Ultem Polyetherimide Resin engineering thermoplastics

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. 

The newest engineering thermoplastic is a polyetherimide that was formally announced by General Electric Company in 1982 (16). This amorphous polymer is designated Ultem resin and resulted from the research work of a team headed by J. G. Wirth in the early 1970s (9). The early laboratory process involved a costly and difficult synthesis. Further development resulted in a number of breakthroughs that led to a simplified, cost-effective production process. The final step of the process involves the imidization of a diacid anhydride with m-phenylene diamine (Figure 13). 

Polyetherimides are a new family of condensation polymers. The key reaction step in each of their synthetic sequences is an aromatic nitro-displacement reaction which produces the diaryl ether linkages in high yield. Physical properties can be varied over a wide range depending on the choices of bis-phenol, diamine, and positional isomer incorporated into the backbone of the polymer. Our study of these materials has led to the commercial introduction of ULTEM Resin as the first in a series of new high performance engineering thermoplastics. 

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