TABLE OF CONTENTS [*]
Thermoplastic polyetherimides provide the strength, heat resistance, and flame retardancy of traditional polyimides with the ease of simple melt processing seen in standard injection-molding resins such as polycarbonate and ABS.
The key performance features of PEI resins include
Excellent dimensional stability at high temperatures under load
Smooth as-molded surfaces that are easily metallized or painted
Transparency, optical properties, and excellent aesthetics
Very high strength and modulus
Good solvent resistance over a wide temperature range
High continuous-use temperature
Inherent ignition resistance without the use of phosphorous or halogen additives
High oxygen index and low smoke
Medical- and food-contact compliance
Sterilizable, and autoclave resistance
Good electrical properties with low ion content
Excellent machinability and secondary-finishing characteristics
[*]Author can be contacted at Robert. Gallucci@ge.com or by writing him at GE Plastics, 1 Lexan Lane, Mt. Vernon, Indiana 47620, USA.
The chemistry of imidization has been reviewed elsewhere [1] ? [5]. It is briefly outlined below in Eq. (8.1). The key elements are reaction of a diamine and a dianhydride to form an amide-acid polymer via ring opening of the anhydride by nucleophilic attack of the diamine. The polyamide acid is then formed into a polyimide by removal of water. These polymerizations are usually conducted in high-boiling polar solvents to dissolve the monomers and keep the polyamide acid in solution. Heating is frequently used to drive off water and form the polyimide. In some cases, other means...
