Properties of novel bismaleimide resins and thermal ageing effects on the ILSS performance of their carbon fibre–bismaleimide composites

An oligomeric bismaleimide (BMI) containing both phthalide cardo and cyano group (PCBMI) was mixed with O,O'‐diallyl bisphenol A (DABPA). The thermal properties of PCBMI/DABPA in different proportions (1:0.87, 1:1, and 1:1.2) and their composites were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). In addition, the mechanical properties of the prepared composites were also investigated. The results exhibited excellent thermal stability, heat resistance, and mechanical properties. We further investigated the effects of thermal ageing at 200°C and 250°C in air for up to 1000 h on inter laminar shear strength (ILSS) of the carbon fiber–bismaleimide composites (T700/DPC87). Scanning electron microscopy (SEM) and scanning acoustic microscope (SAM) were employed to characterize interfacial property changes, and Fourier transform infrared (FTIR) was employed to characterize chemical changes due to ageing. The results indicated PCBMI/DABPA resin had an excellent interface bonding capacity and aging resistance. It can, therefore, be widely used in aeronautics and space industries. POLYM. COMPOS., 40:E1283–E1293, 2019. © 2018 Society of Plastics Engineers