Synthesis of bismaleimide and cyanate ester based sequential IPNs via EB irradiation

High-performance thermosetting resins are designed to provide special properties in highly demanding environments such as those required by aerospace engineering. Bismaleimide (BMI) resins are among the most important advanced thermosetting materials due to their high performance-to-cost ratio. Cyanate ester (CE) resins represent another important class of thermosetting high-performance materials. The use of CE-BMI blends as a way to achieve further improvements in performance and reduction in cost has already been the subject of research and has found some commercial success. However, one of the challenges associated with developing such systems is processibility because of the high melting point of BMI and its low solubility in CE resins. Moreover, these systems require high cure temperature to ensure proper chemical conversion and performance. This adds significant cost to the production of composite parts. However, low temperature processing can be accomplished by using reactive diluents and electron beam (EB) radiation to affect the cure. The overall objective of this work is to obtain tough, high-performance, thermosetting materials by synthesizing sequential interpenetrating polymer networks (BPNs) using cyanate esters cured thermally to form the first network in the presence of BMI and a reactive diluent, and EB to form the second BMI-diluent network at a relatively low temperature.