PEI, or polyetherimide, is a high-performance thermoplastic (relative density: 1500kg/m^3) known for its exceptional heat resistance, solvent resistance, and flame retardancy. Ultem® 1000, a standard unfilled grade of PEI, boasts a high dielectric strength, inherent flame resistance, and extremely low smoke generation. Ultem® also exhibits excellent mechanical properties and can perform well in continuous use at temperatures up to 170°C. However, a current challenge with the material is that it cannot be easily recycled back into the production system and about 500kg/year is instead being incinerated.