Polyamide-imide, properties

As seen from the application examples, polyamide-imides possess a unique blend of high-performance properties. An overview of polyamide-imide properties for compounded materials is shown in Table 12.1. 

TABLE 12.1 Polyamide-imide Properties for Compounded Materials... 

Some typical properties of a fabricated solid grade (Vespel-Du Pont) are given in Table 18.13 together with some data on a graphite-loaded variety and a commercial polyamide-imide (Torlon 2000—Amoco). 

Fig. 6-14 specific modulus = modulus/density. Plastics include use of the heat-resistant TPs such as the polimides, polyamide-imide, and others. Table 6-21 provides data on the thermal properties of RPs. To date at least 80 wt % are glass fiber and about 60 wt% of those are polyester (TS) type RPs. 

Polyamide-imides are appreciated for good mechanical and electrical properties high service temperatures (up to 220°C with possible long service times at 260°C) rigidity good creep behaviour fatigue endurance low shrinkage and moisture uptake inherent flame retardancy chemical resistance usability down to -196°C. 

Polyimide (PI) caps all other polymers in its temperature range of use (-200 to 260 °C in air short-time even up to 500 °C). Because of its high price, it is used in special cases only, such as space vehicles, nuclear reactors and some electronic parts. Newer developments, related to polyimide, are the polyether imides (e.g. Ultem ), polyester imides and polyamide imides (e.g. Torlon ), all with very good mechanical, thermal and electrical properties and self-extinguishing. 

These polyamide imide films have excellent thermal, mechanical, and electrical properties, and they are used to upgrade other enamel films. Other attractive features of polyamide imide film insulations are a low coefficient of friction and good solvent resistance. These enamels are rated for use at 200 °C. 

Polymer Specimens. The materials used in this work were polyimide (PI),polyamide-imide (PAl), polyether-ether-ketone (PEEK), polyphenylene sulfide (PPS) and polyether sulphone (PES). The chemical formulas and physical properties of the specimen polymers are summarized in Table I. The specimen polymers, except PPS, were unfilled while the PPS specimen was filled with glass fiber of Uo wt. %. PAI and PES are amorphous polymer with considerably high glass temperature. The polymers, except PI, can flow at hi temperatures and allow the use of injection molding. 

The Kinel materials produced by Rhone-Poulenc are polybismaleinimides of the type shown in Figure 4.22. These materials have chain-end double bonds, as explained previously, can be processed like conventional thermosetting plastics. The properties of the cured polymers are broadly similar to the polyimides and polyamide-imides. Molding temperatures are usually from 200°C to 260°C. Post-curing at 250°C for about 8 h is necessary to obtain the optimum mechanical properties. 

Polyimide and polyamide-imide Excellent thermal properties Good composite properties Good electrical properties Good fire properties Restricted choice of color Arc resistance Acid and alkali resistance... 

The aliphatic polyamide-imides prepared to date do not possess desirable properties. When aromatic diacids are employed, however, the products exhibit good heat stability and toughness. This led to the development of a number of useful materials. 

Most polyamide-imides are not as heat resistant as are the polyimides discussed in the next section. They are, however, easier to process. The polyester-imides might be considered as upgraded polyesters, though properties vary, depending upon chemical structure. ... 

Table 2.14 Properties of Typical Polyamide-Imide Plastics (1) ...

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