From April 27 to 28, 2024, the 5th National Symposium on Functional Polymer Materials and the 1st Innovation Academic Forum on Dynamic Covalent Driven Polymer Materials were successfully held in Mianyang, Sichuan. The event was co-organized by the New Material Professional Committee of the China Electronics Energy Conservation Technology Association and Southwest University of Science and Technology. The conference attracted over 500 representatives from the academic and industrial sectors to discuss the innovation and development of functional polymer materials.
Achieving excellent flame retardancy, long-term latency, and rapid curing simultaneously is a significant challenge in the field of epoxy resin applications. To address this, the project team organically integrated inherent flame-retardant technology with latent rapid curing technology. Starting from molecular design and employing green synthetic methods, they constructed a phosphorus-containing group with flame retardant properties into the imidazole molecular structure, synthesizing a series of phosphorus imidazole curing agents. During the conference, Dr. Wang provided a detailed introduction to the reaction mechanism of synthesizing phosphorus imidazole curing agents through acid-base and coordination reactions, and explained the advantages of this synthetic method, which received unanimous recognition from the scientific community present.
Research results show that the introduction of the synthesized phosphorus imidazole curing agent (BADM-2) into epoxy resin significantly postponed the curing peak temperature of the modified resin system. The latent period at room temperature was extended to 15 days, and rapid gelation within 10 minutes was achievable at 100°C, demonstrating characteristics of long-term latency at low temperatures and rapid curing at moderate temperatures. At the same time, due to the high-efficiency flame-retardant effect of BADM-2 in both the gas and condensed phase during the combustion of the resin, the limiting oxygen index of the modified resin system increased to 28.2%, meeting the UL94 V-0 rating. Compared with the control group, the glass transition temperature of the modified resin system was increased by 25°C, the crosslinking density was improved by 41%, and the mechanical properties were significantly enhanced, with tensile strength, modulus, and impact strength increased by 35%, 16%, and 61%, respectively. Dr. Wang also conducted a detailed analysis of the latent curing, flame retardancy, and toughening mechanisms of the modified resin system.
This research provides new insights into solving the long-standing problem of traditional epoxy resin systems that struggle to balance excellent flame retardancy with good comprehensive performance, as well as long-term latency with rapid curing. It lays a theoretical and technical foundation for the broader application of epoxy resin in key areas.