POLYETHERIMIDE

Uses

Polymer blends of PEI and polyethylene glycol (PEG) have been used to prepare carbon molecular sieves. PEI has been used as matrix in the fabrication of various composites:

• PEI/ BaTi₄O₉ composites,
• PEI/glass fiber composites,
• Nanocomposite PEI/TiO₂-sulfonated polymer membranes,
• Nanoparticles coated PEI-polyurethane (SiO₂/PEI-PU) nanofibrous composite membranes,
• Single walled nanotubes (SWNTs)/PEI nanocomposites.

General Description

Polyetherimide (PEI) is a thermoplastic polymer, containing cyclic amide. PEI is a polyimide condensation polymer derived from the bifunctional carboxylic anhydrides and primary diamines.

Synthesis

One method of preparing a polyetherimide is by polymerization of an alkali metal salt of a dihydroxyaromatic compound (e.g., a disodium salt of bisphenol A (BPA-Na2)) with bis(halogenated phthalimide). The molecular weight of the resulting polyetherimide can be controlled in two ways. The first is to use a molar excess of bis(halogenated phthalimide) relative to the alkali metal salt of the dihydroxyaromatic compound. The second is to prepare bis(halogenated phthalic anhydride) in the presence of a monofunctional compound (e.g., phthalic anhydride) to form a capping agent. The phthalic anhydride is reacted with a portion of an organic diamine to form monohalogeno-bis(phthalimide). The monohalogenobis(phthalimide) is used as a capping agent in the polymerization reaction step by reacting with the phenol salt end groups in the growing polymer chain.