Polyetherimide chemical structure

Polyetherimide has a chemical structure based on repeating aromatic imide and ether units. High performance strength characterisitics at elevated temperatures are provided by rigid imide units, while the ether linkages confer the chain flexibility necessary for good melt processing and flow. 

Scheme 4 Chemical structures of the synthesized fluorinated polyetherimides...

Materials. As a matrix polymer, polyetherimide (PEI) Ultem KXX) of General Electric and polyphenylenesulfide (PPS) Ryton GR-02 of Phillips Petroleum were used. The reinforcing component was thermotropic liquid crystalline copolyester (LCP) Vectra B950 of Hoechst-Celanese. The chemical structures of PEI and LCP are presented in Figure 1. 

Figure 6 The chemical structure of polysulfone and polyetherimide. Preformed thermoplastic particles...

Tab. 15.4. Chemical structure and thermal stability by thermogravimetry of some representative polyetherimides...

Figure 7.2 Chemical structure of BPADA-PPD polyetherimide (Ultem 5000 series).

Figure 7.3 Chemical structure of biphenol diamine PMDA polyetherimide (Aurum , Vespel TP-8000 series).

Figure 7.4 Chemical structure of BPADA-DDS polyetherimide sulfone (Ultem XH6050).

Figure 7.5 Chemical structure of BPADA-MPD polyetherimide (Ultem 1000 series).

The most extensively studied PBI blend system is PBI blended with a polyetherimide, originally available from GE, Ultem 1000. The chemical structure of Ultem is shown in Fig. 4.2. The early work on that blend led to the phase separation diagram shown in Fig. 4.3. This figure shows that a processing window exists for blends that contain in excess of 75% PBI and also for blends that contain less than about 20% PBI. In this case, the processing window is defined as those temperatures between Tg and the phase separation temperature. For example, for an 85/15 PBI/Ultem blend ratio, the glass transition temperature is 400°C and the processing window is 25°C. 

Polotskaya G. A., Kuznetsov Y. P., Anikin A. V., Chemical Structure and Gas Selectivity of Membranes Manufactured from Aromatic Polyetherimides, Polym. Sci., 1992, 34(5 437. 

To function as a circuit board, the polymer must be metallized. A key aspect of this technology pertains to the adhesion developed and maintained between the metal and polyetherimide. The adhesion between a metal and a ooivmer can be viewed in terms of ohysical or mechanical adhesion, and chemical adhesion. Mechanical adhesion results from interlocking of the metal and polymer phases due to die creation of re-entrant cavities or macroscopic fissures in the polymer structure. Mechanical adhesion may also result from the presence of fine, shallow pits along the polymer surface. Chemical a esion relates to the formation of chemical bonds between the metal and polymer layers. The chemical interactions can result from actual charge transfer, e.g., ionic or covalent bond formation, van der Waals forces, or electrostatic or acid-base interactions. ... 

Introduced by GE Plastics in 1982, polyetherimide (PEI) is an amorphous thermoplastic offering outstanding high heat resistance and strength. The high heat resistance and heat stability are attributable to its imide structure. PEI also has resistance to a broad range of chemicals, and is inherently flame resistant with low smoke emission. A major component of PEI is bisphenol A, which is also produced by GE Plastics, mainly for use in polycarbonates. 

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