Polyimide foams property examples

Specific tensile strength (MPa/density) Tensile strength after 1000 h at 260°C (MPa) Oxygen index (%) 

Syntactic foams are composites made of micro-balloons or hollow macrospheres bound into a plastic matrix. The polyimide syntactic foams are used in specific electronic equipment for microwave and RF applications. They act as structural, dielectric and heat-barrier materials. Micro-balloons can be made of polyimides for special applications. 

Actymid, Aurum, Compimide, Cuming C-Stock, Duratron, Imidex, Kapton, Kerimid, Kinel, Meldin, Neopreg, Nolimid, Nomex, Sintimid, Upilex, Upimol, Vespel, Willmid. 

---

Polyimides are also obtained in one step in the reaction of diisocyanates with tetracarboxylic acid dianhydrides. As an example, BTDA is reacted with a mixture of 2,4-TDI and MDI in DMF (93). This copolyimide, PI 2080, is used as a high temperature fiber and it is also sinter molded into solid shapes with exceptional mechanical properties. From PMDI and benzophenone-tetracarboxylic acid dianhydride polyimide foams with outstanding thermal properties and flame resistance are produced (94). Pol5fimides derived from p-phenylene diisocyanate (PPDI) or naphthalene diisocyanate (NDI) and pyromellitic dianhydride or BTDA are also synthesized using DMAc as solvent (95). 

Polyimide characterised by thermal and thermal-oxidative stability at elevated temperatures, chemical resistance and good mechanical properties is relatively new in the family of polymer foams [3]. In some cases, depending on the nses, additional reinforcement can be inclnded. Examples are fibre reinforced foams and syntactic foams which are composites containing hollow glass, ceramic or plastic micro-spheres dispersed throughout the polymer matrix. 

---