retardant ( LOI 39 to 41), self-extinguishing and melts at 285 ° C. The chemical resistance is good. It is chemically stable against all non-oxidizing acids up to 200 ° C. However, it is sensitive to strongly oxidizing media. With a moisture absorption <0.1%, it is absolutely hydrolysis- proof and even resistant to steam heat. Due to these properties, PPS fibers are used as spunbonded nonwovens and needle punched nonwoven filter bags in hot gas dedusting in waste incineration plants, but also as filter cloths in wet filtration.

For 2007 a worldwide consumption of at least 50,000 t was expected.

Trade names

Norms

  • DIN EN ISO 20558-1: 2019-06 Plastics - Polyphenylene sulfide (PPS) materials - Part 1: Designation system and basis for specifications
  • DIN EN ISO 20558-2: 2019-06 Plastics - Polyphenylene sulfide (PPS) materials - Part 2: Manufacture of test specimens and determination of properties

Individual evidence

  1. ↑ a b c d e f K. Kraft “Polyphenylene sulfide (PPS)” Kunststoffe 77 (1987) 10, pp. 1023-1027.
  2. ↑ LISTE POLYSULFURE DE PHENYLENE - PPS- , accessed on June 4, 2019.
  3. ↑ Fortron data sheet. Retrieved March 28, 2019.
  4. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
  5. ↑ 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 .
  6. ↑ Walter Loy: Chemical fibers for technical textile products. 2nd, fundamental revised and expanded edition. Deutscher Fachverlag, Frankfurt am Main 2008, ISBN 978-3-86641-197-5 , p. 117.
  7. ↑ Hans-J. Koslowski: Chemical fiber - Lexicon. 12th, expanded edition. Deutscher Fachverlag, Frankfurt am Main 2009, ISBN 978-3-87150-876-9 , p. 176.
  8. ^ Derek B. Purchas, Ken Sutherland: Handbook of Filter Media - Second Edition. Elsevier Science, Oxford 2002, ISBN 1 85617 3755 , p. 91.
  9. ↑ Irwin M. Hutten: Handbook of Nonwoven Filter Media. Elsevier, Oxford 2007, ISBN 978-1-85617-441-1 , pp. 156-157.
  10. ↑ Gunther Reitzel: capacities are developing in double digits (trade fair report K 2007): polyphenylene sulfide (PPS) . In: plastics . No. 10 , 2007, p. 124–130 ( online - free full text).