Bismaleimide resin modified by a propargyl substituted aromatic amine with ultrahigh glass transition temperature, thermomechanical stability and intrinsic flame retardancy

Abstract

N, N, N′, N′ -tetrapropargyl-p, p’-diaminodiphenylmethane (TPDDM) was synthesized and used to prepolymerized with 4,4′-bismaleimide diphenylmethane (BDM) in molten state to obtain a new TPDDM modified bismaleimide (BTP) resin by addition reaction. The BTP resin displays a good solubility and meltability with process window of 90 °C. The self-polymerization of TPDDM and BDM and further free radical polymerization of the unsaturated groups construct the cross-linked networks to obtain the cured BTP resin. The apparent activation energy of cure reactions for BTP resin decreases slowly with conversion of reactions, and declines clearly with the conversion of above 60%. The residual yield at 600 °C in nitrogen and air of the cured BTP resin are 60.5% and 60%, respectively, and the glass transition temperature of the cured resin can reach 371 °C. The impact and flexural strengths of the cured BTP resin can increase with increase of BDM content in the BTP resin. The flexural strength of the cured BTP resin can reach 60.8 MPa at 300 °C for 30 min, which retains 94% of that at room temperature. The cured BTP resin displays better non-halogen and non‑phosphorus intrinsic flame retardancy based on its excellent thermal stability.