Cure Kinetics and Mechanical Behaviour of Electromagnetically Processed Polyimides

The processing of epoxy resins using electromagnetic radiation (EMR) has been shown to significantly enhance the rate of cure while maintaining optimal mechanical properties. Furthermore, electromagnetic processing has the potential of increasing energy efficiency, lower initial and production costs, and produce superior mechanical properties for some systems. However, there is no clear understanding of the actual mechanism of the acceleration of the chemical reactions. Thus, polymeric systems cannot yet be optimized to fully exploit these advantages and this work is continuing, Polyimides are high temperature, tough thermoplastics which are traditionally prepared using a heating cycle designed to remove the solvent, (e.g. N-methylpyrolidone, NMP) in addition to imidizing the polyamic acid precursor. The typical cycle consists of 1 hour at each of 100, 200, and 300 C to produce a film which is often insoluble due to chain rigidity, crosslinking, or both.