UV-Induced Magnetorheological Adhesive Combined with a Magnetic Sealing Device: From Material Synthesis to Emergency Online Sealing of Pipeline Leaks

Emergency online sealing of pipeline leaks poses significant challenges due to the complexity of pipeline structure, stress state, and conveying medium. This study developed a magnetorheological adhesive and a synergistic online sealing method combined with a magnetic device. The polymerization process and molecular structural characteristics of the product were analyzed using fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and TG-DSC. The curing mechanism involves the simultaneous radical-induced cationic frontal polymerization of the epoxy group and free radical polymerization of the alkenyl, finally forming a cross-linked network comprising rigid bisphenol A segments and flexible polyethoxy segments. The effects of reactant formulation ratios on polymerization behavior and mechanical properties were systematically investigated. The cured product exhibited a maximum tensile strength of approximately 35.9 MPa and a bonding strength to metals of approximately 9.17 MPa while demonstrating typical soft magnetic behavior with magnetization intensity proportional to the magnetic filler content. Static pressure sealing tests and online pressurized sealing tests were conducted. The flow field characteristics of the leak sealing process were investigated using Fluent simulations, and the sealing device was optimized accordingly. The emergency online sealing can be successfully achieved for leakage diameters up to 10 mm and leakage pressures up to 1.5 MPa, with the entire sealing process completed within 10–20 min. This study provides a feasible and effective strategy for rapid, on-site emergency sealing of pipeline leaks.