Synthesis and Characterization of Hyperbranched Epoxy with Terminal Ally Group and Its Application of Toughen Bismaleimide

A hyperbranched epoxy (AHEP) resin with terminal allyl groups was synthesized. The number average molecular weight of the synthesized AHEP is 1 260, the multi-dispersion coefficient is 1.88, and the branching degree is 0.9. The hyperbranched epoxy resin and bismaleimide(BMI) monomer were heated to extend the chain and then blended and cured with methyl nadic anhydride. Studies have found that when the molar ratio of AHEP: BDM is 1:2, the mechanical properties and heat resistance of the resin casting body reach the best. Among them, the impact toughness was 15.05 kg/m 2 , the bending strength was 101 MPa, and the heat resistance temperature index was 229.23 °C. We used AHEP to toughen bismaleimide resin in three ways simultaneously: hyperbranched structure, allyl copolymerized brackets chain and flexible side chain (epoxy group) addition. Experiments have proved that AHEP can improve the flexibility of the BMI chain and maintain its heat resistance, thereby forming a matrix with excellent mechanical properties and processing properties.