Reducing Activation Energy and Achieving Multifunctionalization of Bismaleimide Resins Modified with Disulfide Compounds

As the most common thermosetting resin, the bismaleimide resin exhibits excellent properties comprehensively. However, its highly symmetrical structure leads to high rigidity, dense cross-linking, and significant brittleness. To address these shortcomings, we synthesized a bismaleimide resin modifier─an allylic compound containing dynamic disulfide bonds (AGESS)─by reacting allyl glycidyl ether with 3,3′-dithiodipropionic acid under tetrabutylammonium bromide catalysis. AGESS, serving as a flexible chain with dynamic disulfide bonds, reduced the viscosity of the bismaleimide resin system and enhanced molecular segment mobility. This facilitated easier contact between imide rings and free radicals, resulting in reductions of up to 29.7% in the apparent activation energy and 7.5% in the curing reaction activation energy, respectively. Notably, incorporating AGESS into the bismaleimide resin system significantly improved its impact toughness, with the impact strength increasing by 40.7%. Meanwhile, the glass transition temperature of the AGESS resin system also decreased by 9 °C. Crucially, AGESS not only optimized the resin properties but also enabled shape memory cycling at Tg + 20 °C and welding at Tg – 30 °C through its inherent dynamic disulfide bonds. This approach enhances material performance while retaining shape memory and weldability, offering a viable strategy for developing sustainable thermosetting polymers.