Polyetherimide properties

UETEM, Polyetherimide Properties Guide, Geneial Electiic Co., Pittsfield, Mass., Mai. 1985. 

Table I. Comparison of Polyetherimide Properties Following Adhesion Treatment...

An all aromatic polyetherimide is made by Du Pont from reaction of pyromelUtic dianhydride and 4,4 -oxydianiline and is sold as Kapton. It possesses excellent thermal stabiUty, mechanical characteristics, and electrical properties, as indicated in Table 3. The high heat-deflection temperature of the resin limits its processibiUty. Kapton is available as general-purpose film and used in appHcations such as washers and gaskets. Often the resin is not used directly rather, the more tractable polyamide acid intermediate is appHed in solution to a surface and then is thermally imidi2ed as the solvent evaporates. 

Table 13. Typical Properties of Polyamide/Elastomer and Polyetherimide/Elastomer Block Copolymers ...

The polyetherimide—polysdoxane multiblock copolymers are relatively hard (about 70 on the Shore D scale). Their main appHcation is flame-resistant wire and cable covering (24), where they combine very low flammabiUty with a low level of toxic products in the smoke. This unusual and vital combination of properties justifies their relatively high price, about 37/kg, at a specific gravity of about 1.2. 

Some of the common types of plastics that ate used ate thermoplastics, such as poly(phenylene sulfide) (PPS) (see Polymers containing sulfur), nylons, Hquid crystal polymer (LCP), the polyesters (qv) such as polyesters that ate 30% glass-fiber reinforced, and poly(ethylene terephthalate) (PET), and polyetherimide (PEI) and thermosets such as diaHyl phthalate and phenoHc resins (qv). Because of the wide variety of manufacturing processes and usage requirements, these materials ate available in several variations which have a range of physical properties. 

Some typical properties of polyetherimides are given Table 18.15. 

Table 18.15 Typical properties of polyetherimide moulding materials (Assessed by use of ASTM test methods)...

Good electrical insulation properties with exceptional tracking resistance for an engineering thermoplastic and, in particular, for an aromatic polymer. In tracking resistance most grades are generally superior to most grades of polycarbonates, modified PPOs, PPS and the polyetherimides. 

Table 29.6 Some typical properties of a polysiloxane-polyetherimide copolymer (Ultem Siltem STM 1500)...

Property Test Method Units PEN Polyimide Polyetherimide Poly(ethylene terephthalate) film Polypropylene sulfide)... 

Connectors, switches, electric distributors, fuse boxes and other electric fittings need a subtle balance of electrical and mechanical properties, durability, cost and aesthetics. This broad field creates fierce competition not only between engineering thermoplastics and SMC/BMC for the main applications but also with polypropylene and polyethylene or PVC for the lower performance parts and, at the opposite end of the scale, with high-tech plastics such as polyetherketone, polyetherimide, liquid crystal polymers. .. For example, without claiming to be exhaustive ... 

The mechanical properties are good with medium to low elongations at break and more limited strains at yield. Moduli and hardnesses are in a high range but notched impact strengths are in a medium range. Polyetherimide displays notch sensitivity and stress concentrators must be avoided when designing. 

Polyetherimide/polycarbonate alloys offer properties, processability and prices intermediate between those of polyetherimide and polycarbonate. 

Table 6.21 shows some examples of polyetherimide foam properties. 

Table 3.9. Some properties of polyetherimides of the general r- O O II —/ o O O formula - n ...

Not all polyetherimides are limited by their tractability, however. Certain aromatic polyetherimides are characterized by a combination of properties that makes them potential engineering thermoplastics (90). One of these polymers contains an isopropylidene unit in the backbone to enhance the solubility. It is a mol ding material introduced by General Electric in 1981 and sold as Ultem resin. Attractive features include high temperature stability, flame resistance without added halogen or phosphoms, high strength, solvent resistance, hydrolytic stability, and injection moldability. 

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