Polyetherimide

• PEI
• Poly ( bisphenol A -co -4- Nitrophthalanhydrid -co- 1 ,3 -phenylene diamine )
• Poly ( bisphenol A anhydride - co -1 ,3- diphenylenediamine )
• Poly [ 2,2 ' -bis- (4 - ( 3,4- dicarboxyphenoxy ) -phenyl ) -1,3 -phenylene- bis-imide ]
• Poly ( bisphenol A dianhydride -co- 1 ,3 -phenylene diamine )

Thermoplastic

Fixed

1.27 g/cm3

About 217 ° C.

140 MPa (ball pressure hardness H358/30 )

4 kJ/m2 (Charpy 23 ° C)

3200 MPa (unfilled)

1.25%

Soluble in dichloromethane

6%

Alcohols, petrol, diesel, sulfuric acid ( 37%, 90 ° C), sodium hydroxide (30%, room temperature), acetic acid (20%, 90 ° C)

190 ° C ( HDT / Ae )

0.24 W / ( m K)

5 10-5 1 / K

Polyetherimide (PEI) is a counting of the group of high-temperature resistant plastics high-performance thermoplastic. This compound from the group of polyimides is transparent and has a golden yellow color. PEI was first brought in 1981 by General Electric Plastics (GE) on the market, the market share of high-tech plastics in 1996 was about 15%.

Production

PEI is formed by the polycondensation of 1,3-diaminobenzene and Bisphthalsäureanhydrid or N- phenyl-4- nitrophthalimide and the disodium salt of bisphenol-A. Polyetherimide is available in pure form and with different aggregates ( glass fibers, carbon fibers) and as a blend with polycarbonate or siloxane copolymer.

Properties

Polyetherimide is inherently flame retardant with low smoke emission. It has also in the unreinforced state has a very high strength, which can be further increased by the addition of glass fibers or carbon fibers. PEI has a high dielectric strength, is resistant to hydrolysis and highly resistant to UV rays and gamma rays.

Processing

Polyetherimide is mainly processed by injection molding. The processing temperature is depending on the type between 320 and 400 ° C, the mold temperature between 120 and 180 ° C. The material must be dried to a moisture content of at most 0.05% before use. Parts of PEI can be welded by means of induction, vibration or ultrasound or are glued with epoxy, polyurethane or silicone adhesive ..

Use

Polyetherimide (PEI ) is preferably processed into plastic parts for the electronics and aerospace industries. In aviation, it is increasingly in the aircraft used indoors because it developed a low smoke density in case of fire. In the structural mechanics field of aircraft its importance is growing as it has a higher impact strength in composite structures as thermoset matrix systems.

Membranes of polyetherimide are characterized by their outstanding mechanical strength, their high thermal stability, their good film-forming ability and their relatively inexpensive production successfully employed in the industrial product. Likewise tweeter diaphragms are manufactured from PEI. Meanwhile, it is known that membranes of polyetherimide also have a great biomedical potential. The surface properties of the material can be targeted by water-loving ( hydrophilic) and water-repellent ( hydrophobic) modify, so that membranes from PEI fulfill various biomedical requirements and so multiple applications can be supplied. In the GKSS Research Centre Geesthacht, it is possible to produce protein- repellent and blood compatible PEI membranes, which are used for example as a support membrane for skin substitutes or could be used as an alternative method for blood purification (dialysis).

Another application is the production of picks for stringed instruments.

Trade names

• General Electric Ultem