Carbon-fibre-reinforced modified cyanate ester winding composites and their thermomechanical properties

Although the extensive research has expanded on the modification of cyanate ester (CE) resins and the mechanical properties of CE composites, very few studies have been conducted on carbon fibre (CF)/modified CE winding composites and the thermomechanical properties of the composites. In this research, epoxy (EP)-modified novolac cyanate ester (NCE) and bismaleimide (BMI)-modified NCE resins were prepared. The CF/modified CE winding composites were manufactured, and their thermomechanical properties were tested. The optimal winding process was determined, and a preheating technique was implemented. Then, the EP/CE resin (10:90) and the BMI–DBA/CE resin (10:90) were selected as the resin matrix of the winding composite based on the viscosity properties, mechanical properties and thermal analysis (using thermogravimetric analysis and differential scanning calorimetry) of the modified CE resin. The selected resin exhibited good manufacturability at 70°C, good thermal stability and high T_g (above 370°C). The thermomechanical property tests indicate that the modified CE resin composite exhibits an outstanding mechanical strength at room temperature and at high temperatures (130°C, 150°C and 180°C) compared with that of the pure CE resin composite. The reasons for this enhancement can be attributed to a toughening mechanism and the effect of sizing agents on the CFs.