Blending Effects of Bismaleimide/Phthalonitrile Co‐Resins on Processing, Thermal Stability, and Thermomechanical Properties

ABSTRACT Thermosetting co‐resins were made by combining a 4,4′‐diaminodiphenyl methane‐based bismaleimide (MDPB) with an allyl‐functional phthalonitrile derived from eugenol (EuPN), resulting in a blended network formed with both the maleimide and phthalonitrile end‐groups. Increased amounts of EuPN were shown to reduce the processing temperature and increased the char yield from 48.3% to 73.6% at 90% loading. However, EuPN led to a reduction in the glass transition and degradation temperatures, and also required higher curing temperatures to achieve maximum performance. An increase in the storage modulus was observed, with a 30% loading of EuPN leading to a storage modulus of 3.7 GPa as compared to 2.5 GPa for the neat BMI.