Preparation and properties of acetylene-terminated benzoxazine/epoxy copolymers

Acetylene-terminated benzoxazines (A-BOZs) were copolymerized with bisphenol A diglycidyl ether (DGEBA) epoxy resin to improve their processibility and adhesive properties without sacrificing much thermal performance. The three possible polymerization reactions for A-BOZs/DGEBA blends were monitored by differential scanning calorimetry (DSC) analysis and Fourier transform infrared (FTIR) spectroscopy. The rheological characterization showed that a much wider processing window could be obtained for A-BOZs/DGEBA because of the dilution effect of the epoxy. The lap shear strength of A-BOZs improved significantly with the incorporation of DGEBA. Furthermore, the cured blends also showed good heat and water resistance properties and high glass transition temperature (Tg).