Copolymerizing behavior and processability of allyl-functional bisphthalonitrile/bismaleimide system

A prepolymer constituted with bisphthalonitrile containing allyl groups (DBPA-Ph) and 4, 4′-bis-(maleimidodiphenyl)methane (BMI) was prepared. The reaction between DBPA-Ph and BMI was characterized with FTIR. The copolymerization behavior and processability of DBPA-Ph/BMI prepolymer was studied by differential scanning calorimetry (DSC) and dynamic rheological analysis. The results of DSC indicated that the DBPA-Ph/BMI system presented two-stage thermal polymerization attributing to the ene reaction between allyl moieties and maleimide at low temperature (around 263°C) and the ring-form polymerization of cyano moieties at high temperature (around 332°C), respectively. The results of dynamic rheological analysis indicated, with the introduction of BMI, the curing properties of DBPA-Ph/BMI system improved. The DBPA-Ph/BMI copolymers were prepared with relatively shorter curing time and shown high glass transition temperature (>350°C). The DBPA-Ph/BMI/glass fiber composite laminates were prepared and exhibited relatively better mechanical properties (>440 MPa) and satisfactory thermal properties (>440°C). The outstanding glass transition temperature, better processability, desirable thermal and thermo-oxidative stabilities demonstrated the introduction of BMI would contribute to the application of DBPA-Ph. POLYM. COMPOS., 38:1591–1599, 2017. © 2015 Society of Plastics Engineers